1 /* userspec.c -- Parse a user and group string.
2 Copyright (C) 1989-1992, 1997-1998, 2000, 2002-2007 Free Software
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
28 #include <sys/types.h>
33 # include <sys/param.h>
48 #define _(msgid) gettext (msgid)
49 #define N_(msgid) msgid
52 # define endgrent() ((void) 0)
56 # define endpwent() ((void) 0)
60 # define UID_T_MAX TYPE_MAXIMUM (uid_t)
64 # define GID_T_MAX TYPE_MAXIMUM (gid_t)
67 /* MAXUID may come from limits.h or sys/params.h. */
69 # define MAXUID UID_T_MAX
72 # define MAXGID GID_T_MAX
75 /* ISDIGIT differs from isdigit, as follows:
76 - Its arg may be any int or unsigned int; it need not be an unsigned char
78 - It's typically faster.
79 POSIX says that only '0' through '9' are digits. Prefer ISDIGIT to
80 isdigit unless it's important to use the locale's definition
81 of `digit' even when the host does not conform to POSIX. */
82 #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
86 /* Return true if STR represents an unsigned decimal integer. */
89 is_number (const char *str)
103 parse_with_separator (char const *spec, char const *separator,
104 uid_t *uid, gid_t *gid,
105 char **username, char **groupname)
107 static const char *E_invalid_user = N_("invalid user");
108 static const char *E_invalid_group = N_("invalid group");
109 static const char *E_bad_spec = N_("invalid spec");
111 const char *error_msg;
121 *username = *groupname = NULL;
123 /* Set U and G to nonzero length strings corresponding to user and
124 group specifiers or to NULL. If U is not NULL, it is a newly
128 if (separator == NULL)
135 size_t ulen = separator - spec;
138 u = xmemdup (spec, ulen + 1);
143 g = (separator == NULL || *(separator + 1) == '\0'
148 /* Pretend that we are the user U whose group is G. This makes
149 pwd and grp functions ``know'' about the UID and GID of these. */
150 if (u && !is_number (u))
151 setenv ("USER", u, 1);
152 if (g && !is_number (g))
153 setenv ("GROUP", g, 1);
158 /* If it starts with "+", skip the look-up. */
159 pwd = (*u == '+' ? NULL : getpwnam (u));
162 bool use_login_group = (separator != NULL && g == NULL);
165 /* If there is no group,
166 then there may not be a trailing ":", either. */
167 error_msg = E_bad_spec;
171 unsigned long int tmp;
172 if (xstrtoul (u, NULL, 10, &tmp, "") == LONGINT_OK
176 error_msg = E_invalid_user;
182 if (g == NULL && separator != NULL)
184 /* A separator was given, but a group was not specified,
185 so get the login group. */
186 char buf[INT_BUFSIZE_BOUND (uintmax_t)];
188 grp = getgrgid (gnum);
189 gname = xstrdup (grp ? grp->gr_name : umaxtostr (gnum, buf));
196 if (g != NULL && error_msg == NULL)
198 /* Explicit group. */
199 /* If it starts with "+", skip the look-up. */
200 grp = (*g == '+' ? NULL : getgrnam (g));
203 unsigned long int tmp;
204 if (xstrtoul (g, NULL, 10, &tmp, "") == LONGINT_OK && tmp <= MAXGID)
207 error_msg = E_invalid_group;
211 endgrent (); /* Save a file descriptor. */
215 if (error_msg == NULL)
230 /* Extract from SPEC, which has the form "[user][:.][group]",
231 a USERNAME, UID U, GROUPNAME, and GID G.
232 Either user or group, or both, must be present.
233 If the group is omitted but the separator is given,
234 use the given user's login group.
235 If SPEC contains a `:', then use that as the separator, ignoring
236 any `.'s. If there is no `:', but there is a `.', then first look
237 up the entire SPEC as a login name. If that look-up fails, then
238 try again interpreting the `.' as a separator.
240 USERNAME and GROUPNAME will be in newly malloc'd memory.
241 Either one might be NULL instead, indicating that it was not
242 given and the corresponding numeric ID was left unchanged.
244 Return NULL if successful, a static error message string if not. */
247 parse_user_spec (char const *spec, uid_t *uid, gid_t *gid,
248 char **username, char **groupname)
250 char const *colon = strchr (spec, ':');
251 char const *error_msg =
252 parse_with_separator (spec, colon, uid, gid, username, groupname);
254 if (!colon && error_msg)
256 /* If there's no colon but there is a dot, and if looking up the
257 whole spec failed (i.e., the spec is not a owner name that
258 includes a dot), then try again, but interpret the dot as a
259 separator. This is a compatible extension to POSIX, since
260 the POSIX-required behavior is always tried first. */
262 char const *dot = strchr (spec, '.');
264 && ! parse_with_separator (spec, dot, uid, gid, username, groupname))
273 # define NULL_CHECK(s) ((s) == NULL ? "(null)" : (s))
276 main (int argc, char **argv)
280 for (i = 1; i < argc; i++)
283 char *username, *groupname;
288 tmp = strdup (argv[i]);
289 e = parse_user_spec (tmp, &uid, &gid, &username, &groupname);
291 printf ("%s: %lu %lu %s %s %s\n",
293 (unsigned long int) uid,
294 (unsigned long int) gid,
295 NULL_CHECK (username),
296 NULL_CHECK (groupname),