deluser: add optional support for removing users from groups

(by Tito <farmatito@tiscali.it>)


git-svn-id: svn://busybox.net/trunk/busybox@18449 69ca8d6d-28ef-0310-b511-8ec308f3f277

4 files changed, 107 insertions, 55 deletions

diff --git a/include/usage.h b/include/usage.h
index 2fb8112b0..afcc4b3d7 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -571,9 +571,10 @@
        "Deallocate unused virtual terminal /dev/ttyN"
 
 #define delgroup_trivial_usage \
-       "GROUP"
+        USE_FEATURE_DEL_USER_FROM_GROUP("[USER] ")"GROUP"
 #define delgroup_full_usage \
-       "Delete group GROUP from the system"
+       "Delete group GROUP from the system" \
+        USE_FEATURE_DEL_USER_FROM_GROUP(" or user USER from group GROUP")
 
 #define deluser_trivial_usage \
        "USER"
diff --git a/loginutils/Config.in b/loginutils/Config.in
index 1d52cdfe5..e8ab9ec3c 100644
--- a/loginutils/Config.in
+++ b/loginutils/Config.in
@@ -74,6 +74,14 @@ config DELGROUP
         help
           Utility for deleting a group account.
 
+config FEATURE_DEL_USER_FROM_GROUP
+        bool "Support for removing users from groups."
+        default n
+        depends on DELGROUP
+        help
+          If called with two non-option arguments, deluser 
+          or delgroup will remove an user from a specified group.
+
 config ADDUSER
         bool "adduser"
         default n
diff --git a/loginutils/deluser.c b/loginutils/deluser.c
index e9bde00bd..2781df319 100644
--- a/loginutils/deluser.c
+++ b/loginutils/deluser.c
@@ -1,10 +1,10 @@
 /* vi: set sw=4 ts=4: */
 /*
- * deluser (remove lusers from the system ;) for TinyLogin
+ * deluser/delgroup implementation for busybox
  *
  * Copyright (C) 1999 by Lineo, inc. and John Beppu
  * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
- * Unified with delgroup by Tito Ragusa <farmatito@tiscali.it>
+ * Copyright (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
  *
  * Licensed under GPL version 2, see file LICENSE in this tarball for details.
  *
@@ -12,72 +12,114 @@
 
 #include "busybox.h"
 
-static void del_line_matching(const char *login, const char *filename)
+/* Status */
+#define STATUS_OK            0
+#define NAME_NOT_FOUND       1
+#define MEMBER_NOT_FOUND     2
+
+static void del_line_matching(char **args,
+                const char *filename,
+                FILE *(*fopen_func)(const char *fileName, const char *mode))
 {
-        char *line;
         FILE *passwd;
-        int len = strlen(login);
-        int found = 0;
-        llist_t *plist = NULL;
+        smallint error = NAME_NOT_FOUND;
+        char *name = (ENABLE_FEATURE_DEL_USER_FROM_GROUP && args[2]) ? args[2] : args[1];
+        char *line, *del;
+        char *new = xzalloc(1);
 
-        passwd = fopen_or_warn(filename, "r");
-        if (!passwd) return;
+        passwd = fopen_func(filename, "r");
+        if (passwd) {
+                while ((line = xmalloc_fgets(passwd))) {
+                        int len = strlen(name);
 
-        while ((line = xmalloc_fgets(passwd))) {
-                if (!strncmp(line, login, len)
-                 && line[len] == ':'
-                ) {
-                        found++;
+                        if (strncmp(line, name, len) == 0
+                         && line[len] == ':'
+                        ) {
+                                error = STATUS_OK;
+                                if (ENABLE_FEATURE_DEL_USER_FROM_GROUP) {
+                                        struct group *gr;
+                                        char *p;
+                                        if (args[2]
+                                         /* There were two args on commandline */
+                                         && (gr = getgrnam(name))
+                                         /* The group was not deleted in the meanwhile */
+                                         && (p = strrchr(line, ':'))
+                                         /* We can find a pointer to the last ':' */
+                                        ) {
+                                                error = MEMBER_NOT_FOUND;
+                                                /* Move past ':' (worst case to '\0') and cut the line */
+                                                p[1] = '\0';
+                                                /* Reuse p */
+                                                for (p = xzalloc(1); *gr->gr_mem != NULL; gr->gr_mem++) {
+                                                        /* Add all the other group members */
+                                                        if (strcmp(args[1], *gr->gr_mem) != 0) {
+                                                                del = p;
+                                                                p = xasprintf("%s%s%s", p, p[0] ? "," : "", *gr->gr_mem);
+                                                                free(del);
+                                                        } else
+                                                                error = STATUS_OK;
+                                                }
+                                                /* Recompose the line */
+                                                line = xasprintf("%s%s\n", line, p);
+                                                if (ENABLE_FEATURE_CLEAN_UP) free(p);
+                                        } else
+                                                goto skip;
+                                }
+                        }
+                        del = new;
+                        new = xasprintf("%s%s", new, line);
+                        free(del);
+ skip:
                         free(line);
-                } else {
-                        llist_add_to_end(&plist, line);
                 }
-        }
 
