417 lines
11 KiB
C
417 lines
11 KiB
C
/* ptrace.c */
|
|
/* By Ross Biro 1/23/92 */
|
|
/* edited by Linus Torvalds */
|
|
/* mangled further by Bob Manson (manson@santafe.edu) */
|
|
/* more mutilation by David Mosberger (davidm@azstarnet.com) */
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/user.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/security.h>
|
|
#include <linux/signal.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/system.h>
|
|
#include <asm/fpu.h>
|
|
|
|
#include "proto.h"
|
|
|
|
#define DEBUG DBG_MEM
|
|
#undef DEBUG
|
|
|
|
#ifdef DEBUG
|
|
enum {
|
|
DBG_MEM = (1<<0),
|
|
DBG_BPT = (1<<1),
|
|
DBG_MEM_ALL = (1<<2)
|
|
};
|
|
#define DBG(fac,args) {if ((fac) & DEBUG) printk args;}
|
|
#else
|
|
#define DBG(fac,args)
|
|
#endif
|
|
|
|
#define BREAKINST 0x00000080 /* call_pal bpt */
|
|
|
|
/*
|
|
* does not yet catch signals sent when the child dies.
|
|
* in exit.c or in signal.c.
|
|
*/
|
|
|
|
/*
|
|
* Processes always block with the following stack-layout:
|
|
*
|
|
* +================================+ <---- task + 2*PAGE_SIZE
|
|
* | PALcode saved frame (ps, pc, | ^
|
|
* | gp, a0, a1, a2) | |
|
|
* +================================+ | struct pt_regs
|
|
* | | |
|
|
* | frame generated by SAVE_ALL | |
|
|
* | | v
|
|
* +================================+
|
|
* | | ^
|
|
* | frame saved by do_switch_stack | | struct switch_stack
|
|
* | | v
|
|
* +================================+
|
|
*/
|
|
|
|
/*
|
|
* The following table maps a register index into the stack offset at
|
|
* which the register is saved. Register indices are 0-31 for integer
|
|
* regs, 32-63 for fp regs, and 64 for the pc. Notice that sp and
|
|
* zero have no stack-slot and need to be treated specially (see
|
|
* get_reg/put_reg below).
|
|
*/
|
|
enum {
|
|
REG_R0 = 0, REG_F0 = 32, REG_FPCR = 63, REG_PC = 64
|
|
};
|
|
|
|
static int regoff[] = {
|
|
PT_REG( r0), PT_REG( r1), PT_REG( r2), PT_REG( r3),
|
|
PT_REG( r4), PT_REG( r5), PT_REG( r6), PT_REG( r7),
|
|
PT_REG( r8), SW_REG( r9), SW_REG( r10), SW_REG( r11),
|
|
SW_REG( r12), SW_REG( r13), SW_REG( r14), SW_REG( r15),
|
|
PT_REG( r16), PT_REG( r17), PT_REG( r18), PT_REG( r19),
|
|
PT_REG( r20), PT_REG( r21), PT_REG( r22), PT_REG( r23),
|
|
PT_REG( r24), PT_REG( r25), PT_REG( r26), PT_REG( r27),
|
|
PT_REG( r28), PT_REG( gp), -1, -1,
|
|
SW_REG(fp[ 0]), SW_REG(fp[ 1]), SW_REG(fp[ 2]), SW_REG(fp[ 3]),
|
|
SW_REG(fp[ 4]), SW_REG(fp[ 5]), SW_REG(fp[ 6]), SW_REG(fp[ 7]),
|
|
SW_REG(fp[ 8]), SW_REG(fp[ 9]), SW_REG(fp[10]), SW_REG(fp[11]),
|
|
SW_REG(fp[12]), SW_REG(fp[13]), SW_REG(fp[14]), SW_REG(fp[15]),
|
|
SW_REG(fp[16]), SW_REG(fp[17]), SW_REG(fp[18]), SW_REG(fp[19]),
|
|
SW_REG(fp[20]), SW_REG(fp[21]), SW_REG(fp[22]), SW_REG(fp[23]),
|
|
SW_REG(fp[24]), SW_REG(fp[25]), SW_REG(fp[26]), SW_REG(fp[27]),
|
|
SW_REG(fp[28]), SW_REG(fp[29]), SW_REG(fp[30]), SW_REG(fp[31]),
|
|
PT_REG( pc)
|
|
};
|
|
|
|
static unsigned long zero;
|
|
|
|
/*
|
|
* Get address of register REGNO in task TASK.
