Add support to display user and group info for any user

Currently we only handle login names - it should be trivial to
fix to allow for parsing UIDs as well.
This commit is contained in:
sin 2013-12-01 10:40:14 +00:00
parent 137ebef3ac
commit dac77d3089
2 changed files with 53 additions and 4 deletions

8
id.1
View File

@ -1,8 +1,12 @@
.TH ID 1 sbase\-VERSION
.SH NAME
id \- print real and effective user and group IDs
.SH DESCRIPTION
.SH SYNOPSIS
.B id
Print user and group information for the current user.
.RB [ user ]
.SH DESCRIPTION
Print user and group information of the calling process to standard output.
If a login name is specified, the user and group information of that user
is displayed.
.SH SEE ALSO
.IR who(1)

47
id.c
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@ -1,5 +1,6 @@
/* See LICENSE file for copyright and license details. */
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
@ -8,27 +9,71 @@
#include <limits.h>
#include "util.h"
static void user(struct passwd *pw);
static void curproc(void);
static void
usage(void)
{
eprintf("usage: %s\n", argv0);
eprintf("usage: %s [user]\n", argv0);
}
int
main(int argc, char *argv[])
{
struct passwd *pw;
ARGBEGIN {
default:
usage();
} ARGEND;
switch (argc) {
case 0:
curproc();
break;
case 1:
errno = 0;
pw = getpwnam(argv[0]);
if (errno != 0)
eprintf("getpwnam %s:", argv[0]);
else if (!pw)
eprintf("getpwnam %s: no such user\n", argv[0]);
user(pw);
break;
default:
usage();
}
return EXIT_SUCCESS;
}
static void
user(struct passwd *pw)
{
struct group *gr;
gid_t gid, groups[NGROUPS_MAX];
int ngroups;
int i;
printf("uid=%u(%s)", pw->pw_uid, pw->pw_name);
printf(" gid=%u", pw->pw_gid);
if (!(gr = getgrgid(pw->pw_gid)))
eprintf("getgrgid:");
printf("(%s)", gr->gr_name);
ngroups = NGROUPS_MAX;
getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
for (i = 0; i < ngroups; i++) {
gid = groups[i];
printf("%s%u", !i ? " groups=" : ",", gid);
if (!(gr = getgrgid(gid)))
eprintf("getgrgid:");
printf("(%s)", gr->gr_name);
}
putchar('\n');
}
static void
curproc(void)
{