Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  linux/fs/fcntl.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 */

#include <linux/syscalls.h>

#include <linux/init.h>

#include <linux/mm.h>

#include <linux/fs.h>

#include <linux/file.h>

#include <linux/capability.h>

#include <linux/dnotify.h>

#include <linux/smp_lock.h>

#include <linux/slab.h>

#include <linux/module.h>

#include <linux/security.h>

#include <linux/ptrace.h>

#include <linux/signal.h>

#include <linux/rcupdate.h>

#include <linux/pid_namespace.h>

#include <asm/poll.h>

#include <asm/siginfo.h>

#include <asm/uaccess.h>

void fastcall set_close_on_exec(unsigned int fd, int flag)

{

        struct files_struct *files = current->files;

        struct fdtable *fdt;

        spin_lock(&files->file_lock);

        fdt = files_fdtable(files);

        if (flag)

                FD_SET(fd, fdt->close_on_exec);

        else

                FD_CLR(fd, fdt->close_on_exec);

        spin_unlock(&files->file_lock);

}

static int get_close_on_exec(unsigned int fd)

{

        struct files_struct *files = current->files;

        struct fdtable *fdt;

        int res;

        rcu_read_lock();

        fdt = files_fdtable(files);

        res = FD_ISSET(fd, fdt->close_on_exec);

        rcu_read_unlock();

        return res;

}

/*

 * locate_fd finds a free file descriptor in the open_fds fdset,

 * expanding the fd arrays if necessary.  Must be called with the

 * file_lock held for write.

 */

static int locate_fd(struct files_struct *files,

                            struct file *file, unsigned int orig_start)

{

        unsigned int newfd;

        unsigned int start;

        int error;

        struct fdtable *fdt;

        error = -EINVAL;

        if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)

                goto out;

repeat:

        fdt = files_fdtable(files);

        /*

         * Someone might have closed fd's in the range

         * orig_start..fdt->next_fd

         */

        start = orig_start;

        if (start < files->next_fd)

                start = files->next_fd;

        newfd = start;

        if (start < fdt->max_fds)

                newfd = find_next_zero_bit(fdt->open_fds->fds_bits,

                                           fdt->max_fds, start);

        error = -EMFILE;

        if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)

                goto out;

        error = expand_files(files, newfd);

        if (error < 0)

                goto out;

        /*

         * If we needed to expand the fs array we

         * might have blocked - try again.

         */

        if (error)

                goto repeat;

        /*

         * We reacquired files_lock, so we are safe as long as

         * we reacquire the fdtable pointer and use it while holding

         * the lock, no one can free it during that time.

         */

        if (start <= files->next_fd)

                files->next_fd = newfd + 1;

        error = newfd;

out:

        return error;

}

static int dupfd(struct file *file, unsigned int start, int cloexec)

{

        struct files_struct * files = current->files;

        struct fdtable *fdt;

        int fd;

        spin_lock(&files->file_lock);

        fd = locate_fd(files, file, start);

        if (fd >= 0) {

                /* locate_fd() may have expanded fdtable, load the ptr */

                fdt = files_fdtable(files);

                FD_SET(fd, fdt->open_fds);

                if (cloexec)

                        FD_SET(fd, fdt->close_on_exec);

                else

                        FD_CLR(fd, fdt->close_on_exec);

                spin_unlock(&files->file_lock);

                fd_install(fd, file);

        } else {

                spin_unlock(&files->file_lock);

                fput(file);

        }

        return fd;

}

asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)

{

        int err = -EBADF;

        struct file * file, *tofree;

        struct files_struct * files = current->files;

        struct fdtable *fdt;

        spin_lock(&files->file_lock);

        if (!(file = fcheck(oldfd)))

                goto out_unlock;

        err = newfd;

        if (newfd == oldfd)

                goto out_unlock;

        err = -EBADF;

        if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)

                goto out_unlock;

        get_file(file);                 /* We are now finished with oldfd */

        err = expand_files(files, newfd);

        if (err < 0)

                goto out_fput;

        /* To avoid races with open() and dup(), we will mark the fd as

         * in-use in the open-file bitmap throughout the entire dup2()

