busybox/libbb/bb_pwd.c
Denis Vlasenko 3734b946bf bb_getpwuid, bb_getgrgid: change order of arguments to more intuitive one;
comment thoroughly when they die and when they dont.
2007-07-27 11:20:10 +00:00

100 lines
2.5 KiB
C

/* vi: set sw=4 ts=4: */
/*
* password utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#include "libbb.h"
#define assert(x) ((void)0)
/* internal function for bb_getpwuid and bb_getgrgid */
/* Hacked by Tito Ragusa (c) 2004 <farmatito@tiscali.it> to make it more
* flexible:
*
* bufsize > 0: If idname is not NULL it is copied to buffer,
* and buffer is returned. Else id as string is written
* to buffer, and NULL is returned.
*
* bufsize == 0: idname is returned.
*
* bufsize < 0: If idname is not NULL it is returned.
* Else an error message is printed and the program exits.
*/
static char* bb_getug(char *buffer, int bufsize, char *idname, long id, char prefix)
{
if (bufsize > 0) {
assert(buffer != NULL);
if (idname) {
return safe_strncpy(buffer, idname, bufsize);
}
snprintf(buffer, bufsize, "%ld", id);
} else if (bufsize < 0 && !idname) {
bb_error_msg_and_die("unknown %cid %ld", prefix, id);
}
return idname;
}
/* bb_getpwuid, bb_getgrgid:
* bb_getXXXid(buf, bufsz, id) - copy user/group name or id
* as a string to buf, return user/group name or NULL
* bb_getXXXid(NULL, 0, id) - return user/group name or NULL
* bb_getXXXid(NULL, -1, id) - return user/group name or exit
*/
/* gets a username given a uid */
char* bb_getpwuid(char *name, int bufsize, long uid)
{
struct passwd *myuser = getpwuid(uid);
return bb_getug(name, bufsize,
(myuser ? myuser->pw_name : (char*)myuser),
uid, 'u');
}
/* gets a groupname given a gid */
char* bb_getgrgid(char *group, int bufsize, long gid)
{
struct group *mygroup = getgrgid(gid);
return bb_getug(group, bufsize,
(mygroup ? mygroup->gr_name : (char*)mygroup),
gid, 'g');
}
/* returns a gid given a group name */
long xgroup2gid(const char *name)
{
struct group *mygroup;
mygroup = getgrnam(name);
if (mygroup == NULL)
bb_error_msg_and_die("unknown group name: %s", name);
return mygroup->gr_gid;
}
/* returns a uid given a username */
long xuname2uid(const char *name)
{
struct passwd *myuser;
myuser = getpwnam(name);
if (myuser == NULL)
bb_error_msg_and_die("unknown user name: %s", name);
return myuser->pw_uid;
}
unsigned long get_ug_id(const char *s,
long (*xname2id)(const char *))
{
unsigned long r;
r = bb_strtoul(s, NULL, 10);
if (errno)
return xname2id(s);
return r;
}