minix/usr.bin/trace/mem.c

   1
   2 #include "inc.h"
   3
   4 /*
   5  * Retrieve 'len' bytes from the memory of the traced process 'pid' at address
   6  * 'addr' and put the result in the buffer pointed to by 'ptr'.  Return 0 on
   7  * success, or otherwise -1 with errno set appropriately.
   8  */
   9 int
  10 mem_get_data(pid_t pid, vir_bytes addr, void * ptr, size_t len)
  11 {
  12         struct ptrace_range pr;
  13
  14         if (len == 0) return 0;
  15
  16         pr.pr_space = TS_DATA;
  17         pr.pr_addr = addr;
  18         pr.pr_size = len;
  19         pr.pr_ptr = ptr;
  20
  21         return ptrace(T_GETRANGE, pid, &pr, 0);
  22 }
  23
  24 /*
  25  * Retrieve 'len' bytes from the kernel structure memory of the traced process
  26  * 'pid' at offset 'addr' and put the result in the buffer pointed to by 'ptr'.
  27  * Return 0 on success, or otherwise -1 with errno set appropriately.
  28  */
  29 int
  30 mem_get_user(pid_t pid, vir_bytes addr, void * ptr, size_t len)
  31 {
  32         long data;
  33         char *p;
  34         size_t off, chunk;
  35
  36         if (len == 0) return 0;
  37
  38         /* Align access to address. */
  39         off = addr & (sizeof(data) - 1);
  40         addr -= off;
  41
  42         p = ptr;
  43
  44         while (len > 0) {
  45                 errno = 0;
  46                 data = ptrace(T_GETUSER, pid, (void *)addr, 0);
  47                 if (errno != 0) return -1;
  48
  49                 chunk = sizeof(data) - off;
  50                 if (chunk > len)
  51                         chunk = len;
  52
  53                 memcpy(p, (char *)&data + off, chunk);
  54                 p += chunk;
  55                 addr += chunk;
  56                 len -= chunk;
  57                 off = 0;
  58         }
  59
  60         return 0;
  61 }