1 /* Auxiliary vector support for GDB, the GNU debugger.
3 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
27 #include "gdb_assert.h"
31 #include "elf/common.h"
37 /* This function handles access via /proc/PID/auxv, which is a common method
38 for native targets. */
41 procfs_xfer_auxv (gdb_byte
*readbuf
,
42 const gdb_byte
*writebuf
,
50 pathname
= xstrprintf ("/proc/%d/auxv", PIDGET (inferior_ptid
));
51 fd
= open (pathname
, writebuf
!= NULL
? O_WRONLY
: O_RDONLY
);
56 if (offset
!= (ULONGEST
) 0
57 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
59 else if (readbuf
!= NULL
)
60 n
= read (fd
, readbuf
, len
);
62 n
= write (fd
, writebuf
, len
);
69 /* This function handles access via ld.so's symbol `_dl_auxv'. */
72 ld_so_xfer_auxv (gdb_byte
*readbuf
,
73 const gdb_byte
*writebuf
,
77 struct minimal_symbol
*msym
;
78 CORE_ADDR data_address
, pointer_address
;
79 struct type
*ptr_type
= builtin_type (target_gdbarch
)->builtin_data_ptr
;
80 size_t ptr_size
= TYPE_LENGTH (ptr_type
);
81 size_t auxv_pair_size
= 2 * ptr_size
;
82 gdb_byte
*ptr_buf
= alloca (ptr_size
);
86 msym
= lookup_minimal_symbol ("_dl_auxv", NULL
, NULL
);
90 if (MSYMBOL_SIZE (msym
) != ptr_size
)
93 /* POINTER_ADDRESS is a location where the `_dl_auxv' variable resides.
94 DATA_ADDRESS is the inferior value present in `_dl_auxv', therefore the
95 real inferior AUXV address. */
97 pointer_address
= SYMBOL_VALUE_ADDRESS (msym
);
99 data_address
= read_memory_typed_address (pointer_address
, ptr_type
);
101 /* Possibly still not initialized such as during an inferior startup. */
102 if (data_address
== 0)
105 data_address
+= offset
;
107 if (writebuf
!= NULL
)
109 if (target_write_memory (data_address
, writebuf
, len
) == 0)
115 /* Stop if trying to read past the existing AUXV block. The final AT_NULL
116 was already returned before. */
118 if (offset
>= auxv_pair_size
)
120 if (target_read_memory (data_address
- auxv_pair_size
, ptr_buf
,
124 if (extract_typed_address (ptr_buf
, ptr_type
) == AT_NULL
)
130 gdb_assert (block
% auxv_pair_size
== 0);
137 /* Reading sizes smaller than AUXV_PAIR_SIZE is not supported. Tails
138 unaligned to AUXV_PAIR_SIZE will not be read during a call (they
139 should be completed during next read with new/extended buffer). */
141 block
&= -auxv_pair_size
;
145 if (target_read_memory (data_address
, readbuf
, block
) != 0)
147 if (block
<= auxv_pair_size
)
150 block
= auxv_pair_size
;
154 data_address
+= block
;
157 /* Check terminal AT_NULL. This function is being called indefinitely
158 being extended its READBUF until it returns EOF (0). */
160 while (block
>= auxv_pair_size
)
162 retval
+= auxv_pair_size
;
164 if (extract_typed_address (readbuf
, ptr_type
) == AT_NULL
)
167 readbuf
+= auxv_pair_size
;
168 block
-= auxv_pair_size
;
175 /* This function is called like a to_xfer_partial hook, but must be
176 called with TARGET_OBJECT_AUXV. It handles access to AUXV. */
179 memory_xfer_auxv (struct target_ops
*ops
,
180 enum target_object object
,
183 const gdb_byte
*writebuf
,
187 gdb_assert (object
== TARGET_OBJECT_AUXV
);
188 gdb_assert (readbuf
|| writebuf
);
190 /* ld_so_xfer_auxv is the only function safe for virtual executables being
191 executed by valgrind's memcheck. As using ld_so_xfer_auxv is problematic
192 during inferior startup GDB does call it only for attached processes. */
194 if (current_inferior ()->attach_flag
!= 0)
198 retval
= ld_so_xfer_auxv (readbuf
, writebuf
, offset
, len
);
203 return procfs_xfer_auxv (readbuf
, writebuf
, offset
, len
);
