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  • This comparison shows the changes necessary to convert path 
    /or1k/tags/LINUX_2_4_26_OR32/linux/linux-2.4/ipc
    from Rev 1279 to Rev 1765
    ↔ Reverse comparison
  •

Rev 1279 → Rev 1765

/util.h
0,0 → 1,107
/*
* linux/ipc/util.h
* Copyright (C) 1999 Christoph Rohland
*
* ipc helper functions (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
*/
 
#define USHRT_MAX 0xffff
#define SEQ_MULTIPLIER (IPCMNI)
 
void sem_init (void);
void msg_init (void);
void shm_init (void);
 
struct ipc_ids {
int size;
int in_use;
int max_id;
unsigned short seq;
unsigned short seq_max;
struct semaphore sem;
spinlock_t ary;
struct ipc_id* entries;
};
 
struct ipc_id {
struct kern_ipc_perm* p;
};
 
 
void __init ipc_init_ids(struct ipc_ids* ids, int size);
 
/* must be called with ids->sem acquired.*/
int ipc_findkey(struct ipc_ids* ids, key_t key);
int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
 
/* must be called with both locks acquired. */
struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
 
int ipcperms (struct kern_ipc_perm *ipcp, short flg);
 
/* for rare, potentially huge allocations.
* both function can sleep
*/
void* ipc_alloc(int size);
void ipc_free(void* ptr, int size);
 
extern inline void ipc_lockall(struct ipc_ids* ids)
{
spin_lock(&ids->ary);
}
 
extern inline struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id)
{
struct kern_ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
if(lid >= ids->size)
return NULL;
 
out = ids->entries[lid].p;
return out;
}
 
extern inline void ipc_unlockall(struct ipc_ids* ids)
{
spin_unlock(&ids->ary);
}
extern inline struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
{
struct kern_ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
if(lid >= ids->size)
return NULL;
 
spin_lock(&ids->ary);
out = ids->entries[lid].p;
if(out==NULL)
spin_unlock(&ids->ary);
return out;
}
 
extern inline void ipc_unlock(struct ipc_ids* ids, int id)
{
spin_unlock(&ids->ary);
}
 
extern inline int ipc_buildid(struct ipc_ids* ids, int id, int seq)
{
return SEQ_MULTIPLIER*seq + id;
}
 
extern inline int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
{
if(uid/SEQ_MULTIPLIER != ipcp->seq)
return 1;
return 0;
}
 
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 
#if defined(__ia64__) || defined(__hppa__)
/* On IA-64 and PA-RISC, we always use the "64-bit version" of the IPC structures. */
# define ipc_parse_version(cmd) IPC_64
#else
int ipc_parse_version (int *cmd);
#endif
/sem.c
0,0 → 1,1125
/*
* linux/ipc/sem.c
* Copyright (C) 1992 Krishna Balasubramanian
* Copyright (C) 1995 Eric Schenk, Bruno Haible
*
* IMPLEMENTATION NOTES ON CODE REWRITE (Eric Schenk, January 1995):
* This code underwent a massive rewrite in order to solve some problems
* with the original code. In particular the original code failed to
* wake up processes that were waiting for semval to go to 0 if the
* value went to 0 and was then incremented rapidly enough. In solving
* this problem I have also modified the implementation so that it
* processes pending operations in a FIFO manner, thus give a guarantee
* that processes waiting for a lock on the semaphore won't starve
* unless another locking process fails to unlock.
* In addition the following two changes in behavior have been introduced:
* - The original implementation of semop returned the value
* last semaphore element examined on success. This does not
* match the manual page specifications, and effectively
* allows the user to read the semaphore even if they do not
* have read permissions. The implementation now returns 0
* on success as stated in the manual page.
* - There is some confusion over whether the set of undo adjustments
* to be performed at exit should be done in an atomic manner.
* That is, if we are attempting to decrement the semval should we queue
* up and wait until we can do so legally?
* The original implementation attempted to do this.
* The current implementation does not do so. This is because I don't
* think it is the right thing (TM) to do, and because I couldn't
* see a clean way to get the old behavior with the new design.
* The POSIX standard and SVID should be consulted to determine
* what behavior is mandated.
*
* Further notes on refinement (Christoph Rohland, December 1998):
* - The POSIX standard says, that the undo adjustments simply should
* redo. So the current implementation is o.K.
* - The previous code had two flaws:
* 1) It actively gave the semaphore to the next waiting process
* sleeping on the semaphore. Since this process did not have the
* cpu this led to many unnecessary context switches and bad
* performance. Now we only check which process should be able to
* get the semaphore and if this process wants to reduce some
* semaphore value we simply wake it up without doing the
* operation. So it has to try to get it later. Thus e.g. the
* running process may reacquire the semaphore during the current
* time slice. If it only waits for zero or increases the semaphore,
* we do the operation in advance and wake it up.
* 2) It did not wake up all zero waiting processes. We try to do
* better but only get the semops right which only wait for zero or
* increase. If there are decrement operations in the operations
* array we do the same as before.
*
* /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
*
* SMP-threaded, sysctl's added
* (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
* Enforced range limit on SEM_UNDO
* (c) 2001 Red Hat Inc <alan@redhat.com>
*/
 
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/time.h>
#include <asm/uaccess.h>
#include "util.h"
 
 
#define sem_lock(id) ((struct sem_array*)ipc_lock(&sem_ids,id))
#define sem_unlock(id) ipc_unlock(&sem_ids,id)
#define sem_rmid(id) ((struct sem_array*)ipc_rmid(&sem_ids,id))
#define sem_checkid(sma, semid) \
ipc_checkid(&sem_ids,&sma->sem_perm,semid)
#define sem_buildid(id, seq) \
ipc_buildid(&sem_ids, id, seq)
static struct ipc_ids sem_ids;
 
static int newary (key_t, int, int);
static void freeary (int id);
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif
 
#define SEMMSL_FAST 256 /* 512 bytes on stack */
#define SEMOPM_FAST 64 /* ~ 372 bytes on stack */
 
/*
* linked list protection:
* sem_undo.id_next,
* sem_array.sem_pending{,last},
* sem_array.sem_undo: sem_lock() for read/write
* sem_undo.proc_next: only "current" is allowed to read/write that field.
*
*/
 
int sem_ctls[4] = {SEMMSL, SEMMNS, SEMOPM, SEMMNI};
#define sc_semmsl (sem_ctls[0])
#define sc_semmns (sem_ctls[1])
#define sc_semopm (sem_ctls[2])
#define sc_semmni (sem_ctls[3])
 
static int used_sems;
 
void __init sem_init (void)
{
used_sems = 0;
ipc_init_ids(&sem_ids,sc_semmni);
 
#ifdef CONFIG_PROC_FS
create_proc_read_entry("sysvipc/sem", 0, 0, sysvipc_sem_read_proc, NULL);
#endif
}
 
static int newary (key_t key, int nsems, int semflg)
{
int id;
struct sem_array *sma;
int size;
 
if (!nsems)
return -EINVAL;
if (used_sems + nsems > sc_semmns)
return -ENOSPC;
 
size = sizeof (*sma) + nsems * sizeof (struct sem);
sma = (struct sem_array *) ipc_alloc(size);
if (!sma) {
return -ENOMEM;
}
memset (sma, 0, size);
id = ipc_addid(&sem_ids, &sma->sem_perm, sc_semmni);
if(id == -1) {
ipc_free(sma, size);
return -ENOSPC;
}
used_sems += nsems;
 
sma->sem_perm.mode = (semflg & S_IRWXUGO);
sma->sem_perm.key = key;
 
sma->sem_base = (struct sem *) &sma[1];
/* sma->sem_pending = NULL; */
sma->sem_pending_last = &sma->sem_pending;
/* sma->undo = NULL; */
sma->sem_nsems = nsems;
sma->sem_ctime = CURRENT_TIME;
sem_unlock(id);
 
return sem_buildid(id, sma->sem_perm.seq);
}
 
asmlinkage long sys_semget (key_t key, int nsems, int semflg)
{
int id, err = -EINVAL;
struct sem_array *sma;
 
if (nsems < 0 || nsems > sc_semmsl)
return -EINVAL;
down(&sem_ids.sem);
if (key == IPC_PRIVATE) {
err = newary(key, nsems, semflg);
} else if ((id = ipc_findkey(&sem_ids, key)) == -1) { /* key not used */
if (!(semflg & IPC_CREAT))
err = -ENOENT;
else
err = newary(key, nsems, semflg);
} else if (semflg & IPC_CREAT && semflg & IPC_EXCL) {
err = -EEXIST;
} else {
sma = sem_lock(id);
if(sma==NULL)
BUG();
if (nsems > sma->sem_nsems)
err = -EINVAL;
else if (ipcperms(&sma->sem_perm, semflg))
err = -EACCES;
else
err = sem_buildid(id, sma->sem_perm.seq);
sem_unlock(id);
}
 
up(&sem_ids.sem);
return err;
}
 
/* doesn't acquire the sem_lock on error! */
static int sem_revalidate(int semid, struct sem_array* sma, int nsems, short flg)
{
struct sem_array* smanew;
 
smanew = sem_lock(semid);
if(smanew==NULL)
return -EIDRM;
if(smanew != sma || sem_checkid(sma,semid) || sma->sem_nsems != nsems) {
sem_unlock(semid);
return -EIDRM;
}
 
if (ipcperms(&sma->sem_perm, flg)) {
sem_unlock(semid);
return -EACCES;
}
return 0;
}
/* Manage the doubly linked list sma->sem_pending as a FIFO:
* insert new queue elements at the tail sma->sem_pending_last.
*/
static inline void append_to_queue (struct sem_array * sma,
struct sem_queue * q)
{
*(q->prev = sma->sem_pending_last) = q;
*(sma->sem_pending_last = &q->next) = NULL;
}
 
static inline void prepend_to_queue (struct sem_array * sma,
struct sem_queue * q)
{
q->next = sma->sem_pending;
*(q->prev = &sma->sem_pending) = q;
if (q->next)
q->next->prev = &q->next;
else /* sma->sem_pending_last == &sma->sem_pending */
sma->sem_pending_last = &q->next;
}
 
static inline void remove_from_queue (struct sem_array * sma,
struct sem_queue * q)
{
*(q->prev) = q->next;
if (q->next)
q->next->prev = q->prev;
else /* sma->sem_pending_last == &q->next */
sma->sem_pending_last = q->prev;
q->prev = NULL; /* mark as removed */
}
 
