1 /* idcache.c -- map user and group IDs, cached for speed
2 Copyright (C) 1985, 1988, 1989, 1990, 2004 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 along
15 with this program; if not, write to the Free Software Foundation, Inc.,
16 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
23 #include <sys/types.h>
27 #if defined(STDC_HEADERS) || defined(HAVE_STRING_H)
36 #ifndef _POSIX_VERSION
37 struct passwd *getpwuid ();
38 struct passwd *getpwnam ();
39 struct group *getgrgid ();
40 struct group *getgrnam ();
57 static struct userid *user_alist;
59 /* The members of this list have names not in the local passwd file. */
60 static struct userid *nouser_alist;
62 /* Translate UID to a login name or a stringified number,
68 register struct userid *tail;
70 char usernum_string[20];
72 for (tail = user_alist; tail; tail = tail->next)
73 if (tail->id.u == uid)
76 pwent = getpwuid (uid);
77 tail = (struct userid *) xmalloc (sizeof (struct userid));
81 sprintf (usernum_string, "%u", (unsigned) uid);
82 tail->name = xstrdup (usernum_string);
85 tail->name = xstrdup (pwent->pw_name);
87 /* Add to the head of the list, so most recently used is first. */
88 tail->next = user_alist;
93 /* Translate USER to a UID, with cache.
94 Return NULL if there is no such user.
95 (We also cache which user names have no passwd entry,
96 so we don't keep looking them up.) */
99 getuidbyname (char *user)
101 register struct userid *tail;
102 struct passwd *pwent;
104 for (tail = user_alist; tail; tail = tail->next)
105 /* Avoid a function call for the most common case. */
106 if (*tail->name == *user && !strcmp (tail->name, user))
109 for (tail = nouser_alist; tail; tail = tail->next)
110 /* Avoid a function call for the most common case. */
111 if (*tail->name == *user && !strcmp (tail->name, user))
114 pwent = getpwnam (user);
116 tail = (struct userid *) xmalloc (sizeof (struct userid));
117 tail->name = xstrdup (user);
119 /* Add to the head of the list, so most recently used is first. */
122 tail->id.u = pwent->pw_uid;
123 tail->next = user_alist;
128 tail->next = nouser_alist;
133 /* Use the same struct as for userids. */
134 static struct userid *group_alist;
135 static struct userid *nogroup_alist;
137 /* Translate GID to a group name or a stringified number,
143 register struct userid *tail;
145 char groupnum_string[20];
147 for (tail = group_alist; tail; tail = tail->next)
148 if (tail->id.g == gid)
151 grent = getgrgid (gid);
152 tail = (struct userid *) xmalloc (sizeof (struct userid));
156 sprintf (groupnum_string, "%u", (unsigned int) gid);
157 tail->name = xstrdup (groupnum_string);
160 tail->name = xstrdup (grent->gr_name);
162 /* Add to the head of the list, so most recently used is first. */
163 tail->next = group_alist;
168 /* Translate GROUP to a UID, with cache.
169 Return NULL if there is no such group.
170 (We also cache which group names have no group entry,
171 so we don't keep looking them up.) */
174 getgidbyname (char *group)
176 register struct userid *tail;
179 for (tail = group_alist; tail; tail = tail->next)
180 /* Avoid a function call for the most common case. */
181 if (*tail->name == *group && !strcmp (tail->name, group))
184 for (tail = nogroup_alist; tail; tail = tail->next)
185 /* Avoid a function call for the most common case. */
186 if (*tail->name == *group && !strcmp (tail->name, group))
189 grent = getgrnam (group);
191 tail = (struct userid *) xmalloc (sizeof (struct userid));
192 tail->name = xstrdup (group);
194 /* Add to the head of the list, so most recently used is first. */
197 tail->id.g = grent->gr_gid;
198 tail->next = group_alist;
203 tail->next = nogroup_alist;
204 nogroup_alist = tail;