|
|
*/
|
|
static unsigned long *
|
|
get_reg_addr(struct task_struct * task, unsigned long regno)
|
|
{
|
|
unsigned long *addr;
|
|
|
|
if (regno == 30) {
|
|
addr = &task->thread_info->pcb.usp;
|
|
} else if (regno == 65) {
|
|
addr = &task->thread_info->pcb.unique;
|
|
} else if (regno == 31 || regno > 65) {
|
|
zero = 0;
|
|
addr = &zero;
|
|
} else {
|
|
addr = (void *)task->thread_info + regoff[regno];
|
|
}
|
|
return addr;
|
|
}
|
|
|
|
/*
|
|
* Get contents of register REGNO in task TASK.
|
|
*/
|
|
static unsigned long
|
|
get_reg(struct task_struct * task, unsigned long regno)
|
|
{
|
|
/* Special hack for fpcr -- combine hardware and software bits. */
|
|
if (regno == 63) {
|
|
unsigned long fpcr = *get_reg_addr(task, regno);
|
|
unsigned long swcr
|
|
= task->thread_info->ieee_state & IEEE_SW_MASK;
|
|
swcr = swcr_update_status(swcr, fpcr);
|
|
return fpcr | swcr;
|
|
}
|
|
return *get_reg_addr(task, regno);
|
|
}
|
|
|
|
/*
|
|
* Write contents of register REGNO in task TASK.
|
|
*/
|
|
static int
|
|
put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
|
|
{
|
|
if (regno == 63) {
|
|
task->thread_info->ieee_state
|
|
= ((task->thread_info->ieee_state & ~IEEE_SW_MASK)
|
|
| (data & IEEE_SW_MASK));
|
|
data = (data & FPCR_DYN_MASK) | ieee_swcr_to_fpcr(data);
|
|
}
|
|
*get_reg_addr(task, regno) = data;
|
|
return 0;
|
|
}
|
|
|
|
static inline int
|
|
read_int(struct task_struct *task, unsigned long addr, int * data)
|
|
{
|
|
int copied = access_process_vm(task, addr, data, sizeof(int), 0);
|
|
return (copied == sizeof(int)) ? 0 : -EIO;
|
|
}
|
|
|
|
static inline int
|
|
write_int(struct task_struct *task, unsigned long addr, int data)
|
|
{
|
|
int copied = access_process_vm(task, addr, &data, sizeof(int), 1);
|
|
return (copied == sizeof(int)) ? 0 : -EIO;
|
|
}
|
|
|
|
/*
|
|
* Set breakpoint.
|
|
*/
|
|
int
|
|
ptrace_set_bpt(struct task_struct * child)
|
|
{
|
|
int displ, i, res, reg_b, nsaved = 0;
|
|
unsigned int insn, op_code;
|
|
unsigned long pc;
|
|
|
|
pc = get_reg(child, REG_PC);
|
|
res = read_int(child, pc, (int *) &insn);
|
|
if (res < 0)
|
|
return res;
|
|
|
|
op_code = insn >> 26;
|
|
if (op_code >= 0x30) {
|
|
/*
|
|
* It's a branch: instead of trying to figure out
|
|
* whether the branch will be taken or not, we'll put
|
|
* a breakpoint at either location. This is simpler,
|
|
* more reliable, and probably not a whole lot slower
|
|
* than the alternative approach of emulating the
|
|
* branch (emulation can be tricky for fp branches).
