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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [mips/] [kernel/] [ptrace.c] - Blame information for rev 1782

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/* ptrace.c */
/* By Ross Biro 1/23/92 */
/* edited by Linus Torvalds */
 
#include <linux/head.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
 
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/system.h>
 
#if 0
/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */
 
/* determines which flags the user has access to. */
/* 1 = access 0 = no access */
#define FLAG_MASK 0x00044dd5
 
/* set's the trap flag. */
#define TRAP_FLAG 0x100
 
/*
 * this is the number to subtract from the top of the stack. To find
 * the local frame.
 */
#define MAGICNUMBER 68
 
/* change a pid into a task struct. */
static inline struct task_struct * get_task(int pid)
{
        int i;
 
        for (i = 1; i < NR_TASKS; i++) {
                if (task[i] != NULL && (task[i]->pid == pid))
                        return task[i];
        }
        return NULL;
}
 
/*
 * this routine will get a word off of the processes privileged stack.
 * the offset is how far from the base addr as stored in the TSS.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline int get_stack_long(struct task_struct *task, int offset)
{
        unsigned char *stack;
 
        stack = (unsigned char *)task->tss.esp0;
        stack += offset;
        return (*((int *)stack));
}
 
/*
 * this routine will put a word on the processes privileged stack.
 * the offset is how far from the base addr as stored in the TSS.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline int put_stack_long(struct task_struct *task, int offset,
        unsigned long data)
{
        unsigned char * stack;
 
        stack = (unsigned char *) task->tss.esp0;
        stack += offset;
        *(unsigned long *) stack = data;
        return 0;
}
 
/*
 * This routine gets a long from any process space by following the page
 * tables. NOTE! You should check that the long isn't on a page boundary,
 * and that it is in the task area before calling this: this routine does
 * no checking.
 */
static unsigned long get_long(struct vm_area_struct * vma, unsigned long addr)
{
        pgd_t * pgdir;
        pte_t * pgtable;
        unsigned long page;
 
repeat:
        pgdir = PAGE_DIR_OFFSET(vma->vm_mm, addr);
        if (pgd_none(*pgdir)) {
                do_no_page(vma, addr, 0);
                goto repeat;
        }
        if (pgd_bad(*pgdir)) {
                printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
                pgd_clear(pgdir);
                return 0;
        }
        pgtable = (pte_t *) (PAGE_PTR(addr) + pgd_page(*pgdir));
        if (!pte_present(*pgtable)) {
                do_no_page(vma, addr, 0);
                goto repeat;
        }
        page = pte_page(*pgtable);
/* this is a hack for non-kernel-mapped video buffers and similar */
        if (page >= high_memory)
                return 0;
        page += addr & ~PAGE_MASK;
        return *(unsigned long *) page;
}
 
/*
 * This routine puts a long into any process space by following the page
 * tables. NOTE! You should check that the long isn't on a page boundary,
 * and that it is in the task area before calling this: this routine does
 * no checking.
 *
 * Now keeps R/W state of page so that a text page stays readonly
 * even if a debugger scribbles breakpoints into it.  -M.U-
 */
static void put_long(struct vm_area_struct * vma, unsigned long addr,
        unsigned long data)
{
        pgd_t *pgdir;
        pte_t *pgtable;
        unsigned long page;
 
repeat:
        pgdir = PAGE_DIR_OFFSET(vma->vm_mm, addr);
        if (!pgd_present(*pgdir)) {
                do_no_page(vma, addr, 1);
                goto repeat;
        }
        if (pgd_bad(*pgdir)) {
                printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
                pgd_clear(pgdir);
                return;
        }
        pgtable = (pte_t *) (PAGE_PTR(addr) + pgd_page(*pgdir));
        if (!pte_present(*pgtable)) {
                do_no_page(vma, addr, 1);
                goto repeat;
        }
        page = pte_page(*pgtable);
        if (!pte_write(*pgtable)) {
                do_wp_page(vma, addr, 1);
                goto repeat;
        }
/* this is a hack for non-kernel-mapped video buffers and similar */
        if (page < high_memory)
                *(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
/* this should also re-instate whatever read-only mode there was before */
        set_pte(pgtable, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
        invalidate();
}
 
static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)
{
        struct vm_area_struct * vma;
 
        addr &= PAGE_MASK;
        vma = find_vma(tsk, addr);
        if (!vma)
                return NULL;
        if (vma->vm_start <= addr)
                return vma;
        if (!(vma->vm_flags & VM_GROWSDOWN))
                return NULL;
        if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)
                return NULL;
        vma->vm_offset -= vma->vm_start - addr;
        vma->vm_start = addr;
        return vma;
}
 
