add -U option to groupadd and groupmod

Add a -U option which adds new usernames as members.  For groupmod,
also add -a (append), without which existing members are removed.

Closes #265

lib/groupmem.c

@@ -87,6 +87,18 @@
 	return gr;
 }
 
+void gr_free_members (struct group *grent)
+{
+	if (NULL != grent->gr_mem) {
+		size_t i;
+		for (i = 0; NULL != grent->gr_mem[i]; i++) {
+			free (grent->gr_mem[i]);
+		}
+		free (grent->gr_mem);
+		grent->gr_mem = NULL;
+	}
+}
+
 void gr_free (/*@out@*/ /*@only@*/struct group *grent)
 {
 	free (grent->gr_name);
@@ -94,13 +106,36 @@ void gr_free (/*@out@*/ /*@only@*/struct group *grent)
 		memzero (grent->gr_passwd, strlen (grent->gr_passwd));
 		free (grent->gr_passwd);
 	}
-	if (NULL != grent->gr_mem) {
+	gr_free_members(grent);
-		size_t i;
-		for (i = 0; NULL != grent->gr_mem[i]; i++) {
-			free (grent->gr_mem[i]);
-		}
-		free (grent->gr_mem);
-	}
 	free (grent);
 }
 
+bool gr_append_member(struct group *grp, char *member)
+{
+	int i;
+
+	if (NULL == grp->gr_mem || grp->gr_mem[0] == NULL) {
+		grp->gr_mem = (char **)malloc(2 * sizeof(char *));
+		if (!grp->gr_mem) {
+			return false;
+		}
+		grp->gr_mem[0] = strdup(member);
+		if (!grp->gr_mem[0]) {
+			return false;
+		}
+		grp->gr_mem[1] = NULL;
+		return true;
+	}
+
+	for (i = 0; grp->gr_mem[i]; i++) ;
+	grp->gr_mem = realloc(grp->gr_mem, (i + 2) * sizeof(char *));
+	if (NULL == grp->gr_mem) {
+		return false;
+	}
+	grp->gr_mem[i] = strdup(member);
+	if (NULL == grp->gr_mem[i]) {
+		return false;
+	}
+	grp->gr_mem[i + 1] = NULL;
+	return true;
+}

lib/prototypes.h

@@ -206,7 +206,9 @@ extern void __gr_set_changed (void);
 
 /* groupmem.c */
 extern /*@null@*/ /*@only@*/struct group *__gr_dup (const struct group *grent);
+extern void gr_free_members (struct group *grent);
 extern void gr_free (/*@out@*/ /*@only@*/struct group *grent);
+extern bool gr_append_member (struct group *grp, char *member);
 
 /* hushed.c */
 extern bool hushed (const char *username);

man/groupadd.8.xml

@@ -229,6 +229,22 @@
 	  </para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term>
+	  <option>-U</option>, <option>--users</option>
+	</term>
+	<listitem>
+	  <para>
+	    A list of usernames to add as members of the group.
+	  </para>
+	  <para>
+	    The default behavior (if the <option>-g</option>,
+	    <option>-N</option>, and <option>-U</option> options are not
+	    specified) is defined by the <option>USERGROUPS_ENAB</option>
+	    variable in <filename>/etc/login.defs</filename>.
+	  </para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

