arch/um/kernel/ptrace.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/audit.h>
   7 #include <linux/ptrace.h>
   8 #include <linux/sched.h>
   9 #include <linux/tracehook.h>
  10 #include <linux/uaccess.h>
  11 #include <asm/ptrace-abi.h>
  12
  13 void user_enable_single_step(struct task_struct *child)
  14 {
  15         child->ptrace |= PT_DTRACE;
  16         child->thread.singlestep_syscall = 0;
  17
  18 #ifdef SUBARCH_SET_SINGLESTEPPING
  19         SUBARCH_SET_SINGLESTEPPING(child, 1);
  20 #endif
  21 }
  22
  23 void user_disable_single_step(struct task_struct *child)
  24 {
  25         child->ptrace &= ~PT_DTRACE;
  26         child->thread.singlestep_syscall = 0;
  27
  28 #ifdef SUBARCH_SET_SINGLESTEPPING
  29         SUBARCH_SET_SINGLESTEPPING(child, 0);
  30 #endif
  31 }
  32
  33 /*
  34  * Called by kernel/ptrace.c when detaching..
  35  */
  36 void ptrace_disable(struct task_struct *child)
  37 {
  38         user_disable_single_step(child);
  39 }
  40
  41 extern int peek_user(struct task_struct * child, long addr, long data);
  42 extern int poke_user(struct task_struct * child, long addr, long data);
  43
  44 long arch_ptrace(struct task_struct *child, long request,
  45                  unsigned long addr, unsigned long data)
  46 {
  47         int i, ret;
  48         unsigned long __user *p = (void __user *)data;
  49         void __user *vp = p;
  50
  51         switch (request) {
  52         /* read the word at location addr in the USER area. */
  53         case PTRACE_PEEKUSR:
  54                 ret = peek_user(child, addr, data);
  55                 break;
  56
  57         /* write the word at location addr in the USER area */
  58         case PTRACE_POKEUSR:
  59                 ret = poke_user(child, addr, data);
  60                 break;
  61
  62         case PTRACE_SYSEMU:
  63         case PTRACE_SYSEMU_SINGLESTEP:
  64                 ret = -EIO;
  65                 break;
  66
  67 #ifdef PTRACE_GETREGS
  68         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
  69                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
  70                         ret = -EIO;
  71                         break;
  72                 }
  73                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  74                         __put_user(getreg(child, i), p);
  75                         p++;
  76                 }
  77                 ret = 0;
  78                 break;
  79         }
  80 #endif
  81 #ifdef PTRACE_SETREGS
  82         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
  83                 unsigned long tmp = 0;
  84                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
  85                         ret = -EIO;
  86                         break;
  87                 }
  88                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  89                         __get_user(tmp, p);
  90                         putreg(child, i, tmp);
  91                         p++;
  92                 }
  93                 ret = 0;
  94                 break;
  95         }
  96 #endif
  97         case PTRACE_GET_THREAD_AREA:
  98                 ret = ptrace_get_thread_area(child, addr, vp);
  99                 break;
 100
 101         case PTRACE_SET_THREAD_AREA:
 102                 ret = ptrace_set_thread_area(child, addr, vp);
 103                 break;
 104
 105         default:
 106                 ret = ptrace_request(child, request, addr, data);
 107                 if (ret == -EIO)
 108                         ret = subarch_ptrace(child, request, addr, data);
 109                 break;
 110         }
 111
 112         return ret;
 113 }
 114
 115 static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 116                   int error_code)
 117 {
 118         /* Send us the fake SIGTRAP */
 119         force_sig_fault(SIGTRAP, TRAP_BRKPT,
 120                         /* User-mode eip? */
 121                         UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL, tsk);
 122 }
 123
 124 /*
 125  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 126  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 127  */
 128 int syscall_trace_enter(struct pt_regs *regs)
 129 {
 130         audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
 131                             UPT_SYSCALL_ARG1(&regs->regs),
 132                             UPT_SYSCALL_ARG2(&regs->regs),
 133                             UPT_SYSCALL_ARG3(&regs->regs),
 134                             UPT_SYSCALL_ARG4(&regs->regs));
 135
 136         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 137                 return 0;
 138
 139         return tracehook_report_syscall_entry(regs);
 140 }
 141
 142 void syscall_trace_leave(struct pt_regs *regs)
 143 {
 144         int ptraced = current->ptrace;
 145
 146         audit_syscall_exit(regs);
 147
 148         /* Fake a debug trap */
 149         if (ptraced & PT_DTRACE)
 150                 send_sigtrap(current, &regs->regs, 0);
 151
 152         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 153                 return;
 154
 155         tracehook_report_syscall_exit(regs, 0);
 156         /* force do_signal() --> is_syscall() */
 157         if (ptraced & PT_PTRACED)
 158                 set_thread_flag(TIF_SIGPENDING);
 159 }