[projects/setup.git] / joinpasswd.c

/*
 * $Id$
 * 
 * Copyright (c) 2001 Michal Moskal <malekith@pld.org.pl>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Michal Moskal.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY MICHAL MOSKAL AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * 
 * USAGE: joinpasswd
 *
 * Add entries from freshly created {passwd,shadow,group}.rpmnew to existing
 * {passwd,shadow,group}. It is usable as part of setup package, during upgrade
 * where new system user/group is to be added. If entry is already found in 
 * system database, it is left, otherwise it is added. UIDs/GIDs are *not* 
 * checked anyhow. 
 *
 * For typical sizes of files in setup package, it takes about 1 second per
 * 20000 users in system database on Pentium class machine. After static link
 * against uClibc it is under 2k on x86. Stdio hasn't been used intentionally.
 * 
 * Written for PLD GNU/Linux (http://www.pld.org.pl) setup package.
 *
 * Compilation against uClibc:
 * UCROOT=/usr/lib/bootdisk/usr
 * gcc -I$UCROOT/include -nostdlib -O2 joinpasswd.c $UCROOT/lib/crt0.o \
 * 		$UCROOT/lib/libc.a -lgcc -o joinpasswd
 * strip -R .comment -R .note joinpasswd
 *
 * The idea of this program comes from Lukasz Dobrek <dobrek@pld.org.pl>.
 * 
 */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>

#define FILE1 "/etc/passwd"
#define FILE2 "/etc/shadow"
#define FILE3 "/etc/group"
#define FILE4 "/etc/gshadow"

#define SUFFIX ".rpmnew"
/* maybe "-" or sth? */
#define BACKUP ".old"

/* #define SILENT */

void eputs(const char *msg)
{
	write(2, msg, strlen(msg));
}

void fatal(const char *msg)
{
	eputs(msg);
	eputs("\n");
	exit(1);
}

char *map_file(const char *name, int *sz)
{
	int fd;
	void *ptr;
	struct stat st;

	fd = open(name, O_RDONLY);
	if (fd == -1)
		return NULL;
	fstat(fd, &st);
	*sz = st.st_size;
	ptr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	if (ptr == MAP_FAILED)
		return NULL;

	return ptr;
}

int exist(char *id, int id_len, char *ptr, int sz)
{
	int i;

	for (i = 0; i < sz; ) {
		if (sz - i > id_len && memcmp(id, ptr + i, id_len + 1) == 0)
			return 1;
		while (i < sz && ptr[i] != '\n')
			i++;
		i++;
	}

	return 0;
}

void itoa(char *buf, long i)
{
	char tmp[32];
	char *p;

	if (i < 0) {
		strcpy(buf, "-");
		buf++;
		i = -i;
	}
	if (i == 0) {
		strcpy(buf, "0"); 
		return;
	}
	for (p = tmp; i; i /= 10)
		*p++ = (i % 10) + '0';
	while (p > tmp)
		*buf++ = *--p;
	*buf = 0;
}

int try_lock(const char *name)
{
	char file[strlen(name) + 32], lock[strlen(name) + 32];
	char buf[32];
	int fd;
	long pid;

	strcpy(lock, name);
	strcpy(file, name);
	strcat(lock, ".lock");
	itoa(buf, (long)getpid());
	strcat(file, ".");
	strcat(file, buf);
	
	fd = open(file, O_WRONLY|O_CREAT|O_EXCL|O_TRUNC, 0600);
	if (fd < 0)
		return -1;
	write(fd, buf, strlen(buf));
	close(fd);

	if (link(file, lock) == 0) {
		unlink(file);
		return 0;
	}

	fd = open(lock, O_RDONLY);
	if (fd < 0)
		goto oops;
	memset(buf, 0, sizeof(buf));
	read(fd, buf, sizeof(buf));
	pid = atol(buf);
	if (pid == 0 || kill(pid, 0) != 0) {
		/* stale lock */
		unlink(file);
		unlink(lock);
		/* try again */
		return try_lock(name);
	}