/*
* Determine whether a sequence of semaphore operations would succeed
* all at once. Return 0 if yes, 1 if need to sleep, else return error code.
*/
 
static int try_atomic_semop (struct sem_array * sma, struct sembuf * sops,
int nsops, struct sem_undo *un, int pid,
int do_undo)
{
int result, sem_op;
struct sembuf *sop;
struct sem * curr;
 
for (sop = sops; sop < sops + nsops; sop++) {
curr = sma->sem_base + sop->sem_num;
sem_op = sop->sem_op;
result = curr->semval;
if (!sem_op && result)
goto would_block;
 
result += sem_op;
if (result < 0)
goto would_block;
if (result > SEMVMX)
goto out_of_range;
if (sop->sem_flg & SEM_UNDO) {
int undo = un->semadj[sop->sem_num] - sem_op;
/*
* Exceeding the undo range is an error.
*/
if (undo < (-SEMAEM - 1) || undo > SEMAEM)
goto out_of_range;
}
curr->semval = result;
}
 
if (do_undo) {
result = 0;
goto undo;
}
sop--;
while (sop >= sops) {
sma->sem_base[sop->sem_num].sempid = pid;
if (sop->sem_flg & SEM_UNDO)
un->semadj[sop->sem_num] -= sop->sem_op;
sop--;
}
sma->sem_otime = CURRENT_TIME;
return 0;
 
out_of_range:
result = -ERANGE;
goto undo;
 
would_block:
if (sop->sem_flg & IPC_NOWAIT)
result = -EAGAIN;
else
result = 1;
 
undo:
sop--;
while (sop >= sops) {
sma->sem_base[sop->sem_num].semval -= sop->sem_op;
sop--;
}
 
return result;
}
 
/* Go through the pending queue for the indicated semaphore
* looking for tasks that can be completed.
*/
static void update_queue (struct sem_array * sma)
{
int error;
struct sem_queue * q;
 
for (q = sma->sem_pending; q; q = q->next) {
if (q->status == 1)
continue; /* this one was woken up before */
 
error = try_atomic_semop(sma, q->sops, q->nsops,
q->undo, q->pid, q->alter);
 
/* Does q->sleeper still need to sleep? */
if (error <= 0) {
/* Found one, wake it up */
wake_up_process(q->sleeper);
if (error == 0 && q->alter) {
/* if q-> alter let it self try */
q->status = 1;
return;
}
q->status = error;
remove_from_queue(sma,q);
}
}
}
 
/* The following counts are associated to each semaphore:
* semncnt number of tasks waiting on semval being nonzero
* semzcnt number of tasks waiting on semval being zero
* This model assumes that a task waits on exactly one semaphore.
* Since semaphore operations are to be performed atomically, tasks actually
* wait on a whole sequence of semaphores simultaneously.
* The counts we return here are a rough approximation, but still
* warrant that semncnt+semzcnt>0 if the task is on the pending queue.
*/
static int count_semncnt (struct sem_array * sma, ushort semnum)
{
int semncnt;
struct sem_queue * q;
 
semncnt = 0;
for (q = sma->sem_pending; q; q = q->next) {
struct sembuf * sops = q->sops;
int nsops = q->nsops;
int i;
for (i = 0; i < nsops; i++)
if (sops[i].sem_num == semnum
&& (sops[i].sem_op < 0)
&& !(sops[i].sem_flg & IPC_NOWAIT))
semncnt++;
}
return semncnt;
}
static int count_semzcnt (struct sem_array * sma, ushort semnum)
{
int semzcnt;
struct sem_queue * q;
 
semzcnt = 0;
for (q = sma->sem_pending; q; q = q->next) {
struct sembuf * sops = q->sops;
int nsops = q->nsops;
int i;
for (i = 0; i < nsops; i++)
if (sops[i].sem_num == semnum
&& (sops[i].sem_op == 0)
&& !(sops[i].sem_flg & IPC_NOWAIT))
semzcnt++;
}
return semzcnt;
}
 
/* Free a semaphore set. */
static void freeary (int id)
{
struct sem_array *sma;
struct sem_undo *un;
struct sem_queue *q;
int size;
 
sma = sem_rmid(id);
 
/* Invalidate the existing undo structures for this semaphore set.
* (They will be freed without any further action in sem_exit()
* or during the next semop.)
*/
for (un = sma->undo; un; un = un->id_next)
un->semid = -1;
 
/* Wake up all pending processes and let them fail with EIDRM. */
for (q = sma->sem_pending; q; q = q->next) {
q->status = -EIDRM;
q->prev = NULL;
wake_up_process(q->sleeper); /* doesn't sleep */
}
sem_unlock(id);
 
used_sems -= sma->sem_nsems;
size = sizeof (*sma) + sma->sem_nsems * sizeof (struct sem);
ipc_free(sma, size);
}
 
static unsigned long copy_semid_to_user(void *buf, struct semid64_ds *in, int version)
{
switch(version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct semid_ds out;
 
ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm);
 
out.sem_otime = in->sem_otime;
out.sem_ctime = in->sem_ctime;
out.sem_nsems = in->sem_nsems;
 
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
 
static int semctl_nolock(int semid, int semnum, int cmd, int version, union semun arg)
{
int err = -EINVAL;
 
switch(cmd) {
case IPC_INFO:
case SEM_INFO:
{
struct seminfo seminfo;
int max_id;
 
memset(&seminfo,0,sizeof(seminfo));
seminfo.semmni = sc_semmni;
seminfo.semmns = sc_semmns;
seminfo.semmsl = sc_semmsl;
seminfo.semopm = sc_semopm;
seminfo.semvmx = SEMVMX;
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
down(&sem_ids.sem);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids.in_use;
seminfo.semaem = used_sems;
} else {
seminfo.semusz = SEMUSZ;
seminfo.semaem = SEMAEM;
}
max_id = sem_ids.max_id;
up(&sem_ids.sem);
if (copy_to_user (arg.__buf, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
}
case SEM_STAT:
{
struct sem_array *sma;
struct semid64_ds tbuf;
int id;
 
if(semid >= sem_ids.size)
return -EINVAL;
 
memset(&tbuf,0,sizeof(tbuf));
 
sma = sem_lock(semid);
if(sma == NULL)
return -EINVAL;
 
err = -EACCES;
if (ipcperms (&sma->sem_perm, S_IRUGO))
goto out_unlock;
id = sem_buildid(semid, sma->sem_perm.seq);
 
kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
tbuf.sem_otime = sma->sem_otime;
tbuf.sem_ctime = sma->sem_ctime;
tbuf.sem_nsems = sma->sem_nsems;
sem_unlock(semid);
if (copy_semid_to_user (arg.buf, &tbuf, version))
return -EFAULT;
return id;
}
default:
return -EINVAL;
}
return err;
out_unlock:
sem_unlock(semid);
return err;
}
 
static int semctl_main(int semid, int semnum, int cmd, int version, union semun arg)
{
struct sem_array *sma;
struct sem* curr;
int err;
ushort fast_sem_io[SEMMSL_FAST];
ushort* sem_io = fast_sem_io;
int nsems;
 
sma = sem_lock(semid);
if(sma==NULL)
return -EINVAL;
 
nsems = sma->sem_nsems;
 
err=-EIDRM;
if (sem_checkid(sma,semid))
goto out_unlock;
 
err = -EACCES;
if (ipcperms (&sma->sem_perm, (cmd==SETVAL||cmd==SETALL)?S_IWUGO:S_IRUGO))
goto out_unlock;
 
switch (cmd) {
case GETALL:
{
ushort *array = arg.array;
int i;
 
if(nsems > SEMMSL_FAST) {
sem_unlock(semid);
sem_io = ipc_alloc(sizeof(ushort)*nsems);
if(sem_io == NULL)
return -ENOMEM;
err = sem_revalidate(semid, sma, nsems, S_IRUGO);
if(err)
goto out_free;
}
 
for (i = 0; i < sma->sem_nsems; i++)
sem_io[i] = sma->sem_base[i].semval;
sem_unlock(semid);
err = 0;
if(copy_to_user(array, sem_io, nsems*sizeof(ushort)))
err = -EFAULT;
goto out_free;
}
case SETALL:
{
int i;
struct sem_undo *un;
 
sem_unlock(semid);
 
if(nsems > SEMMSL_FAST) {
sem_io = ipc_alloc(sizeof(ushort)*nsems);
if(sem_io == NULL)
return -ENOMEM;
}
 
if (copy_from_user (sem_io, arg.array, nsems*sizeof(ushort))) {
err = -EFAULT;
goto out_free;
}
 
for (i = 0; i < nsems; i++) {
if (sem_io[i] > SEMVMX) {
err = -ERANGE;
goto out_free;
}
}
err = sem_revalidate(semid, sma, nsems, S_IWUGO);
if(err)
goto out_free;
 
for (i = 0; i < nsems; i++)
sma->sem_base[i].semval = sem_io[i];
for (un = sma->undo; un; un = un->id_next)
for (i = 0; i < nsems; i++)
un->semadj[i] = 0;
sma->sem_ctime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
err = 0;
goto out_unlock;
}
case IPC_STAT:
{
struct semid64_ds tbuf;
memset(&tbuf,0,sizeof(tbuf));
kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
tbuf.sem_otime = sma->sem_otime;
tbuf.sem_ctime = sma->sem_ctime;
tbuf.sem_nsems = sma->sem_nsems;
sem_unlock(semid);
if (copy_semid_to_user (arg.buf, &tbuf, version))
return -EFAULT;
return 0;
}
/* GETVAL, GETPID, GETNCTN, GETZCNT, SETVAL: fall-through */
}
err = -EINVAL;
if(semnum < 0 || semnum >= nsems)
goto out_unlock;
 
curr = &sma->sem_base[semnum];
 
switch (cmd) {
case GETVAL:
err = curr->semval;
goto out_unlock;
case GETPID:
err = curr->sempid;
goto out_unlock;
case GETNCNT:
err = count_semncnt(sma,semnum);
goto out_unlock;
case GETZCNT:
err = count_semzcnt(sma,semnum);
goto out_unlock;
case SETVAL:
{
int val = arg.val;
struct sem_undo *un;
err = -ERANGE;
if (val > SEMVMX || val < 0)
goto out_unlock;
 
for (un = sma->undo; un; un = un->id_next)
un->semadj[semnum] = 0;
curr->semval = val;
curr->sempid = current->pid;
sma->sem_ctime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
err = 0;
goto out_unlock;
}
}
out_unlock:
sem_unlock(semid);
out_free:
if(sem_io != fast_sem_io)
ipc_free(sem_io, sizeof(ushort)*nsems);
return err;
}
 