|
|
*/
|
|
displ = ((s32)(insn << 11)) >> 9;
|
|
child->thread_info->bpt_addr[nsaved++] = pc + 4;
|
|
if (displ) /* guard against unoptimized code */
|
|
child->thread_info->bpt_addr[nsaved++]
|
|
= pc + 4 + displ;
|
|
DBG(DBG_BPT, ("execing branch\n"));
|
|
} else if (op_code == 0x1a) {
|
|
reg_b = (insn >> 16) & 0x1f;
|
|
child->thread_info->bpt_addr[nsaved++] = get_reg(child, reg_b);
|
|
DBG(DBG_BPT, ("execing jump\n"));
|
|
} else {
|
|
child->thread_info->bpt_addr[nsaved++] = pc + 4;
|
|
DBG(DBG_BPT, ("execing normal insn\n"));
|
|
}
|
|
|
|
/* install breakpoints: */
|
|
for (i = 0; i < nsaved; ++i) {
|
|
res = read_int(child, child->thread_info->bpt_addr[i],
|
|
(int *) &insn);
|
|
if (res < 0)
|
|
return res;
|
|
child->thread_info->bpt_insn[i] = insn;
|
|
DBG(DBG_BPT, (" -> next_pc=%lx\n",
|
|
child->thread_info->bpt_addr[i]));
|
|
res = write_int(child, child->thread_info->bpt_addr[i],
|
|
BREAKINST);
|
|
if (res < 0)
|
|
return res;
|
|
}
|
|
child->thread_info->bpt_nsaved = nsaved;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Ensure no single-step breakpoint is pending. Returns non-zero
|
|
* value if child was being single-stepped.
|
|
*/
|
|
int
|
|
ptrace_cancel_bpt(struct task_struct * child)
|
|
{
|
|
int i, nsaved = child->thread_info->bpt_nsaved;
|
|
|
|
child->thread_info->bpt_nsaved = 0;
|
|
|
|
if (nsaved > 2) {
|
|
printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
|
|
nsaved = 2;
|
|
}
|
|
|
|
for (i = 0; i < nsaved; ++i) {
|
|
write_int(child, child->thread_info->bpt_addr[i],
|
|
child->thread_info->bpt_insn[i]);
|
|
}
|
|
return (nsaved != 0);
|
|
}
|
|
|
|
/*
|
|
* Called by kernel/ptrace.c when detaching..
|
|
*
|
|
* Make sure the single step bit is not set.
|
|
*/
|
|
void ptrace_disable(struct task_struct *child)
|
|
{
|
|
ptrace_cancel_bpt(child);
|
|
}
|
|
|
|
asmlinkage long
|
|
do_sys_ptrace(long request, long pid, long addr, long data,
|
|
struct pt_regs *regs)
|
|
{
|
|
struct task_struct *child;
|
|
unsigned long tmp;
|
|
size_t copied;
|
|
long ret;
|
|
|
|
lock_kernel();
|
|
DBG(DBG_MEM, ("request=%ld pid=%ld addr=0x%lx data=0x%lx\n",
|
|
request, pid, addr, data));
|
|
ret = -EPERM;
|
|
if (request == PTRACE_TRACEME) {
|
|
/* are we already being traced? */
|
|
if (current->ptrace & PT_PTRACED)
|
|
goto out_notsk;
|
|
ret = security_ptrace(current->parent, current);
|
|
if (ret)
|
|
goto out_notsk;
|
|
/* set the ptrace bit in the process ptrace flags. */
|
|
current->ptrace |= PT_PTRACED;
|
|
ret = 0;
|
|
goto out_notsk;
|
|
}
|
|
if (pid == 1) /* you may not mess with init */
|
|
goto out_notsk;
|
|
|
|
ret = -ESRCH;
|
|
read_lock(&tasklist_lock);
|
|
child = find_task_by_pid(pid);
|
|
if (child)
|
|
get_task_struct(child);
|
|
read_unlock(&tasklist_lock);
|
|
if (!child)
|
|
goto out_notsk;
|
|
|
|
if (request == PTRACE_ATTACH) {
|
|
ret = ptrace_attach(child);
|
|
goto out;
|
|
}
|
|
|
|