man/groupmod.8.xml

@@ -93,6 +93,15 @@
     </para>
     <variablelist remap='IP'>
       <varlistentry>
+	<term>
+	  <option>-a</option>, <option>--append</option>&nbsp;<replaceable>GID</replaceable>
+	</term>
+	<listitem>
+      <para>If group members are specified with -U, append them to the existing
+            member list, rather than replacing it.</para>
+    </listitem>
+    </varlistentry>
+    <varlistentry>
 	<term>
 	  <option>-g</option>, <option>--gid</option>&nbsp;<replaceable>GID</replaceable>
 	</term>
@@ -203,6 +212,22 @@
 	  </para>
 	</listitem>
       </varlistentry>
+      <varlistentry>
+	<term>
+	  <option>-U</option>, <option>--users</option>
+	</term>
+	<listitem>
+	  <para>
+	    A list of usernames to add as members of the group.
+	  </para>
+	  <para>
+	    The default behavior (if the <option>-g</option>,
+	    <option>-N</option>, and <option>-U</option> options are not
+	    specified) is defined by the <option>USERGROUPS_ENAB</option>
+	    variable in <filename>/etc/login.defs</filename>.
+	  </para>
+	</listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

src/groupadd.c

@@ -79,6 +79,7 @@ static /*@null@*/char *group_passwd;
 static /*@null@*/char *empty_list = NULL;
 
 static const char *prefix = "";
+static char *user_list;
 
 static bool oflg = false;	/* permit non-unique group ID to be specified with -g */
 static bool gflg = false;	/* ID value for the new group */
@@ -126,7 +127,8 @@ static /*@noreturn@*/void usage (int status)
 	(void) fputs (_("  -p, --password PASSWORD       use this encrypted password for the new group\n"), usageout);
 	(void) fputs (_("  -r, --system                  create a system account\n"), usageout);
 	(void) fputs (_("  -R, --root CHROOT_DIR         directory to chroot into\n"), usageout);
-	(void) fputs (_("  -P, --prefix PREFIX_DIR       directory prefix\n"), usageout);
+	(void) fputs (_("  -P, --prefix PREFIX_DI        directory prefix\n"), usageout);
+	(void) fputs (_("  -U, --users USERS             list of user members of this group\n"), usageout);
 	(void) fputs ("\n", usageout);
 	exit (status);
 }
@@ -207,6 +209,19 @@ static void grp_update (void)
 	}
 #endif				/* SHADOWGRP */
 
+	if (user_list) {
+		char *token;
+		token = strtok(user_list, ",");
+		while (token) {
+			if (prefix_getpwnam (token) == NULL) {
+				fprintf (stderr, _("Invalid member username %s\n"), token);
+				exit (E_GRP_UPDATE);
+			}
+			grp.gr_mem = add_list(grp.gr_mem, token);
+			token = strtok(NULL, ",");
+		}
+	}
+
 	/*
 	 * Write out the new group file entry.
 	 */
@@ -391,10 +406,11 @@ static void process_flags (int argc, char **argv)
 		{"system",     no_argument,       NULL, 'r'},
 		{"root",       required_argument, NULL, 'R'},
 		{"prefix",     required_argument, NULL, 'P'},
+		{"users",      required_argument, NULL, 'U'},
 		{NULL, 0, NULL, '\0'}
 	};
 
-	while ((c = getopt_long (argc, argv, "fg:hK:op:rR:P:",
+	while ((c = getopt_long (argc, argv, "fg:hK:op:rR:P:U:",
 		                 long_options, NULL)) != -1) {
 		switch (c) {
 		case 'f':
@@ -453,6 +469,9 @@ static void process_flags (int argc, char **argv)
 			break;
 		case 'P': /* no-op, handled in process_prefix_flag () */
 			break;
+		case 'U':
+			user_list = optarg;
+			break;
 		default:
 			usage (E_USAGE);
 		}

src/groupmod.c

@@ -87,6 +87,7 @@ static gid_t group_id;
 static gid_t group_newid;
 
 static const char* prefix = "";
+static char *user_list;
 
 static struct cleanup_info_mod info_passwd;
 static struct cleanup_info_mod info_group;
@@ -95,6 +96,7 @@ static struct cleanup_info_mod info_gshadow;
 #endif
 
 static bool
+    aflg = false,               /* append -U members rather than replace them */
     oflg = false,		/* permit non-unique group ID to be specified with -g */
     gflg = false,		/* new ID value for the group */
     nflg = false,		/* a new name has been specified for the group */
@@ -117,6 +119,7 @@ static void open_files (void);
 static void close_files (void);
 static void update_primary_groups (gid_t ogid, gid_t ngid);
 
