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DEFINITIONS
This source file includes following definitions.
- usage
- main
- print_user
- print_group
- xgetgroups
- print_group_list
- print_full_info
/* id -- print real and effective UIDs and GIDs
Copyright (C) 1989-2005 Free Software Foundation, Inc.
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, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* Written by Arnold Robbins.
Major rewrite by David MacKenzie, djm@gnu.ai.mit.edu. */
#include <config.h>
#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include <getopt.h>
#include "system.h"
#include "error.h"
#include "quote.h"
/* The official name of this program (e.g., no `g' prefix). */
#define PROGRAM_NAME "id"
#define AUTHORS "Arnold Robbins", "David MacKenzie"
int getugroups ();
static void print_user (uid_t uid);
static void print_group (gid_t gid);
static void print_group_list (const char *username);
static void print_full_info (const char *username);
/* The name this program was run with. */
char *program_name;
/* If true, output user/group name instead of ID number. -n */
static bool use_name = false;
/* The real and effective IDs of the user to print. */
static uid_t ruid, euid;
static gid_t rgid, egid;
/* True unless errors have been encountered. */
static bool ok = true;
static struct option const longopts[] =
{
{"group", no_argument, NULL, 'g'},
{"groups", no_argument, NULL, 'G'},
{"name", no_argument, NULL, 'n'},
{"real", no_argument, NULL, 'r'},
{"user", no_argument, NULL, 'u'},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
void
usage (int status)
{
if (status != EXIT_SUCCESS)
fprintf (stderr, _("Try `%s --help' for more information.\n"),
program_name);
else
{
printf (_("Usage: %s [OPTION]... [USERNAME]\n"), program_name);
fputs (_("\
Print information for USERNAME, or the current user.\n\
\n\
-a ignore, for compatibility with other versions\n\
-g, --group print only the effective group ID\n\
-G, --groups print all group IDs\n\
-n, --name print a name instead of a number, for -ugG\n\
-r, --real print the real ID instead of the effective ID, with -ugG\n\
-u, --user print only the effective user ID\n\
"), stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
fputs (_("\
\n\
Without any OPTION, print some useful set of identified information.\n\
"), stdout);
printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
}
exit (status);
}
int
main (int argc, char **argv)
{
int optc;
/* If true, output the list of all group IDs. -G */
bool just_group_list = false;
/* If true, output only the group ID(s). -g */
bool just_group = false;
/* If true, output real UID/GID instead of default effective UID/GID. -r */
bool use_real = false;
/* If true, output only the user ID(s). -u */
bool just_user = false;
initialize_main (&argc, &argv);
program_name = argv[0];
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
atexit (close_stdout);
while ((optc = getopt_long (argc, argv, "agnruG", longopts, NULL)) != -1)
{
switch (optc)
{
case 'a':
/* Ignore -a, for compatibility with SVR4. */
break;
case 'g':
just_group = true;
break;
case 'n':
use_name = true;
break;
case 'r':
use_real = true;
break;
case 'u':
just_user = true;
break;
case 'G':
just_group_list = true;
break;
case_GETOPT_HELP_CHAR;
case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
default:
usage (EXIT_FAILURE);
}
}
if (just_user + just_group + just_group_list > 1)
error (EXIT_FAILURE, 0, _("cannot print only user and only group"));
if (just_user + just_group + just_group_list == 0 && (use_real | use_name))
error (EXIT_FAILURE, 0,
_("cannot print only names or real IDs in default format"));
if (argc - optind > 1)
{