/*
 * This routine checks the page boundaries, and that the offset is
 * within the task area. It then calls get_long() to read a long.
 */
static int read_long(struct task_struct * tsk, unsigned long addr,
        unsigned long * result)
{
        struct vm_area_struct * vma = find_extend_vma(tsk, addr);
 
        if (!vma)
                return -EIO;
        if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
                unsigned long low,high;
                struct vm_area_struct * vma_high = vma;
 
                if (addr + sizeof(long) >= vma->vm_end) {
                        vma_high = vma->vm_next;
                        if (!vma_high || vma_high->vm_start != vma->vm_end)
                                return -EIO;
                }
                low = get_long(vma, addr & ~(sizeof(long)-1));
                high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));
                switch (addr & (sizeof(long)-1)) {
                        case 1:
                                low >>= 8;
                                low |= high << 24;
                                break;
                        case 2:
                                low >>= 16;
                                low |= high << 16;
                                break;
                        case 3:
                                low >>= 24;
                                low |= high << 8;
                                break;
                }
                *result = low;
        } else
                *result = get_long(vma, addr);
        return 0;
}
 
/*
 * This routine checks the page boundaries, and that the offset is
 * within the task area. It then calls put_long() to write a long.
 */
static int write_long(struct task_struct * tsk, unsigned long addr,
        unsigned long data)
{
        struct vm_area_struct * vma = find_extend_vma(tsk, addr);
 
        if (!vma)
                return -EIO;
        if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
                unsigned long low,high;
                struct vm_area_struct * vma_high = vma;
 
                if (addr + sizeof(long) >= vma->vm_end) {
                        vma_high = vma->vm_next;
                        if (!vma_high || vma_high->vm_start != vma->vm_end)
                                return -EIO;
                }
                low = get_long(vma, addr & ~(sizeof(long)-1));
                high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));
                switch (addr & (sizeof(long)-1)) {
                        case 0: /* shouldn't happen, but safety first */
                                low = data;
                                break;
                        case 1:
                                low &= 0x000000ff;
                                low |= data << 8;
                                high &= ~0xff;
                                high |= data >> 24;
                                break;
                        case 2:
                                low &= 0x0000ffff;
                                low |= data << 16;
                                high &= ~0xffff;
                                high |= data >> 16;
                                break;
                        case 3:
                                low &= 0x00ffffff;
                                low |= data << 24;
                                high &= ~0xffffff;
                                high |= data >> 8;
                                break;
                }
                put_long(vma, addr & ~(sizeof(long)-1),low);
                put_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1),high);
        } else
                put_long(vma, addr, data);
        return 0;
}
#endif
 
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
#if 1
        return -ENOSYS;
#else
        struct task_struct *child;
        struct user * dummy;
        int i;
 
 
        dummy = NULL;
 
        if (request == PTRACE_TRACEME) {
                /* are we already being traced? */
                if (current->flags & PF_PTRACED)
                        return -EPERM;
                /* set the ptrace bit in the process flags. */
                current->flags |= PF_PTRACED;
                return 0;
        }
        if (pid == 1)           /* you may not mess with init */
                return -EPERM;
        if (!(child = get_task(pid)))
                return -ESRCH;
        if (request == PTRACE_ATTACH) {
                if (child == current)
                        return -EPERM;
                if ((!child->dumpable ||
                    (current->uid != child->euid) ||
                    (current->uid != child->uid) ||
                    (current->gid != child->egid) ||
                    (current->gid != child->gid)) && !suser())
                        return -EPERM;
                /* the same process cannot be attached many times */
                if (child->flags & PF_PTRACED)
                        return -EPERM;
                child->flags |= PF_PTRACED;
                if (child->p_pptr != current) {
                        REMOVE_LINKS(child);
                        child->p_pptr = current;
                        SET_LINKS(child);
                }
                send_sig(SIGSTOP, child, 1);
                return 0;
        }
        if (!(child->flags & PF_PTRACED))
                return -ESRCH;
        if (child->state != TASK_STOPPED) {
                if (request != PTRACE_KILL)
                        return -ESRCH;
        }
        if (child->p_pptr != current)
                return -ESRCH;
 
        switch (request) {
        /* when I and D space are separate, these will need to be fixed. */
                case PTRACE_PEEKTEXT: /* read word at location addr. */
                case PTRACE_PEEKDATA: {
                        unsigned long tmp;
                        int res;
 
