sbase

commit dac77d3089f3b5233ca6f0a4c10ebc860c54bf9a
parent 137ebef3aca354e79d259553c3a0756cda0af9cc
Author: sin <sin@2f30.org>
Date:   Sun,  1 Dec 2013 10:40:14 +0000

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.

Diffstat:
M
id.1
 | 
8
++++++--
M
id.c
 | 
49
+++++++++++++++++++++++++++++++++++++++++++++++--

2 files changed, 53 insertions(+), 4 deletions(-)
diff --git a/id.1 b/id.1
@@ -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)
diff --git a/id.c b/id.c
@@ -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>
@@ -8,28 +9,72 @@
 #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;
 
-	curproc();
+	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)
 {
 	struct passwd *pw;