1 /* userspec.c -- Parse a user and group string.
2 Copyright (C) 1989, 1990, 1991, 1992, 1997, 1998 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software Foundation,
16 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
25 # define alloca __builtin_alloca
39 #include <sys/types.h>
60 #ifndef _POSIX_VERSION
61 struct passwd *getpwnam ();
62 struct group *getgrnam ();
63 struct group *getgrgid ();
67 # define endgrent() ((void) 0)
71 # define endpwent() ((void) 0)
74 /* Perform the equivalent of the statement `dest = strdup (src);',
75 but obtaining storage via alloca instead of from the heap. */
77 #define V_STRDUP(dest, src) \
80 int _len = strlen ((src)); \
81 (dest) = (char *) alloca (_len + 1); \
86 #define isdigit(c) ((c) >= '0' && (c) <= '9')
92 /* Return nonzero if STR represents an unsigned decimal integer,
93 otherwise return 0. */
105 /* Extract from NAME, which has the form "[user][:.][group]",
106 a USERNAME, UID U, GROUPNAME, and GID G.
107 Either user or group, or both, must be present.
108 If the group is omitted but the ":" or "." separator is given,
109 use the given user's login group.
111 USERNAME and GROUPNAME will be in newly malloc'd memory.
112 Either one might be NULL instead, indicating that it was not
113 given and the corresponding numeric ID was left unchanged.
115 Return NULL if successful, a static error message string if not. */
118 parse_user_spec (spec_arg, uid, gid, username_arg, groupname_arg)
119 const char *spec_arg;
122 char **username_arg, **groupname_arg;
124 static const char *tired = "virtual memory exhausted";
125 const char *error_msg;
126 char *spec; /* A copy we can write on. */
129 char *g, *u, *separator;
133 *username_arg = *groupname_arg = NULL;
136 V_STRDUP (spec, spec_arg);
138 /* Find the separator if there is one. */
139 separator = strchr (spec, ':');
140 if (separator == NULL)
141 separator = strchr (spec, '.');
143 /* Replace separator with a NUL. */
144 if (separator != NULL)
147 /* Set U and G to non-zero length strings corresponding to user and
148 group specifiers or to NULL. */
149 u = (*spec == '\0' ? NULL : spec);
151 g = (separator == NULL || *(separator + 1) == '\0'
155 if (u == NULL && g == NULL)
156 return "can not omit both user and group";
159 /* Pretend that we are the user U whose group is G. This makes
160 pwd and grp functions ``know'' about the UID and GID of these. */
161 if (u && !is_number (u))
162 setenv ("USER", u, 1);
163 if (g && !is_number (g))
164 setenv ("GROUP", g, 1);
174 error_msg = "invalid user";
178 use_login_group = (separator != NULL && g == NULL);
180 error_msg = "cannot get the login group of a numeric UID";
188 if (g == NULL && separator != NULL)
190 /* A separator was given, but a group was not specified,
191 so get the login group. */
193 grp = getgrgid (pwd->pw_gid);
196 /* This is enough room to hold the unsigned decimal
197 representation of any 32-bit quantity and the trailing
200 sprintf (uint_buf, "%u", (unsigned) (pwd->pw_gid));
201 V_STRDUP (groupname, uint_buf);
205 V_STRDUP (groupname, grp->gr_name);
213 if (g != NULL && error_msg == NULL)
215 /* Explicit group. */
220 error_msg = "invalid group";
226 endgrent (); /* Save a file descriptor. */
228 if (error_msg == NULL)
229 V_STRDUP (groupname, g);
232 if (error_msg == NULL)
236 *username_arg = strdup (u);
237 if (*username_arg == NULL)
241 if (groupname != NULL && error_msg == NULL)
243 *groupname_arg = strdup (groupname);
244 if (*groupname_arg == NULL)
246 if (*username_arg != NULL)
248 free (*username_arg);
249 *username_arg = NULL;
261 # define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s))
264 main (int argc, char **argv)
268 for (i = 1; i < argc; i++)
271 char *username, *groupname;
276 tmp = strdup (argv[i]);
277 e = parse_user_spec (tmp, &uid, &gid, &username, &groupname);
279 printf ("%s: %u %u %s %s %s\n",
283 NULL_CHECK (username),
284 NULL_CHECK (groupname),