/tools/joinpasswd.c
C | 359 lines | 251 code | 44 blank | 64 comment | 64 complexity | c15bc3ee171f85a1f67169c776f7ff8c MD5 | raw file
- /*
- * $Id: joinpasswd.c,v 1.14 2011/12/08 19:25:04 arekm Exp $
- *
- * Copyright (c) 2001 Michal Moskal <malekith@pld-linux.org>.
- * 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 Linux (http://www.pld-linux.org/) 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-linux.org>.
- *
- */
- #include <sys/types.h>
- #include <sys/mman.h>
- #include <sys/stat.h>
- #include <stdio.h>
- #include <errno.h>
- #include <unistd.h>
- #include <stdarg.h>
- #include <fcntl.h>
- #include <stdlib.h>
- #include <string.h>
- #include <signal.h>
- #define FILE1 "/etc/passwd"
- #define FILE2 "/etc/shadow"
- #define FILE3 "/etc/group"
- #define FILE4 "/etc/gshadow"
- /* #define OLD_LOCK */
- #define LOCK_FILE "/etc/.pwd.lock"
- #define SUFFIX ".rpmnew"
- /* maybe "-" or sth? */
- #define BACKUP ".old"
- /* #define SILENT */
- void eputs(const char *fmt, ...)
- {
- va_list args;
- va_start(args, fmt);
- vfprintf(stderr, fmt, args);
- va_end(args);
- }
- void fatal(const char *fmt, ...)
- {
- va_list args;
- va_start(args, fmt);
- eputs(fmt, args);
- va_end(args);
- 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;
- if (fstat(fd, &st) < 0)
- return NULL;
- *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;
- }
- #ifndef OLD_LOCK
- int lock_fd = -1;
- void noop(int x)
- {
- (void)x;
- }
- #endif
- int try_lock(const char *name)
- {
- #ifdef OLD_LOCK
- 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;
- if (write(fd, buf, strlen(buf)) < 0) {
- close(fd);
- return -1;
- }
- if (close(fd) < 0)
- return -1;
- 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;
- #else
- struct flock fl;
- if (lock_fd != -1)
- return -1;
- lock_fd = open(LOCK_FILE, O_RDWR|O_CREAT, 0600);
- if (lock_fd == -1)
- return -1;
- signal(SIGALRM, noop);
- alarm(15);
- memset(&fl, 0, sizeof(fl));
- fl.l_type = F_WRLCK;
- fl.l_whence = SEEK_SET;
- if (fcntl(lock_fd, F_SETLKW, &fl) != 0) {
- alarm(0);
- close(lock_fd);
- lock_fd = -1;
- return -1;
- }
- alarm(0);
- return 0;
- #endif
- }
- void unlock(const char *name)
- {
- #ifdef OLD_LOCK
- char lock[strlen(name) + 32];
- strcpy(lock, name);
- strcat(lock, ".lock");
- unlink(lock);
- #else
- if (lock_fd != -1)
- close(lock_fd);
- lock_fd = -1;
- #endif
- }
- 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 file `%s': %m", old_name);
- fd = open(backup_name, O_WRONLY|O_CREAT|O_TRUNC, 0600);
- if (fd < 0)
- fatal("cannot create backup file `%s': %m", backup_name);
- if (write(fd, old, old_sz) < 0)
- fatal("writting to backup file `%s' failed: %m", backup_name);
- if (fsync(fd) < 0)
- fatal("syncing backup file `%s' failed: %m", backup_name);
- if (close(fd) < 0)
- fatal("closing backup file `%s' failed: %m", backup_name);
- #ifndef SILENT
- eputs("merging content of `");
- eputs(old_name);
- eputs("' with `");
- eputs(new_name);
- eputs("'\n");
- #endif /* SILENT */
- fd = open(old_name, O_WRONLY|O_APPEND);
- if (fd < 0)
- fatal("cannot open old file `%s': %m", old_name);
- 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 */
- if (write(fd, id, line_len) < 0)
- fatal("writting line to `%s' failed, check backup file: %m", old_name);
- }
- } else if (i < new_sz)
- i++;
- }
- fsync(fd);
- close(fd);
- #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;
- }