struct sem_setbuf {
uid_t uid;
gid_t gid;
mode_t mode;
};
 
static inline unsigned long copy_semid_from_user(struct sem_setbuf *out, void *buf, int version)
{
switch(version) {
case IPC_64:
{
struct semid64_ds tbuf;
 
if(copy_from_user(&tbuf, buf, sizeof(tbuf)))
return -EFAULT;
 
out->uid = tbuf.sem_perm.uid;
out->gid = tbuf.sem_perm.gid;
out->mode = tbuf.sem_perm.mode;
 
return 0;
}
case IPC_OLD:
{
struct semid_ds tbuf_old;
 
if(copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
return -EFAULT;
 
out->uid = tbuf_old.sem_perm.uid;
out->gid = tbuf_old.sem_perm.gid;
out->mode = tbuf_old.sem_perm.mode;
 
return 0;
}
default:
return -EINVAL;
}
}
 
static int semctl_down(int semid, int semnum, int cmd, int version, union semun arg)
{
struct sem_array *sma;
int err;
struct sem_setbuf setbuf;
struct kern_ipc_perm *ipcp;
 
if(cmd == IPC_SET) {
if(copy_semid_from_user (&setbuf, arg.buf, version))
return -EFAULT;
}
sma = sem_lock(semid);
if(sma==NULL)
return -EINVAL;
 
if (sem_checkid(sma,semid)) {
err=-EIDRM;
goto out_unlock;
}
ipcp = &sma->sem_perm;
if (current->euid != ipcp->cuid &&
current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) {
err=-EPERM;
goto out_unlock;
}
 
switch(cmd){
case IPC_RMID:
freeary(semid);
err = 0;
break;
case IPC_SET:
ipcp->uid = setbuf.uid;
ipcp->gid = setbuf.gid;
ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
| (setbuf.mode & S_IRWXUGO);
sma->sem_ctime = CURRENT_TIME;
sem_unlock(semid);
err = 0;
break;
default:
sem_unlock(semid);
err = -EINVAL;
break;
}
return err;
 
out_unlock:
sem_unlock(semid);
return err;
}
 
asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
{
int err = -EINVAL;
int version;
 
if (semid < 0)
return -EINVAL;
 
version = ipc_parse_version(&cmd);
 
switch(cmd) {
case IPC_INFO:
case SEM_INFO:
case SEM_STAT:
err = semctl_nolock(semid,semnum,cmd,version,arg);
return err;
case GETALL:
case GETVAL:
case GETPID:
case GETNCNT:
case GETZCNT:
case IPC_STAT:
case SETVAL:
case SETALL:
err = semctl_main(semid,semnum,cmd,version,arg);
return err;
case IPC_RMID:
case IPC_SET:
down(&sem_ids.sem);
err = semctl_down(semid,semnum,cmd,version,arg);
up(&sem_ids.sem);
return err;
default:
return -EINVAL;
}
}
 
static struct sem_undo* freeundos(struct sem_array *sma, struct sem_undo* un)
{
struct sem_undo* u;
struct sem_undo** up;
 
for(up = &current->semundo;(u=*up);up=&u->proc_next) {
if(un==u) {
un=u->proc_next;
*up=un;
kfree(u);
return un;
}
}
printk ("freeundos undo list error id=%d\n", un->semid);
return un->proc_next;
}
 
/* returns without sem_lock on error! */
static int alloc_undo(struct sem_array *sma, struct sem_undo** unp, int semid, int alter)
{
int size, nsems, error;
struct sem_undo *un;
 
nsems = sma->sem_nsems;
size = sizeof(struct sem_undo) + sizeof(short)*nsems;
sem_unlock(semid);
 
un = (struct sem_undo *) kmalloc(size, GFP_KERNEL);
if (!un)
return -ENOMEM;
 
memset(un, 0, size);
error = sem_revalidate(semid, sma, nsems, alter ? S_IWUGO : S_IRUGO);
if(error) {
kfree(un);
return error;
}
 
un->semadj = (short *) &un[1];
un->semid = semid;
un->proc_next = current->semundo;
current->semundo = un;
un->id_next = sma->undo;
sma->undo = un;
*unp = un;
return 0;
}
 
asmlinkage long sys_semop (int semid, struct sembuf *tsops, unsigned nsops)
{
return sys_semtimedop(semid, tsops, nsops, NULL);
}
 
asmlinkage long sys_semtimedop (int semid, struct sembuf *tsops,
unsigned nsops, const struct timespec *timeout)
{
int error = -EINVAL;
struct sem_array *sma;
struct sembuf fast_sops[SEMOPM_FAST];
struct sembuf* sops = fast_sops, *sop;
struct sem_undo *un;
int undos = 0, decrease = 0, alter = 0;
struct sem_queue queue;
unsigned long jiffies_left = 0;
 
if (nsops < 1 || semid < 0)
return -EINVAL;
if (nsops > sc_semopm)
return -E2BIG;
if(nsops > SEMOPM_FAST) {
sops = kmalloc(sizeof(*sops)*nsops,GFP_KERNEL);
if(sops==NULL)
return -ENOMEM;
}
if (copy_from_user (sops, tsops, nsops * sizeof(*tsops))) {
error=-EFAULT;
goto out_free;
}
if (timeout) {
struct timespec _timeout;
if (copy_from_user(&_timeout, timeout, sizeof(*timeout))) {
error = -EFAULT;
goto out_free;
}
if (_timeout.tv_sec < 0 || _timeout.tv_nsec < 0 ||
_timeout.tv_nsec >= 1000000000L) {
error = -EINVAL;
goto out_free;
}
jiffies_left = timespec_to_jiffies(&_timeout);
}
sma = sem_lock(semid);
error=-EINVAL;
if(sma==NULL)
goto out_free;
error = -EIDRM;
if (sem_checkid(sma,semid))
goto out_unlock_free;
error = -EFBIG;
for (sop = sops; sop < sops + nsops; sop++) {
if (sop->sem_num >= sma->sem_nsems)
goto out_unlock_free;
if (sop->sem_flg & SEM_UNDO)
undos++;
if (sop->sem_op < 0)
decrease = 1;
if (sop->sem_op > 0)
alter = 1;
}
alter |= decrease;
 
error = -EACCES;
if (ipcperms(&sma->sem_perm, alter ? S_IWUGO : S_IRUGO))
goto out_unlock_free;
if (undos) {
/* Make sure we have an undo structure
* for this process and this semaphore set.
*/
un=current->semundo;
while(un != NULL) {
if(un->semid==semid)
break;
if(un->semid==-1)
un=freeundos(sma,un);
else
un=un->proc_next;
}
if (!un) {
error = alloc_undo(sma,&un,semid,alter);
if(error)
goto out_free;
}
} else
un = NULL;
 
error = try_atomic_semop (sma, sops, nsops, un, current->pid, 0);
if (error <= 0)
goto update;
 
/* We need to sleep on this operation, so we put the current
* task into the pending queue and go to sleep.
*/
queue.sma = sma;
queue.sops = sops;
queue.nsops = nsops;
queue.undo = un;
queue.pid = current->pid;
queue.alter = decrease;
queue.id = semid;
if (alter)
append_to_queue(sma ,&queue);
else
prepend_to_queue(sma ,&queue);
current->semsleeping = &queue;
 
for (;;) {
struct sem_array* tmp;
queue.status = -EINTR;
queue.sleeper = current;
current->state = TASK_INTERRUPTIBLE;
sem_unlock(semid);
 
if (timeout)
jiffies_left = schedule_timeout(jiffies_left);
else
schedule();
 
tmp = sem_lock(semid);
if(tmp==NULL) {
if(queue.prev != NULL)
BUG();
current->semsleeping = NULL;
error = -EIDRM;
goto out_free;
}
/*
* If queue.status == 1 we where woken up and
* have to retry else we simply return.
* If an interrupt occurred we have to clean up the
* queue
*
*/
if (queue.status == 1)
{
error = try_atomic_semop (sma, sops, nsops, un,
current->pid,0);
if (error <= 0)
break;
} else {
error = queue.status;
if (error == -EINTR && timeout && jiffies_left == 0)
error = -EAGAIN;
if (queue.prev) /* got Interrupt */
break;
/* Everything done by update_queue */
current->semsleeping = NULL;
goto out_unlock_free;
}
}
current->semsleeping = NULL;
remove_from_queue(sma,&queue);
update:
if (alter)
update_queue (sma);
out_unlock_free:
sem_unlock(semid);
out_free:
if(sops != fast_sops)
kfree(sops);
return error;
}
 
/*
* add semadj values to semaphores, free undo structures.
* undo structures are not freed when semaphore arrays are destroyed
* so some of them may be out of date.
* IMPLEMENTATION NOTE: There is some confusion over whether the
* set of adjustments that needs to be done should be done in an atomic
* manner or not. That is, if we are attempting to decrement the semval
* should we queue up and wait until we can do so legally?
* The original implementation attempted to do this (queue and wait).
* The current implementation does not do so. The POSIX standard
* and SVID should be consulted to determine what behavior is mandated.
*/
void sem_exit (void)
{
struct sem_queue *q;
struct sem_undo *u, *un = NULL, **up, **unp;
struct sem_array *sma;
int nsems, i;
 
/* If the current process was sleeping for a semaphore,
* remove it from the queue.
*/
if ((q = current->semsleeping)) {
int semid = q->id;
sma = sem_lock(semid);
current->semsleeping = NULL;
 
if (q->prev) {
if(sma==NULL)
BUG();
remove_from_queue(q->sma,q);
}
if(sma!=NULL)
sem_unlock(semid);
}
 
for (up = &current->semundo; (u = *up); *up = u->proc_next, kfree(u)) {
int semid = u->semid;
if(semid == -1)
continue;
sma = sem_lock(semid);
if (sma == NULL)
continue;
 
if (u->semid == -1)
goto next_entry;
 
if (sem_checkid(sma,u->semid))
goto next_entry;
 
/* remove u from the sma->undo list */
for (unp = &sma->undo; (un = *unp); unp = &un->id_next) {
if (u == un)
goto found;
}
printk ("sem_exit undo list error id=%d\n", u->semid);
goto next_entry;
found:
*unp = un->id_next;
/* perform adjustments registered in u */
nsems = sma->sem_nsems;
for (i = 0; i < nsems; i++) {
struct sem * sem = &sma->sem_base[i];
sem->semval += u->semadj[i];
if (sem->semval < 0)
sem->semval = 0; /* shouldn't happen */
sem->sempid = current->pid;
}
sma->sem_otime = CURRENT_TIME;
/* maybe some queued-up processes were waiting for this */
update_queue(sma);
next_entry:
sem_unlock(semid);
}
current->semundo = NULL;
}
 
