adduser/addgroup: support specifying uid/gid, add system

 account creation mode. By Tito.

function                                             old     new   delta
adduser_main                                         650     726     +76
addgroup_main                                        341     402     +61
addgroup_longopts                                      -      16     +16
adduser_longopts                                      97     103      +6
packed_usage                                       26161   26163      +2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 161/0)             Total: 161 bytes

1 files changed, 43 insertions, 20 deletions

diff --git a/loginutils/addgroup.c b/loginutils/addgroup.c
index 5a0cf3fff..cb839290d 100644
--- a/loginutils/addgroup.c
+++ b/loginutils/addgroup.c
@@ -11,34 +11,50 @@
  */
 #include "libbb.h"
 
+#define OPT_GID                       (1 << 0)
+#define OPT_SYSTEM_ACCOUNT            (1 << 1)
+
+/* We assume GID_T_MAX == INT_MAX */
 static void xgroup_study(struct group *g)
 {
+        unsigned max = INT_MAX;
+
         /* Make sure gr_name is unused */
         if (getgrnam(g->gr_name)) {
-                goto error;
+                bb_error_msg_and_die("%s '%s' in use", "group", g->gr_name);
+                /* these format strings are reused in adduser and addgroup */
         }
 
+        /* if a specific gid is requested, the --system switch and */
+        /* min and max values are overriden, and the range of valid */
+        /* gid values is set to [0, INT_MAX] */
+        if (!(option_mask32 & OPT_GID)) {
+                if (option_mask32 & OPT_SYSTEM_ACCOUNT) {
+                        g->gr_gid = 100; /* FIRST_SYSTEM_GID */
+                        max = 999;       /* LAST_SYSTEM_GID */
+                } else {
+                        g->gr_gid = 1000; /* FIRST_GID */
+                        max = 64999;      /* LAST_GID */
+                }
+        }
         /* Check if the desired gid is free
          * or find the first free one */
         while (1) {
                 if (!getgrgid(g->gr_gid)) {
                         return; /* found free group: return */
                 }
-                if (option_mask32) {
+                if (option_mask32 & OPT_GID) {
                         /* -g N, cannot pick gid other than N: error */
-                        g->gr_name = itoa(g->gr_gid);
-                        goto error;
+                        bb_error_msg_and_die("%s '%s' in use", "gid", itoa(g->gr_gid));
+                        /* this format strings is reused in adduser and addgroup */
                 }
-                g->gr_gid++;
-                if (g->gr_gid <= 0) {
+                if (g->gr_gid == max) {
                         /* overflowed: error */
-                        bb_error_msg_and_die("no gids left");
+                        bb_error_msg_and_die("no %cids left", 'g');
+                        /* this format string is reused in adduser and addgroup */
                 }
+                g->gr_gid++;
         }
-
- error:
-        /* exit */
-        bb_error_msg_and_die("group %s already exists", g->gr_name);
 }
 
 /* append a new user to the passwd file */
@@ -53,7 +69,7 @@ static void new_group(char *group, gid_t gid)
         xgroup_study(&gr);
 
         /* add entry to group */
-        p = xasprintf("x:%u:", gr.gr_gid);
+        p = xasprintf("x:%u:", (unsigned) gr.gr_gid);
         if (update_passwd(bb_path_group_file, group, p, NULL) < 0)
                 exit(EXIT_FAILURE);
         if (ENABLE_FEATURE_CLEAN_UP)
@@ -64,6 +80,13 @@ static void new_group(char *group, gid_t gid)
 #endif
 }
 
+#if ENABLE_FEATURE_ADDGROUP_LONG_OPTIONS
+static const char addgroup_longopts[] ALIGN1 =
+                "gid\0"                 Required_argument "g"
+                "system\0"              No_argument       "S"
+                ;
+#endif
+
 /*
  * addgroup will take a login_name as its first parameter.
  *
@@ -74,23 +97,23 @@ static void new_group(char *group, gid_t gid)
 int addgroup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int addgroup_main(int argc UNUSED_PARAM, char **argv)
 {
-        char *group;
-        gid_t gid = 0;
+        unsigned opts;
+        unsigned gid = 0;
 
         /* need to be root */
         if (geteuid()) {
                 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
         }
-
+#if ENABLE_FEATURE_ADDGROUP_LONG_OPTIONS
+        applet_long_options = addgroup_longopts;
+#endif
         /* Syntax:
          *  addgroup group
          *  addgroup -g num group
          *  addgroup user group
          * Check for min, max and missing args */
-        opt_complementary = "-1:?2";
-        if (getopt32(argv, "g:", &group)) {
-                gid = xatoul_range(group, 0, ((unsigned long)(gid_t)ULONG_MAX) >> 1);
-        }
+        opt_complementary = "-1:?2:g+";
+        opts = getopt32(argv, "g:S", &gid);
         /* move past the commandline options */
         argv += optind;
         //argc -= optind;
@@ -99,7 +122,7 @@ int addgroup_main(int argc UNUSED_PARAM, char **argv)
         if (argv[1]) {
                 struct group *gr;
 
-                if (option_mask32) {
+                if (opts & OPT_GID) {
                         /* -g was there, but "addgroup -g num user group"
                          * is a no-no */
                         bb_show_usage();