4 files changed, 114 insertions, 43 deletions

diff --git a/include/usage.h b/include/usage.h
index f4edf0556..c729532e5 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -12,9 +12,9 @@
 #define __BB_USAGE_H__
 
 #define addgroup_trivial_usage \
-       "[-g GID] group_name [user_name]"
+       "[-g GID]"USE_FEATURE_ADDUSER_TO_GROUP(" [user_name]")" group_name"
 #define addgroup_full_usage \
-       "Add a group to the system" \
+       "Add a group to the system"USE_FEATURE_ADDUSER_TO_GROUP(" or add an user to a group") \
        "\n\nOptions:\n" \
        "        -g GID  Specify gid"
 
diff --git a/loginutils/Config.in b/loginutils/Config.in
index 03a638c00..1d52cdfe5 100644
--- a/loginutils/Config.in
+++ b/loginutils/Config.in
@@ -59,6 +59,15 @@ config ADDGROUP
         help
           Utility for creating a new group account.
 
+config FEATURE_ADDUSER_TO_GROUP
+        bool "Support for adding users to groups"
+        default n
+        depends on ADDGROUP
+        help
+          If  called  with two non-option arguments,
+          addgroup will add an existing user to an
+          existing group.
+
 config DELGROUP
         bool "delgroup"
         default n
diff --git a/loginutils/addgroup.c b/loginutils/addgroup.c
index 78250a418..5aefda6ff 100644
--- a/loginutils/addgroup.c
+++ b/loginutils/addgroup.c
@@ -1,9 +1,10 @@
 /* vi: set sw=4 ts=4: */
 /*
- * addgroup - add users to /etc/passwd and /etc/shadow
+ * addgroup - add groups to /etc/group and /etc/gshadow
  *
  * Copyright (C) 1999 by Lineo, inc. and John Beppu
  * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
+ * Copyright (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
  *
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  *
@@ -11,48 +12,40 @@
 
 #include "busybox.h"
 
-/* make sure gr_name isn't taken, make sure gid is kosher
- * return 1 on failure */
-static int group_study(struct group *g)
+static void xgroup_study(struct group *g)
 {
         enum { max = 65000 };
-        FILE *etc_group;
-        gid_t desired;
-        /* Using _r function to avoid static buffers pulled in */
-        char buffer[256];
-        struct group grp;
-        struct group *result;
-
-        etc_group = xfopen(bb_path_group_file, "r");
-
-        /* make sure gr_name isn't taken, make sure gid is kosher */
-        desired = g->gr_gid;
-        while (!fgetgrent_r(etc_group, &grp, buffer, sizeof(buffer), &result)) {
-                if ((strcmp(grp.gr_name, g->gr_name)) == 0) {
-                        bb_error_msg_and_die("%s: group already in use", g->gr_name);
+        /* Use a particular gid. */
+        int desired = (g->gr_gid > 0);
+
+        /* Make sure gr_name is unused */
+        if (getgrnam(g->gr_name)) {
+                goto error;
+        }
+
+        /* Check if the desired gid is free or 
+           find the first free one */
+        do {
+                if (g->gr_gid == max) { /* out of bounds: exit */
+                        bb_error_msg_and_die("no gids left");
                 }
-                if ((desired) && grp.gr_gid == desired) {
-                        bb_error_msg_and_die("%d: gid already in use",
-                                                          desired);
+                if (!getgrgid(g->gr_gid)) {
+                        return; /* ok */
                 }
-                if ((grp.gr_gid > g->gr_gid) && (grp.gr_gid < max)) {
-                        g->gr_gid = grp.gr_gid;
+                if (desired) { /* the desired gid is already in use: exit */
+                        g->gr_name = itoa(g->gr_gid);
+                        goto error;
                 }
-        }
-        if (ENABLE_FEATURE_CLEAN_UP)
-                fclose(etc_group);
+                g->gr_gid++;
+        } while (1);
 
-        /* gid */
-        g->gr_gid++;
-        if (desired) {
-                g->gr_gid = desired;
-        }
-        /* return 1; */
-        return 0;
+error:
+        /* exit */
+        bb_error_msg_and_die("%s: already in use", g->gr_name);
 }
 
 /* append a new user to the passwd file */
-static int addgroup(char *group, gid_t gid, const char *user)
+static void new_group(char *group, gid_t gid)
 {
         FILE *file;
         struct group gr;
@@ -60,16 +53,14 @@ static int addgroup(char *group, gid_t gid, const char *user)
         /* make sure gid and group haven't already been allocated */
         gr.gr_gid = gid;
         gr.gr_name = group;
-        if (group_study(&gr))
-                return 1;
+        xgroup_study( &gr);
 