                        res = read_long(child, addr, &tmp);
                        if (res < 0)
                                return res;
                        res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
                        if (!res)
                                put_fs_long(tmp,(unsigned long *) data);
                        return res;
                }
 
        /* read the word at location addr in the USER area. */
                case PTRACE_PEEKUSR: {
                        unsigned long tmp;
                        int res;
 
                        if ((addr & 3) || addr < 0 ||
                            addr > sizeof(struct user) - 3)
                                return -EIO;
 
                        res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
                        if (res)
                                return res;
                        tmp = 0;  /* Default return condition */
                        if(addr < 17*sizeof(long)) {
                          addr = addr >> 2; /* temporary hack. */
 
                          tmp = get_stack_long(child, sizeof(long)*addr - MAGICNUMBER);
                          if (addr == DS || addr == ES ||
                              addr == FS || addr == GS ||
                              addr == CS || addr == SS)
                            tmp &= 0xffff;
                        };
                        if(addr >= (long) &dummy->u_debugreg[0] &&
                           addr <= (long) &dummy->u_debugreg[7]){
                                addr -= (long) &dummy->u_debugreg[0];
                                addr = addr >> 2;
                                tmp = child->debugreg[addr];
                        };
                        put_fs_long(tmp,(unsigned long *) data);
                        return 0;
                }
 
      /* when I and D space are separate, this will have to be fixed. */
                case PTRACE_POKETEXT: /* write the word at location addr. */
                case PTRACE_POKEDATA:
                        return write_long(child,addr,data);
 
                case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
                        if ((addr & 3) || addr < 0 ||
                            addr > sizeof(struct user) - 3)
                                return -EIO;
 
                        addr = addr >> 2; /* temporary hack. */
 
                        if (addr == ORIG_EAX)
                                return -EIO;
                        if (addr == DS || addr == ES ||
                            addr == FS || addr == GS ||
                            addr == CS || addr == SS) {
                                data &= 0xffff;
                                if (data && (data & 3) != 3)
                                        return -EIO;
                        }
                        if (addr == EFL) {   /* flags. */
                                data &= FLAG_MASK;
                                data |= get_stack_long(child, EFL*sizeof(long)-MAGICNUMBER)  & ~FLAG_MASK;
                        }
                  /* Do not allow the user to set the debug register for kernel
                     address space */
                  if(addr < 17){
                          if (put_stack_long(child, sizeof(long)*addr-MAGICNUMBER, data))
                                return -EIO;
                        return 0;
                        };
 
                  /* We need to be very careful here.  We implicitly
                     want to modify a portion of the task_struct, and we
                     have to be selective about what portions we allow someone
                     to modify. */
 
                  addr = addr << 2;  /* Convert back again */
                  if(addr >= (long) &dummy->u_debugreg[0] &&
                     addr <= (long) &dummy->u_debugreg[7]){
 
                          if(addr == (long) &dummy->u_debugreg[4]) return -EIO;
                          if(addr == (long) &dummy->u_debugreg[5]) return -EIO;
                          if(addr < (long) &dummy->u_debugreg[4] &&
                             ((unsigned long) data) >= 0xbffffffd) return -EIO;
 
                          if(addr == (long) &dummy->u_debugreg[7]) {
                                  data &= ~DR_CONTROL_RESERVED;
                                  for(i=0; i<4; i++)
                                          if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
                                                  return -EIO;
                          };
 
                          addr -= (long) &dummy->u_debugreg;
                          addr = addr >> 2;
                          child->debugreg[addr] = data;
                          return 0;
                  };
                  return -EIO;
 
                case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
                case PTRACE_CONT: { /* restart after signal. */
                        long tmp;
 
                        if ((unsigned long) data > NSIG)
                                return -EIO;
                        if (request == PTRACE_SYSCALL)
                                child->flags |= PF_TRACESYS;
                        else
                                child->flags &= ~PF_TRACESYS;
                        child->exit_code = data;
                        wake_up_process(child);
        /* make sure the single step bit is not set. */
                        tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
                        put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
                        return 0;
                }
 