#ifdef CONFIG_PROC_FS
static int sysvipc_sem_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
off_t pos = 0;
off_t begin = 0;
int i, len = 0;
 
len += sprintf(buffer, " key semid perms nsems uid gid cuid cgid otime ctime\n");
down(&sem_ids.sem);
 
for(i = 0; i <= sem_ids.max_id; i++) {
struct sem_array *sma;
sma = sem_lock(i);
if(sma) {
len += sprintf(buffer + len, "%10d %10d %4o %10lu %5u %5u %5u %5u %10lu %10lu\n",
sma->sem_perm.key,
sem_buildid(i,sma->sem_perm.seq),
sma->sem_perm.mode,
sma->sem_nsems,
sma->sem_perm.uid,
sma->sem_perm.gid,
sma->sem_perm.cuid,
sma->sem_perm.cgid,
sma->sem_otime,
sma->sem_ctime);
sem_unlock(i);
 
pos += len;
if(pos < offset) {
len = 0;
begin = pos;
}
if(pos > offset + length)
goto done;
}
}
*eof = 1;
done:
up(&sem_ids.sem);
*start = buffer + (offset - begin);
len -= (offset - begin);
if(len > length)
len = length;
if(len < 0)
len = 0;
return len;
}
#endif
/msg.c
0,0 → 1,905
/*
* linux/ipc/msg.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Removed all the remaining kerneld mess
* Catch the -EFAULT stuff properly
* Use GFP_KERNEL for messages as in 1.2
* Fixed up the unchecked user space derefs
* Copyright (C) 1998 Alan Cox & Andi Kleen
*
* /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
*
* mostly rewritten, threaded and wake-one semantics added
* MSGMAX limit removed, sysctl's added
* (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
*/
 
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/msg.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include "util.h"
 
/* sysctl: */
int msg_ctlmax = MSGMAX;
int msg_ctlmnb = MSGMNB;
int msg_ctlmni = MSGMNI;
 
/* one msg_receiver structure for each sleeping receiver */
struct msg_receiver {
struct list_head r_list;
struct task_struct* r_tsk;
 
int r_mode;
long r_msgtype;
long r_maxsize;
 
struct msg_msg* volatile r_msg;
};
 
/* one msg_sender for each sleeping sender */
struct msg_sender {
struct list_head list;
struct task_struct* tsk;
};
 
struct msg_msgseg {
struct msg_msgseg* next;
/* the next part of the message follows immediately */
};
/* one msg_msg structure for each message */
struct msg_msg {
struct list_head m_list;
long m_type;
int m_ts; /* message text size */
struct msg_msgseg* next;
/* the actual message follows immediately */
};
 
#define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
#define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
 
/* one msq_queue structure for each present queue on the system */
struct msg_queue {
struct kern_ipc_perm q_perm;
time_t q_stime; /* last msgsnd time */
time_t q_rtime; /* last msgrcv time */
time_t q_ctime; /* last change time */
unsigned long q_cbytes; /* current number of bytes on queue */
unsigned long q_qnum; /* number of messages in queue */
unsigned long q_qbytes; /* max number of bytes on queue */
pid_t q_lspid; /* pid of last msgsnd */
pid_t q_lrpid; /* last receive pid */
 
struct list_head q_messages;
struct list_head q_receivers;
struct list_head q_senders;
};
 
#define SEARCH_ANY 1
#define SEARCH_EQUAL 2
#define SEARCH_NOTEQUAL 3
#define SEARCH_LESSEQUAL 4
 
static atomic_t msg_bytes = ATOMIC_INIT(0);
static atomic_t msg_hdrs = ATOMIC_INIT(0);
 
static struct ipc_ids msg_ids;
 
#define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id))
#define msg_unlock(id) ipc_unlock(&msg_ids,id)
#define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id))
#define msg_checkid(msq, msgid) \
ipc_checkid(&msg_ids,&msq->q_perm,msgid)
#define msg_buildid(id, seq) \
ipc_buildid(&msg_ids, id, seq)
 
static void freeque (int id);
static int newque (key_t key, int msgflg);
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif
 
void __init msg_init (void)
{
ipc_init_ids(&msg_ids,msg_ctlmni);
 
#ifdef CONFIG_PROC_FS
create_proc_read_entry("sysvipc/msg", 0, 0, sysvipc_msg_read_proc, NULL);
#endif
}
 
static int newque (key_t key, int msgflg)
{
int id;
struct msg_queue *msq;
 
msq = (struct msg_queue *) kmalloc (sizeof (*msq), GFP_KERNEL);
if (!msq)
return -ENOMEM;
id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni);
if(id == -1) {
kfree(msq);
return -ENOSPC;
}
msq->q_perm.mode = (msgflg & S_IRWXUGO);
msq->q_perm.key = key;
 
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = CURRENT_TIME;
msq->q_cbytes = msq->q_qnum = 0;
msq->q_qbytes = msg_ctlmnb;
msq->q_lspid = msq->q_lrpid = 0;
INIT_LIST_HEAD(&msq->q_messages);
INIT_LIST_HEAD(&msq->q_receivers);
INIT_LIST_HEAD(&msq->q_senders);
msg_unlock(id);
 
return msg_buildid(id,msq->q_perm.seq);
}
 
static void free_msg(struct msg_msg* msg)
{
struct msg_msgseg* seg;
seg = msg->next;
kfree(msg);
while(seg != NULL) {
struct msg_msgseg* tmp = seg->next;
kfree(seg);
seg = tmp;
}
}
 
static struct msg_msg* load_msg(void* src, int len)
{
struct msg_msg* msg;
struct msg_msgseg** pseg;
int err;
int alen;
 
alen = len;
if(alen > DATALEN_MSG)
alen = DATALEN_MSG;
 
msg = (struct msg_msg *) kmalloc (sizeof(*msg) + alen, GFP_KERNEL);
if(msg==NULL)
return ERR_PTR(-ENOMEM);
 
msg->next = NULL;
 
if (copy_from_user(msg+1, src, alen)) {
err = -EFAULT;
goto out_err;
}
 
len -= alen;
src = ((char*)src)+alen;
pseg = &msg->next;
while(len > 0) {
struct msg_msgseg* seg;
alen = len;
if(alen > DATALEN_SEG)
alen = DATALEN_SEG;
seg = (struct msg_msgseg *) kmalloc (sizeof(*seg) + alen, GFP_KERNEL);
if(seg==NULL) {
err=-ENOMEM;
goto out_err;
}
*pseg = seg;
seg->next = NULL;
if(copy_from_user (seg+1, src, alen)) {
err = -EFAULT;
goto out_err;
}
pseg = &seg->next;
len -= alen;
src = ((char*)src)+alen;
}
return msg;
 
out_err:
free_msg(msg);
return ERR_PTR(err);
}
 
static int store_msg(void* dest, struct msg_msg* msg, int len)
{
int alen;
struct msg_msgseg *seg;
 
alen = len;
if(alen > DATALEN_MSG)
alen = DATALEN_MSG;
if(copy_to_user (dest, msg+1, alen))
return -1;
 
len -= alen;
dest = ((char*)dest)+alen;
seg = msg->next;
while(len > 0) {
alen = len;
if(alen > DATALEN_SEG)
alen = DATALEN_SEG;
if(copy_to_user (dest, seg+1, alen))
return -1;
len -= alen;
dest = ((char*)dest)+alen;
seg=seg->next;
}
return 0;
}
 
static inline void ss_add(struct msg_queue* msq, struct msg_sender* mss)
{
mss->tsk=current;
current->state=TASK_INTERRUPTIBLE;
list_add_tail(&mss->list,&msq->q_senders);
}
 
static inline void ss_del(struct msg_sender* mss)
{
if(mss->list.next != NULL)
list_del(&mss->list);
}
 
static void ss_wakeup(struct list_head* h, int kill)
{
struct list_head *tmp;
 
tmp = h->next;
while (tmp != h) {
struct msg_sender* mss;
mss = list_entry(tmp,struct msg_sender,list);
tmp = tmp->next;
if(kill)
mss->list.next=NULL;
wake_up_process(mss->tsk);
}
}
 
static void expunge_all(struct msg_queue* msq, int res)
{
struct list_head *tmp;
 
tmp = msq->q_receivers.next;
while (tmp != &msq->q_receivers) {
struct msg_receiver* msr;
msr = list_entry(tmp,struct msg_receiver,r_list);
tmp = tmp->next;
msr->r_msg = ERR_PTR(res);
wake_up_process(msr->r_tsk);
}
}
 
static void freeque (int id)
{
struct msg_queue *msq;
struct list_head *tmp;
 
msq = msg_rmid(id);
 
expunge_all(msq,-EIDRM);
ss_wakeup(&msq->q_senders,1);
msg_unlock(id);
tmp = msq->q_messages.next;
while(tmp != &msq->q_messages) {
struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list);
tmp = tmp->next;
atomic_dec(&msg_hdrs);
free_msg(msg);
}
atomic_sub(msq->q_cbytes, &msg_bytes);
kfree(msq);
}
 
asmlinkage long sys_msgget (key_t key, int msgflg)
{
int id, ret = -EPERM;
struct msg_queue *msq;
down(&msg_ids.sem);
if (key == IPC_PRIVATE)
ret = newque(key, msgflg);
else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */
if (!(msgflg & IPC_CREAT))
ret = -ENOENT;
else
ret = newque(key, msgflg);
} else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
ret = -EEXIST;
} else {
msq = msg_lock(id);
if(msq==NULL)
BUG();
if (ipcperms(&msq->q_perm, msgflg))
ret = -EACCES;
else
ret = msg_buildid(id, msq->q_perm.seq);
msg_unlock(id);
}
up(&msg_ids.sem);
return ret;
}
 
static inline unsigned long copy_msqid_to_user(void *buf, struct msqid64_ds *in, int version)
{
switch(version) {
case IPC_64:
return copy_to_user (buf, in, sizeof(*in));
case IPC_OLD:
{
struct msqid_ds out;
 
memset(&out,0,sizeof(out));
 
ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
 
out.msg_stime = in->msg_stime;
out.msg_rtime = in->msg_rtime;
out.msg_ctime = in->msg_ctime;
 
if(in->msg_cbytes > USHRT_MAX)
out.msg_cbytes = USHRT_MAX;
else
out.msg_cbytes = in->msg_cbytes;
out.msg_lcbytes = in->msg_cbytes;
 
if(in->msg_qnum > USHRT_MAX)
out.msg_qnum = USHRT_MAX;
else
out.msg_qnum = in->msg_qnum;
 
if(in->msg_qbytes > USHRT_MAX)
out.msg_qbytes = USHRT_MAX;
else
out.msg_qbytes = in->msg_qbytes;
out.msg_lqbytes = in->msg_qbytes;
 
out.msg_lspid = in->msg_lspid;
out.msg_lrpid = in->msg_lrpid;
 
return copy_to_user (buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
 
struct msq_setbuf {
unsigned long qbytes;
uid_t uid;
gid_t gid;
mode_t mode;
};
 
static inline unsigned long copy_msqid_from_user(struct msq_setbuf *out, void *buf, int version)
{
switch(version) {
case IPC_64:
{
struct msqid64_ds tbuf;
 
if (copy_from_user (&tbuf, buf, sizeof (tbuf)))
return -EFAULT;
 
out->qbytes = tbuf.msg_qbytes;
out->uid = tbuf.msg_perm.uid;
out->gid = tbuf.msg_perm.gid;
out->mode = tbuf.msg_perm.mode;
 
return 0;
}
case IPC_OLD:
{
struct msqid_ds tbuf_old;
 
if (copy_from_user (&tbuf_old, buf, sizeof (tbuf_old)))
return -EFAULT;
 
out->uid = tbuf_old.msg_perm.uid;
out->gid = tbuf_old.msg_perm.gid;
out->mode = tbuf_old.msg_perm.mode;
 
if(tbuf_old.msg_qbytes == 0)
out->qbytes = tbuf_old.msg_lqbytes;
else
out->qbytes = tbuf_old.msg_qbytes;
 
return 0;
}
default:
return -EINVAL;
}
}
 
asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds *buf)
{
int err, version;
struct msg_queue *msq;
struct msq_setbuf setbuf;
struct kern_ipc_perm *ipcp;
if (msqid < 0 || cmd < 0)
return -EINVAL;
 
version = ipc_parse_version(&cmd);
 
switch (cmd) {
case IPC_INFO:
case MSG_INFO:
{
struct msginfo msginfo;
int max_id;
if (!buf)
return -EFAULT;
/* We must not return kernel stack data.
* due to padding, it's not enough
* to set all member fields.
*/
memset(&msginfo,0,sizeof(msginfo));
msginfo.msgmni = msg_ctlmni;
msginfo.msgmax = msg_ctlmax;
msginfo.msgmnb = msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
down(&msg_ids.sem);
if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids.in_use;
msginfo.msgmap = atomic_read(&msg_hdrs);
msginfo.msgtql = atomic_read(&msg_bytes);
} else {
msginfo.msgmap = MSGMAP;
msginfo.msgpool = MSGPOOL;
msginfo.msgtql = MSGTQL;
}
max_id = msg_ids.max_id;
up(&msg_ids.sem);
if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
}
case MSG_STAT:
case IPC_STAT:
{
struct msqid64_ds tbuf;
int success_return;
if (!buf)
return -EFAULT;
if(cmd == MSG_STAT && msqid >= msg_ids.size)
return -EINVAL;
 
memset(&tbuf,0,sizeof(tbuf));
 
msq = msg_lock(msqid);
if (msq == NULL)
return -EINVAL;
 
if(cmd == MSG_STAT) {
success_return = msg_buildid(msqid, msq->q_perm.seq);
} else {
err = -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock;
success_return = 0;
}
err = -EACCES;
if (ipcperms (&msq->q_perm, S_IRUGO))
goto out_unlock;
 
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
tbuf.msg_stime = msq->q_stime;
tbuf.msg_rtime = msq->q_rtime;
tbuf.msg_ctime = msq->q_ctime;
tbuf.msg_cbytes = msq->q_cbytes;
tbuf.msg_qnum = msq->q_qnum;
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
msg_unlock(msqid);
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
return success_return;
}
case IPC_SET:
if (!buf)
return -EFAULT;
if (copy_msqid_from_user (&setbuf, buf, version))
return -EFAULT;
break;
case IPC_RMID:
break;
default:
return -EINVAL;
}
 
down(&msg_ids.sem);
msq = msg_lock(msqid);
err=-EINVAL;
if (msq == NULL)
goto out_up;
 
err = -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock_up;
ipcp = &msq->q_perm;
err = -EPERM;
if (current->euid != ipcp->cuid &&
current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
/* We _could_ check for CAP_CHOWN above, but we don't */
goto out_unlock_up;
 
switch (cmd) {
case IPC_SET:
{
if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
goto out_unlock_up;
msq->q_qbytes = setbuf.qbytes;
 
ipcp->uid = setbuf.uid;
ipcp->gid = setbuf.gid;
ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
(S_IRWXUGO & setbuf.mode);
msq->q_ctime = CURRENT_TIME;
/* sleeping receivers might be excluded by
* stricter permissions.
*/
expunge_all(msq,-EAGAIN);
/* sleeping senders might be able to send
* due to a larger queue size.
*/
ss_wakeup(&msq->q_senders,0);
msg_unlock(msqid);
break;
}
case IPC_RMID:
freeque (msqid);
break;
}
err = 0;
out_up:
up(&msg_ids.sem);
return err;
out_unlock_up:
msg_unlock(msqid);
goto out_up;
out_unlock:
msg_unlock(msqid);
return err;
}
 
static int testmsg(struct msg_msg* msg,long type,int mode)
{
switch(mode)
{
case SEARCH_ANY:
return 1;
case SEARCH_LESSEQUAL:
if(msg->m_type <=type)
return 1;
break;
case SEARCH_EQUAL:
if(msg->m_type == type)
return 1;
break;
case SEARCH_NOTEQUAL:
if(msg->m_type != type)
return 1;
break;
}
return 0;
}
 
static int inline pipelined_send(struct msg_queue* msq, struct msg_msg* msg)
{
struct list_head* tmp;
 
tmp = msq->q_receivers.next;
while (tmp != &msq->q_receivers) {
struct msg_receiver* msr;
msr = list_entry(tmp,struct msg_receiver,r_list);
tmp = tmp->next;
if(testmsg(msg,msr->r_msgtype,msr->r_mode)) {
list_del(&msr->r_list);
if(msr->r_maxsize < msg->m_ts) {
msr->r_msg = ERR_PTR(-E2BIG);
wake_up_process(msr->r_tsk);
} else {
msr->r_msg = msg;
msq->q_lrpid = msr->r_tsk->pid;
msq->q_rtime = CURRENT_TIME;
wake_up_process(msr->r_tsk);
return 1;
}
}
}
return 0;
}
 
asmlinkage long sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg)
{
struct msg_queue *msq;
struct msg_msg *msg;
long mtype;
int err;
if (msgsz > msg_ctlmax || (long) msgsz < 0 || msqid < 0)
return -EINVAL;
if (get_user(mtype, &msgp->mtype))
return -EFAULT;
if (mtype < 1)
return -EINVAL;
 
msg = load_msg(msgp->mtext, msgsz);
if(IS_ERR(msg))
return PTR_ERR(msg);
 
msg->m_type = mtype;
msg->m_ts = msgsz;
 
msq = msg_lock(msqid);
err=-EINVAL;
if(msq==NULL)
goto out_free;
retry:
err= -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock_free;
 
err=-EACCES;
if (ipcperms(&msq->q_perm, S_IWUGO))
goto out_unlock_free;
 
if(msgsz + msq->q_cbytes > msq->q_qbytes ||
1 + msq->q_qnum > msq->q_qbytes) {
struct msg_sender s;
 
if(msgflg&IPC_NOWAIT) {
err=-EAGAIN;
goto out_unlock_free;
}
ss_add(msq, &s);
msg_unlock(msqid);
schedule();
current->state= TASK_RUNNING;
 
msq = msg_lock(msqid);
err = -EIDRM;
if(msq==NULL)
goto out_free;
ss_del(&s);
if (signal_pending(current)) {
err=-EINTR;
goto out_unlock_free;
}
goto retry;
}
 
msq->q_lspid = current->pid;
msq->q_stime = CURRENT_TIME;
 
if(!pipelined_send(msq,msg)) {
/* noone is waiting for this message, enqueue it */
list_add_tail(&msg->m_list,&msq->q_messages);
msq->q_cbytes += msgsz;
msq->q_qnum++;
atomic_add(msgsz,&msg_bytes);
atomic_inc(&msg_hdrs);
}
err = 0;
msg = NULL;
 
out_unlock_free:
msg_unlock(msqid);
out_free:
if(msg!=NULL)
free_msg(msg);
return err;
}
 
static int inline convert_mode(long* msgtyp, int msgflg)
{
/*
* find message of correct type.
* msgtyp = 0 => get first.
* msgtyp > 0 => get first message of matching type.
* msgtyp < 0 => get message with least type must be < abs(msgtype).
*/
if(*msgtyp==0)
return SEARCH_ANY;
if(*msgtyp<0) {
*msgtyp=-(*msgtyp);
return SEARCH_LESSEQUAL;
}
if(msgflg & MSG_EXCEPT)
return SEARCH_NOTEQUAL;
return SEARCH_EQUAL;
}
 
asmlinkage long sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz,
long msgtyp, int msgflg)
{
struct msg_queue *msq;
struct msg_receiver msr_d;
struct list_head* tmp;
struct msg_msg* msg, *found_msg;
int err;
int mode;
 
if (msqid < 0 || (long) msgsz < 0)
return -EINVAL;
mode = convert_mode(&msgtyp,msgflg);
 
msq = msg_lock(msqid);
if(msq==NULL)
return -EINVAL;
retry:
err = -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock;
 
err=-EACCES;
if (ipcperms (&msq->q_perm, S_IRUGO))
goto out_unlock;
 
tmp = msq->q_messages.next;
found_msg=NULL;
while (tmp != &msq->q_messages) {
msg = list_entry(tmp,struct msg_msg,m_list);
if(testmsg(msg,msgtyp,mode)) {
found_msg = msg;
if(mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
found_msg=msg;
msgtyp=msg->m_type-1;
} else {
found_msg=msg;
break;
}
}
tmp = tmp->next;
}
if(found_msg) {
msg=found_msg;
if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
err=-E2BIG;
goto out_unlock;
}
list_del(&msg->m_list);
msq->q_qnum--;
msq->q_rtime = CURRENT_TIME;
msq->q_lrpid = current->pid;
msq->q_cbytes -= msg->m_ts;
atomic_sub(msg->m_ts,&msg_bytes);
atomic_dec(&msg_hdrs);
ss_wakeup(&msq->q_senders,0);
msg_unlock(msqid);
out_success:
msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz;
if (put_user (msg->m_type, &msgp->mtype) ||
store_msg(msgp->mtext, msg, msgsz)) {
msgsz = -EFAULT;
}
free_msg(msg);
return msgsz;
} else
{
struct msg_queue *t;
/* no message waiting. Prepare for pipelined
* receive.
*/
if (msgflg & IPC_NOWAIT) {
err=-ENOMSG;
goto out_unlock;
}
list_add_tail(&msr_d.r_list,&msq->q_receivers);
msr_d.r_tsk = current;
msr_d.r_msgtype = msgtyp;
msr_d.r_mode = mode;
if(msgflg & MSG_NOERROR)
msr_d.r_maxsize = INT_MAX;
else
msr_d.r_maxsize = msgsz;
msr_d.r_msg = ERR_PTR(-EAGAIN);
current->state = TASK_INTERRUPTIBLE;
msg_unlock(msqid);
 
schedule();
current->state = TASK_RUNNING;
 
