blob: 8504a5f3afc1a88668e300edecd0b3f59dd22f90 [file] [log] [blame]
/* Standard libdwfl callbacks for debugging a live Linux process.
Copyright (C) 2005-2010 Red Hat, Inc.
This file is part of Red Hat elfutils.
Red Hat elfutils 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; version 2 of the License.
Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
In addition, as a special exception, Red Hat, Inc. gives You the
additional right to link the code of Red Hat elfutils with code licensed
under any Open Source Initiative certified open source license
(http://www.opensource.org/licenses/index.php) which requires the
distribution of source code with any binary distribution and to
distribute linked combinations of the two. Non-GPL Code permitted under
this exception must only link to the code of Red Hat elfutils through
those well defined interfaces identified in the file named EXCEPTION
found in the source code files (the "Approved Interfaces"). The files
of Non-GPL Code may instantiate templates or use macros or inline
functions from the Approved Interfaces without causing the resulting
work to be covered by the GNU General Public License. Only Red Hat,
Inc. may make changes or additions to the list of Approved Interfaces.
Red Hat's grant of this exception is conditioned upon your not adding
any new exceptions. If you wish to add a new Approved Interface or
exception, please contact Red Hat. You must obey the GNU General Public
License in all respects for all of the Red Hat elfutils code and other
code used in conjunction with Red Hat elfutils except the Non-GPL Code
covered by this exception. If you modify this file, you may extend this
exception to your version of the file, but you are not obligated to do
so. If you do not wish to provide this exception without modification,
you must delete this exception statement from your version and license
this file solely under the GPL without exception.
Red Hat elfutils is an included package of the Open Invention Network.
An included package of the Open Invention Network is a package for which
Open Invention Network licensees cross-license their patents. No patent
license is granted, either expressly or impliedly, by designation as an
included package. Should you wish to participate in the Open Invention
Network licensing program, please visit www.openinventionnetwork.com
<http://www.openinventionnetwork.com>. */
#include "libdwflP.h"
#include <inttypes.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <endian.h>
#define PROCMAPSFMT "/proc/%d/maps"
#define PROCMEMFMT "/proc/%d/mem"
#define PROCAUXVFMT "/proc/%d/auxv"
/* Search /proc/PID/auxv for the AT_SYSINFO_EHDR tag. */
static int
grovel_auxv (pid_t pid, Dwfl *dwfl, GElf_Addr *sysinfo_ehdr)
{
char *fname;
if (asprintf (&fname, PROCAUXVFMT, pid) < 0)
return ENOMEM;
int fd = open64 (fname, O_RDONLY);
free (fname);
if (fd < 0)
return errno == ENOENT ? 0 : errno;
ssize_t nread;
do
{
union
{
char buffer[sizeof (long int) * 2 * 64];
Elf64_auxv_t a64[sizeof (long int) * 2 * 64 / sizeof (Elf64_auxv_t)];
Elf32_auxv_t a32[sizeof (long int) * 2 * 32 / sizeof (Elf32_auxv_t)];
} d;
nread = read (fd, &d, sizeof d);
if (nread > 0)
{
switch (sizeof (long int))
{
case 4:
for (size_t i = 0; (char *) &d.a32[i] < &d.buffer[nread]; ++i)
if (d.a32[i].a_type == AT_SYSINFO_EHDR)
{
*sysinfo_ehdr = d.a32[i].a_un.a_val;
if (dwfl->segment_align > 1)
{
nread = 0;
break;
}
}
else if (d.a32[i].a_type == AT_PAGESZ
&& dwfl->segment_align <= 1)
dwfl->segment_align = d.a32[i].a_un.a_val;
break;
case 8:
for (size_t i = 0; (char *) &d.a64[i] < &d.buffer[nread]; ++i)
if (d.a64[i].a_type == AT_SYSINFO_EHDR)
{
*sysinfo_ehdr = d.a64[i].a_un.a_val;
if (dwfl->segment_align > 1)
{
nread = 0;
break;
}
}
else if (d.a64[i].a_type == AT_PAGESZ
&& dwfl->segment_align <= 1)
dwfl->segment_align = d.a64[i].a_un.a_val;
break;
default:
abort ();
break;
}
}
}
while (nread > 0);
close (fd);
return nread < 0 ? errno : 0;
}
static int
proc_maps_report (Dwfl *dwfl, FILE *f, GElf_Addr sysinfo_ehdr, pid_t pid)
{
