diff options
Diffstat (limited to 'lib/idcache.c')
-rw-r--r-- | lib/idcache.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/lib/idcache.c b/lib/idcache.c new file mode 100644 index 000000000..3e5f134ae --- /dev/null +++ b/lib/idcache.c @@ -0,0 +1,206 @@ +/* idcache.c -- map user and group IDs, cached for speed + Copyright (C) 1985, 1988, 1989, 1990 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include <stdio.h> +#include <sys/types.h> +#include <pwd.h> +#include <grp.h> + +#if defined(USG) || defined(STDC_HEADERS) +#include <string.h> +#else +#include <strings.h> +#endif + +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif +#ifndef _POSIX_VERSION +struct passwd *getpwuid (); +struct passwd *getpwnam (); +struct group *getgrgid (); +struct group *getgrnam (); +#endif + +char *xmalloc (); +char *xstrdup (); + +struct userid +{ + union + { + uid_t u; + gid_t g; + } id; + char *name; + struct userid *next; +}; + +static struct userid *user_alist; + +/* The members of this list have names not in the local passwd file. */ +static struct userid *nouser_alist; + +/* Translate UID to a login name or a stringified number, + with cache. */ + +char * +getuser (uid) + uid_t uid; +{ + register struct userid *tail; + struct passwd *pwent; + char usernum_string[20]; + + for (tail = user_alist; tail; tail = tail->next) + if (tail->id.u == uid) + return tail->name; + + pwent = getpwuid (uid); + tail = (struct userid *) xmalloc (sizeof (struct userid)); + tail->id.u = uid; + if (pwent == 0) + { + sprintf (usernum_string, "%u", (unsigned) uid); + tail->name = xstrdup (usernum_string); + } + else + tail->name = xstrdup (pwent->pw_name); + + /* Add to the head of the list, so most recently used is first. */ + tail->next = user_alist; + user_alist = tail; + return tail->name; +} + +/* Translate USER to a UID, with cache. + Return NULL if there is no such user. + (We also cache which user names have no passwd entry, + so we don't keep looking them up.) */ + +uid_t * +getuidbyname (user) + char *user; +{ + register struct userid *tail; + struct passwd *pwent; + + for (tail = user_alist; tail; tail = tail->next) + /* Avoid a function call for the most common case. */ + if (*tail->name == *user && !strcmp (tail->name, user)) + return &tail->id.u; + + for (tail = nouser_alist; tail; tail = tail->next) + /* Avoid a function call for the most common case. */ + if (*tail->name == *user && !strcmp (tail->name, user)) + return 0; + + pwent = getpwnam (user); + + tail = (struct userid *) xmalloc (sizeof (struct userid)); + tail->name = xstrdup (user); + + /* Add to the head of the list, so most recently used is first. */ + if (pwent) + { + tail->id.u = pwent->pw_uid; + tail->next = user_alist; + user_alist = tail; + return &tail->id.u; + } + + tail->next = nouser_alist; + nouser_alist = tail; + return 0; +} + +/* Use the same struct as for userids. */ +static struct userid *group_alist; +static struct userid *nogroup_alist; + +/* Translate GID to a group name or a stringified number, + with cache. */ + +char * +getgroup (gid) + gid_t gid; +{ + register struct userid *tail; + struct group *grent; + char groupnum_string[20]; + + for (tail = group_alist; tail; tail = tail->next) + if (tail->id.g == gid) + return tail->name; + + grent = getgrgid (gid); + tail = (struct userid *) xmalloc (sizeof (struct userid)); + tail->id.g = gid; + if (grent == 0) + { + sprintf (groupnum_string, "%u", (unsigned int) gid); + tail->name = xstrdup (groupnum_string); + } + else + tail->name = xstrdup (grent->gr_name); + + /* Add to the head of the list, so most recently used is first. */ + tail->next = group_alist; + group_alist = tail; + return tail->name; +} + +/* Translate GROUP to a UID, with cache. + Return NULL if there is no such group. + (We also cache which group names have no group entry, + so we don't keep looking them up.) */ + +gid_t * +getgidbyname (group) + char *group; +{ + register struct userid *tail; + struct group *grent; + + for (tail = group_alist; tail; tail = tail->next) + /* Avoid a function call for the most common case. */ + if (*tail->name == *group && !strcmp (tail->name, group)) + return &tail->id.g; + + for (tail = nogroup_alist; tail; tail = tail->next) + /* Avoid a function call for the most common case. */ + if (*tail->name == *group && !strcmp (tail->name, group)) + return 0; + + grent = getgrnam (group); + + tail = (struct userid *) xmalloc (sizeof (struct userid)); + tail->name = xstrdup (group); + + /* Add to the head of the list, so most recently used is first. */ + if (grent) + { + tail->id.g = grent->gr_gid; + tail->next = group_alist; + group_alist = tail; + return &tail->id.g; + } + + tail->next = nogroup_alist; + nogroup_alist = tail; + return 0; +} |