gdb/auxv.c

   1 /* Auxiliary vector support for GDB, the GNU debugger.
   2
   3    Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "target.h"
  24 #include "gdbtypes.h"
  25 #include "command.h"
  26 #include "inferior.h"
  27 #include "valprint.h"
  28 #include "gdb_assert.h"
  29
  30 #include "auxv.h"
  31 #include "elf/common.h"
  32
  33 #include <unistd.h>
  34 #include <fcntl.h>
  35
  36
  37 /* This function is called like a to_xfer_partial hook,
  38    but must be called with TARGET_OBJECT_AUXV.
  39    It handles access via /proc/PID/auxv, which is the common method.
  40    This function is appropriate for doing:
  41            #define NATIVE_XFER_AUXV     procfs_xfer_auxv
  42    for a native target that uses inftarg.c's child_xfer_partial hook.  */
  43
  44 LONGEST
  45 procfs_xfer_auxv (struct target_ops *ops,
  46                   int /* enum target_object */ object,
  47                   const char *annex,
  48                   gdb_byte *readbuf,
  49                   const gdb_byte *writebuf,
  50                   ULONGEST offset,
  51                   LONGEST len)
  52 {
  53   char *pathname;
  54   int fd;
  55   LONGEST n;
  56
  57   gdb_assert (object == TARGET_OBJECT_AUXV);
  58   gdb_assert (readbuf || writebuf);
  59
  60   pathname = xstrprintf ("/proc/%d/auxv", PIDGET (inferior_ptid));
  61   fd = open (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY);
  62   xfree (pathname);
  63   if (fd < 0)
  64     return -1;
  65
  66   if (offset != (ULONGEST) 0
  67       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
  68     n = -1;
  69   else if (readbuf != NULL)
  70     n = read (fd, readbuf, len);
  71   else
  72     n = write (fd, writebuf, len);
  73
  74   (void) close (fd);
  75
  76   return n;
  77 }
  78
  79 /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
  80    Return 0 if *READPTR is already at the end of the buffer.
  81    Return -1 if there is insufficient buffer for a whole entry.
  82    Return 1 if an entry was read into *TYPEP and *VALP.  */
  83 int
  84 target_auxv_parse (struct target_ops *ops, gdb_byte **readptr,
  85                    gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
  86 {
  87   const int sizeof_auxv_field = TYPE_LENGTH (builtin_type_void_data_ptr);
  88   gdb_byte *ptr = *readptr;
  89
  90   if (endptr == ptr)
  91     return 0;
  92
  93   if (endptr - ptr < sizeof_auxv_field * 2)
  94     return -1;
  95
  96   *typep = extract_unsigned_integer (ptr, sizeof_auxv_field);
  97   ptr += sizeof_auxv_field;
  98   *valp = extract_unsigned_integer (ptr, sizeof_auxv_field);
  99   ptr += sizeof_auxv_field;
 100
 101   *readptr = ptr;
 102   return 1;
 103 }
 104
 105 /* Extract the auxiliary vector entry with a_type matching MATCH.
 106    Return zero if no such entry was found, or -1 if there was
 107    an error getting the information.  On success, return 1 after
 108    storing the entry's value field in *VALP.  */
 109 int
 110 target_auxv_search (struct target_ops *ops, CORE_ADDR match, CORE_ADDR *valp)
 111 {
 112   CORE_ADDR type, val;
 113   gdb_byte *data;
 114   LONGEST n = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL, &data);
 115   gdb_byte *ptr = data;
 116   int ents = 0;
 117
 118   if (n <= 0)
 119     return n;
 120
 121   while (1)
 122     switch (target_auxv_parse (ops, &ptr, data + n, &type, &val))
 123       {
 124       case 1:                   /* Here's an entry, check it.  */
 125         if (type == match)
 126           {
 127             xfree (data);
 128             *valp = val;
 129             return 1;
 130           }
 131         break;
 132       case 0:                   /* End of the vector.  */
 133         xfree (data);
 134         return 0;
 135       default:                  /* Bogosity.  */
 136         xfree (data);
 137         return -1;
 138       }
 139
 140   /*NOTREACHED*/
 141 }
 142
 143
 144 /* Print the contents of the target's AUXV on the specified file. */
 145 int
 146 fprint_target_auxv (struct ui_file *file, struct target_ops *ops)
 147 {
 148   CORE_ADDR type, val;
 149   gdb_byte *data;
 150   LONGEST len = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL,
 151                                    &data);
 152   gdb_byte *ptr = data;
 153   int ents = 0;
 154
 155   if (len <= 0)
 156     return len;
 157
 158   while (target_auxv_parse (ops, &ptr, data + len, &type, &val) > 0)
 159     {
 160       extern int addressprint;
 161       const char *name = "???";
 162       const char *description = "";
 163       enum { dec, hex, str } flavor = hex;
 164
 165       switch (type)
 166         {
