Goal: Support numerical UID and ranges in lastlog -u
Fixes: #259494

Status wrt upstream: not reported yet.

Note: It also allows to mix -u and -t

Index: shadow-4.0.18.1/man/lastlog.8.xml
===================================================================
--- shadow-4.0.18.1.orig/man/lastlog.8.xml	2007-06-19 13:23:42.000000000 +0100
+++ shadow-4.0.18.1/man/lastlog.8.xml	2007-06-19 14:35:26.000000000 +0100
@@ -71,22 +71,20 @@
       <varlistentry>
 	<term>
 	  <option>-u</option>, <option>--user</option>
-	  <replaceable>LOGIN</replaceable>
+	  <replaceable>LOGIN</replaceable>|<replaceable>RANGE</replaceable>
 	</term>
 	<listitem>
 	  <para>Print the lastlog record for user with specified
 	    <emphasis remap='I'>LOGIN</emphasis> only.
 	  </para>
-	</listitem>
-      </varlistentry>
-    </variablelist>
-    <variablelist remap='TP'>
-      <varlistentry>
-	<term>
-	  The <option>-t</option> flag overrides the use of <option>-u</option>.
-	</term>
-	<listitem>
-	  <para></para>
+	  <para>Instead of a login name, <command>lastlog</command> also
+	  accepts a numerical user ID or a <replaceable>RANGE</replaceable> of
+	  users. This <replaceable>RANGE</replaceable> of users can be
+	  specified with a min and max values
+	  (<replaceable>UID_MIN-UID_MAX</replaceable>), a max value
+	  (<replaceable>-UID_MAX</replaceable>) or a min value
+	  (<replaceable>UID_MIN-</replaceable>).
+	  </para>
 	</listitem>
       </varlistentry>
     </variablelist>
Index: shadow-4.0.18.1/src/lastlog.c
===================================================================
--- shadow-4.0.18.1.orig/src/lastlog.c	2007-06-19 13:23:35.000000000 +0100
+++ shadow-4.0.18.1/src/lastlog.c	2007-06-19 14:22:21.000000000 +0100
@@ -51,6 +51,8 @@
  */
 static FILE *lastlogfile;	/* lastlog file stream */
 static off_t user;		/* one single user, specified on command line */
+static long umin;		/* one single user, specified on command line */
+static long umax;		/* one single user, specified on command line */
 static int days;		/* number of days to consider for print command */
 static time_t seconds;		/* that number of days in seconds */
 static int inverse_days;	/* number of days to consider for print command */
@@ -58,6 +60,7 @@
 
 
 static int uflg = 0;		/* set if user is a valid user id */
+static int urange = 0;		/* set if user is a valid user id range */
 static int tflg = 0;		/* print is restricted to most recent days */
 static int bflg = 0;		/* print excludes most recent days */
 static struct lastlog lastlog;	/* scratch structure to play with ... */
@@ -127,26 +130,16 @@
 {
 	off_t offset;
 
-	if (uflg) {
-		offset = user * sizeof lastlog;
-
-		if (fstat (fileno (lastlogfile), &statbuf)) {
-			perror (LASTLOG_FILE);
-			return;
-		}
-		if (offset >= statbuf.st_size)
-			return;
-
-		fseeko (lastlogfile, offset, SEEK_SET);
-		if (fread ((char *) &lastlog, sizeof lastlog, 1,
-			   lastlogfile) == 1)
-			print_one (pwent);
-		else
-			perror (LASTLOG_FILE);
-	} else {
+	{
 		setpwent ();
 		while ((pwent = getpwent ())) {
+			if (uflg && user != pwent->pw_uid)
+				continue;
 			user = pwent->pw_uid;
+			if (urange &&
+			    ((umin != -1 && user < umin) ||
+			     (umax != -1 && user > umax)))
+				continue;
 			offset = user * sizeof lastlog;
 
 			fseeko (lastlogfile, offset, SEEK_SET);
@@ -199,15 +192,47 @@
 				bflg++;
 				break;
 			case 'u':
+				/*
+				 * The user can be:
+				 *  - a login name
+				 *  - numerical
+				 *  - a numerical login ID
+				 *  - a range (-x, x-, x-y)
+				 */
 				pwent = xgetpwnam (optarg);
-				if (!pwent) {
-					fprintf (stderr,
-						 _("Unknown User: %s\n"),
-						 optarg);
-					exit (1);
+				if (pwent) {
+					uflg = 1;
+					user = pwent->pw_uid;
+				} else {
+					char *endptr = NULL;
+					user = strtol(optarg, &endptr, 10);
+					if (*optarg != '\0' && *endptr == '\0') {
+						if (user < 0) {
+							/* -<userid> */
+							urange = 1;
+							umin = -1;
+							umax = -user;
+						} else {
+							/* <userid> */
+							uflg = 1;
+						}
+					} else if (endptr[0] == '-' && endptr[1] == '\0') {
+						/* <userid>- */
+						urange = 1;
+						umin = user;
+						umax = -1;
+					} else if (*endptr == '-') {
+						/* <userid>-<userid> */
+						urange = 1;
+						umin = user;
+						umax = atol(endptr+1);
+					} else {
+						fprintf (stderr,
+							 _("Unknown user or range: %s\n"),
+							 optarg);
+						exit (1);
+					}
 				}
-				uflg++;
-				user = pwent->pw_uid;
 				break;
 			default:
 				usage ();