         * process.  This is quite safe: do_close() uses the fd array

         * entry, not the bitmap, to decide what work needs to be

         * done.  --sct */

        /* Doesn't work. open() might be there first. --AV */

        /* Yes. It's a race. In user space. Nothing sane to do */

        err = -EBUSY;

        fdt = files_fdtable(files);

        tofree = fdt->fd[newfd];

        if (!tofree && FD_ISSET(newfd, fdt->open_fds))

                goto out_fput;

        rcu_assign_pointer(fdt->fd[newfd], file);

        FD_SET(newfd, fdt->open_fds);

        FD_CLR(newfd, fdt->close_on_exec);

        spin_unlock(&files->file_lock);

        if (tofree)

                filp_close(tofree, files);

        err = newfd;

out:

        return err;

out_unlock:

        spin_unlock(&files->file_lock);

        goto out;

out_fput:

        spin_unlock(&files->file_lock);

        fput(file);

        goto out;

}

asmlinkage long sys_dup(unsigned int fildes)

{

        int ret = -EBADF;

        struct file * file = fget(fildes);

        if (file)

                ret = dupfd(file, 0, 0);

        return ret;

}

#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME)

static int setfl(int fd, struct file * filp, unsigned long arg)

{

        struct inode * inode = filp->f_path.dentry->d_inode;

        int error = 0;

        /*

         * O_APPEND cannot be cleared if the file is marked as append-only

         * and the file is open for write.

         */

        if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))

                return -EPERM;

        /* O_NOATIME can only be set by the owner or superuser */

        if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))

                if (!is_owner_or_cap(inode))

                        return -EPERM;

        /* required for strict SunOS emulation */

        if (O_NONBLOCK != O_NDELAY)

               if (arg & O_NDELAY)

                   arg |= O_NONBLOCK;

        if (arg & O_DIRECT) {

                if (!filp->f_mapping || !filp->f_mapping->a_ops ||

                        !filp->f_mapping->a_ops->direct_IO)

                                return -EINVAL;

        }

        if (filp->f_op && filp->f_op->check_flags)

                error = filp->f_op->check_flags(arg);

        if (error)

                return error;

        lock_kernel();

        if ((arg ^ filp->f_flags) & FASYNC) {

                if (filp->f_op && filp->f_op->fasync) {

                        error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);

                        if (error < 0)

                                goto out;

                }

        }

        filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);

 out:

        unlock_kernel();

        return error;

}

static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,

                     uid_t uid, uid_t euid, int force)

{

        write_lock_irq(&filp->f_owner.lock);

        if (force || !filp->f_owner.pid) {

                put_pid(filp->f_owner.pid);

                filp->f_owner.pid = get_pid(pid);

                filp->f_owner.pid_type = type;

                filp->f_owner.uid = uid;

                filp->f_owner.euid = euid;

        }

        write_unlock_irq(&filp->f_owner.lock);

}

int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,

                int force)

{

        int err;

        err = security_file_set_fowner(filp);

        if (err)

                return err;

        f_modown(filp, pid, type, current->uid, current->euid, force);

        return 0;

}

EXPORT_SYMBOL(__f_setown);

int f_setown(struct file *filp, unsigned long arg, int force)

{

        enum pid_type type;

        struct pid *pid;

        int who = arg;

        int result;

        type = PIDTYPE_PID;

        if (who < 0) {

                type = PIDTYPE_PGID;

                who = -who;

        }

        rcu_read_lock();

        pid = find_vpid(who);

        result = __f_setown(filp, pid, type, force);

        rcu_read_unlock();

        return result;

}

EXPORT_SYMBOL(f_setown);

void f_delown(struct file *filp)

{

        f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);

}

pid_t f_getown(struct file *filp)

{

        pid_t pid;

        read_lock(&filp->f_owner.lock);

        pid = pid_nr_ns(filp->f_owner.pid, current->nsproxy->pid_ns);

        if (filp->f_owner.pid_type == PIDTYPE_PGID)

                pid = -pid;

        read_unlock(&filp->f_owner.lock);

        return pid;

}

static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,

                struct file *filp)

{

        long err = -EINVAL;

        switch (cmd) {

        case F_DUPFD:

        case F_DUPFD_CLOEXEC:

                get_file(filp);

                err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);

                break;

        case F_GETFD:

                err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;

                break;

        case F_SETFD:

                err = 0;

                set_close_on_exec(fd, arg & FD_CLOEXEC);

                break;

        case F_GETFL:

                err = filp->f_flags;

                break;

        case F_SETFL:

                err = setfl(fd, filp, arg);

                break;

        case F_GETLK:

                err = fcntl_getlk(filp, (struct flock __user *) arg);

                break;

        case F_SETLK:

        case F_SETLKW:

                err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);

                break;

        case F_GETOWN:

                /*

                 * XXX If f_owner is a process group, the

                 * negative return value will get converted

                 * into an error.  Oops.  If we keep the

                 * current syscall conventions, the only way

                 * to fix this will be in libc.

