1 files changed, 119 insertions, 0 deletions
diff --git a/toys/posix/id.c b/toys/posix/id.c
new file mode 100644
index 00000000..973cda5a
--- /dev/null
+++ b/toys/posix/id.c
@@ -0,0 +1,119 @@
+/* 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 "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
+
+static void s_or_u(char *s, unsigned u, int done)
+{
+	if (toys.optflags & FLAG_n) printf("%s", s);
+	else printf("%u", u);
+	if (done) {
+		xputc('\n');
+		exit(0);
+	}
+}
+
+static void showid(char *header, unsigned u, char *s)
+{
+	printf("%s%u(%s)", header, u, s);
+}
+
+struct passwd *xgetpwuid(uid_t uid)
+{
+	struct passwd *pwd = getpwuid(uid);
+	if (!pwd) error_exit(NULL);
+	return pwd;
+}
+
+struct group *xgetgrgid(gid_t gid)
+{
+	struct group *group = getgrgid(gid);
+	if (!group) error_exit(NULL);
+	return group;
+}
+
+void id_main(void)
+{
+	int flags = toys.optflags, i, ngroups;
+	struct passwd *pw;
+	struct group *grp;
+	uid_t uid = getuid(), euid = geteuid();
+	gid_t gid = getgid(), egid = getegid(), *groups;
+
+	/* check if a username is given */
+	if (*toys.optargs) {
+		if (!(pw = getpwnam(*toys.optargs)))
+			error_exit("no such user '%s'", *toys.optargs);
+		uid = euid = pw->pw_uid;
+		gid = egid = pw->pw_gid;
+	}
+
+	i = toys.optflags & FLAG_r;
+	pw = xgetpwuid(i ? uid : euid);
+	if (flags & FLAG_u) s_or_u(pw->pw_name, pw->pw_uid, 1);
+
+	grp = xgetgrgid(i ? gid : egid);
+	if (flags & FLAG_g) s_or_u(grp->gr_name, grp->gr_gid, 1);
+
+	if (!(flags & FLAG_G)) {
+		showid("uid=", pw->pw_uid, pw->pw_name);
+		showid(" gid=", grp->gr_gid, grp->gr_name);
+
+		if (!i) {
+			if (uid != euid) {
+				pw = xgetpwuid(euid);
+				showid(" euid=", pw->pw_uid, pw->pw_name);
+			}
+			if (gid != egid) {
+				grp = xgetgrgid(egid);
+				showid(" egid=", grp->gr_gid, grp->gr_name);
+			}
+		}
+
+		showid(" groups=", grp->gr_gid, grp->gr_name);
+	}
+
+
+	groups = (gid_t *)toybuf;
+	if (0 >= (ngroups = getgroups(sizeof(toybuf)/sizeof(gid_t), groups)))
+		perror_exit(0);
+
+	for (i = 0; i < ngroups; i++) {
+		xputc(' ');
+		if (!(grp = getgrgid(groups[i]))) perror_msg(0);
+		else if (flags & FLAG_G)
+			s_or_u(grp->gr_name, grp->gr_gid, 0);
+		else if (grp->gr_gid != egid) showid("", grp->gr_gid, grp->gr_name);
+	}
+	xputc('\n');
+}