/*
 * make the child exit.  Best I can do is send it a sigkill.
 * perhaps it should be put in the status that it wants to
 * exit.
 */
                case PTRACE_KILL: {
                        long tmp;
 
                        if (child->state == TASK_ZOMBIE)        /* already dead */
                                return 0;
                        wake_up_process(child);
                        child->exit_code = SIGKILL;
        /* make sure the single step bit is not set. */
                        tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
                        put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
                        return 0;
                }
 
                case PTRACE_SINGLESTEP: {  /* set the trap flag. */
                        long tmp;
 
                        if ((unsigned long) data > NSIG)
                                return -EIO;
                        child->flags &= ~PF_TRACESYS;
                        tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) | TRAP_FLAG;
                        put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
                        wake_up_process(child);
                        child->exit_code = data;
        /* give it a chance to run. */
                        return 0;
                }
 
                case PTRACE_DETACH: { /* detach a process that was attached. */
                        long tmp;
 
                        if ((unsigned long) data > NSIG)
                                return -EIO;
                        child->flags &= ~(PF_PTRACED|PF_TRACESYS);
                        wake_up_process(child);
                        child->exit_code = data;
                        REMOVE_LINKS(child);
                        child->p_pptr = child->p_opptr;
                        SET_LINKS(child);
                        /* make sure the single step bit is not set. */
                        tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;
                        put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);
                        return 0;
                }
 
                default:
                        return -EIO;
        }
#endif
}
 
asmlinkage void syscall_trace(void)
{
        if ((current->flags & (PF_PTRACED|PF_TRACESYS))
                        != (PF_PTRACED|PF_TRACESYS))
                return;
        current->exit_code = SIGTRAP;
        current->state = TASK_STOPPED;
        notify_parent(current);
        schedule();
        /*
         * this isn't the same as continuing with a signal, but it will do
         * for normal use.  strace only continues with a signal if the
         * stopping signal is not SIGTRAP.  -brl
         */
        if (current->exit_code)
                current->signal |= (1 << (current->exit_code - 1));
        current->exit_code = 0;
}

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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [mips/] [kernel/] [ptrace.c] - Blame information for rev 1782

