glibc/elf/pldd.c

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/* List dynamic shared objects linked into given process.
Copyright (C) 2011-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
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#include <alloca.h>
#include <argp.h>
#include <assert.h>
#include <dirent.h>
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#include <elf.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <libintl.h>
#include <link.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <sys/stat.h>
#include <sys/wait.h>
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#include <ldsodefs.h>
#include <version.h>
/* Global variables. */
extern char *program_invocation_short_name;
#define PACKAGE _libc_intl_domainname
/* External functions. */
#include <programs/xmalloc.h>
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/* Name and version of program. */
static void print_version (FILE *stream, struct argp_state *state);
void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;
/* Function to print some extra text in the help message. */
static char *more_help (int key, const char *text, void *input);
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/* Definitions of arguments for argp functions. */
static const struct argp_option options[] =
{
{ NULL, 0, NULL, 0, NULL }
};
/* Short description of program. */
static const char doc[] = N_("\
List dynamic shared objects loaded into process.");
/* Strings for arguments in help texts. */
static const char args_doc[] = N_("PID");
/* Prototype for option handler. */
static error_t parse_opt (int key, char *arg, struct argp_state *state);
/* Data structure to communicate with argp functions. */
static struct argp argp =
{
options, parse_opt, args_doc, doc, NULL, more_help, NULL
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};
// File descriptor of /proc/*/mem file.
static int memfd;
/* Name of the executable */
static char *exe;
/* Local functions. */
static int get_process_info (int dfd, long int pid);
static void wait_for_ptrace_stop (long int pid);
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int
main (int argc, char *argv[])
{
/* Parse and process arguments. */
int remaining;
argp_parse (&argp, argc, argv, 0, &remaining, NULL);
if (remaining != argc - 1)
{
fprintf (stderr,
gettext ("Exactly one parameter with process ID required.\n"));
argp_help (&argp, stderr, ARGP_HELP_SEE, program_invocation_short_name);
return 1;
}
assert (sizeof (pid_t) == sizeof (int)
|| sizeof (pid_t) == sizeof (long int));
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char *endp;
errno = 0;
long int pid = strtol (argv[remaining], &endp, 10);
if (pid < 0 || (pid == ULONG_MAX && errno == ERANGE) || *endp != '\0'
|| (sizeof (pid_t) < sizeof (pid) && pid > INT_MAX))
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error (EXIT_FAILURE, 0, gettext ("invalid process ID '%s'"),
argv[remaining]);
/* Determine the program name. */
char buf[7 + 3 * sizeof (pid)];
snprintf (buf, sizeof (buf), "/proc/%lu", pid);
int dfd = open (buf, O_RDONLY | O_DIRECTORY);
if (dfd == -1)
error (EXIT_FAILURE, errno, gettext ("cannot open %s"), buf);
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size_t exesize = 1024;
#ifdef PATH_MAX
exesize = PATH_MAX;
#endif
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exe = alloca (exesize);
ssize_t nexe;
while ((nexe = readlinkat (dfd, "exe", exe, exesize)) == exesize)
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extend_alloca (exe, exesize, 2 * exesize);
if (nexe == -1)
exe = (char *) "<program name undetermined>";
else
exe[nexe] = '\0';
/* Stop all threads since otherwise the list of loaded modules might
change while we are reading it. */
struct thread_list
{
pid_t tid;
struct thread_list *next;
} *thread_list = NULL;
int taskfd = openat (dfd, "task", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (taskfd == 1)
error (EXIT_FAILURE, errno, gettext ("cannot open %s/task"), buf);
DIR *dir = fdopendir (taskfd);
if (dir == NULL)
error (EXIT_FAILURE, errno, gettext ("cannot prepare reading %s/task"),
buf);
struct dirent64 *d;
while ((d = readdir64 (dir)) != NULL)
{
if (! isdigit (d->d_name[0]))
continue;
errno = 0;
long int tid = strtol (d->d_name, &endp, 10);
if (tid < 0 || (tid == ULONG_MAX && errno == ERANGE) || *endp != '\0'
|| (sizeof (pid_t) < sizeof (pid) && tid > INT_MAX))