-        if (!ENABLE_FEATURE_CLEAN_UP) {
-                if (!found) {
-                        bb_error_msg("can't find '%s' in '%s'", login, filename);
-                        return;
-                }
-                passwd = fopen_or_warn(filename, "w");
-                if (passwd)
-                        while ((line = llist_pop(&plist)))
-                                fputs(line, passwd);
-        } else {
-                if (!found) {
-                        bb_error_msg("can't find '%s' in '%s'", login, filename);
-                        goto clean_up;
-                }
-                fclose(passwd);
-                passwd = fopen_or_warn(filename, "w");
-                if (passwd) {
- clean_up:
-                        while ((line = llist_pop(&plist))) {
-                                if (found) fputs(line, passwd);
-                                free(line);
+                if (ENABLE_FEATURE_CLEAN_UP) fclose(passwd);
+
+                if (error) {
+                        if (ENABLE_FEATURE_DEL_USER_FROM_GROUP && error == MEMBER_NOT_FOUND) {
+                                /* Set the correct values for error message */
+                                filename = name;
+                                name = args[1];
+                        }
+                        bb_error_msg("can't find %s in %s", name, filename);
+                } else {
+                        passwd = fopen_func(filename, "w");
+                        if (passwd) {
+                                fputs(new, passwd);
+                                if (ENABLE_FEATURE_CLEAN_UP) fclose(passwd);
                         }
-                        fclose(passwd);
                 }
         }
+        free(new);
 }
 
 int deluser_main(int argc, char **argv);
 int deluser_main(int argc, char **argv)
 {
-        if (argc != 2)
-                bb_show_usage();
-
-        if (ENABLE_DELUSER
-         && (!ENABLE_DELGROUP || applet_name[3] == 'u')
+        if (argc == 2 
+         || (ENABLE_FEATURE_DEL_USER_FROM_GROUP 
+            && (applet_name[3] == 'g' && argc == 3))
         ) {
-                del_line_matching(argv[1], bb_path_passwd_file);
+                if (geteuid())
+                        bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+                
+                if ((ENABLE_FEATURE_DEL_USER_FROM_GROUP && argc != 3) 
+                 || ENABLE_DELUSER
+                 || (ENABLE_DELGROUP && ENABLE_DESKTOP)
+                ) {
+                        if (ENABLE_DELUSER
+                         && (!ENABLE_DELGROUP || applet_name[3] == 'u')
+                        ) {
+                                del_line_matching(argv, bb_path_passwd_file, xfopen);
+                                if (ENABLE_FEATURE_SHADOWPASSWDS)
+                                        del_line_matching(argv, bb_path_shadow_file, fopen_or_warn);
+                        } else if (ENABLE_DESKTOP && ENABLE_DELGROUP && getpwnam(argv[1]))
+                                bb_error_msg_and_die("can't remove primary group of user %s", argv[1]);
+                }
+                del_line_matching(argv, bb_path_group_file, xfopen);
                 if (ENABLE_FEATURE_SHADOWPASSWDS)
-                        del_line_matching(argv[1], bb_path_shadow_file);
-        }
-        del_line_matching(argv[1], bb_path_group_file);
-        if (ENABLE_FEATURE_SHADOWPASSWDS)
-                del_line_matching(argv[1], bb_path_gshadow_file);
-
-        return EXIT_SUCCESS;
+                        del_line_matching(argv, bb_path_gshadow_file, fopen_or_warn);
+                return EXIT_SUCCESS;
+        } else
+                bb_show_usage();
 }
-
diff --git a/scripts/defconfig b/scripts/defconfig
index 009026e5a..c9086eb13 100644
--- a/scripts/defconfig
+++ b/scripts/defconfig
@@ -349,6 +349,7 @@ CONFIG_USE_BB_PWD_GRP=y
 CONFIG_ADDGROUP=y
 CONFIG_FEATURE_ADDUSER_TO_GROUP=y
 CONFIG_DELGROUP=y
+CONFIG_FEATURE_DEL_USER_FROM_GROUP=y
 CONFIG_ADDUSER=y
 CONFIG_DELUSER=y
 CONFIG_GETTY=y