/* Auxiliary vector support for GDB, the GNU debugger.
- Copyright 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "target.h"
#include "inferior.h"
#include "valprint.h"
#include "gdb_assert.h"
+#include "gdbcore.h"
#include "auxv.h"
#include "elf/common.h"
#include <fcntl.h>
-/* This function is called like a to_xfer_partial hook,
- but must be called with TARGET_OBJECT_AUXV.
- It handles access via /proc/PID/auxv, which is the common method.
- This function is appropriate for doing:
- #define NATIVE_XFER_AUXV procfs_xfer_auxv
- for a native target that uses inftarg.c's child_xfer_partial hook. */
+/* This function handles access via /proc/PID/auxv, which is a common method
+ for native targets. */
-LONGEST
-procfs_xfer_auxv (struct target_ops *ops,
- int /* enum target_object */ object,
- const char *annex,
- void *readbuf,
- const void *writebuf,
+static LONGEST
+procfs_xfer_auxv (gdb_byte *readbuf,
+ const gdb_byte *writebuf,
ULONGEST offset,
LONGEST len)
{
int fd;
LONGEST n;
- gdb_assert (object == TARGET_OBJECT_AUXV);
- gdb_assert (readbuf || writebuf);
-
pathname = xstrprintf ("/proc/%d/auxv", PIDGET (inferior_ptid));
fd = open (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY);
xfree (pathname);
return n;
}
-/* Read all the auxv data into a contiguous xmalloc'd buffer,
- stored in *DATA. Return the size in bytes of this data.
- If zero, there is no data and *DATA is null.
- if < 0, there was an error and *DATA is null. */
-LONGEST
-target_auxv_read (struct target_ops *ops, char **data)
+/* This function handles access via ld.so's symbol `_dl_auxv'. */
+
+static LONGEST
+ld_so_xfer_auxv (gdb_byte *readbuf,
+ const gdb_byte *writebuf,
+ ULONGEST offset,
+ LONGEST len)
{
- size_t auxv_alloc = 512, auxv_pos = 0;
- char *auxv = xmalloc (auxv_alloc);
- int n;
+ struct minimal_symbol *msym;
+ CORE_ADDR data_address, pointer_address;
+ struct type *ptr_type = builtin_type (target_gdbarch)->builtin_data_ptr;
+ size_t ptr_size = TYPE_LENGTH (ptr_type);
+ size_t auxv_pair_size = 2 * ptr_size;
+ gdb_byte *ptr_buf = alloca (ptr_size);
+ LONGEST retval;
+ size_t block;
+
+ msym = lookup_minimal_symbol ("_dl_auxv", NULL, NULL);
+ if (msym == NULL)
+ return -1;
- while (1)
+ if (MSYMBOL_SIZE (msym) != ptr_size)
+ return -1;
+
+ /* POINTER_ADDRESS is a location where the `_dl_auxv' variable resides.
+ DATA_ADDRESS is the inferior value present in `_dl_auxv', therefore the
+ real inferior AUXV address. */
+
+ pointer_address = SYMBOL_VALUE_ADDRESS (msym);
+
+ /* The location of the _dl_auxv symbol may no longer be correct if
+ ld.so runs at a different address than the one present in the file.
+ This is very common case - for unprelinked ld.so or with a PIE executable.
+ PIE executable forces random address even for libraries already being
+ prelinked to some address. PIE executables themselves are never prelinked
+ even on prelinked systems. Prelinking of a PIE executable would block
+ their purpose of randomizing load of everything including the executable.
+
+ If the memory read fails, return -1 to fallback on another mechanism for
+ retrieving the AUXV.