Line No.	Rev	Author	Line
1	1624	jcastillo	`/* ptrace.c */`
2			`/* By Ross Biro 1/23/92 */`
3			`/* edited by Linus Torvalds */`
4
5			`#include <linux/head.h>`
6			`#include <linux/kernel.h>`
7			`#include <linux/sched.h>`
8			`#include <linux/mm.h>`
9			`#include <linux/errno.h>`
10			`#include <linux/ptrace.h>`
11			`#include <linux/user.h>`
12
13			`#include <asm/segment.h>`
14			`#include <asm/pgtable.h>`
15			`#include <asm/system.h>`
16
17			`#if 0`
18			`/*`
19			`* does not yet catch signals sent when the child dies.`
20			`* in exit.c or in signal.c.`
21			`*/`
22
23			`/* determines which flags the user has access to. */`
24			`/* 1 = access 0 = no access */`
25			`#define FLAG_MASK 0x00044dd5`
26
27			`/* set's the trap flag. */`
28			`#define TRAP_FLAG 0x100`
29
30			`/*`
31			`* this is the number to subtract from the top of the stack. To find`
32			`* the local frame.`
33			`*/`
34			`#define MAGICNUMBER 68`
35
36			`/* change a pid into a task struct. */`
37			`static inline struct task_struct * get_task(int pid)`
38			`{`
39			`int i;`
40
41			`for (i = 1; i < NR_TASKS; i++) {`
42			`if (task[i] != NULL && (task[i]->pid == pid))`
43			`return task[i];`
44			`}`
45			`return NULL;`
46			`}`
47
48			`/*`
49			`* this routine will get a word off of the processes privileged stack.`
50			`* the offset is how far from the base addr as stored in the TSS.`
51			`* this routine assumes that all the privileged stacks are in our`
52			`* data space.`
53			`*/`
54			`static inline int get_stack_long(struct task_struct *task, int offset)`
55			`{`
56			`unsigned char *stack;`
57
58			`stack = (unsigned char *)task->tss.esp0;`
59			`stack += offset;`
60			`return (((int )stack));`
61			`}`
62
63			`/*`
64			`* this routine will put a word on the processes privileged stack.`
65			`* the offset is how far from the base addr as stored in the TSS.`
66			`* this routine assumes that all the privileged stacks are in our`
67			`* data space.`
68			`*/`
69			`static inline int put_stack_long(struct task_struct *task, int offset,`
70			`unsigned long data)`
71			`{`
72			`unsigned char * stack;`
73
74			`stack = (unsigned char *) task->tss.esp0;`
75			`stack += offset;`
76			`(unsigned long ) stack = data;`
77			`return 0;`
78			`}`
79
80			`/*`
81			`* This routine gets a long from any process space by following the page`
82			`* tables. NOTE! You should check that the long isn't on a page boundary,`
83			`* and that it is in the task area before calling this: this routine does`
84			`* no checking.`
85			`*/`
86			`static unsigned long get_long(struct vm_area_struct * vma, unsigned long addr)`
87			`{`
88			`pgd_t * pgdir;`
89			`pte_t * pgtable;`
90			`unsigned long page;`
91
92			`repeat:`
93			`pgdir = PAGE_DIR_OFFSET(vma->vm_mm, addr);`
94			`if (pgd_none(*pgdir)) {`
95			`do_no_page(vma, addr, 0);`
96			`goto repeat;`
97			`}`
98			`if (pgd_bad(*pgdir)) {`
99			`printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));`
100			`pgd_clear(pgdir);`
101			`return 0;`
102			`}`
103			`pgtable = (pte_t ) (PAGE_PTR(addr) + pgd_page(pgdir));`
104			`if (!pte_present(*pgtable)) {`
105			`do_no_page(vma, addr, 0);`
106			`goto repeat;`
107			`}`
108			`page = pte_page(*pgtable);`
109			`/* this is a hack for non-kernel-mapped video buffers and similar */`
110			`if (page >= high_memory)`
111			`return 0;`
112			`page += addr & ~PAGE_MASK;`
113			`return (unsigned long ) page;`
114			`}`
115
116			`/*`
117			`* This routine puts a long into any process space by following the page`
118			`* tables. NOTE! You should check that the long isn't on a page boundary,`
119			`* and that it is in the task area before calling this: this routine does`
120			`* no checking.`
121			`*`
122			`* Now keeps R/W state of page so that a text page stays readonly`
123			`* even if a debugger scribbles breakpoints into it. -M.U-`
124			`*/`
125			`static void put_long(struct vm_area_struct * vma, unsigned long addr,`
126			`unsigned long data)`
127			`{`
128			`pgd_t *pgdir;`
129			`pte_t *pgtable;`
130			`unsigned long page;`
131
132			`repeat:`
133			`pgdir = PAGE_DIR_OFFSET(vma->vm_mm, addr);`
134			`if (!pgd_present(*pgdir)) {`