         /* add entry to group */
         file = xfopen(bb_path_group_file, "a");
         /* group:passwd:gid:userlist */
-        fprintf(file, "%s:%s:%d:%s\n", group, "x", gr.gr_gid, user);
+        fprintf(file, "%s:x:%d:\n", group, gr.gr_gid);
         if (ENABLE_FEATURE_CLEAN_UP)
                 fclose(file);
-
 #if ENABLE_FEATURE_SHADOWPASSWDS
         file = fopen_or_warn(bb_path_gshadow_file, "a");
         if (file) {
@@ -78,15 +69,60 @@ static int addgroup(char *group, gid_t gid, const char *user)
                         fclose(file);
         }
 #endif
+}
+
+#if ENABLE_FEATURE_ADDUSER_TO_GROUP
+static void add_user_to_group(char **args,
+                const char *path,
+                FILE *(*fopen_func)(const char *fileName, const char *mode))
+{
+        char *line;
+        int len = strlen(args[1]);
+        llist_t *plist = NULL;
+        FILE *group_file;
+
+        group_file = fopen_func(path, "r");
 
-        /* return 1; */
-        return 0;
+        if (!group_file) return;
+
+        while ((line = xmalloc_getline(group_file))) {
+                /* Find the group */
+                if (!strncmp(line, args[1], len)
+                && line[len] == ':'
+                ) {
+                        /* Add the new user */
+                        line = xasprintf("%s%s%s", line,
+                                                last_char_is(line, ':') ? "" : ",",
+                                                args[0]);
+                }
+                llist_add_to_end(&plist, line);
+        }
+
+        if (ENABLE_FEATURE_CLEAN_UP) {
+                fclose(group_file);
+                group_file = fopen_func(path, "w");
+                while ((line = llist_pop(&plist))) {
+                        if (group_file)
+                                fprintf(group_file, "%s\n", line);
+                        free(line);
+                }
+                if (group_file)
+                        fclose(group_file);
+        } else {
+                group_file = fopen_func(path, "w");
+                if (group_file)
+                        while ((line = llist_pop(&plist)))
+                                fprintf(group_file, "%s\n", line);
+        }
 }
+#endif
 
 /*
  * addgroup will take a login_name as its first parameter.
  *
  * gid can be customized via command-line parameters.
+ * If  called with two non-option arguments, addgroup
+ * will add an existing user to an existing group.
  */
 int addgroup_main(int argc, char **argv);
 int addgroup_main(int argc, char **argv)
@@ -101,11 +137,36 @@ int addgroup_main(int argc, char **argv)
         }
         /* move past the commandline options */
         argv += optind;
+        argc -= optind;
 
         /* need to be root */
         if (geteuid()) {
                 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
         }
 
-        return addgroup(argv[0], gid, argv[1] ? argv[1] : "");
+#if ENABLE_FEATURE_ADDUSER_TO_GROUP
+        if (argc == 2) {
+                struct group *gr;
+                
+                /* check if group and user exist */
+                xuname2uid(argv[0]); /* unknown user: exit */
+                xgroup2gid(argv[1]); /* unknown group: exit */
+                /* check if user is already in this group */
+                gr = getgrnam(argv[1]);
+                for (; *(gr->gr_mem) != NULL; (gr->gr_mem)++) {
+                        if (!strcmp(argv[0], *(gr->gr_mem))) {
+                                /* user is already in group: do nothing */
+                                return EXIT_SUCCESS;
+                        }
+                }
+                add_user_to_group(argv, bb_path_group_file, xfopen);
+#if ENABLE_FEATURE_SHADOWPASSWDS
+                add_user_to_group(argv, bb_path_gshadow_file, fopen_or_warn);
+#endif /* ENABLE_FEATURE_SHADOWPASSWDS */
+        } else
+#endif /* ENABLE_FEATURE_ADDUSER_TO_GROUP */
+                new_group(argv[0], gid);
+
+        /* Reached only on success */
+        return EXIT_SUCCESS;
 }
diff --git a/scripts/defconfig b/scripts/defconfig
index 42f3605da..6864b2fa6 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -347,6 +347,7 @@ CONFIG_FEATURE_SHADOWPASSWDS=y
 CONFIG_USE_BB_SHADOW=y
 CONFIG_USE_BB_PWD_GRP=y
 CONFIG_ADDGROUP=y
+CONFIG_FEATURE_ADDUSER_TO_GROUP=y
 CONFIG_DELGROUP=y
 CONFIG_ADDUSER=y
 CONFIG_DELUSER=y