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Diffstat (limited to 'src/id.c')
| -rw-r--r-- | src/id.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/src/id.c b/src/id.c new file mode 100644 index 0000000..7abb3e5 --- /dev/null +++ b/src/id.c @@ -0,0 +1,388 @@ +/* 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 */ +} |