                 */

                err = f_getown(filp);

                force_successful_syscall_return();

                break;

        case F_SETOWN:

                err = f_setown(filp, arg, 1);

                break;

        case F_GETSIG:

                err = filp->f_owner.signum;

                break;

        case F_SETSIG:

                /* arg == 0 restores default behaviour. */

                if (!valid_signal(arg)) {

                        break;

                }

                err = 0;

                filp->f_owner.signum = arg;

                break;

        case F_GETLEASE:

                err = fcntl_getlease(filp);

                break;

        case F_SETLEASE:

                err = fcntl_setlease(fd, filp, arg);

                break;

        case F_NOTIFY:

                err = fcntl_dirnotify(fd, filp, arg);

                break;

        default:

                break;

        }

        return err;

}

asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)

{

        struct file *filp;

        long err = -EBADF;

        filp = fget(fd);

        if (!filp)

                goto out;

        err = security_file_fcntl(filp, cmd, arg);

        if (err) {

                fput(filp);

                return err;

        }

        err = do_fcntl(fd, cmd, arg, filp);

        fput(filp);

out:

        return err;

}

#if BITS_PER_LONG == 32

asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)

{

        struct file * filp;

        long err;

        err = -EBADF;

        filp = fget(fd);

        if (!filp)

                goto out;

        err = security_file_fcntl(filp, cmd, arg);

        if (err) {

                fput(filp);

                return err;

        }

        err = -EBADF;

        switch (cmd) {

                case F_GETLK64:

                        err = fcntl_getlk64(filp, (struct flock64 __user *) arg);

                        break;

                case F_SETLK64:

                case F_SETLKW64:

                        err = fcntl_setlk64(fd, filp, cmd,

                                        (struct flock64 __user *) arg);

                        break;

                default:

                        err = do_fcntl(fd, cmd, arg, filp);

                        break;

        }

        fput(filp);

out:

        return err;

}

#endif

/* Table to convert sigio signal codes into poll band bitmaps */

static const long band_table[NSIGPOLL] = {

        POLLIN | POLLRDNORM,                    /* POLL_IN */

        POLLOUT | POLLWRNORM | POLLWRBAND,      /* POLL_OUT */

        POLLIN | POLLRDNORM | POLLMSG,          /* POLL_MSG */

        POLLERR,                                /* POLL_ERR */

        POLLPRI | POLLRDBAND,                   /* POLL_PRI */

        POLLHUP | POLLERR                       /* POLL_HUP */

};

static inline int sigio_perm(struct task_struct *p,

                             struct fown_struct *fown, int sig)

{

        return (((fown->euid == 0) ||

                 (fown->euid == p->suid) || (fown->euid == p->uid) ||

                 (fown->uid == p->suid) || (fown->uid == p->uid)) &&

                !security_file_send_sigiotask(p, fown, sig));

}

static void send_sigio_to_task(struct task_struct *p,

                               struct fown_struct *fown,

                               int fd,

                               int reason)

{

        if (!sigio_perm(p, fown, fown->signum))

                return;

        switch (fown->signum) {

                siginfo_t si;

                default:

                        /* Queue a rt signal with the appropriate fd as its

                           value.  We use SI_SIGIO as the source, not

                           SI_KERNEL, since kernel signals always get

                           delivered even if we can't queue.  Failure to

                           queue in this case _should_ be reported; we fall

                           back to SIGIO in that case. --sct */

                        si.si_signo = fown->signum;

                        si.si_errno = 0;

                        si.si_code  = reason;

                        /* Make sure we are called with one of the POLL_*

                           reasons, otherwise we could leak kernel stack into

                           userspace.  */

                        BUG_ON((reason & __SI_MASK) != __SI_POLL);