+
+ In most cases of a PIE running under valgrind there is no way to find
+ out the base addresses of any of ld.so, executable or AUXV as everything
+ is randomized and /proc information is not relevant for the virtual
+ executable running under valgrind. We think that we might need a valgrind
+ extension to make it work. This is PR 11440. */
+
+ if (target_read_memory (pointer_address, ptr_buf, ptr_size) != 0)
+ return -1;
+
+ data_address = extract_typed_address (ptr_buf, ptr_type);
+
+ /* Possibly still not initialized such as during an inferior startup. */
+ if (data_address == 0)
+ return -1;
+
+ data_address += offset;
+
+ if (writebuf != NULL)
{
- n = target_read_partial (ops, TARGET_OBJECT_AUXV,
- NULL, &auxv[auxv_pos], 0,
- auxv_alloc - auxv_pos);
- if (n <= 0)
- break;
- auxv_pos += n;
- if (auxv_pos < auxv_alloc) /* Read all there was. */
- break;
- gdb_assert (auxv_pos == auxv_alloc);
- auxv_alloc *= 2;
- auxv = xrealloc (auxv, auxv_alloc);
+ if (target_write_memory (data_address, writebuf, len) == 0)
+ return len;
+ else
+ return -1;
}
- if (auxv_pos == 0)
+ /* Stop if trying to read past the existing AUXV block. The final AT_NULL
+ was already returned before. */
+
+ if (offset >= auxv_pair_size)
{
- xfree (auxv);
- *data = NULL;
- return n;
+ if (target_read_memory (data_address - auxv_pair_size, ptr_buf,
+ ptr_size) != 0)
+ return -1;
+
+ if (extract_typed_address (ptr_buf, ptr_type) == AT_NULL)
+ return 0;
}
- *data = auxv;
- return auxv_pos;
+ retval = 0;
+ block = 0x400;
+ gdb_assert (block % auxv_pair_size == 0);
+
+ while (len > 0)
+ {
+ if (block > len)
+ block = len;
+
+ /* Reading sizes smaller than AUXV_PAIR_SIZE is not supported. Tails
+ unaligned to AUXV_PAIR_SIZE will not be read during a call (they
+ should be completed during next read with new/extended buffer). */
+
+ block &= -auxv_pair_size;
+ if (block == 0)
+ return retval;
+
+ if (target_read_memory (data_address, readbuf, block) != 0)
+ {
+ if (block <= auxv_pair_size)
+ return retval;
+
+ block = auxv_pair_size;
+ continue;
+ }
+
+ data_address += block;
+ len -= block;
+
+ /* Check terminal AT_NULL. This function is being called indefinitely
+ being extended its READBUF until it returns EOF (0). */
+
+ while (block >= auxv_pair_size)
+ {
+ retval += auxv_pair_size;
+
+ if (extract_typed_address (readbuf, ptr_type) == AT_NULL)
+ return retval;
+
+ readbuf += auxv_pair_size;
+ block -= auxv_pair_size;
+ }
+ }
+
+ return retval;
+}
+
+/* This function is called like a to_xfer_partial hook, but must be
+ called with TARGET_OBJECT_AUXV. It handles access to AUXV. */
+
+LONGEST
+memory_xfer_auxv (struct target_ops *ops,
+ enum target_object object,
+ const char *annex,
+ gdb_byte *readbuf,
+ const gdb_byte *writebuf,
+ ULONGEST offset,
+ LONGEST len)
+{
+ gdb_assert (object == TARGET_OBJECT_AUXV);
+ gdb_assert (readbuf || writebuf);
+
+ /* ld_so_xfer_auxv is the only function safe for virtual executables being
+ executed by valgrind's memcheck. Using ld_so_xfer_auxv during inferior
+ startup is problematic, because ld.so symbol tables have not yet been
+ relocated. So GDB uses this function only when attaching to a process.
+ */
+
+ if (current_inferior ()->attach_flag != 0)
+ {
+ LONGEST retval;
+
+ retval = ld_so_xfer_auxv (readbuf, writebuf, offset, len);
+ if (retval != -1)
+ return retval;
+ }
+
+ return procfs_xfer_auxv (readbuf, writebuf, offset, len);
}
/* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
Return 0 if *READPTR is already at the end of the buffer.
Return -1 if there is insufficient buffer for a whole entry.
Return 1 if an entry was read into *TYPEP and *VALP. */
-int
-target_auxv_parse (struct target_ops *ops, char **readptr, char *endptr,
- CORE_ADDR *typep, CORE_ADDR *valp)
+static int
+default_auxv_parse (struct target_ops *ops, gdb_byte **readptr,
+ gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
{
- const int sizeof_auxv_field = TYPE_LENGTH (builtin_type_void_data_ptr);
- char *ptr = *readptr;
+ const int sizeof_auxv_field = gdbarch_ptr_bit (target_gdbarch)
+ / TARGET_CHAR_BIT;
+ const enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
+ gdb_byte *ptr = *readptr;
if (endptr == ptr)
return 0;
if (endptr - ptr < sizeof_auxv_field * 2)
return -1;
- *typep = extract_unsigned_integer (ptr, sizeof_auxv_field);
+ *typep = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
ptr += sizeof_auxv_field;
- *valp = extract_unsigned_integer (ptr, sizeof_auxv_field);
+ *valp = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
ptr += sizeof_auxv_field;
*readptr = ptr;
return 1;
}
+/* Read one auxv entry from *READPTR, not reading locations >= ENDPTR.
