binutils-gdb/gdb/auxv.c

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/* Auxiliary vector support for GDB, the GNU debugger.
Copyright 2004 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
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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. */
#include "defs.h"
#include "target.h"
#include "gdbtypes.h"
#include "command.h"
#include "inferior.h"
#include "valprint.h"
#include "gdb_assert.h"
#include "auxv.h"
#include "elf/common.h"
#include <unistd.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. */
LONGEST
procfs_xfer_auxv (struct target_ops *ops,
int /* enum target_object */ object,
const char *annex,
void *readbuf,
const void *writebuf,
ULONGEST offset,
LONGEST len)
{
char *pathname;
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);
if (fd < 0)
return -1;
if (offset != (ULONGEST) 0
&& lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
n = -1;
else if (readbuf != NULL)
n = read (fd, readbuf, len);
else
n = write (fd, writebuf, len);
(void) close (fd);
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)
{
size_t auxv_alloc = 512, auxv_pos = 0;
char *auxv = xmalloc (auxv_alloc);
int n;
while (1)
{
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 (auxv_pos == 0)
{
xfree (auxv);
*data = NULL;
return n;
}
*data = auxv;
return auxv_pos;
}
/* 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)
{
const int sizeof_auxv_field = TYPE_LENGTH (builtin_type_void_data_ptr);
char *ptr = *readptr;
if (endptr == ptr)
return 0;
if (endptr - ptr < sizeof_auxv_field * 2)
return -1;
*typep = extract_unsigned_integer (ptr, sizeof_auxv_field);
ptr += sizeof_auxv_field;
*valp = extract_unsigned_integer (ptr, sizeof_auxv_field);
ptr += sizeof_auxv_field;
*readptr = ptr;
return 1;
}
/* 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
storing the entry's value field in *VALP. */
int
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;
if (n <= 0)
return n;
while (1)
switch (target_auxv_parse (ops, &ptr, data + n, &type, &val))
{
case 1: /* Here's an entry, check it. */
if (type == match)
{
xfree (data);
*valp = val;
return 1;
}
break;
case 0: /* End of the vector. */
xfree (data);
return 0;
default: /* Bogosity. */
xfree (data);
return -1;
}
/*NOTREACHED*/
}
/* Print the contents of the target's AUXV on the specified file. */
int
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;
int ents = 0;
if (len <= 0)
return len;
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;
switch (type)
{
#define TAG(tag, text, kind) \
case tag: name = #tag; description = text; flavor = kind; break
TAG (AT_NULL, _("End of vector"), hex);
TAG (AT_IGNORE, _("Entry should be ignored"), hex);
TAG (AT_EXECFD, _("File descriptor of program"), dec);
TAG (AT_PHDR, _("Program headers for program"), hex);
TAG (AT_PHENT, _("Size of program header entry"), dec);
TAG (AT_PHNUM, _("Number of program headers"), dec);
TAG (AT_PAGESZ, _("System page size"), dec);
TAG (AT_BASE, _("Base address of interpreter"), hex);
TAG (AT_FLAGS, _("Flags"), hex);
TAG (AT_ENTRY, _("Entry point of program"), hex);
TAG (AT_NOTELF, _("Program is not ELF"), dec);
TAG (AT_UID, _("Real user ID"), dec);
TAG (AT_EUID, _("Effective user ID"), dec);
TAG (AT_GID, _("Real group ID"), dec);
TAG (AT_EGID, _("Effective group ID"), dec);
TAG (AT_CLKTCK, _("Frequency of times()"), dec);
TAG (AT_PLATFORM, _("String identifying platform"), str);
TAG (AT_HWCAP, _("Machine-dependent CPU capability hints"), hex);
TAG (AT_FPUCW, _("Used FPU control word"), dec);
TAG (AT_DCACHEBSIZE, _("Data cache block size"), dec);
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_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);
TAG (AT_SUN_RGID, _("Real group ID"), dec);
TAG (AT_SUN_LDELF, _("Dynamic linker's ELF header"), hex);
TAG (AT_SUN_LDSHDR, _("Dynamic linker's section headers"), hex);
TAG (AT_SUN_LDNAME, _("String giving name of dynamic linker"), str);
TAG (AT_SUN_LPAGESZ, _("Large pagesize"), dec);
TAG (AT_SUN_PLATFORM, _("Platform name string"), str);
TAG (AT_SUN_HWCAP, _("Machine-dependent CPU capability hints"), hex);
TAG (AT_SUN_IFLUSH, _("Should flush icache?"), dec);
TAG (AT_SUN_CPU, _("CPU name string"), str);
TAG (AT_SUN_EMUL_ENTRY, _("COFF entry point address"), hex);
TAG (AT_SUN_EMUL_EXECFD, _("COFF executable file descriptor"), dec);
TAG (AT_SUN_EXECNAME,
_("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);
}
fprintf_filtered (file, "%-4s %-20s %-30s ",
paddr_d (type), name, description);
switch (flavor)
{
case dec:
fprintf_filtered (file, "%s\n", paddr_d (val));
break;
case hex:
fprintf_filtered (file, "0x%s\n", paddr_nz (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");
break;
}
++ents;
}
xfree (data);
return ents;
}
static void
info_auxv_command (char *cmd, int from_tty)
{
if (! target_has_stack)
error (_("The program has no auxiliary information now."));
else
{
int ents = fprint_target_auxv (gdb_stdout, &current_target);
if (ents < 0)
error (_("No auxiliary vector found, or failed reading it."));
else if (ents == 0)
error (_("Auxiliary vector is empty."));
}
}
extern initialize_file_ftype _initialize_auxv; /* -Wmissing-prototypes; */
void
_initialize_auxv (void)
{
add_info ("auxv", info_auxv_command,
_("Display the inferior's auxiliary vector.\n\
This is information provided by the operating system at program startup."));
}