+
 /*
  * usage - display usage message and exit
  */
@@ -129,6 +132,8 @@ static void usage (int status)
 	                  "\n"
 	                  "Options:\n"),
 	                Prog);
+	(void) fputs (_("  -a, --append                  append the users mentioned by -U option to the group \n"
+	                "                                without removing existing user members\n"), usageout);
 	(void) fputs (_("  -g, --gid GID                 change the group ID to GID\n"), usageout);
 	(void) fputs (_("  -h, --help                    display this help message and exit\n"), usageout);
 	(void) fputs (_("  -n, --new-name NEW_GROUP      change the name to NEW_GROUP\n"), usageout);
@@ -137,6 +142,7 @@ static void usage (int status)
 	                "                                PASSWORD\n"), usageout);
 	(void) fputs (_("  -R, --root CHROOT_DIR         directory to chroot into\n"), usageout);
 	(void) fputs (_("  -P, --prefix PREFIX_DIR       prefix directory where are located the /etc/* files\n"), usageout);
+	(void) fputs (_("  -U, --users USERS             list of user members of this group\n"), usageout);
 	(void) fputs ("\n", usageout);
 	exit (status);
 }
@@ -255,6 +261,32 @@ static void grp_update (void)
 		update_primary_groups (ogrp->gr_gid, group_newid);
 	}
 
+	if (user_list) {
+		char *token;
+
+		if (!aflg) {
+			// requested to replace the existing groups
+			if (NULL != grp.gr_mem[0])
+				gr_free_members(&grp);
+			grp.gr_mem = (char **)xmalloc(sizeof(char *));
+			grp.gr_mem[0] = (char *)0;
+		} else {
+			// append to existing groups
+			if (NULL != grp.gr_mem[0])
+				grp.gr_mem = dup_list (grp.gr_mem);
+		}
+
+		token = strtok(user_list, ",");
+		while (token) {
+			if (prefix_getpwnam (token) == NULL) {
+				fprintf (stderr, _("Invalid member username %s\n"), token);
+				exit (E_GRP_UPDATE);
+			}
+			grp.gr_mem = add_list(grp.gr_mem, token);
+			token = strtok(NULL, ",");
+		}
+	}
+
 	/*
 	 * Write out the new group file entry.
 	 */
@@ -379,6 +411,7 @@ static void process_flags (int argc, char **argv)
 {
 	int c;
 	static struct option long_options[] = {
+		{"append",     no_argument,       NULL, 'a'},
 		{"gid",        required_argument, NULL, 'g'},
 		{"help",       no_argument,       NULL, 'h'},
 		{"new-name",   required_argument, NULL, 'n'},
@@ -386,11 +419,15 @@ static void process_flags (int argc, char **argv)
 		{"password",   required_argument, NULL, 'p'},
 		{"root",       required_argument, NULL, 'R'},
 		{"prefix",     required_argument, NULL, 'P'},
+		{"users",      required_argument, NULL, 'U'},
 		{NULL, 0, NULL, '\0'}
 	};
-	while ((c = getopt_long (argc, argv, "g:hn:op:R:P:",
+	while ((c = getopt_long (argc, argv, "ag:hn:op:R:P:U:",
 		                 long_options, NULL)) != -1) {
 		switch (c) {
+		case 'a':
+			aflg = true;
+			break;
 		case 'g':
 			gflg = true;
 			if (   (get_gid (optarg, &group_newid) == 0)
@@ -419,6 +456,9 @@ static void process_flags (int argc, char **argv)
 			break;
 		case 'P': /* no-op, handled in process_prefix_flag () */
 			break;
+		case 'U':
+			user_list = optarg;
+			break;
 		default:
 			usage (E_USAGE);
 		}