135			`do_no_page(vma, addr, 1);`
136			`goto repeat;`
137			`}`
138			`if (pgd_bad(*pgdir)) {`
139			`printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));`
140			`pgd_clear(pgdir);`
141			`return;`
142			`}`
143			`pgtable = (pte_t ) (PAGE_PTR(addr) + pgd_page(pgdir));`
144			`if (!pte_present(*pgtable)) {`
145			`do_no_page(vma, addr, 1);`
146			`goto repeat;`
147			`}`
148			`page = pte_page(*pgtable);`
149			`if (!pte_write(*pgtable)) {`
150			`do_wp_page(vma, addr, 1);`
151			`goto repeat;`
152			`}`
153			`/* this is a hack for non-kernel-mapped video buffers and similar */`
154			`if (page < high_memory)`
155			`(unsigned long ) (page + (addr & ~PAGE_MASK)) = data;`
156			`/* we're bypassing pagetables, so we have to set the dirty bit ourselves */`
157			`/* this should also re-instate whatever read-only mode there was before */`
158			`set_pte(pgtable, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));`
159			`invalidate();`
160			`}`
161
162			`static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)`
163			`{`
164			`struct vm_area_struct * vma;`
165
166			`addr &= PAGE_MASK;`
167			`vma = find_vma(tsk, addr);`
168			`if (!vma)`
169			`return NULL;`
170			`if (vma->vm_start <= addr)`
171			`return vma;`
172			`if (!(vma->vm_flags & VM_GROWSDOWN))`
173			`return NULL;`
174			`if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)`
175			`return NULL;`
176			`vma->vm_offset -= vma->vm_start - addr;`
177			`vma->vm_start = addr;`
178			`return vma;`
179			`}`
180
181			`/*`
182			`* This routine checks the page boundaries, and that the offset is`
183			`* within the task area. It then calls get_long() to read a long.`
184			`*/`
185			`static int read_long(struct task_struct * tsk, unsigned long addr,`
186			`unsigned long * result)`
187			`{`
188			`struct vm_area_struct * vma = find_extend_vma(tsk, addr);`
189
190			`if (!vma)`
191			`return -EIO;`
192			`if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {`
193			`unsigned long low,high;`
194			`struct vm_area_struct * vma_high = vma;`
195
196			`if (addr + sizeof(long) >= vma->vm_end) {`
197			`vma_high = vma->vm_next;`
198			`if (!vma_high \|\| vma_high->vm_start != vma->vm_end)`
199			`return -EIO;`
200			`}`
201			`low = get_long(vma, addr & ~(sizeof(long)-1));`
202			`high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));`
203			`switch (addr & (sizeof(long)-1)) {`
204			`case 1:`
205			`low >>= 8;`
206			`low \|= high << 24;`
207			`break;`
208			`case 2:`
209			`low >>= 16;`
210			`low \|= high << 16;`
211			`break;`
212			`case 3:`
213			`low >>= 24;`
214			`low \|= high << 8;`
215			`break;`
216			`}`
217			`*result = low;`
218			`} else`
219			`*result = get_long(vma, addr);`
220			`return 0;`
221			`}`
222
223			`/*`
224			`* This routine checks the page boundaries, and that the offset is`
225			`* within the task area. It then calls put_long() to write a long.`
226			`*/`
227			`static int write_long(struct task_struct * tsk, unsigned long addr,`
228			`unsigned long data)`
229			`{`
230			`struct vm_area_struct * vma = find_extend_vma(tsk, addr);`
231
232			`if (!vma)`
233			`return -EIO;`
234			`if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {`
235			`unsigned long low,high;`
236			`struct vm_area_struct * vma_high = vma;`
237
238			`if (addr + sizeof(long) >= vma->vm_end) {`
239			`vma_high = vma->vm_next;`
240			`if (!vma_high \|\| vma_high->vm_start != vma->vm_end)`
241			`return -EIO;`
242			`}`
243			`low = get_long(vma, addr & ~(sizeof(long)-1));`
244			`high = get_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1));`
245			`switch (addr & (sizeof(long)-1)) {`
246			`case 0: /* shouldn't happen, but safety first */`
247			`low = data;`
248			`break;`
249			`case 1:`
250			`low &= 0x000000ff;`
251			`low \|= data << 8;`
252			`high &= ~0xff;`
253			`high \|= data >> 24;`
254			`break;`
255			`case 2:`
256			`low &= 0x0000ffff;`
257			`low \|= data << 16;`
258			`high &= ~0xffff;`
259			`high \|= data >> 16;`
260			`break;`
261			`case 3:`
262			`low &= 0x00ffffff;`
263			`low \|= data << 24;`
264			`high &= ~0xffffff;`
265			`high \|= data >> 8;`
266			`break;`
267			`}`
268			`put_long(vma, addr & ~(sizeof(long)-1),low);`