206 /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
207 Return 0 if *READPTR is already at the end of the buffer.
208 Return -1 if there is insufficient buffer for a whole entry.
209 Return 1 if an entry was read into *TYPEP and *VALP. */
211 default_auxv_parse (struct target_ops
*ops
, gdb_byte
**readptr
,
212 gdb_byte
*endptr
, CORE_ADDR
*typep
, CORE_ADDR
*valp
)
214 const int sizeof_auxv_field
= gdbarch_ptr_bit (target_gdbarch
)
216 const enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch
);
217 gdb_byte
*ptr
= *readptr
;
222 if (endptr
- ptr
< sizeof_auxv_field
* 2)
225 *typep
= extract_unsigned_integer (ptr
, sizeof_auxv_field
, byte_order
);
226 ptr
+= sizeof_auxv_field
;
227 *valp
= extract_unsigned_integer (ptr
, sizeof_auxv_field
, byte_order
);
228 ptr
+= sizeof_auxv_field
;
234 /* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
235 Return 0 if *READPTR is already at the end of the buffer.
236 Return -1 if there is insufficient buffer for a whole entry.
237 Return 1 if an entry was read into *TYPEP and *VALP. */
239 target_auxv_parse (struct target_ops
*ops
, gdb_byte
**readptr
,
240 gdb_byte
*endptr
, CORE_ADDR
*typep
, CORE_ADDR
*valp
)
242 struct target_ops
*t
;
243 for (t
= ops
; t
!= NULL
; t
= t
->beneath
)
244 if (t
->to_auxv_parse
!= NULL
)
245 return t
->to_auxv_parse (t
, readptr
, endptr
, typep
, valp
);
247 return default_auxv_parse (ops
, readptr
, endptr
, typep
, valp
);
250 /* Extract the auxiliary vector entry with a_type matching MATCH.
251 Return zero if no such entry was found, or -1 if there was
252 an error getting the information. On success, return 1 after
253 storing the entry's value field in *VALP. */
255 target_auxv_search (struct target_ops
*ops
, CORE_ADDR match
, CORE_ADDR
*valp
)
259 LONGEST n
= target_read_alloc (ops
, TARGET_OBJECT_AUXV
, NULL
, &data
);
260 gdb_byte
*ptr
= data
;
267 switch (target_auxv_parse (ops
, &ptr
, data
+ n
, &type
, &val
))
269 case 1: /* Here's an entry, check it. */
277 case 0: /* End of the vector. */
280 default: /* Bogosity. */
289 /* Print the contents of the target's AUXV on the specified file. */
291 fprint_target_auxv (struct ui_file
*file
, struct target_ops
*ops
)
295 LONGEST len
= target_read_alloc (ops
, TARGET_OBJECT_AUXV
, NULL
,
297 gdb_byte
*ptr
= data
;
303 while (target_auxv_parse (ops
, &ptr
, data
+ len
, &type
, &val
) > 0)
305 const char *name
= "???";
306 const char *description
= "";
307 enum { dec
, hex
, str
} flavor
= hex
;
311 #define TAG(tag, text, kind) \
312 case tag: name = #tag; description = text; flavor = kind; break
313 TAG (AT_NULL
, _("End of vector"), hex
);
314 TAG (AT_IGNORE
, _("Entry should be ignored"), hex
);
315 TAG (AT_EXECFD
, _("File descriptor of program"), dec
);
316 TAG (AT_PHDR
, _("Program headers for program"), hex
);
317 TAG (AT_PHENT
, _("Size of program header entry"), dec
);
318 TAG (AT_PHNUM
, _("Number of program headers"), dec
);
319 TAG (AT_PAGESZ
, _("System page size"), dec
);
320 TAG (AT_BASE
, _("Base address of interpreter"), hex
);
321 TAG (AT_FLAGS
, _("Flags"), hex
);
322 TAG (AT_ENTRY
, _("Entry point of program"), hex
);
323 TAG (AT_NOTELF
, _("Program is not ELF"), dec
);
324 TAG (AT_UID
, _("Real user ID"), dec
);
325 TAG (AT_EUID
, _("Effective user ID"), dec
);
