-
-static int update_passwd(const char *filename, const char *username,
- const char *new_pw)
-{
- struct stat sb;
- struct flock lock;
- FILE *old_fp;
- FILE *new_fp;
- char *new_name;
- char *last_char;
- unsigned user_len;
- int old_fd;
- int new_fd;
- int i;
- int ret = 1; /* failure */
-
- logmode = LOGMODE_STDIO;
- /* New passwd file, "/etc/passwd+" for now */
- new_name = xasprintf("%s+", filename);
- last_char = &new_name[strlen(new_name)-1];
- username = xasprintf("%s:", username);
- user_len = strlen(username);
-
- old_fp = fopen(filename, "r+");
- if (!old_fp)
- goto free_mem;
- old_fd = fileno(old_fp);
-
- /* Try to create "/etc/passwd+". Wait if it exists. */
- i = 30;
- do {
- // FIXME: on last iteration try w/o O_EXCL but with O_TRUNC?
- new_fd = open(new_name, O_WRONLY|O_CREAT|O_EXCL,0600);
- if (new_fd >= 0) goto created;
- if (errno != EEXIST) break;
- usleep(100000); /* 0.1 sec */
- } while (--i);
- bb_perror_msg("cannot create '%s'", new_name);
- goto close_old_fp;
- created:
- if (!fstat(old_fd, &sb)) {
- fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
- fchown(new_fd, sb.st_uid, sb.st_gid);
- }
- new_fp = fdopen(new_fd, "w");
- if (!new_fp) {
- close(new_fd);
- goto unlink_new;
- }
-
- /* Backup file is "/etc/passwd-" */
- last_char[0] = '-';
- /* Delete old one, create new as a hardlink to current */
- i = (unlink(new_name) && errno != ENOENT);
- if (i || link(filename, new_name))
- bb_perror_msg("warning: cannot create backup copy '%s'", new_name);
- last_char[0] = '+';
-
- /* Lock the password file before updating */
- lock.l_type = F_WRLCK;
- lock.l_whence = SEEK_SET;
- lock.l_start = 0;
- lock.l_len = 0;
- if (fcntl(old_fd, F_SETLK, &lock) < 0)
- bb_perror_msg("warning: cannot lock '%s'", filename);
- lock.l_type = F_UNLCK;
-
- /* Read current password file, write updated one */
- while (1) {
- char *line = xmalloc_fgets(old_fp);
- if (!line) break; /* EOF/error */
- if (strncmp(username, line, user_len) == 0) {
- /* we have a match with "username:"... */
- const char *cp = line + user_len;
- /* now cp -> old passwd, skip it: */
- cp = strchr(cp, ':');
- if (!cp) cp = "";
- /* now cp -> ':' after old passwd or -> "" */
- fprintf(new_fp, "%s%s%s", username, new_pw, cp);
- /* Erase password in memory */
- } else
- fputs(line, new_fp);
- free(line);
- }
- fcntl(old_fd, F_SETLK, &lock);
-
- /* We do want all of them to execute, thus | instead of || */
- if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
- || rename(new_name, filename)
- ) {
- /* At least one of those failed */
- goto unlink_new;
- }
- ret = 0; /* whee, success! */
-
- unlink_new:
- if (ret) unlink(new_name);
-
- close_old_fp:
- fclose(old_fp);
-
- free_mem:
- if (ENABLE_FEATURE_CLEAN_UP) free(new_name);
- if (ENABLE_FEATURE_CLEAN_UP) free((char*)username);
- logmode = LOGMODE_BOTH;
- return ret;
-}
-
-
-int passwd_main(int argc, char **argv);
-int passwd_main(int argc, char **argv)