269			`put_long(vma_high, (addr+sizeof(long)) & ~(sizeof(long)-1),high);`
270			`} else`
271			`put_long(vma, addr, data);`
272			`return 0;`
273			`}`
274			`#endif`
275
276			`asmlinkage int sys_ptrace(long request, long pid, long addr, long data)`
277			`{`
278			`#if 1`
279			`return -ENOSYS;`
280			`#else`
281			`struct task_struct *child;`
282			`struct user * dummy;`
283			`int i;`
284
285
286			`dummy = NULL;`
287
288			`if (request == PTRACE_TRACEME) {`
289			`/* are we already being traced? */`
290			`if (current->flags & PF_PTRACED)`
291			`return -EPERM;`
292			`/* set the ptrace bit in the process flags. */`
293			`current->flags \|= PF_PTRACED;`
294			`return 0;`
295			`}`
296			`if (pid == 1) /* you may not mess with init */`
297			`return -EPERM;`
298			`if (!(child = get_task(pid)))`
299			`return -ESRCH;`
300			`if (request == PTRACE_ATTACH) {`
301			`if (child == current)`
302			`return -EPERM;`
303			`if ((!child->dumpable \|\|`
304			`(current->uid != child->euid) \|\|`
305			`(current->uid != child->uid) \|\|`
306			`(current->gid != child->egid) \|\|`
307			`(current->gid != child->gid)) && !suser())`
308			`return -EPERM;`
309			`/* the same process cannot be attached many times */`
310			`if (child->flags & PF_PTRACED)`
311			`return -EPERM;`
312			`child->flags \|= PF_PTRACED;`
313			`if (child->p_pptr != current) {`
314			`REMOVE_LINKS(child);`
315			`child->p_pptr = current;`
316			`SET_LINKS(child);`
317			`}`
318			`send_sig(SIGSTOP, child, 1);`
319			`return 0;`
320			`}`
321			`if (!(child->flags & PF_PTRACED))`
322			`return -ESRCH;`
323			`if (child->state != TASK_STOPPED) {`
324			`if (request != PTRACE_KILL)`
325			`return -ESRCH;`
326			`}`
327			`if (child->p_pptr != current)`
328			`return -ESRCH;`
329
330			`switch (request) {`
331			`/* when I and D space are separate, these will need to be fixed. */`
332			`case PTRACE_PEEKTEXT: /* read word at location addr. */`
333			`case PTRACE_PEEKDATA: {`
334			`unsigned long tmp;`
335			`int res;`
336
337			`res = read_long(child, addr, &tmp);`
338			`if (res < 0)`
339			`return res;`
340			`res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));`
341			`if (!res)`
342			`put_fs_long(tmp,(unsigned long *) data);`
343			`return res;`
344			`}`
345
346			`/* read the word at location addr in the USER area. */`
347			`case PTRACE_PEEKUSR: {`
348			`unsigned long tmp;`
349			`int res;`
350
351			`if ((addr & 3) \|\| addr < 0 \|\|`
352			`addr > sizeof(struct user) - 3)`
353			`return -EIO;`
354
355			`res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));`
356			`if (res)`
357			`return res;`
358			`tmp = 0; /* Default return condition */`
359			`if(addr < 17*sizeof(long)) {`
360			`addr = addr >> 2; /* temporary hack. */`
361
362			`tmp = get_stack_long(child, sizeof(long)*addr - MAGICNUMBER);`
363			`if (addr == DS \|\| addr == ES \|\|`
364			`addr == FS \|\| addr == GS \|\|`
365			`addr == CS \|\| addr == SS)`
366			`tmp &= 0xffff;`
367			`};`
368			`if(addr >= (long) &dummy->u_debugreg[0] &&`
369			`addr <= (long) &dummy->u_debugreg[7]){`
370			`addr -= (long) &dummy->u_debugreg[0];`
371			`addr = addr >> 2;`
372			`tmp = child->debugreg[addr];`
373			`};`
374			`put_fs_long(tmp,(unsigned long *) data);`
375			`return 0;`
376			`}`
377
378			`/* when I and D space are separate, this will have to be fixed. */`
379			`case PTRACE_POKETEXT: /* write the word at location addr. */`
380			`case PTRACE_POKEDATA:`
381			`return write_long(child,addr,data);`
382
383			`case PTRACE_POKEUSR: /* write the word at location addr in the USER area */`
384			`if ((addr & 3) \|\| addr < 0 \|\|`
385			`addr > sizeof(struct user) - 3)`
386			`return -EIO;`
387
388			`addr = addr >> 2; /* temporary hack. */`
389
390			`if (addr == ORIG_EAX)`
391			`return -EIO;`
392			`if (addr == DS \|\| addr == ES \|\|`
393			`addr == FS \|\| addr == GS \|\|`
394			`addr == CS \|\| addr == SS) {`
395			`data &= 0xffff;`
396			`if (data && (data & 3) != 3)`
397			`return -EIO;`
398			`}`
399			`if (addr == EFL) { /* flags. */`
400			`data &= FLAG_MASK;`
401			`data \|= get_stack_long(child, EFL*sizeof(long)-MAGICNUMBER) & ~FLAG_MASK;`
402			`}`
