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 <asm/uaccess.h>
  11 #include <skas_ptrace.h>
  12
  13
  14
  15 void user_enable_single_step(struct task_struct *child)
  16 {
  17         child->ptrace |= PT_DTRACE;
  18         child->thread.singlestep_syscall = 0;
  19
  20 #ifdef SUBARCH_SET_SINGLESTEPPING
  21         SUBARCH_SET_SINGLESTEPPING(child, 1);
  22 #endif
  23 }
  24
  25 void user_disable_single_step(struct task_struct *child)
  26 {
  27         child->ptrace &= ~PT_DTRACE;
  28         child->thread.singlestep_syscall = 0;
  29
  30 #ifdef SUBARCH_SET_SINGLESTEPPING
  31         SUBARCH_SET_SINGLESTEPPING(child, 0);
  32 #endif
  33 }
  34
  35 /*
  36  * Called by kernel/ptrace.c when detaching..
  37  */
  38 void ptrace_disable(struct task_struct *child)
  39 {
  40         user_disable_single_step(child);
  41 }
  42
  43 extern int peek_user(struct task_struct * child, long addr, long data);
  44 extern int poke_user(struct task_struct * child, long addr, long data);
  45
  46 long arch_ptrace(struct task_struct *child, long request,
  47                  unsigned long addr, unsigned long data)
  48 {
  49         int i, ret;
  50         unsigned long __user *p = (void __user *)data;
  51         void __user *vp = p;
  52
  53         switch (request) {
  54         /* read the word at location addr in the USER area. */
  55         case PTRACE_PEEKUSR:
  56                 ret = peek_user(child, addr, data);
  57                 break;
  58
  59         /* write the word at location addr in the USER area */
  60         case PTRACE_POKEUSR:
  61                 ret = poke_user(child, addr, data);
  62                 break;
  63
  64         case PTRACE_SYSEMU:
  65         case PTRACE_SYSEMU_SINGLESTEP:
  66                 ret = -EIO;
  67                 break;
  68
  69 #ifdef PTRACE_GETREGS
  70         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
  71                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
  72                         ret = -EIO;
  73                         break;
  74                 }
  75                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  76                         __put_user(getreg(child, i), p);
  77                         p++;
  78                 }
  79                 ret = 0;
  80                 break;
  81         }
  82 #endif
  83 #ifdef PTRACE_SETREGS
  84         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
  85                 unsigned long tmp = 0;
  86                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
  87                         ret = -EIO;
  88                         break;
  89                 }
  90                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  91                         __get_user(tmp, p);
  92                         putreg(child, i, tmp);
  93                         p++;
  94                 }
  95                 ret = 0;
  96                 break;
  97         }
  98 #endif
  99         case PTRACE_GET_THREAD_AREA:
 100                 ret = ptrace_get_thread_area(child, addr, vp);
 101                 break;
 102
 103         case PTRACE_SET_THREAD_AREA:
 104                 ret = ptrace_set_thread_area(child, addr, vp);
 105                 break;
 106
 107         case PTRACE_FAULTINFO: {
 108                 /*
 109                  * Take the info from thread->arch->faultinfo,
 110                  * but transfer max. sizeof(struct ptrace_faultinfo).
 111                  * On i386, ptrace_faultinfo is smaller!
 112                  */
 113                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 114                                    sizeof(struct ptrace_faultinfo)) ?
 115                         -EIO : 0;
 116                 break;
 117         }
 118
 119 #ifdef PTRACE_LDT
 120         case PTRACE_LDT: {
 121                 struct ptrace_ldt ldt;
 122
 123                 if (copy_from_user(&ldt, p, sizeof(ldt))) {
 124                         ret = -EIO;
 125                         break;
 126                 }
 127
 128                 /*
 129                  * This one is confusing, so just punt and return -EIO for
 130                  * now
 131                  */
 132                 ret = -EIO;
 133                 break;
 134         }
 135 #endif
 136         default:
 137                 ret = ptrace_request(child, request, addr, data);
 138                 if (ret == -EIO)
 139                         ret = subarch_ptrace(child, request, addr, data);
 140                 break;
 141         }
 142
 143         return ret;
 144 }
 145
 146 static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 147                   int error_code)
 148 {
 149         struct siginfo info;
 150
 151         memset(&info, 0, sizeof(info));
 152         info.si_signo = SIGTRAP;
 153         info.si_code = TRAP_BRKPT;
 154
 155         /* User-mode eip? */
 156         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 157
 158         /* Send us the fake SIGTRAP */
 159         force_sig_info(SIGTRAP, &info, tsk);
 160 }
 161
 162 /*
 163  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 164  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 165  */
 166 void syscall_trace_enter(struct pt_regs *regs)
 167 {
 168         audit_syscall_entry(HOST_AUDIT_ARCH,
 169                             UPT_SYSCALL_NR(&regs->regs),
 170                             UPT_SYSCALL_ARG1(&regs->regs),
 171                             UPT_SYSCALL_ARG2(&regs->regs),
 172                             UPT_SYSCALL_ARG3(&regs->regs),
 173                             UPT_SYSCALL_ARG4(&regs->regs));
 174
 175         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 176                 return;
 177
 178         tracehook_report_syscall_entry(regs);
 179 }
 180
 181 void syscall_trace_leave(struct pt_regs *regs)
 182 {
 183         int ptraced = current->ptrace;
 184
 185         audit_syscall_exit(regs);
 186
 187         /* Fake a debug trap */
 188         if (ptraced & PT_DTRACE)
 189                 send_sigtrap(current, &regs->regs, 0);
 190
 191         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 192                 return;
 193
 194         tracehook_report_syscall_exit(regs, 0);
 195         /* force do_signal() --> is_syscall() */
 196         if (ptraced & PT_PTRACED)
 197                 set_thread_flag(TIF_SIGPENDING);
 198 }