/* This introduces a race so we must always take
the slow path
msg = (struct msg_msg*) msr_d.r_msg;
if(!IS_ERR(msg))
goto out_success;
*/
t = msg_lock(msqid);
if(t==NULL)
msqid=-1;
msg = (struct msg_msg*)msr_d.r_msg;
if(!IS_ERR(msg)) {
/* our message arived while we waited for
* the spinlock. Process it.
*/
if(msqid!=-1)
msg_unlock(msqid);
goto out_success;
}
err = PTR_ERR(msg);
if(err == -EAGAIN) {
if(msqid==-1)
BUG();
list_del(&msr_d.r_list);
if (signal_pending(current))
err=-EINTR;
else
goto retry;
}
}
out_unlock:
if(msqid!=-1)
msg_unlock(msqid);
return err;
}
 
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
off_t pos = 0;
off_t begin = 0;
int i, len = 0;
 
down(&msg_ids.sem);
len += sprintf(buffer, " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n");
 
for(i = 0; i <= msg_ids.max_id; i++) {
struct msg_queue * msq;
msq = msg_lock(i);
if(msq != NULL) {
len += sprintf(buffer + len, "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n",
msq->q_perm.key,
msg_buildid(i,msq->q_perm.seq),
msq->q_perm.mode,
msq->q_cbytes,
msq->q_qnum,
msq->q_lspid,
msq->q_lrpid,
msq->q_perm.uid,
msq->q_perm.gid,
msq->q_perm.cuid,
msq->q_perm.cgid,
msq->q_stime,
msq->q_rtime,
msq->q_ctime);
msg_unlock(i);
 
pos += len;
if(pos < offset) {
len = 0;
begin = pos;
}
if(pos > offset + length)
goto done;
}
 
}
*eof = 1;
done:
up(&msg_ids.sem);
*start = buffer + (offset - begin);
len -= (offset - begin);
if(len > length)
len = length;
if(len < 0)
len = 0;
return len;
}
#endif
/shm.c
0,0 → 1,751
/*
* linux/ipc/shm.c
* Copyright (C) 1992, 1993 Krishna Balasubramanian
* Many improvements/fixes by Bruno Haible.
* Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
* Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
*
* /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
* BIGMEM support, Andrea Arcangeli <andrea@suse.de>
* SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
* HIGHMEM support, Ingo Molnar <mingo@redhat.com>
* Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
* Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
* Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
*
*/
 
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/mman.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
 
#include "util.h"
 
struct shmid_kernel /* private to the kernel */
{
struct kern_ipc_perm shm_perm;
struct file * shm_file;
int id;
unsigned long shm_nattch;
unsigned long shm_segsz;
time_t shm_atim;
time_t shm_dtim;
time_t shm_ctim;
pid_t shm_cprid;
pid_t shm_lprid;
};
 
#define shm_flags shm_perm.mode
 
static struct file_operations shm_file_operations;
static struct vm_operations_struct shm_vm_ops;
 
static struct ipc_ids shm_ids;
 
#define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
#define shm_unlock(id) ipc_unlock(&shm_ids,id)
#define shm_lockall() ipc_lockall(&shm_ids)
#define shm_unlockall() ipc_unlockall(&shm_ids)
#define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
#define shm_buildid(id, seq) \
ipc_buildid(&shm_ids, id, seq)
 
static int newseg (key_t key, int shmflg, size_t size);
static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif
 
size_t shm_ctlmax = SHMMAX;
size_t shm_ctlall = SHMALL;
int shm_ctlmni = SHMMNI;
 
static int shm_tot; /* total number of shared memory pages */
 
void __init shm_init (void)
{
ipc_init_ids(&shm_ids, 1);
#ifdef CONFIG_PROC_FS
create_proc_read_entry("sysvipc/shm", 0, 0, sysvipc_shm_read_proc, NULL);
#endif
}
 
static inline int shm_checkid(struct shmid_kernel *s, int id)
{
if (ipc_checkid(&shm_ids,&s->shm_perm,id))
return -EIDRM;
return 0;
}
 
static inline struct shmid_kernel *shm_rmid(int id)
{
return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
}
 
static inline int shm_addid(struct shmid_kernel *shp)
{
return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni+1);
}
 
 
 
static inline void shm_inc (int id) {
struct shmid_kernel *shp;
 
if(!(shp = shm_lock(id)))
BUG();
shp->shm_atim = CURRENT_TIME;
shp->shm_lprid = current->pid;
shp->shm_nattch++;
shm_unlock(id);
}
 
/* This is called by fork, once for every shm attach. */
static void shm_open (struct vm_area_struct *shmd)
{
shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
}
 
/*
* shm_destroy - free the struct shmid_kernel
*
* @shp: struct to free
*
* It has to be called with shp and shm_ids.sem locked,
* but returns with shp unlocked and freed.
*/
static void shm_destroy (struct shmid_kernel *shp)
{
shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
shm_rmid (shp->id);
shm_unlock(shp->id);
shmem_lock(shp->shm_file, 0);
fput (shp->shm_file);
kfree (shp);
}
 
/*
* remove the attach descriptor shmd.
* free memory for segment if it is marked destroyed.
* The descriptor has already been removed from the current->mm->mmap list
* and will later be kfree()d.
*/
static void shm_close (struct vm_area_struct *shmd)
{
struct file * file = shmd->vm_file;
int id = file->f_dentry->d_inode->i_ino;
struct shmid_kernel *shp;
 
down (&shm_ids.sem);
/* remove from the list of attaches of the shm segment */
if(!(shp = shm_lock(id)))
BUG();
shp->shm_lprid = current->pid;
shp->shm_dtim = CURRENT_TIME;
shp->shm_nattch--;
if(shp->shm_nattch == 0 &&
shp->shm_flags & SHM_DEST)
shm_destroy (shp);
else
shm_unlock(id);
up (&shm_ids.sem);
}
 
static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
UPDATE_ATIME(file->f_dentry->d_inode);
vma->vm_ops = &shm_vm_ops;
shm_inc(file->f_dentry->d_inode->i_ino);
return 0;
}
 
static struct file_operations shm_file_operations = {
mmap: shm_mmap
};
 
static struct vm_operations_struct shm_vm_ops = {
open: shm_open, /* callback for a new vm-area open */
close: shm_close, /* callback for when the vm-area is released */
nopage: shmem_nopage,
};
 
static int newseg (key_t key, int shmflg, size_t size)
{
int error;
struct shmid_kernel *shp;
int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
struct file * file;
char name[13];
int id;
 
if (size < SHMMIN || size > shm_ctlmax)
return -EINVAL;
 
if (shm_tot + numpages >= shm_ctlall)
return -ENOSPC;
 
shp = (struct shmid_kernel *) kmalloc (sizeof (*shp), GFP_USER);
if (!shp)
return -ENOMEM;
sprintf (name, "SYSV%08x", key);
file = shmem_file_setup(name, size);
error = PTR_ERR(file);
if (IS_ERR(file))
goto no_file;
 
error = -ENOSPC;
id = shm_addid(shp);
if(id == -1)
goto no_id;
shp->shm_perm.key = key;
shp->shm_flags = (shmflg & S_IRWXUGO);
shp->shm_cprid = current->pid;
shp->shm_lprid = 0;
shp->shm_atim = shp->shm_dtim = 0;
shp->shm_ctim = CURRENT_TIME;
shp->shm_segsz = size;
shp->shm_nattch = 0;
shp->id = shm_buildid(id,shp->shm_perm.seq);
shp->shm_file = file;
file->f_dentry->d_inode->i_ino = shp->id;
file->f_op = &shm_file_operations;
shm_tot += numpages;
shm_unlock (id);
return shp->id;
 
no_id:
fput(file);
no_file:
kfree(shp);
return error;
}
 
asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
{
struct shmid_kernel *shp;
int err, id = 0;
 
down(&shm_ids.sem);
if (key == IPC_PRIVATE) {
err = newseg(key, shmflg, size);
} else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
if (!(shmflg & IPC_CREAT))
err = -ENOENT;
else
err = newseg(key, shmflg, size);
} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
err = -EEXIST;
} else {
shp = shm_lock(id);
if(shp==NULL)
BUG();
if (shp->shm_segsz < size)
err = -EINVAL;
else if (ipcperms(&shp->shm_perm, shmflg))
err = -EACCES;
else
err = shm_buildid(id, shp->shm_perm.seq);
shm_unlock(id);
}
up(&shm_ids.sem);
return err;
}
 
static inline unsigned long copy_shmid_to_user(void *buf, struct shmid64_ds *in, int version)
{
switch(version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct shmid_ds out;
 
ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
out.shm_segsz = in->shm_segsz;
out.shm_atime = in->shm_atime;
out.shm_dtime = in->shm_dtime;
out.shm_ctime = in->shm_ctime;
out.shm_cpid = in->shm_cpid;
out.shm_lpid = in->shm_lpid;
out.shm_nattch = in->shm_nattch;
 
