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/* vi: set sw=4 ts=4:
*
* id.c - print real and effective user and group IDs
*
* Copyright 2012 Sony Network Entertainment, Inc.
*
* by Tim Bird <tim.bird@am.sony.com>
*
* See http://www.opengroup.org/onlinepubs/009695399/utilities/id.html
USE_ID(NEWTOY(id, "nGgru", TOYFLAG_BIN))
config ID
bool "id"
default y
help
usage: id [-nGgru]
Print user and group ID.
-n print names instead of numeric IDs (to be used with -Ggu)
-G Show only the group IDs
-g Show only the effective group ID
-r Show real ID instead of effective ID
-u Show only the effective user ID
*/
#include <sys/types.h>
#include <pwd.h>
#include <grp.h>
#include "toys.h"
#define FLAG_n (1<<4)
#define FLAG_G (1<<3)
#define FLAG_g (1<<2)
#define FLAG_r (1<<1)
#define FLAG_u 1
void
pretty_print(struct passwd *pw, struct group *grp, struct group **grps, int n)
{
int i;
printf("uid= %d(%s) gid= %d(%s)", pw->pw_uid, pw->pw_name,
grp->gr_gid, grp->gr_name);
if (n) {
printf(" groups= ");
}
for (i = 0; i < n; i++) {
printf("%d(%s)%s", grps[i]->gr_gid, grps[i]->gr_name,
(i < n-1) ? ",": "");
}
printf("\n");
}
void id_main(void)
{
int flags = toys.optflags;
struct passwd *pw;
struct group *grp;
struct group **grps;
uid_t uid;
gid_t gid;
gid_t *groups;
int i;
int ngroups;
char *username;
/* check if a username is given */
if (*toys.optargs) {
username = *(toys.optargs);
pw = getpwnam(username);
if (!pw) {
printf("id: %s: no such user\n", username);
toys.exitval = 1;
return;
}
uid = pw->pw_uid;
gid = pw->pw_gid;
} else {
/* show effective, unless user specifies real */
if (flags & FLAG_r) {
uid = getuid();
gid = getgid();
} else {
uid = geteuid();
gid = getegid();
}
}
pw = getpwuid(uid);
if (!pw) {
perror("id");
toys.exitval = 1;
return;
}
grp = getgrgid(pw->pw_gid);
if (!grp) {
perror("id");
toys.exitval = 1;
return;
}
if (flags & FLAG_u) {
if (flags & FLAG_n)
printf("%s\n", pw->pw_name);
else
printf("%d\n", pw->pw_uid);
return;
}
if (flags & FLAG_g) {
if (flags & FLAG_n)
printf("%s\n", grp->gr_name);
else
printf("%d\n", grp->gr_gid);
return;
}
if (flags & FLAG_r) {
printf("-r can only be used in combination with -u or -g\n");
toys.exitval = 1;
return;
}
ngroups = sysconf(_SC_NGROUPS_MAX);
/* fallback for number of groups to 32 */
if (ngroups < 0)
ngroups = 32;
groups = malloc(ngroups * sizeof(gid_t));
if (!groups) {
perror("id");
toys.exitval = 1;
return;
}
if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups) < 0) {
perror("id");
toys.exitval = 1;
return;
}
grps = malloc(ngroups * sizeof(struct group *));
for (i = 0; i < ngroups; i++) {
struct group *tmp;
grps[i] = malloc(sizeof(struct group));
size_t f = sysconf(_SC_GETGR_R_SIZE_MAX);
char *buf = malloc(f);
if (getgrgid_r(groups[i], grps[i], buf, f, &tmp) < 0) {
perror("id");
continue;
}
if (tmp == NULL) {
perror("id");
continue;
}
}
if (flags & FLAG_G) {
for (i = 0; i < ngroups; i++) {
if (flags & FLAG_n)
printf("%s%s", !i ? "" : " ", grps[i]->gr_name);
else
printf("%s%d", !i ? "" : " ", grps[i]->gr_gid);
}
printf("\n");
return;
}
pretty_print(pw, grp, grps, ngroups);
for (i=0; i < ngroups; i++)
free(grps[i]);
}
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