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/*
* UNG's Not GNU
*
* Copyright (c) 2011-2019, Jakob Kaivo <jkk@ung.org>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#define _XOPEN_SOURCE 700
#include <grp.h>
#include <pwd.h>
#include <locale.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
enum type { USER, GROUP };
enum mode { DEFAULT, UID, GID, ALL_GID };
enum display { FULL, NAMES, NUMBERS };
static char *get_name(enum type type, id_t id)
{
if (type == GROUP) {
struct group *grp = getgrgid(id);
if (grp) {
return grp->gr_name;
}
} else {
struct passwd *pwd = getpwuid(id);
if (pwd) {
return pwd->pw_name;
}
}
return NULL;
}
static void print_id(const char *prefix, const char *name, id_t id, enum display mode)
{
printf("%s", prefix);
if (mode == FULL || mode == NUMBERS || name == NULL) {
printf("%ju", (uintmax_t)id);
}
if (name != NULL) {
if (mode == FULL) {
printf("(%s)", name);
} else if (mode == NAMES) {
printf("%s", name);
}
}
}
static void print_groups(uid_t uid, gid_t rgid, gid_t egid, enum display mode)
{
char *name = get_name(USER, uid);
if (name == NULL) {
return;
}
char *prefix = "";
if (mode == FULL) {
prefix = " groups=";
}
print_id(prefix, get_name(GROUP, rgid), rgid, mode);
if (mode == FULL) {
prefix = ",";
} else {
prefix = " ";
}
if (rgid != egid) {
print_id(prefix, get_name(GROUP, egid), egid, mode);
}
struct group *grp = NULL;
setgrent();
while ((grp = getgrent()) != NULL) {
if (grp->gr_gid == rgid || grp->gr_gid == egid) {
continue;
}
for (int i = 0; grp->gr_mem[i] != NULL; i++) {
if (!strcmp(name, grp->gr_mem[i])) {
print_id(prefix, grp->gr_name, grp->gr_gid, mode);
}
}
}
endgrent();
}
int main(int argc, char *argv[])
{
enum display dmode = NUMBERS;
enum mode mode = DEFAULT;
uid_t ruid = getuid();
uid_t euid = geteuid();
gid_t rgid = getgid();
gid_t egid = getegid();
uid_t uid = euid;
gid_t gid = egid;
setlocale(LC_ALL, "");
int c;
while ((c = getopt(argc, argv, "Ggunr")) != -1) {
switch (c) {
case 'G':
mode = ALL_GID;
break;
case 'g':
mode = GID;
break;
case 'u':
mode = UID;
break;
case 'n':
dmode = NAMES;
break;
case 'r':
uid = ruid;
gid = rgid;
break;
default:
return 1;
}
}
/* TODO: validate arguments together */
if (optind < argc - 1) {
fprintf(stderr, "id: too many operands\n");
return 1;
}
if (optind == argc - 1) {
struct passwd *pwd = getpwnam(argv[optind]);
if (pwd == NULL) {
fprintf(stderr, "id: user '%s' not found\n",
argv[optind]);
return 1;
}
uid = ruid = euid = pwd->pw_uid;
gid = rgid = egid = pwd->pw_gid;
}
if (mode == ALL_GID) {
print_groups(uid, rgid, egid, dmode);
} else if (mode == GID) {
print_id("", get_name(GROUP, gid), gid, dmode);
} else if (mode == UID) {
print_id("", get_name(USER, uid), uid, dmode);
} else {
print_id("uid=", get_name(USER, ruid), ruid, 0);
print_id(" gid=", get_name(GROUP, rgid), rgid, 0);
if (ruid != euid) {
print_id(" euid=", get_name(USER, euid), euid, 0);
}
if (rgid != egid) {
print_id(" egid=", get_name(GROUP, egid), egid, 0);
}
print_groups(ruid, rgid, egid, FULL);
}
printf("\n");
return 0;
}
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