326 TAG (AT_GID
, _("Real group ID"), dec
);
327 TAG (AT_EGID
, _("Effective group ID"), dec
);
328 TAG (AT_CLKTCK
, _("Frequency of times()"), dec
);
329 TAG (AT_PLATFORM
, _("String identifying platform"), str
);
330 TAG (AT_HWCAP
, _("Machine-dependent CPU capability hints"), hex
);
331 TAG (AT_FPUCW
, _("Used FPU control word"), dec
);
332 TAG (AT_DCACHEBSIZE
, _("Data cache block size"), dec
);
333 TAG (AT_ICACHEBSIZE
, _("Instruction cache block size"), dec
);
334 TAG (AT_UCACHEBSIZE
, _("Unified cache block size"), dec
);
335 TAG (AT_IGNOREPPC
, _("Entry should be ignored"), dec
);
336 TAG (AT_BASE_PLATFORM
, _("String identifying base platform"), str
);
337 TAG (AT_RANDOM
, _("Address of 16 random bytes"), hex
);
338 TAG (AT_EXECFN
, _("File name of executable"), str
);
339 TAG (AT_SECURE
, _("Boolean, was exec setuid-like?"), dec
);
340 TAG (AT_SYSINFO
, _("Special system info/entry points"), hex
);
341 TAG (AT_SYSINFO_EHDR
, _("System-supplied DSO's ELF header"), hex
);
342 TAG (AT_SUN_UID
, _("Effective user ID"), dec
);
343 TAG (AT_SUN_RUID
, _("Real user ID"), dec
);
344 TAG (AT_SUN_GID
, _("Effective group ID"), dec
);
345 TAG (AT_SUN_RGID
, _("Real group ID"), dec
);
346 TAG (AT_SUN_LDELF
, _("Dynamic linker's ELF header"), hex
);
347 TAG (AT_SUN_LDSHDR
, _("Dynamic linker's section headers"), hex
);
348 TAG (AT_SUN_LDNAME
, _("String giving name of dynamic linker"), str
);
349 TAG (AT_SUN_LPAGESZ
, _("Large pagesize"), dec
);
350 TAG (AT_SUN_PLATFORM
, _("Platform name string"), str
);
351 TAG (AT_SUN_HWCAP
, _("Machine-dependent CPU capability hints"), hex
);
352 TAG (AT_SUN_IFLUSH
, _("Should flush icache?"), dec
);
353 TAG (AT_SUN_CPU
, _("CPU name string"), str
);
354 TAG (AT_SUN_EMUL_ENTRY
, _("COFF entry point address"), hex
);
355 TAG (AT_SUN_EMUL_EXECFD
, _("COFF executable file descriptor"), dec
);
356 TAG (AT_SUN_EXECNAME
,
357 _("Canonicalized file name given to execve"), str
);
358 TAG (AT_SUN_MMU
, _("String for name of MMU module"), str
);
359 TAG (AT_SUN_LDDATA
, _("Dynamic linker's data segment address"), hex
);
360 TAG (AT_SUN_AUXFLAGS
,
361 _("AF_SUN_ flags passed from the kernel"), hex
);
364 fprintf_filtered (file
, "%-4s %-20s %-30s ",
365 plongest (type
), name
, description
);
369 fprintf_filtered (file
, "%s\n", plongest (val
));
372 fprintf_filtered (file
, "%s\n", paddress (target_gdbarch
, val
));
376 struct value_print_options opts
;
377 get_user_print_options (&opts
);
378 if (opts
.addressprint
)
379 fprintf_filtered (file
, "%s", paddress (target_gdbarch
, val
));
380 val_print_string (builtin_type (target_gdbarch
)->builtin_char
,
381 val
, -1, file
, &opts
);
382 fprintf_filtered (file
, "\n");
397 info_auxv_command (char *cmd
, int from_tty
)
399 if (! target_has_stack
)
400 error (_("The program has no auxiliary information now."));
403 int ents
= fprint_target_auxv (gdb_stdout
, ¤t_target
);
405 error (_("No auxiliary vector found, or failed reading it."));
407 error (_("Auxiliary vector is empty."));
412 extern initialize_file_ftype _initialize_auxv
; /* -Wmissing-prototypes; */
415 _initialize_auxv (void)
417 add_info ("auxv", info_auxv_command
,
418 _("Display the inferior's auxiliary vector.\n\
419 This is information provided by the operating system at program startup."));