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
 
struct shm_setbuf {
uid_t uid;
gid_t gid;
mode_t mode;
};
 
static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void *buf, int version)
{
switch(version) {
case IPC_64:
{
struct shmid64_ds tbuf;
 
if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
return -EFAULT;
 
out->uid = tbuf.shm_perm.uid;
out->gid = tbuf.shm_perm.gid;
out->mode = tbuf.shm_flags;
 
return 0;
}
case IPC_OLD:
{
struct shmid_ds tbuf_old;
 
if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
return -EFAULT;
 
out->uid = tbuf_old.shm_perm.uid;
out->gid = tbuf_old.shm_perm.gid;
out->mode = tbuf_old.shm_flags;
 
return 0;
}
default:
return -EINVAL;
}
}
 
static inline unsigned long copy_shminfo_to_user(void *buf, struct shminfo64 *in, int version)
{
switch(version) {
case IPC_64:
return copy_to_user(buf, in, sizeof(*in));
case IPC_OLD:
{
struct shminfo out;
 
if(in->shmmax > INT_MAX)
out.shmmax = INT_MAX;
else
out.shmmax = (int)in->shmmax;
 
out.shmmin = in->shmmin;
out.shmmni = in->shmmni;
out.shmseg = in->shmseg;
out.shmall = in->shmall;
 
return copy_to_user(buf, &out, sizeof(out));
}
default:
return -EINVAL;
}
}
 
static void shm_get_stat (unsigned long *rss, unsigned long *swp)
{
struct shmem_inode_info *info;
int i;
 
*rss = 0;
*swp = 0;
 
for(i = 0; i <= shm_ids.max_id; i++) {
struct shmid_kernel* shp;
struct inode * inode;
 
shp = shm_get(i);
if(shp == NULL)
continue;
inode = shp->shm_file->f_dentry->d_inode;
info = SHMEM_I(inode);
spin_lock (&info->lock);
*rss += inode->i_mapping->nrpages;
*swp += info->swapped;
spin_unlock (&info->lock);
}
}
 
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
struct shm_setbuf setbuf;
struct shmid_kernel *shp;
int err, version;
 
if (cmd < 0 || shmid < 0)
return -EINVAL;
 
version = ipc_parse_version(&cmd);
 
switch (cmd) { /* replace with proc interface ? */
case IPC_INFO:
{
struct shminfo64 shminfo;
 
memset(&shminfo,0,sizeof(shminfo));
shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
shminfo.shmmax = shm_ctlmax;
shminfo.shmall = shm_ctlall;
 
shminfo.shmmin = SHMMIN;
if(copy_shminfo_to_user (buf, &shminfo, version))
return -EFAULT;
/* reading a integer is always atomic */
err= shm_ids.max_id;
if(err<0)
err = 0;
return err;
}
case SHM_INFO:
{
struct shm_info shm_info;
 
memset(&shm_info,0,sizeof(shm_info));
down(&shm_ids.sem);
shm_lockall();
shm_info.used_ids = shm_ids.in_use;
shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
shm_info.shm_tot = shm_tot;
shm_info.swap_attempts = 0;
shm_info.swap_successes = 0;
err = shm_ids.max_id;
shm_unlockall();
up(&shm_ids.sem);
if(copy_to_user (buf, &shm_info, sizeof(shm_info)))
return -EFAULT;
 
return err < 0 ? 0 : err;
}
case SHM_STAT:
case IPC_STAT:
{
struct shmid64_ds tbuf;
int result;
memset(&tbuf, 0, sizeof(tbuf));
shp = shm_lock(shmid);
if(shp==NULL)
return -EINVAL;
if(cmd==SHM_STAT) {
err = -EINVAL;
if (shmid > shm_ids.max_id)
goto out_unlock;
result = shm_buildid(shmid, shp->shm_perm.seq);
} else {
err = shm_checkid(shp,shmid);
if(err)
goto out_unlock;
result = 0;
}
err=-EACCES;
if (ipcperms (&shp->shm_perm, S_IRUGO))
goto out_unlock;
kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
tbuf.shm_segsz = shp->shm_segsz;
tbuf.shm_atime = shp->shm_atim;
tbuf.shm_dtime = shp->shm_dtim;
tbuf.shm_ctime = shp->shm_ctim;
tbuf.shm_cpid = shp->shm_cprid;
tbuf.shm_lpid = shp->shm_lprid;
tbuf.shm_nattch = shp->shm_nattch;
shm_unlock(shmid);
if(copy_shmid_to_user (buf, &tbuf, version))
return -EFAULT;
return result;
}
case SHM_LOCK:
case SHM_UNLOCK:
{
/* Allow superuser to lock segment in memory */
/* Should the pages be faulted in here or leave it to user? */
/* need to determine interaction with current->swappable */
if (!capable(CAP_IPC_LOCK))
return -EPERM;
 
shp = shm_lock(shmid);
if(shp==NULL)
return -EINVAL;
err = shm_checkid(shp,shmid);
if(err)
goto out_unlock;
if(cmd==SHM_LOCK) {
shmem_lock(shp->shm_file, 1);
shp->shm_flags |= SHM_LOCKED;
} else {
shmem_lock(shp->shm_file, 0);
shp->shm_flags &= ~SHM_LOCKED;
}
shm_unlock(shmid);
return err;
}
case IPC_RMID:
{
/*
* We cannot simply remove the file. The SVID states
* that the block remains until the last person
* detaches from it, then is deleted. A shmat() on
* an RMID segment is legal in older Linux and if
* we change it apps break...
*
* Instead we set a destroyed flag, and then blow
* the name away when the usage hits zero.
*/
down(&shm_ids.sem);
shp = shm_lock(shmid);
err = -EINVAL;
if (shp == NULL)
goto out_up;
err = shm_checkid(shp, shmid);
if(err)
goto out_unlock_up;
if (current->euid != shp->shm_perm.uid &&
current->euid != shp->shm_perm.cuid &&
!capable(CAP_SYS_ADMIN)) {
err=-EPERM;
goto out_unlock_up;
}
if (shp->shm_nattch){
shp->shm_flags |= SHM_DEST;
/* Do not find it any more */
shp->shm_perm.key = IPC_PRIVATE;
shm_unlock(shmid);
} else
shm_destroy (shp);
up(&shm_ids.sem);
return err;
}
 
case IPC_SET:
{
if(copy_shmid_from_user (&setbuf, buf, version))
return -EFAULT;
down(&shm_ids.sem);
shp = shm_lock(shmid);
err=-EINVAL;
if(shp==NULL)
goto out_up;
err = shm_checkid(shp,shmid);
if(err)
goto out_unlock_up;
err=-EPERM;
if (current->euid != shp->shm_perm.uid &&
current->euid != shp->shm_perm.cuid &&
!capable(CAP_SYS_ADMIN)) {
goto out_unlock_up;
}
 
shp->shm_perm.uid = setbuf.uid;
shp->shm_perm.gid = setbuf.gid;
shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
| (setbuf.mode & S_IRWXUGO);
shp->shm_ctim = CURRENT_TIME;
break;
}
 
default:
return -EINVAL;
}
 
err = 0;
out_unlock_up:
shm_unlock(shmid);
out_up:
up(&shm_ids.sem);
return err;
out_unlock:
shm_unlock(shmid);
return err;
}
 
/*
* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
*/
asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr)
{
struct shmid_kernel *shp;
unsigned long addr;
unsigned long size;
struct file * file;
int err;
unsigned long flags;
unsigned long prot;
unsigned long o_flags;
int acc_mode;
void *user_addr;
 
if (shmid < 0)
return -EINVAL;
 
if ((addr = (ulong)shmaddr)) {
if (addr & (SHMLBA-1)) {
if (shmflg & SHM_RND)
addr &= ~(SHMLBA-1); /* round down */
else
return -EINVAL;
}
flags = MAP_SHARED | MAP_FIXED;
} else {
if ((shmflg & SHM_REMAP))
return -EINVAL;
 
flags = MAP_SHARED;
}
 
if (shmflg & SHM_RDONLY) {
prot = PROT_READ;
o_flags = O_RDONLY;
acc_mode = S_IRUGO;
} else {
prot = PROT_READ | PROT_WRITE;
o_flags = O_RDWR;
acc_mode = S_IRUGO | S_IWUGO;
}
 
/*
* We cannot rely on the fs check since SYSV IPC does have an
* additional creator id...
*/
shp = shm_lock(shmid);
if(shp == NULL)
return -EINVAL;
err = shm_checkid(shp,shmid);
if (err) {
shm_unlock(shmid);
return err;
}
if (ipcperms(&shp->shm_perm, acc_mode)) {
shm_unlock(shmid);
return -EACCES;
}
file = shp->shm_file;
size = file->f_dentry->d_inode->i_size;
shp->shm_nattch++;
shm_unlock(shmid);
 
down_write(&current->mm->mmap_sem);
if (addr && !(shmflg & SHM_REMAP)) {
user_addr = ERR_PTR(-EINVAL);
if (find_vma_intersection(current->mm, addr, addr + size))
goto invalid;
/*
* If shm segment goes below stack, make sure there is some
* space left for the stack to grow (at least 4 pages).
*/
if (addr < current->mm->start_stack &&
addr > current->mm->start_stack - size - PAGE_SIZE * 5)
goto invalid;
}
user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
 
invalid:
up_write(&current->mm->mmap_sem);
 
down (&shm_ids.sem);
if(!(shp = shm_lock(shmid)))
BUG();
shp->shm_nattch--;
if(shp->shm_nattch == 0 &&
shp->shm_flags & SHM_DEST)
shm_destroy (shp);
else
shm_unlock(shmid);
up (&shm_ids.sem);
 
*raddr = (unsigned long) user_addr;
err = 0;
if (IS_ERR(user_addr))
err = PTR_ERR(user_addr);
return err;
 
}
 
/*
* detach and kill segment if marked destroyed.
* The work is done in shm_close.
*/
asmlinkage long sys_shmdt (char *shmaddr)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *shmd, *shmdnext;
int retval = -EINVAL;
 
down_write(&mm->mmap_sem);
for (shmd = mm->mmap; shmd; shmd = shmdnext) {
shmdnext = shmd->vm_next;
if (shmd->vm_ops == &shm_vm_ops
&& shmd->vm_start - (shmd->vm_pgoff << PAGE_SHIFT) == (ulong) shmaddr) {
do_munmap(mm, shmd->vm_start, shmd->vm_end - shmd->vm_start);
retval = 0;
}
}
up_write(&mm->mmap_sem);
return retval;
}
 
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
off_t pos = 0;
off_t begin = 0;
int i, len = 0;
 
down(&shm_ids.sem);
len += sprintf(buffer, " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n");
 
for(i = 0; i <= shm_ids.max_id; i++) {
struct shmid_kernel* shp;
 
shp = shm_lock(i);
if(shp!=NULL) {
#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
char *format;
 
if (sizeof(size_t) <= sizeof(int))
format = SMALL_STRING;
else
format = BIG_STRING;
len += sprintf(buffer + len, format,
shp->shm_perm.key,
shm_buildid(i, shp->shm_perm.seq),
shp->shm_flags,
shp->shm_segsz,
shp->shm_cprid,
shp->shm_lprid,
shp->shm_nattch,
shp->shm_perm.uid,
shp->shm_perm.gid,
shp->shm_perm.cuid,
shp->shm_perm.cgid,
shp->shm_atim,
shp->shm_dtim,
shp->shm_ctim);
shm_unlock(i);
 
pos += len;
if(pos < offset) {
len = 0;
begin = pos;
}
if(pos > offset + length)
goto done;
}
}
*eof = 1;
done:
up(&shm_ids.sem);
*start = buffer + (offset - begin);
len -= (offset - begin);
if(len > length)
len = length;
if(len < 0)
len = 0;
return len;
}
#endif
/Makefile
0,0 → 1,16
#
# Makefile for the linux ipc.
#
# Note! Dependencies are done automagically by 'make dep', which also
# removes any old dependencies. DON'T put your own dependencies here
# unless it's something special (ie not a .c file).
#
# Note 2! The CFLAGS definition is now in the main makefile...
 