ret = ptrace_check_attach(child, request == PTRACE_KILL);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
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:
|
|
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
|
|
ret = -EIO;
|
|
if (copied != sizeof(tmp))
|
|
break;
|
|
|
|
regs->r0 = 0; /* special return: no errors */
|
|
ret = tmp;
|
|
break;
|
|
|
|
/* Read register number ADDR. */
|
|
case PTRACE_PEEKUSR:
|
|
regs->r0 = 0; /* special return: no errors */
|
|
ret = get_reg(child, addr);
|
|
DBG(DBG_MEM, ("peek $%ld->%#lx\n", addr, ret));
|
|
break;
|
|
|
|
/* 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:
|
|
tmp = data;
|
|
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
|
|
ret = (copied == sizeof(tmp)) ? 0 : -EIO;
|
|
break;
|
|
|
|
case PTRACE_POKEUSR: /* write the specified register */
|
|
DBG(DBG_MEM, ("poke $%ld<-%#lx\n", addr, data));
|
|
ret = put_reg(child, addr, data);
|
|
break;
|
|
|
|
case PTRACE_SYSCALL:
|
|
/* continue and stop at next (return from) syscall */
|
|
case PTRACE_CONT: /* restart after signal. */
|
|
ret = -EIO;
|
|
if (!valid_signal(data))
|
|
break;
|
|
if (request == PTRACE_SYSCALL)
|
|
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
else
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
child->exit_code = data;
|
|
/* make sure single-step breakpoint is gone. */
|
|
ptrace_cancel_bpt(child);
|
|
wake_up_process(child);
|
|
ret = 0;
|
|
break;
|
|
|
|
/*
|
|
* 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:
|
|
ret = 0;
|
|
if (child->exit_state == EXIT_ZOMBIE)
|
|
break;
|
|
child->exit_code = SIGKILL;
|
|
/* make sure single-step breakpoint is gone. */
|
|
ptrace_cancel_bpt(child);
|
|
wake_up_process(child);
|
|
goto out;
|
|
|
|
case PTRACE_SINGLESTEP: /* execute single instruction. */
|
|
ret = -EIO;
|
|
if (!valid_signal(data))
|
|
break;
|
|
/* Mark single stepping. */
|
|
child->thread_info->bpt_nsaved = -1;
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
|
|
child->exit_code = data;
|
|
wake_up_process(child);
|
|
/* give it a chance to run. */
|
|
ret = 0;
|
|
goto out;
|
|
|
|
case PTRACE_DETACH: /* detach a process that was attached. */
|
|
ret = ptrace_detach(child, data);
|
|
goto out;
|
|
|
|
default:
|
|
ret = ptrace_request(child, request, addr, data);
|
|
goto out;
|
|
}
|
|
out:
|
|
put_task_struct(child);
|
|
out_notsk:
|
|
unlock_kernel();
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage void
|
|
syscall_trace(void)
|
|
{
|
|
if (!test_thread_flag(TIF_SYSCALL_TRACE))
|
|
return;
|
|
if (!(current->ptrace & PT_PTRACED))
|
|
return;
|
|
/* The 0x80 provides a way for the tracing parent to distinguish
|
|
between a syscall stop and SIGTRAP delivery */
|
|
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
|
|
? 0x80 : 0));
|
|
|
|
/*
|
|
* 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) {
|
|
send_sig(current->exit_code, current, 1);
|
|
current->exit_code = 0;
|
|
}
|
|
}
|