                        if (reason - POLL_IN >= NSIGPOLL)

                                si.si_band  = ~0L;

                        else

                                si.si_band = band_table[reason - POLL_IN];

                        si.si_fd    = fd;

                        if (!group_send_sig_info(fown->signum, &si, p))

                                break;

                /* fall-through: fall back on the old plain SIGIO signal */

                case 0:

                        group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);

        }

}

void send_sigio(struct fown_struct *fown, int fd, int band)

{

        struct task_struct *p;

        enum pid_type type;

        struct pid *pid;

        read_lock(&fown->lock);

        type = fown->pid_type;

        pid = fown->pid;

        if (!pid)

                goto out_unlock_fown;

        read_lock(&tasklist_lock);

        do_each_pid_task(pid, type, p) {

                send_sigio_to_task(p, fown, fd, band);

        } while_each_pid_task(pid, type, p);

        read_unlock(&tasklist_lock);

 out_unlock_fown:

        read_unlock(&fown->lock);

}

static void send_sigurg_to_task(struct task_struct *p,

                                struct fown_struct *fown)

{

        if (sigio_perm(p, fown, SIGURG))

                group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);

}

int send_sigurg(struct fown_struct *fown)

{

        struct task_struct *p;

        enum pid_type type;

        struct pid *pid;

        int ret = 0;

        read_lock(&fown->lock);

        type = fown->pid_type;

        pid = fown->pid;

        if (!pid)

                goto out_unlock_fown;

        ret = 1;

        read_lock(&tasklist_lock);

        do_each_pid_task(pid, type, p) {

                send_sigurg_to_task(p, fown);

        } while_each_pid_task(pid, type, p);

        read_unlock(&tasklist_lock);

 out_unlock_fown:

        read_unlock(&fown->lock);

        return ret;

}

static DEFINE_RWLOCK(fasync_lock);

static struct kmem_cache *fasync_cache __read_mostly;

/*

 * fasync_helper() is used by some character device drivers (mainly mice)

 * to set up the fasync queue. It returns negative on error, 0 if it did

 * no changes and positive if it added/deleted the entry.

 */

int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)

{

        struct fasync_struct *fa, **fp;

        struct fasync_struct *new = NULL;

        int result = 0;

        if (on) {

                new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);

                if (!new)

                        return -ENOMEM;

        }

        write_lock_irq(&fasync_lock);

        for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {

                if (fa->fa_file == filp) {

                        if(on) {

                                fa->fa_fd = fd;

                                kmem_cache_free(fasync_cache, new);

                        } else {

                                *fp = fa->fa_next;

                                kmem_cache_free(fasync_cache, fa);

                                result = 1;

                        }

                        goto out;

                }

        }

        if (on) {

                new->magic = FASYNC_MAGIC;

                new->fa_file = filp;

                new->fa_fd = fd;

                new->fa_next = *fapp;

                *fapp = new;

                result = 1;

        }

out:

        write_unlock_irq(&fasync_lock);

        return result;

}

EXPORT_SYMBOL(fasync_helper);

void __kill_fasync(struct fasync_struct *fa, int sig, int band)

{

        while (fa) {

                struct fown_struct * fown;

                if (fa->magic != FASYNC_MAGIC) {

                        printk(KERN_ERR "kill_fasync: bad magic number in "

                               "fasync_struct!\n");

                        return;

                }

                fown = &fa->fa_file->f_owner;

                /* Don't send SIGURG to processes which have not set a

                   queued signum: SIGURG has its own default signalling

                   mechanism. */

                if (!(sig == SIGURG && fown->signum == 0))

                        send_sigio(fown, fa->fa_fd, band);

                fa = fa->fa_next;

        }

}

EXPORT_SYMBOL(__kill_fasync);

void kill_fasync(struct fasync_struct **fp, int sig, int band)

{

        /* First a quick test without locking: usually

         * the list is empty.

         */

        if (*fp) {

                read_lock(&fasync_lock);

                /* reread *fp after obtaining the lock */

                __kill_fasync(*fp, sig, band);

                read_unlock(&fasync_lock);

        }

}

EXPORT_SYMBOL(kill_fasync);

static int __init fasync_init(void)

{

        fasync_cache = kmem_cache_create("fasync_cache",

                sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);

        return 0;

}

module_init(fasync_init)