403			`/* Do not allow the user to set the debug register for kernel`
404			`address space */`
405			`if(addr < 17){`
406			`if (put_stack_long(child, sizeof(long)*addr-MAGICNUMBER, data))`
407			`return -EIO;`
408			`return 0;`
409			`};`
410
411			`/* We need to be very careful here. We implicitly`
412			`want to modify a portion of the task_struct, and we`
413			`have to be selective about what portions we allow someone`
414			`to modify. */`
415
416			`addr = addr << 2; /* Convert back again */`
417			`if(addr >= (long) &dummy->u_debugreg[0] &&`
418			`addr <= (long) &dummy->u_debugreg[7]){`
419
420			`if(addr == (long) &dummy->u_debugreg[4]) return -EIO;`
421			`if(addr == (long) &dummy->u_debugreg[5]) return -EIO;`
422			`if(addr < (long) &dummy->u_debugreg[4] &&`
423			`((unsigned long) data) >= 0xbffffffd) return -EIO;`
424
425			`if(addr == (long) &dummy->u_debugreg[7]) {`
426			`data &= ~DR_CONTROL_RESERVED;`
427			`for(i=0; i<4; i++)`
428			`if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)`
429			`return -EIO;`
430			`};`
431
432			`addr -= (long) &dummy->u_debugreg;`
433			`addr = addr >> 2;`
434			`child->debugreg[addr] = data;`
435			`return 0;`
436			`};`
437			`return -EIO;`
438
439			`case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */`
440			`case PTRACE_CONT: { /* restart after signal. */`
441			`long tmp;`
442
443			`if ((unsigned long) data > NSIG)`
444			`return -EIO;`
445			`if (request == PTRACE_SYSCALL)`
446			`child->flags \|= PF_TRACESYS;`
447			`else`
448			`child->flags &= ~PF_TRACESYS;`
449			`child->exit_code = data;`
450			`wake_up_process(child);`
451			`/* make sure the single step bit is not set. */`
452			`tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;`
453			`put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);`
454			`return 0;`
455			`}`
456
457			`/*`
458			`* make the child exit. Best I can do is send it a sigkill.`
459			`* perhaps it should be put in the status that it wants to`
460			`* exit.`
461			`*/`
462			`case PTRACE_KILL: {`
463			`long tmp;`
464
465			`if (child->state == TASK_ZOMBIE) /* already dead */`
466			`return 0;`
467			`wake_up_process(child);`
468			`child->exit_code = SIGKILL;`
469			`/* make sure the single step bit is not set. */`
470			`tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;`
471			`put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);`
472			`return 0;`
473			`}`
474
475			`case PTRACE_SINGLESTEP: { /* set the trap flag. */`
476			`long tmp;`
477
478			`if ((unsigned long) data > NSIG)`
479			`return -EIO;`
480			`child->flags &= ~PF_TRACESYS;`
481			`tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) \| TRAP_FLAG;`
482			`put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);`
483			`wake_up_process(child);`
484			`child->exit_code = data;`
485			`/* give it a chance to run. */`
486			`return 0;`
487			`}`
488
489			`case PTRACE_DETACH: { /* detach a process that was attached. */`
490			`long tmp;`
491
492			`if ((unsigned long) data > NSIG)`
493			`return -EIO;`
494			`child->flags &= ~(PF_PTRACED\|PF_TRACESYS);`
495			`wake_up_process(child);`
496			`child->exit_code = data;`
497			`REMOVE_LINKS(child);`
498			`child->p_pptr = child->p_opptr;`
499			`SET_LINKS(child);`
500			`/* make sure the single step bit is not set. */`
501			`tmp = get_stack_long(child, sizeof(long)*EFL-MAGICNUMBER) & ~TRAP_FLAG;`
502			`put_stack_long(child, sizeof(long)*EFL-MAGICNUMBER,tmp);`
503			`return 0;`
504			`}`
505
506			`default:`
507			`return -EIO;`
508			`}`
509			`#endif`
510			`}`
511
512			`asmlinkage void syscall_trace(void)`
513			`{`
514			`if ((current->flags & (PF_PTRACED\|PF_TRACESYS))`
515			`!= (PF_PTRACED\|PF_TRACESYS))`
516			`return;`
517			`current->exit_code = SIGTRAP;`
518			`current->state = TASK_STOPPED;`
519			`notify_parent(current);`
520			`schedule();`
521			`/*`
522			`* this isn't the same as continuing with a signal, but it will do`
523			`* for normal use. strace only continues with a signal if the`
524			`* stopping signal is not SIGTRAP. -brl`
525			`*/`
526			`if (current->exit_code)`
527			`current->signal \|= (1 << (current->exit_code - 1));`
528			`current->exit_code = 0;`
529			`}`