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')
90 /* Return nonzero if STR represents an unsigned decimal integer,
91 otherwise return 0. */
103 /* Extract from NAME, which has the form "[user][:.][group]",
104 a USERNAME, UID U, GROUPNAME, and GID G.
105 Either user or group, or both, must be present.
106 If the group is omitted but the ":" or "." separator is given,
107 use the given user's login group.
109 USERNAME and GROUPNAME will be in newly malloc'd memory.
110 Either one might be NULL instead, indicating that it was not
111 given and the corresponding numeric ID was left unchanged.
113 Return NULL if successful, a static error message string if not. */
116 parse_user_spec (spec_arg, uid, gid, username_arg, groupname_arg)
117 const char *spec_arg;
120 char **username_arg, **groupname_arg;
122 static const char *tired = "virtual memory exhausted";
123 const char *error_msg;
124 char *spec; /* A copy we can write on. */
127 char *g, *u, *separator;
131 *username_arg = *groupname_arg = NULL;
134 V_STRDUP (spec, spec_arg);
136 /* Find the separator if there is one. */
137 separator = strchr (spec, ':');
138 if (separator == NULL)
139 separator = strchr (spec, '.');
141 /* Replace separator with a NUL. */
142 if (separator != NULL)
145 /* Set U and G to non-zero length strings corresponding to user and
146 group specifiers or to NULL. */
147 u = (*spec == '\0' ? NULL : spec);
149 g = (separator == NULL || *(separator + 1) == '\0'
153 if (u == NULL && g == NULL)
154 return "can not omit both user and group";
157 /* Pretend that we are the user U whose group is G. This makes
158 pwd and grp functions ``know'' about the UID and GID of these. */
159 if (u && !is_number (u))
160 setenv ("USER", u, 1);
161 if (g && !is_number (g))
162 setenv ("GROUP", g, 1);
172 error_msg = "invalid user";
176 use_login_group = (separator != NULL && g == NULL);
178 error_msg = "cannot get the login group of a numeric UID";
186 if (g == NULL && separator != NULL)
188 /* A separator was given, but a group was not specified,
189 so get the login group. */
191 grp = getgrgid (pwd->pw_gid);
194 /* This is enough room to hold the unsigned decimal
195 representation of any 32-bit quantity and the trailing
198 sprintf (uint_buf, "%u", (unsigned) (pwd->pw_gid));
199 V_STRDUP (groupname, uint_buf);
203 V_STRDUP (groupname, grp->gr_name);
211 if (g != NULL && error_msg == NULL)
213 /* Explicit group. */
218 error_msg = "invalid group";
224 endgrent (); /* Save a file descriptor. */
226 if (error_msg == NULL)
227 V_STRDUP (groupname, g);
230 if (error_msg == NULL)
234 *username_arg = strdup (u);
235 if (*username_arg == NULL)
239 if (groupname != NULL && error_msg == NULL)
241 *groupname_arg = strdup (groupname);
242 if (*groupname_arg == NULL)
244 if (*username_arg != NULL)
246 free (*username_arg);
247 *username_arg = NULL;
259 # define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s))
262 main (int argc, char **argv)
266 for (i = 1; i < argc; i++)
269 char *username, *groupname;
274 tmp = strdup (argv[i]);
275 e = parse_user_spec (tmp, &uid, &gid, &username, &groupname);
277 printf ("%s: %u %u %s %s %s\n",
281 NULL_CHECK (username),
282 NULL_CHECK (groupname),