O_TARGET := ipc.o
 
obj-y := util.o
 
obj-$(CONFIG_SYSVIPC) += msg.o sem.o shm.o
 
include $(TOPDIR)/Rules.make
/util.c
0,0 → 1,414
/*
* linux/ipc/util.c
* Copyright (C) 1992 Krishna Balasubramanian
*
* Sep 1997 - Call suser() last after "normal" permission checks so we
* get BSD style process accounting right.
* Occurs in several places in the IPC code.
* Chris Evans, <chris@ferret.lmh.ox.ac.uk>
* Nov 1999 - ipc helper functions, unified SMP locking
* Manfred Spraul <manfreds@colorfullife.com>
*/
 
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/msg.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/highuid.h>
 
#if defined(CONFIG_SYSVIPC)
 
#include "util.h"
 
/**
* ipc_init - initialise IPC subsystem
*
* The various system5 IPC resources (semaphores, messages and shared
* memory are initialised
*/
void __init ipc_init (void)
{
sem_init();
msg_init();
shm_init();
return;
}
 
/**
* ipc_init_ids - initialise IPC identifiers
* @ids: Identifier set
* @size: Number of identifiers
*
* Given a size for the ipc identifier range (limited below IPCMNI)
* set up the sequence range to use then allocate and initialise the
* array itself.
*/
void __init ipc_init_ids(struct ipc_ids* ids, int size)
{
int i;
sema_init(&ids->sem,1);
 
if(size > IPCMNI)
size = IPCMNI;
ids->size = size;
ids->in_use = 0;
ids->max_id = -1;
ids->seq = 0;
{
int seq_limit = INT_MAX/SEQ_MULTIPLIER;
if(seq_limit > USHRT_MAX)
ids->seq_max = USHRT_MAX;
else
ids->seq_max = seq_limit;
}
 
ids->entries = ipc_alloc(sizeof(struct ipc_id)*size);
 
if(ids->entries == NULL) {
printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n");
ids->size = 0;
}
ids->ary = SPIN_LOCK_UNLOCKED;
for(i=0;i<ids->size;i++)
ids->entries[i].p = NULL;
}
 
/**
* ipc_findkey - find a key in an ipc identifier set
* @ids: Identifier set
* @key: The key to find
*
* Returns the identifier if found or -1 if not.
*/
int ipc_findkey(struct ipc_ids* ids, key_t key)
{
int id;
struct kern_ipc_perm* p;
 
for (id = 0; id <= ids->max_id; id++) {
p = ids->entries[id].p;
if(p==NULL)
continue;
if (key == p->key)
return id;
}
return -1;
}
 
static int grow_ary(struct ipc_ids* ids, int newsize)
{
struct ipc_id* new;
struct ipc_id* old;
int i;
 
if(newsize > IPCMNI)
newsize = IPCMNI;
if(newsize <= ids->size)
return newsize;
 
new = ipc_alloc(sizeof(struct ipc_id)*newsize);
if(new == NULL)
return ids->size;
memcpy(new, ids->entries, sizeof(struct ipc_id)*ids->size);
for(i=ids->size;i<newsize;i++) {
new[i].p = NULL;
}
spin_lock(&ids->ary);
 
old = ids->entries;
ids->entries = new;
i = ids->size;
ids->size = newsize;
spin_unlock(&ids->ary);
ipc_free(old, sizeof(struct ipc_id)*i);
return ids->size;
}
 
/**
* ipc_addid - add an IPC identifier
* @ids: IPC identifier set
* @new: new IPC permission set
* @size: new size limit for the id array
*
* Add an entry 'new' to the IPC arrays. The permissions object is
* initialised and the first free entry is set up and the id assigned
* is returned. The list is returned in a locked state on success.
* On failure the list is not locked and -1 is returned.
*/
int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
{
int id;
 
size = grow_ary(ids,size);
for (id = 0; id < size; id++) {
if(ids->entries[id].p == NULL)
goto found;
}
return -1;
found:
ids->in_use++;
if (id > ids->max_id)
ids->max_id = id;
 
new->cuid = new->uid = current->euid;
new->gid = new->cgid = current->egid;
 
new->seq = ids->seq++;
if(ids->seq > ids->seq_max)
ids->seq = 0;
 
spin_lock(&ids->ary);
ids->entries[id].p = new;
return id;
}
 
/**
* ipc_rmid - remove an IPC identifier
* @ids: identifier set
* @id: Identifier to remove
*
* The identifier must be valid, and in use. The kernel will panic if
* fed an invalid identifier. The entry is removed and internal
* variables recomputed. The object associated with the identifier
* is returned.
*/
struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id)
{
struct kern_ipc_perm* p;
int lid = id % SEQ_MULTIPLIER;
if(lid >= ids->size)
BUG();
p = ids->entries[lid].p;
ids->entries[lid].p = NULL;
if(p==NULL)
BUG();
ids->in_use--;
 
if (lid == ids->max_id) {
do {
lid--;
if(lid == -1)
break;
} while (ids->entries[lid].p == NULL);
ids->max_id = lid;
}
return p;
}
 
/**
* ipc_alloc - allocate ipc space
* @size: size desired
*
* Allocate memory from the appropriate pools and return a pointer to it.
* NULL is returned if the allocation fails
*/
void* ipc_alloc(int size)
{
void* out;
if(size > PAGE_SIZE)
out = vmalloc(size);
else
out = kmalloc(size, GFP_KERNEL);
return out;
}
 
/**
* ipc_free - free ipc space
* @ptr: pointer returned by ipc_alloc
* @size: size of block
*
* Free a block created with ipc_alloc. The caller must know the size
* used in the allocation call.
*/
void ipc_free(void* ptr, int size)
{
if(size > PAGE_SIZE)
vfree(ptr);
else
kfree(ptr);
}
 
/**
* ipcperms - check IPC permissions
* @ipcp: IPC permission set
* @flag: desired permission set.
*
* Check user, group, other permissions for access
* to ipc resources. return 0 if allowed
*/
int ipcperms (struct kern_ipc_perm *ipcp, short flag)
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
int requested_mode, granted_mode;
 
requested_mode = (flag >> 6) | (flag >> 3) | flag;
granted_mode = ipcp->mode;
if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
granted_mode >>= 6;
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
granted_mode >>= 3;
/* is there some bit set in requested_mode but not in granted_mode? */
if ((requested_mode & ~granted_mode & 0007) &&
!capable(CAP_IPC_OWNER))
return -1;
 
return 0;
}
 
/*
* Functions to convert between the kern_ipc_perm structure and the
* old/new ipc_perm structures
*/
 
/**
* kernel_to_ipc64_perm - convert kernel ipc permissions to user
* @in: kernel permissions
* @out: new style IPC permissions
*
* Turn the kernel object 'in' into a set of permissions descriptions
* for returning to userspace (out).
*/
 
void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
{
out->key = in->key;
out->uid = in->uid;
out->gid = in->gid;
out->cuid = in->cuid;
out->cgid = in->cgid;
out->mode = in->mode;
out->seq = in->seq;
}
 
/**
* ipc64_perm_to_ipc_perm - convert old ipc permissions to new
* @in: new style IPC permissions
* @out: old style IPC permissions
*
* Turn the new style permissions object in into a compatibility
* object and store it into the 'out' pointer.
*/
void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
{
out->key = in->key;
out->uid = NEW_TO_OLD_UID(in->uid);
out->gid = NEW_TO_OLD_GID(in->gid);
out->cuid = NEW_TO_OLD_UID(in->cuid);
out->cgid = NEW_TO_OLD_GID(in->cgid);
out->mode = in->mode;
out->seq = in->seq;
}
 
#if !defined(__ia64__) && !defined(__hppa__)
 
/**
* ipc_parse_version - IPC call version
* @cmd: pointer to command
*
* Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
* The cmd value is turned from an encoding command and version into
* just the command code.
*/
int ipc_parse_version (int *cmd)
{
#ifdef __x86_64__
if (!(current->thread.flags & THREAD_IA32))
return IPC_64;
#endif
if (*cmd & IPC_64) {
*cmd ^= IPC_64;
return IPC_64;
} else {
return IPC_OLD;
}
}
 
#endif /* __ia64__ */
 
#else
/*
* Dummy functions when SYSV IPC isn't configured
*/
 
void sem_exit (void)
{
return;
}
 
asmlinkage long sys_semget (key_t key, int nsems, int semflg)
{
return -ENOSYS;
}
 
asmlinkage long sys_semop (int semid, struct sembuf *sops, unsigned nsops)
{
return -ENOSYS;
}
 
asmlinkage long sys_semtimedop(int semid, struct sembuf *sops, unsigned nsops,
const struct timespec *timeout)
{
return -ENOSYS;
}
 
asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
{
return -ENOSYS;
}
 
asmlinkage long sys_msgget (key_t key, int msgflg)
{
return -ENOSYS;
}
 
asmlinkage long sys_msgsnd (int msqid, struct msgbuf *msgp, size_t msgsz, int msgflg)
{
return -ENOSYS;
}
 
asmlinkage long sys_msgrcv (int msqid, struct msgbuf *msgp, size_t msgsz, long msgtyp,
int msgflg)
{
return -ENOSYS;
}
 
asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds *buf)
{
return -ENOSYS;
}
 
asmlinkage long sys_shmget (key_t key, size_t size, int shmflag)
{
return -ENOSYS;
}
 
asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *addr)
{
return -ENOSYS;
}
 
asmlinkage long sys_shmdt (char *shmaddr)
{
return -ENOSYS;
}
 
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
return -ENOSYS;
}
 
#endif /* CONFIG_SYSVIPC */

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