error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
usage (EXIT_FAILURE);
}
if (argc - optind == 1)
{
struct passwd *pwd = getpwnam (argv[optind]);
if (pwd == NULL)
error (EXIT_FAILURE, 0, _("%s: No such user"), argv[optind]);
ruid = euid = pwd->pw_uid;
rgid = egid = pwd->pw_gid;
}
else
{
euid = geteuid ();
ruid = getuid ();
egid = getegid ();
rgid = getgid ();
}
if (just_user)
print_user (use_real ? ruid : euid);
else if (just_group)
print_group (use_real ? rgid : egid);
else if (just_group_list)
print_group_list (argv[optind]);
else
print_full_info (argv[optind]);
putchar ('\n');
exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
}
/* Print the name or value of user ID UID. */
static void
print_user (uid_t uid)
{
struct passwd *pwd = NULL;
if (use_name)
{
pwd = getpwuid (uid);
if (pwd == NULL)
{
error (0, 0, _("cannot find name for user ID %lu"),
(unsigned long int) uid);
ok = false;
}
}
if (pwd == NULL)
printf ("%lu", (unsigned long int) uid);
else
printf ("%s", pwd->pw_name);
}
/* Print the name or value of group ID GID. */
static void
print_group (gid_t gid)
{
struct group *grp = NULL;
if (use_name)
{
grp = getgrgid (gid);
if (grp == NULL)
{
error (0, 0, _("cannot find name for group ID %lu"),
(unsigned long int) gid);
ok = false;
}
}
if (grp == NULL)
printf ("%lu", (unsigned long int) gid);
else
printf ("%s", grp->gr_name);
}
#if HAVE_GETGROUPS
/* FIXME: document */
static bool
xgetgroups (const char *username, gid_t gid, int *n_groups,
GETGROUPS_T **groups)
{
int max_n_groups;
int ng;
GETGROUPS_T *g = NULL;
if (!username)
max_n_groups = getgroups (0, NULL);
else
max_n_groups = getugroups (0, NULL, username, gid);
if (max_n_groups < 0)
ng = -1;
else
{
g = xnmalloc (max_n_groups, sizeof *g);
if (!username)
ng = getgroups (max_n_groups, g);
else
ng = getugroups (max_n_groups, g, username, gid);
}
if (ng < 0)
{
error (0, errno, _("cannot get supplemental group list"));
free (g);
return false;
}
else
{
*n_groups = ng;
*groups = g;
return true;
}
}
#endif /* HAVE_GETGROUPS */
/* Print all of the distinct groups the user is in. */
static void
print_group_list (const char *username)
{
struct passwd *pwd;
pwd = getpwuid (ruid);
if (pwd == NULL)
ok = false;
print_group (rgid);
if (egid != rgid)
{
putchar (' ');
print_group (egid);
}
#if HAVE_GETGROUPS
{
int n_groups;
GETGROUPS_T *groups;
int i;
if (! xgetgroups (username, (pwd ? pwd->pw_gid : (gid_t) -1),
&n_groups, &groups))
{
ok = false;
return;
}
for (i = 0; i < n_groups; i++)
if (groups[i] != rgid && groups[i] != egid)
{
putchar (' ');
print_group (groups[i]);
}
free (groups);
}
#endif /* HAVE_GETGROUPS */
}
/* Print all of the info about the user's user and group IDs. */
static void
print_full_info (const char *username)
{
struct passwd *pwd;
struct group *grp;
printf ("uid=%lu", (unsigned long int) ruid);
pwd = getpwuid (ruid);
if (pwd)
printf ("(%s)", pwd->pw_name);
printf (" gid=%lu", (unsigned long int) rgid);
grp = getgrgid (rgid);
if (grp)
printf ("(%s)", grp->gr_name);
if (euid != ruid)
{
printf (" euid=%lu", (unsigned long int) euid);
pwd = getpwuid (euid);
if (pwd)
printf ("(%s)", pwd->pw_name);
}
if (egid != rgid)
{
printf (" egid=%lu", (unsigned long int) egid);
grp = getgrgid (egid);
if (grp)
printf ("(%s)", grp->gr_name);
}
#if HAVE_GETGROUPS
{
int n_groups;
GETGROUPS_T *groups;
int i;
if (! xgetgroups (username, (pwd ? pwd->pw_gid : (gid_t) -1),
&n_groups, &groups))
{
ok = false;
return;
}
if (n_groups > 0)
fputs (_(" groups="), stdout);
for (i = 0; i < n_groups; i++)
{
if (i > 0)
putchar (',');
printf ("%lu", (unsigned long int) groups[i]);
grp = getgrgid (groups[i]);
if (grp)
printf ("(%s)", grp->gr_name);
}
free (groups);
}
#endif /* HAVE_GETGROUPS */
}