+ Return 0 if *READPTR is already at the end of the buffer.
+ Return -1 if there is insufficient buffer for a whole entry.
+ Return 1 if an entry was read into *TYPEP and *VALP. */
+int
+target_auxv_parse (struct target_ops *ops, gdb_byte **readptr,
+ gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
+{
+ struct target_ops *t;
+
+ for (t = ops; t != NULL; t = t->beneath)
+ if (t->to_auxv_parse != NULL)
+ return t->to_auxv_parse (t, readptr, endptr, typep, valp);
+
+ return default_auxv_parse (ops, readptr, endptr, typep, valp);
+}
+
/* Extract the auxiliary vector entry with a_type matching MATCH.
Return zero if no such entry was found, or -1 if there was
an error getting the information. On success, return 1 after
target_auxv_search (struct target_ops *ops, CORE_ADDR match, CORE_ADDR *valp)
{
CORE_ADDR type, val;
- char *data;
- int n = target_auxv_read (ops, &data);
- char *ptr = data;
- int ents = 0;
+ gdb_byte *data;
+ LONGEST n = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL, &data);
+ gdb_byte *ptr = data;
if (n <= 0)
return n;
fprint_target_auxv (struct ui_file *file, struct target_ops *ops)
{
CORE_ADDR type, val;
- char *data;
- int len = target_auxv_read (ops, &data);
- char *ptr = data;
+ gdb_byte *data;
+ LONGEST len = target_read_alloc (ops, TARGET_OBJECT_AUXV, NULL,
+ &data);
+ gdb_byte *ptr = data;
int ents = 0;
if (len <= 0)
while (target_auxv_parse (ops, &ptr, data + len, &type, &val) > 0)
{
- extern int addressprint;
const char *name = "???";
const char *description = "";
enum { dec, hex, str } flavor = hex;
TAG (AT_ICACHEBSIZE, _("Instruction cache block size"), dec);
TAG (AT_UCACHEBSIZE, _("Unified cache block size"), dec);
TAG (AT_IGNOREPPC, _("Entry should be ignored"), dec);
+ TAG (AT_BASE_PLATFORM, _("String identifying base platform"), str);
+ TAG (AT_RANDOM, _("Address of 16 random bytes"), hex);
+ TAG (AT_EXECFN, _("File name of executable"), str);
+ TAG (AT_SECURE, _("Boolean, was exec setuid-like?"), dec);
TAG (AT_SYSINFO, _("Special system info/entry points"), hex);
TAG (AT_SYSINFO_EHDR, _("System-supplied DSO's ELF header"), hex);
- TAG (AT_SECURE, _("Boolean, was exec setuid-like?"), dec);
TAG (AT_SUN_UID, _("Effective user ID"), dec);
TAG (AT_SUN_RUID, _("Real user ID"), dec);
TAG (AT_SUN_GID, _("Effective group ID"), dec);
_("Canonicalized file name given to execve"), str);
TAG (AT_SUN_MMU, _("String for name of MMU module"), str);
TAG (AT_SUN_LDDATA, _("Dynamic linker's data segment address"), hex);
+ TAG (AT_SUN_AUXFLAGS,
+ _("AF_SUN_ flags passed from the kernel"), hex);
}
fprintf_filtered (file, "%-4s %-20s %-30s ",
- paddr_d (type), name, description);
+ plongest (type), name, description);
switch (flavor)
{
case dec:
- fprintf_filtered (file, "%s\n", paddr_d (val));
+ fprintf_filtered (file, "%s\n", plongest (val));
break;
case hex:
- fprintf_filtered (file, "0x%s\n", paddr_nz (val));
+ fprintf_filtered (file, "%s\n", paddress (target_gdbarch, val));
break;
case str:
- if (addressprint)
- fprintf_filtered (file, "0x%s", paddr_nz (val));
- val_print_string (val, -1, 1, file);
- fprintf_filtered (file, "\n");
+ {
+ struct value_print_options opts;
+
+ get_user_print_options (&opts);
+ if (opts.addressprint)
+ fprintf_filtered (file, "%s", paddress (target_gdbarch, val));
+ val_print_string (builtin_type (target_gdbarch)->builtin_char,
+ val, -1, file, &opts);
+ fprintf_filtered (file, "\n");
+ }
break;
}
++ents;
+ if (type == AT_NULL)
+ break;
}
xfree (data);
else
{
int ents = fprint_target_auxv (gdb_stdout, ¤t_target);
+
if (ents < 0)
error (_("No auxiliary vector found, or failed reading it."));
else if (ents == 0)