 167 #define TAG(tag, text, kind) \
 168         case tag: name = #tag; description = text; flavor = kind; break
 169           TAG (AT_NULL, _("End of vector"), hex);
 170           TAG (AT_IGNORE, _("Entry should be ignored"), hex);
 171           TAG (AT_EXECFD, _("File descriptor of program"), dec);
 172           TAG (AT_PHDR, _("Program headers for program"), hex);
 173           TAG (AT_PHENT, _("Size of program header entry"), dec);
 174           TAG (AT_PHNUM, _("Number of program headers"), dec);
 175           TAG (AT_PAGESZ, _("System page size"), dec);
 176           TAG (AT_BASE, _("Base address of interpreter"), hex);
 177           TAG (AT_FLAGS, _("Flags"), hex);
 178           TAG (AT_ENTRY, _("Entry point of program"), hex);
 179           TAG (AT_NOTELF, _("Program is not ELF"), dec);
 180           TAG (AT_UID, _("Real user ID"), dec);
 181           TAG (AT_EUID, _("Effective user ID"), dec);
 182           TAG (AT_GID, _("Real group ID"), dec);
 183           TAG (AT_EGID, _("Effective group ID"), dec);
 184           TAG (AT_CLKTCK, _("Frequency of times()"), dec);
 185           TAG (AT_PLATFORM, _("String identifying platform"), str);
 186           TAG (AT_HWCAP, _("Machine-dependent CPU capability hints"), hex);
 187           TAG (AT_FPUCW, _("Used FPU control word"), dec);
 188           TAG (AT_DCACHEBSIZE, _("Data cache block size"), dec);
 189           TAG (AT_ICACHEBSIZE, _("Instruction cache block size"), dec);
 190           TAG (AT_UCACHEBSIZE, _("Unified cache block size"), dec);
 191           TAG (AT_IGNOREPPC, _("Entry should be ignored"), dec);
 192           TAG (AT_SYSINFO, _("Special system info/entry points"), hex);
 193           TAG (AT_SYSINFO_EHDR, _("System-supplied DSO's ELF header"), hex);
 194           TAG (AT_SECURE, _("Boolean, was exec setuid-like?"), dec);
 195           TAG (AT_SUN_UID, _("Effective user ID"), dec);
 196           TAG (AT_SUN_RUID, _("Real user ID"), dec);
 197           TAG (AT_SUN_GID, _("Effective group ID"), dec);
 198           TAG (AT_SUN_RGID, _("Real group ID"), dec);
 199           TAG (AT_SUN_LDELF, _("Dynamic linker's ELF header"), hex);
 200           TAG (AT_SUN_LDSHDR, _("Dynamic linker's section headers"), hex);
 201           TAG (AT_SUN_LDNAME, _("String giving name of dynamic linker"), str);
 202           TAG (AT_SUN_LPAGESZ, _("Large pagesize"), dec);
 203           TAG (AT_SUN_PLATFORM, _("Platform name string"), str);
 204           TAG (AT_SUN_HWCAP, _("Machine-dependent CPU capability hints"), hex);
 205           TAG (AT_SUN_IFLUSH, _("Should flush icache?"), dec);
 206           TAG (AT_SUN_CPU, _("CPU name string"), str);
 207           TAG (AT_SUN_EMUL_ENTRY, _("COFF entry point address"), hex);
 208           TAG (AT_SUN_EMUL_EXECFD, _("COFF executable file descriptor"), dec);
 209           TAG (AT_SUN_EXECNAME,
 210                _("Canonicalized file name given to execve"), str);
 211           TAG (AT_SUN_MMU, _("String for name of MMU module"), str);
 212           TAG (AT_SUN_LDDATA, _("Dynamic linker's data segment address"), hex);
 213         }
 214
 215       fprintf_filtered (file, "%-4s %-20s %-30s ",
 216                         paddr_d (type), name, description);
 217       switch (flavor)
 218         {
 219         case dec:
 220           fprintf_filtered (file, "%s\n", paddr_d (val));
 221           break;
 222         case hex:
 223           fprintf_filtered (file, "0x%s\n", paddr_nz (val));
 224           break;
 225         case str:
 226           if (addressprint)
 227             fprintf_filtered (file, "0x%s", paddr_nz (val));
 228           val_print_string (val, -1, 1, file);
 229           fprintf_filtered (file, "\n");
 230           break;
 231         }
 232       ++ents;
 233     }
 234
 235   xfree (data);
 236
 237   return ents;
 238 }
 239
 240 static void
 241 info_auxv_command (char *cmd, int from_tty)
 242 {
 243   if (! target_has_stack)
 244     error (_("The program has no auxiliary information now."));
 245   else
 246     {
 247       int ents = fprint_target_auxv (gdb_stdout, &current_target);
 248       if (ents < 0)
 249         error (_("No auxiliary vector found, or failed reading it."));
 250       else if (ents == 0)
 251         error (_("Auxiliary vector is empty."));
 252     }
 253 }
 254
 255
 256 extern initialize_file_ftype _initialize_auxv; /* -Wmissing-prototypes; */
 257
 258 void
 259 _initialize_auxv (void)
 260 {
 261   add_info ("auxv", info_auxv_command,
 262             _("Display the inferior's auxiliary vector.\n\
 263 This is information provided by the operating system at program startup."));
 264 }