error (EXIT_FAILURE, 0, gettext ("invalid thread ID '%s'"),
d->d_name);
if (ptrace (PTRACE_ATTACH, tid, NULL, NULL) != 0)
{
/* There might be a race between reading the directory and
threads terminating. Ignore errors attaching to unknown
threads unless this is the main thread. */
if (errno == ESRCH && tid != pid)
continue;
error (EXIT_FAILURE, errno, gettext ("cannot attach to process %lu"),
tid);
}
wait_for_ptrace_stop (tid);
struct thread_list *newp = alloca (sizeof (*newp));
newp->tid = tid;
newp->next = thread_list;
thread_list = newp;
}
closedir (dir);
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int status = get_process_info (dfd, pid);
assert (thread_list != NULL);
do
{
ptrace (PTRACE_DETACH, thread_list->tid, NULL, NULL);
thread_list = thread_list->next;
}
while (thread_list != NULL);
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close (dfd);
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return status;
}
/* Wait for PID to enter ptrace-stop state after being attached. */
static void
wait_for_ptrace_stop (long int pid)
{
int status;
/* While waiting for SIGSTOP being delivered to the tracee we have to
reinject any other pending signal. Ignore all other errors. */
while (waitpid (pid, &status, __WALL) == pid && WIFSTOPPED (status))
{
/* The STOP signal should not be delivered to the tracee. */
if (WSTOPSIG (status) == SIGSTOP)
return;
if (ptrace (PTRACE_CONT, pid, NULL,
(void *) (uintptr_t) WSTOPSIG (status)))
/* The only possible error is that the process died. */
return;
}
}
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/* Handle program arguments. */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
switch (key)
{
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
/* Print bug-reporting information in the help message. */
static char *
more_help (int key, const char *text, void *input)
{
char *tp = NULL;
switch (key)
{
case ARGP_KEY_HELP_EXTRA:
/* We print some extra information. */
if (asprintf (&tp, gettext ("\
For bug reporting instructions, please see:\n\
%s.\n"), REPORT_BUGS_TO) < 0)
return NULL;
return tp;
default:
break;
}
return (char *) text;
}
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/* Print the version information. */
static void
print_version (FILE *stream, struct argp_state *state)
{
fprintf (stream, "pldd %s%s\n", PKGVERSION, VERSION);
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fprintf (stream, gettext ("\
Copyright (C) %s Free Software Foundation, Inc.\n\
This is free software; see the source for copying conditions. There is NO\n\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
"), "2014");
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fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
}
#define CLASS 32
#include "pldd-xx.c"
#define CLASS 64
#include "pldd-xx.c"
static int
get_process_info (int dfd, long int pid)
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{
memfd = openat (dfd, "mem", O_RDONLY);
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if (memfd == -1)
goto no_info;
int fd = openat (dfd, "exe", O_RDONLY);
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if (fd == -1)
{
no_info:
error (0, errno, gettext ("cannot get information about process %lu"),
pid);
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return EXIT_FAILURE;
}
char e_ident[EI_NIDENT];
if (read (fd, e_ident, EI_NIDENT) != EI_NIDENT)
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goto no_info;
close (fd);
if (memcmp (e_ident, ELFMAG, SELFMAG) != 0)
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{
error (0, 0, gettext ("process %lu is no ELF program"), pid);
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return EXIT_FAILURE;
}
fd = openat (dfd, "auxv", O_RDONLY);
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if (fd == -1)
goto no_info;
size_t auxv_size = 0;
void *auxv = NULL;
while (1)
{
auxv_size += 512;
auxv = xrealloc (auxv, auxv_size);
ssize_t n = pread (fd, auxv, auxv_size, 0);
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if (n < 0)
goto no_info;
if (n < auxv_size)
{
auxv_size = n;
break;
}
}
close (fd);
int retval;
if (e_ident[EI_CLASS] == ELFCLASS32)
retval = find_maps32 (pid, auxv, auxv_size);
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else
retval = find_maps64 (pid, auxv, auxv_size);
free (auxv);
close (memfd);
return retval;
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}