oops:
	unlink(file);
	return -1;
}

void unlock(const char *name)
{
	char lock[strlen(name) + 32];

	strcpy(lock, name);
	strcat(lock, ".lock");
	unlink(lock);
}

void lock(const char *name)
{
	int n;

	n = 5;
	while (n--) {
		if (try_lock(name) == 0)
			return;
		eputs("waiting for lock...\n");
		sleep(1);
	}
	fatal("cannot get lock");
}

int join(const char *old_name, const char *new_name, const char *backup_name)
{
	char *old, *new, *id;
	int i, fd;
	int old_sz, new_sz;

	new = map_file(new_name, &new_sz);
	if (new == NULL)
		return -1;
	
	lock(old_name);
	old = map_file(old_name, &old_sz);
	if (old == NULL)
		fatal("cannot mmap old");
	
	fd = open(backup_name, O_WRONLY|O_CREAT|O_TRUNC, 0600);
	if (fd < 0)
		fatal("cannot make backup");
	write(fd, old, old_sz);
	close(fd);
	
#ifndef SILENT
	eputs("marging contest of `");
	eputs(old_name);
	eputs("' with `");
	eputs(new_name);
	eputs("'\n");
#endif /* SILENT */

	fd = open(old_name, O_WRONLY|O_APPEND);
	
	for (i = 0; i < new_sz; ) {
		id = new + i;
		while (i < new_sz && new[i] != ':' && new[i] != '\n')
			i++;
		if (i < new_sz && new[i] == ':') {
			int id_len, line_len;

			id_len = i - (id - new);
			while (i < new_sz && new[i] != '\n')
				i++;
			if (i < new_sz)
				i++;
			line_len = i - (id - new);
			
			if (!exist(id, id_len, old, old_sz)) {
#ifndef SILENT
				eputs(old_name);
				eputs(": adding `");
				write(2, id, id_len);
				eputs("'\n");
#endif /* SILENT */
				write(fd, id, line_len);
			}
		} else if (i < new_sz)
			i++;
	}

#if 0
	/* user may want to exime this file... */
	unlink(new_name);
#endif
	unlock(old_name);

