Implement -G support for id(1)

This commit is contained in:
sin 2013-12-01 17:29:20 +00:00
parent d453be2ae1
commit 5534e60703
2 changed files with 43 additions and 5 deletions

6
id.1
View File

@ -3,10 +3,16 @@
id \- print real and effective user and group IDs
.SH SYNOPSIS
.B id
.RB [ -G ]
.RB [ user | uid ]
.SH DESCRIPTION
Print user and group information of the calling process to standard output.
If a login name or uid is specified, the user and group information of that
user is displayed.
.SH OPTIONS
.TP
.B \-G
Display group information as whitespace separated numbers, in no particular
order.
.SH SEE ALSO
.IR who(1)

38
id.c
View File

@ -10,6 +10,7 @@
#include <ctype.h>
#include "util.h"
static void groupid(struct passwd *pw);
static void user(struct passwd *pw);
static void userid(uid_t id);
static void usernam(const char *nam);
@ -17,13 +18,18 @@ static void usernam(const char *nam);
static void
usage(void)
{
eprintf("usage: %s [user | uid]\n", argv0);
eprintf("usage: %s [-G] [user | uid]\n", argv0);
}
static int Gflag = 0;
int
main(int argc, char *argv[])
{
ARGBEGIN {
case 'G':
Gflag = 1;
break;
default:
usage();
} ARGEND;
@ -47,7 +53,26 @@ main(int argc, char *argv[])
return EXIT_SUCCESS;
}
static void usernam(const char *nam)
static void
groupid(struct passwd *pw)
{
gid_t gid, groups[NGROUPS_MAX];
int ngroups;
int i;
ngroups = NGROUPS_MAX;
getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
for (i = 0; i < ngroups; i++) {
gid = groups[i];
printf("%u", gid);
if (i < ngroups - 1)
putchar(' ');
}
putchar('\n');
}
static void
usernam(const char *nam)
{
struct passwd *pw;
@ -57,10 +82,14 @@ static void usernam(const char *nam)
eprintf("getpwnam %s:", nam);
else if (!pw)
eprintf("getpwnam %s: no such user\n", nam);
if (Gflag)
groupid(pw);
else
user(pw);
}
static void userid(uid_t id)
static void
userid(uid_t id)
{
struct passwd *pw;
@ -70,6 +99,9 @@ static void userid(uid_t id)
eprintf("getpwuid %d:", id);
else if (!pw)
eprintf("getpwuid %d: no such user\n", id);
if (Gflag)
groupid(pw);
else
user(pw);
}