unsigned int last_dmajor = -1, last_dminor = -1;
uint64_t last_ino = -1;
char *last_file = NULL;
Dwarf_Addr low = 0, high = 0;
inline bool report (void)
{
if (last_file != NULL)
{
Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, last_file,
low, high);
free (last_file);
last_file = NULL;
if (unlikely (mod == NULL))
return true;
}
return false;
}
char *line = NULL;
size_t linesz;
ssize_t len;
while ((len = getline (&line, &linesz, f)) > 0)
{
if (line[len - 1] == '\n')
line[len - 1] = '\0';
Dwarf_Addr start, end, offset;
unsigned int dmajor, dminor;
uint64_t ino;
int nread = -1;
if (sscanf (line, "%" PRIx64 "-%" PRIx64 " %*s %" PRIx64
" %x:%x %" PRIi64 " %n",
&start, &end, &offset, &dmajor, &dminor, &ino, &nread) < 6
|| nread <= 0)
{
free (line);
return ENOEXEC;
}
/* If this is the special mapping AT_SYSINFO_EHDR pointed us at,
report the last one and then this special one. */
if (start == sysinfo_ehdr && start != 0)
{
if (report ())
{
bad_report:
free (line);
fclose (f);
return -1;
}
low = start;
high = end;
if (asprintf (&last_file, "[vdso: %d]", (int) pid) < 0
|| report ())
goto bad_report;
}
char *file = line + nread + strspn (line + nread, " \t");
if (file[0] == '\0' || (ino == 0 && dmajor == 0 && dminor == 0))
/* This line doesn't indicate a file mapping. */
continue;
if (last_file != NULL
&& ino == last_ino && dmajor == last_dmajor && dminor == last_dminor)
{
/* This is another portion of the same file's mapping. */
assert (!strcmp (last_file, file));
high = end;
}
else
{
/* This is a different file mapping. Report the last one. */
if (report ())
goto bad_report;
low = start;
high = end;
last_file = strdup (file);
last_ino = ino;
last_dmajor = dmajor;
last_dminor = dminor;
}
}
free (line);
int result = ferror_unlocked (f) ? errno : feof_unlocked (f) ? 0 : ENOEXEC;
/* Report the final one. */
bool lose = report ();
return result != 0 ? result : lose ? -1 : 0;
}
int
dwfl_linux_proc_maps_report (Dwfl *dwfl, FILE *f)
{
return proc_maps_report (dwfl, f, 0, 0);
}
INTDEF (dwfl_linux_proc_maps_report)
int
dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid)
{
if (dwfl == NULL)
return -1;
/* We'll notice the AT_SYSINFO_EHDR address specially when we hit it. */
GElf_Addr sysinfo_ehdr = 0;
int result = grovel_auxv (pid, dwfl, &sysinfo_ehdr);
if (result != 0)
return result;
char *fname;
if (asprintf (&fname, PROCMAPSFMT, pid) < 0)
return ENOMEM;
FILE *f = fopen (fname, "r");
free (fname);
if (f == NULL)
return errno;
(void) __fsetlocking (f, FSETLOCKING_BYCALLER);
result = proc_maps_report (dwfl, f, sysinfo_ehdr, pid);
fclose (f);
return result;
}
INTDEF (dwfl_linux_proc_report)
static ssize_t
read_proc_memory (void *arg, void *data, GElf_Addr address,
size_t minread, size_t maxread)
{
const int fd = *(const int *) arg;
ssize_t nread = pread64 (fd, data, maxread, (off64_t) address);
/* Some kernels don't actually let us do this read, ignore those errors. */
if (nread < 0 && (errno == EINVAL || errno == EPERM))
return 0;
if (nread > 0 && (size_t) nread < minread)
nread = 0;
return nread;
}
extern Elf *elf_from_remote_memory (GElf_Addr ehdr_vma,
GElf_Addr *loadbasep,
ssize_t (*read_memory) (void *arg,
void *data,
GElf_Addr address,
size_t minread,
size_t maxread),
void *arg);
/* Dwfl_Callbacks.find_elf */
int
dwfl_linux_proc_find_elf (Dwfl_Module *mod __attribute__ ((unused)),
void **userdata __attribute__ ((unused)),
const char *module_name, Dwarf_Addr base,
char **file_name, Elf **elfp)
{
if (module_name[0] == '/')
{
int fd = open64 (module_name, O_RDONLY);
if (fd >= 0)
{
*file_name = strdup (module_name);
if (*file_name == NULL)
{
close (fd);
return ENOMEM;
}
}
return fd;
}
int pid;
if (sscanf (module_name, "[vdso: %d]", &pid) == 1)
{
/* Special case for in-memory ELF image. */
char *fname;
if (asprintf (&fname, PROCMEMFMT, pid) < 0)
return -1;
int fd = open64 (fname, O_RDONLY);
free (fname);
if (fd < 0)
return -1;
*elfp = elf_from_remote_memory (base, NULL, &read_proc_memory, &fd);
close (fd);
*file_name = NULL;
return -1;
}
abort ();
return -1;
}
INTDEF (dwfl_linux_proc_find_elf)