	return 0;
}

int main()
{
#if 1
	join(FILE1, FILE1 SUFFIX, FILE1 BACKUP);
	join(FILE2, FILE2 SUFFIX, FILE2 BACKUP);
	join(FILE3, FILE3 SUFFIX, FILE3 BACKUP);
	join(FILE4, FILE4 SUFFIX, FILE4 BACKUP);
#else
	join("test", "test.new", "test.old");
#endif
	return 0;
}
Commit	Line	Data
31aff165 MM	1	/*
	2	* $Id$
	3	*
	4	* Copyright (c) 2001 Michal Moskal <malekith@pld.org.pl>.
	5	* All rights reserved.
	6	*
	7	* Redistribution and use in source and binary forms, with or without
	8	* modification, are permitted provided that the following conditions
	9	* are met:
	10	* 1. Redistributions of source code must retain the above copyright
	11	* notice, this list of conditions and the following disclaimer.
	12	* 2. Redistributions in binary form must reproduce the above copyright
	13	* notice, this list of conditions and the following disclaimer in the
	14	* documentation and/or other materials provided with the distribution.
	15	* 3. All advertising materials mentioning features or use of this software
	16	* must display the following acknowledgement:
	17	* This product includes software developed by Michal Moskal.
	18	* 4. Neither the name of the author nor the names of any co-contributors
	19	* may be used to endorse or promote products derived from this software
	20	* without specific prior written permission.
	21	*
	22	* THIS SOFTWARE IS PROVIDED BY MICHAL MOSKAL AND CONTRIBUTORS ``AS IS'' AND
	23	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	24	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	25	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	26	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	27	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	28	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	29	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	30	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	31	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	32	* SUCH DAMAGE.
	33	*
	34	*
	35	*
	36	* USAGE: joinpasswd
	37	*
	38	* Add entries from freshly created {passwd,shadow,group}.rpmnew to existing
	39	* {passwd,shadow,group}. It is usable as part of setup package, during upgrade
	40	* where new system user/group is to be added. If entry is already found in
3da0d83f MM	41	* system database, it is left, otherwise it is added. UIDs/GIDs are not
3da0d83f MM	42	* checked anyhow.
31aff165 MM	43	*
	44	* For typical sizes of files in setup package, it takes about 1 second per
	45	* 20000 users in system database on Pentium class machine. After static link
	46	* against uClibc it is under 2k on x86. Stdio hasn't been used intentionally.
	47	*
	48	* Written for PLD GNU/Linux (http://www.pld.org.pl) setup package.
	49	*
	50	* Compilation against uClibc:
	51	* UCROOT=/usr/lib/bootdisk/usr
	52	* gcc -I$UCROOT/include -nostdlib -O2 joinpasswd.c $UCROOT/lib/crt0.o \
	53	* $UCROOT/lib/libc.a -lgcc -o joinpasswd
	54	* strip -R .comment -R .note joinpasswd
	55	*
	56	* The idea of this program comes from Lukasz Dobrek <dobrek@pld.org.pl>.
	57	*
	58	*/
	59
	60	#include <sys/types.h>
	61	#include <sys/mman.h>
	62	#include <sys/stat.h>
	63	#include <unistd.h>
	64	#include <fcntl.h>
	65	#include <stdlib.h>
	66	#include <string.h>
	67
	68	#define FILE1 "/etc/passwd"
	69	#define FILE2 "/etc/shadow"
	70	#define FILE3 "/etc/group"
1a43487e	71	#define FILE4 "/etc/gshadow"
31aff165 MM	72
31aff165 MM	73	#define SUFFIX ".rpmnew"
f88ff4b9 MM	74	/* maybe "-" or sth? */
f88ff4b9 MM	75	#define BACKUP ".old"
31aff165 MM	76
	77	/* #define SILENT */
	78
	79	void eputs(const char *msg)
	80	{
	81	write(2, msg, strlen(msg));
	82	}
	83
	84	void fatal(const char *msg)
	85	{
	86	eputs(msg);
	87	eputs("\n");
	88	exit(1);
	89	}
	90
	91	char map_file(const char name, int *sz)
	92	{
	93	int fd;
	94	void *ptr;
	95	struct stat st;
	96
	97	fd = open(name, O_RDONLY);
	98	if (fd == -1)
	99	return NULL;
	100	fstat(fd, &st);
	101	*sz = st.st_size;
	102	ptr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	103	if (ptr == MAP_FAILED)
