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| -rw-r--r-- | id.c | 147 |
1 files changed, 147 insertions, 0 deletions
@@ -0,0 +1,147 @@ +/* + * UNG's Not GNU + * + * Copyright (c) 2011-2014, Jakob Kaivo <jakob@kaivo.net> + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +#include <stdio.h> +#include <pwd.h> +#include <grp.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> + +const char *id_desc = "return user identity"; +const char *id_inv = "id [user]\nid -G [-n] [user]\nid -g [-nr] user\nid -u [-nr] [user]"; + +#define FULL 0 +#define NAMES 1 +#define NUMS 2 + +void id_printgids (char *user, int mode) +{ + struct group *gr = NULL; + struct group *current = NULL; + int num_groups = 0; + char sep = ' '; + int i = 0; + + setgrent(); + while ((current = getgrent()) != NULL) { + for (i = 0; current->gr_mem[i] != NULL; i++) { + if (!strcmp (user, current->gr_mem[i])) { + num_groups++; + gr = realloc (gr, num_groups * sizeof(struct group)); + gr[num_groups-1].gr_gid = current->gr_gid; + gr[num_groups-1].gr_name = strdup (current->gr_name); + } + } + } + endgrent(); + + if (mode == FULL && num_groups > 0) { + printf (" groups="); + sep = ','; + } + + while (i < num_groups) { + if (i > 0) + putchar (sep); + switch (mode) { + case NAMES: + printf ("%s", gr[i].gr_name); + break; + case NUMS: + printf ("%u", gr[i].gr_gid); + break; + default: + printf ("%u(%s)", gr[i].gr_gid, gr[i].gr_name); + break; + } + free (gr[i].gr_name); + i++; + } + free (gr); +} + +int +main (int argc, char **argv) +{ + int n = 0, r = 0; + char mode = 0; + int c; + struct passwd pw; + struct group gr; + + while ((c = getopt (argc, argv, ":Ggunr")) != -1) { + switch (c) { + case 'G': + case 'g': + case 'u': + if (mode) + return 1; + mode = c; + break; + case 'n': + n = 1; + break; + case 'r': + r = 1; + break; + default: + return 1; + } + } + + if ((mode == 0 && (n == 1 || r == 1)) || (mode == 'G' && r == 1)) + return 1; + + if (optind >= argc) + pw = *getpwuid (mode == 'u' && r == 0 ? geteuid() : getuid()); + else if (optind == argc -1) + pw = *getpwnam (argv[optind]); + else + return 1; + + switch (mode) { + case 'G': + id_printgids (pw.pw_name, n ? NAMES : NUMS); + break; + case 'g': + gr = *getgrgid (r ? getgid() : getegid()); + if (n) printf ("%s", gr.gr_name); + else printf ("%u", gr.gr_gid); + break; + case 'u': + if (n) printf ("%s", pw.pw_name); + else printf ("%u", pw.pw_uid); + break; + default: + gr = *getgrgid (pw.pw_uid == getuid() ? getgid() : pw.pw_gid); + printf ("uid=%u(%s) gid=%u(%s)", pw.pw_uid, pw.pw_name, gr.gr_gid, gr.gr_name); + if (pw.pw_uid != geteuid()) { + pw = *getpwuid (geteuid()); + printf (" euid=%u(%s)", pw.pw_uid, pw.pw_name); + } + if (gr.gr_gid != getegid()) { + gr = *getgrgid (getegid()); + printf (" egid=%u(%s)", gr.gr_gid, gr.gr_name); + } + id_printgids (pw.pw_name, FULL); + } + printf ("\n"); + return 0; +} |