	104	return NULL;
	105
	106	return ptr;
	107	}
	108
	109	int exist(char id, int id_len, char ptr, int sz)
	110	{
	111	int i;
	112
	113	for (i = 0; i < sz; ) {
	114	if (sz - i > id_len && memcmp(id, ptr + i, id_len + 1) == 0)
	115	return 1;
	116	while (i < sz && ptr[i] != '\n')
	117	i++;
	118	i++;
	119	}
	120
	121	return 0;
	122	}
	123
3da0d83f MM	124	void itoa(char *buf, long i)
	125	{
	126	char tmp[32];
	127	char *p;
	128
	129	if (i < 0) {
	130	strcpy(buf, "-");
	131	buf++;
	132	i = -i;
	133	}
	134	if (i == 0) {
	135	strcpy(buf, "0");
	136	return;
	137	}
	138	for (p = tmp; i; i /= 10)
	139	*p++ = (i % 10) + '0';
	140	while (p > tmp)
	141	buf++ = --p;
	142	*buf = 0;
	143	}
	144
	145	int try_lock(const char *name)
	146	{
	147	char file[strlen(name) + 32], lock[strlen(name) + 32];
	148	char buf[32];
	149	int fd;
	150	long pid;
	151
	152	strcpy(lock, name);
	153	strcpy(file, name);
	154	strcat(lock, ".lock");
	155	itoa(buf, (long)getpid());
	156	strcat(file, ".");
	157	strcat(file, buf);
	158
	159	fd = open(file, O_WRONLY\|O_CREAT\|O_EXCL\|O_TRUNC, 0600);
	160	if (fd < 0)
	161	return -1;
	162	write(fd, buf, strlen(buf));
	163	close(fd);
	164
	165	if (link(file, lock) == 0) {
	166	unlink(file);
	167	return 0;
	168	}
	169
	170	fd = open(lock, O_RDONLY);
	171	if (fd < 0)
	172	goto oops;
	173	memset(buf, 0, sizeof(buf));
	174	read(fd, buf, sizeof(buf));
	175	pid = atol(buf);
	176	if (pid == 0 \|\| kill(pid, 0) != 0) {
	177	/* stale lock */
	178	unlink(file);
	179	unlink(lock);
	180	/* try again */
	181	return try_lock(name);
	182	}
	183
	184	oops:
	185	unlink(file);
	186	return -1;
	187	}
188
189	void unlock(const char *name)
190	{
191	char lock[strlen(name) + 32];
192
193	strcpy(lock, name);
194	strcat(lock, ".lock");
195	unlink(lock);
196	}
197
198	void lock(const char *name)
199	{
200	int n;
201
202	n = 5;
203	while (n--) {
204	if (try_lock(name) == 0)
205	return;
206	eputs("waiting for lock...\n");
207	sleep(1);
208	}
209	fatal("cannot get lock");
210	}
211
f88ff4b9	212	int join(const char old_name, const char new_name, const char *backup_name)
31aff165 MM	213	{
	214	char old, new, *id;
	215	int i, fd;
	216	int old_sz, new_sz;
	217
	218	new = map_file(new_name, &new_sz);
	219	if (new == NULL)
	220	return -1;
3da0d83f MM	221
3da0d83f MM	222	lock(old_name);
31aff165 MM	223	old = map_file(old_name, &old_sz);
	224	if (old == NULL)
	225	fatal("cannot mmap old");
f88ff4b9 MM	226
	227	fd = open(backup_name, O_WRONLY\|O_CREAT\|O_TRUNC, 0600);
	228	if (fd < 0)
	229	fatal("cannot make backup");
	230	write(fd, old, old_sz);
	231	close(fd);
	232
31aff165 MM	233	#ifndef SILENT
	234	eputs("marging contest of `");
	235	eputs(old_name);
	236	eputs("' with `");
	237	eputs(new_name);
	238	eputs("'\n");
	239	#endif /* SILENT */
	240
	241	fd = open(old_name, O_WRONLY\|O_APPEND);
	242
	243	for (i = 0; i < new_sz; ) {
	244	id = new + i;
	245	while (i < new_sz && new[i] != ':' && new[i] != '\n')
	246	i++;
	247	if (i < new_sz && new[i] == ':') {
	248	int id_len, line_len;
	249
	250	id_len = i - (id - new);
	251	while (i < new_sz && new[i] != '\n')
	252	i++;
	253	if (i < new_sz)
	254	i++;
	255	line_len = i - (id - new);
	256
	257	if (!exist(id, id_len, old, old_sz)) {
	258	#ifndef SILENT
	259	eputs(old_name);
	260	eputs(": adding `");
	261	write(2, id, id_len);
	262	eputs("'\n");
	263	#endif /* SILENT */
	264	write(fd, id, line_len);
	265	}
	266	} else if (i < new_sz)
	267	i++;
	268	}
	269
	270	#if 0
	271	/* user may want to exime this file... */
	272	unlink(new_name);
	273	#endif
3da0d83f	274	unlock(old_name);
31aff165 MM	275
	276	return 0;
	277	}
	278
	279	int main()
	280	{
1a43487e	281	#if 1
3da0d83f MM	282	join(FILE1, FILE1 SUFFIX, FILE1 BACKUP);
	283	join(FILE2, FILE2 SUFFIX, FILE2 BACKUP);
	284	join(FILE3, FILE3 SUFFIX, FILE3 BACKUP);
1a43487e	285	join(FILE4, FILE4 SUFFIX, FILE4 BACKUP);
31aff165	286	#else
3da0d83f	287	join("test", "test.new", "test.old");
31aff165 MM	288	#endif
	289	return 0;
	290	}