/*
1) add a user: update_passwd(FILE, USER, REMAINING_PWLINE, NULL)
only if CONFIG_ADDUSER=y and applet_name[0] == 'a' like in adduser
2) add a group: update_passwd(FILE, GROUP, REMAINING_GRLINE, NULL)
only if CONFIG_ADDGROUP=y and applet_name[0] == 'a' like in addgroup
3) add a user to a group: update_passwd(FILE, GROUP, NULL, MEMBER)
only if CONFIG_FEATURE_ADDUSER_TO_GROUP=y, applet_name[0] == 'a'
like in addgroup and member != NULL
4) delete a user: update_passwd(FILE, USER, NULL, NULL)
5) delete a group: update_passwd(FILE, GROUP, NULL, NULL)
6) delete a user from a group: update_passwd(FILE, GROUP, NULL, MEMBER)
only if CONFIG_FEATURE_DEL_USER_FROM_GROUP=y and member != NULL
7) change user's password: update_passwd(FILE, USER, NEW_PASSWD, NULL)
only if CONFIG_PASSWD=y and applet_name[0] == 'p' like in passwd
or if CONFIG_CHPASSWD=y and applet_name[0] == 'c' like in chpasswd
8) delete a user from all groups: update_passwd(FILE, NULL, NULL, MEMBER)
This function does not validate the arguments fed to it
so the calling program should take care of that.
Returns number of lines changed, or -1 on error.
*/
int FAST_FUNC update_passwd(const char *filename,
const char *name,
const char *new_passwd,
const char *member)
{
#if !(ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP)
#define member NULL
#endif
struct stat sb;
struct flock lock;
FILE *old_fp;
FILE *new_fp;
char *fnamesfx;
char *sfx_char;
char *name_colon;
int old_fd;
int new_fd;
int i;
int changed_lines;
int ret = -1; /* failure */
/* used as a bool: "are we modifying /etc/shadow?" */
#if ENABLE_FEATURE_SHADOWPASSWDS
const char *shadow = strstr(filename, "shadow");
#else
# define shadow NULL
#endif
filename = xmalloc_follow_symlinks(filename);
if (filename == NULL)
return ret;
if (name)
check_selinux_update_passwd(name);
/* New passwd file, "/etc/passwd+" for now */
fnamesfx = xasprintf("%s+", filename);
sfx_char = &fnamesfx[strlen(fnamesfx)-1];
name_colon = xasprintf("%s:", name ? name : "");
if (shadow)
old_fp = fopen(filename, "r+");
else
old_fp = fopen_or_warn(filename, "r+");
if (!old_fp) {
if (shadow)
ret = 0; /* missing shadow is not an error */
goto free_mem;
}
old_fd = fileno(old_fp);
selinux_preserve_fcontext(old_fd);
/* 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(fnamesfx, 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("can't create '%s'", fnamesfx);
goto close_old_fp;
created:
if (fstat(old_fd, &sb) == 0) {
fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */
fchown(new_fd, sb.st_uid, sb.st_gid);
}
errno = 0;
new_fp = xfdopen_for_write(new_fd);
/* Backup file is "/etc/passwd-" */
*sfx_char = '-';
/* Delete old backup */
i = (unlink(fnamesfx) && errno != ENOENT);
/* Create backup as a hardlink to current */
if (i || link(filename, fnamesfx))
bb_perror_msg("warning: can't create backup copy '%s'",
fnamesfx);
*sfx_char = '+';
/* 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: can't lock '%s'", filename);
lock.l_type = F_UNLCK;
/* Read current password file, write updated /etc/passwd+ */
changed_lines = 0;
while (1) {
char *cp, *line;
line = xmalloc_fgetline(old_fp);
if (!line) /* EOF/error */
break;
if (!name && member) {
/* Delete member from all groups */
/* line is "GROUP:PASSWD:[member1[,member2]...]" */
unsigned member_len = strlen(member);
char *list = strrchr(line, ':');
while (list) {
list++;
next_list_element:
if (is_prefixed_with(list, member)) {
char c;
changed_lines++;
c = list[member_len];
if (c == '\0') {
if (list[-1] == ',')
list--;
*list = '\0';
break;
}
if (c == ',') {
overlapping_strcpy(list, list + member_len + 1);
goto next_list_element;
}
changed_lines--;
}
list = strchr(list, ',');
}
fprintf(new_fp, "%s\n", line);
goto next;
}
cp = is_prefixed_with(line, name_colon);
if (!cp) {
fprintf(new_fp, "%s\n", line);
goto next;
}
/* We have a match with "name:"... */
/* cp points past "name:" */
#if ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP
if (member) {
/* It's actually /etc/group+, not /etc/passwd+ */
if (ENABLE_FEATURE_ADDUSER_TO_GROUP
&& applet_name[0] == 'a'
) {
/* Add user to group */
fprintf(new_fp, "%s%s%s\n", line,
last_char_is(line, ':') ? "" : ",",
member);
changed_lines++;
} else if (ENABLE_FEATURE_DEL_USER_FROM_GROUP
/* && applet_name[0] == 'd' */
) {
/* Delete user from group */
char *tmp;
const char *fmt = "%s";
/* find the start of the member list: last ':' */
cp = strrchr(line, ':');
/* cut it */
*cp++ = '\0';
/* write the cut line name:passwd:gid:
* or name:!:: */
fprintf(new_fp, "%s:", line);
/* parse the tokens of the member list */
tmp = cp;
while ((cp = strsep(&tmp, ",")) != NULL) {
if (strcmp(member, cp) != 0) {
fprintf(new_fp, fmt, cp);
fmt = ",%s";
} else {
/* found member, skip it */
changed_lines++;
}
}
fprintf(new_fp, "\n");
}
} else
#endif
if ((ENABLE_PASSWD && applet_name[0] == 'p')
|| (ENABLE_CHPASSWD && applet_name[0] == 'c')
) {
/* Change passwd */
cp = strchrnul(cp, ':'); /* move past old passwd */
if (shadow && *cp == ':') {
/* /etc/shadow's field 3 (passwd change date) needs updating */
/* move past old change date */
cp = strchrnul(cp + 1, ':');
/* "name:" + "new_passwd" + ":" + "change date" + ":rest of line" */
fprintf(new_fp, "%s%s:%u%s\n", name_colon, new_passwd,
(unsigned)(time(NULL)) / (24*60*60), cp);
} else {
/* "name:" + "new_passwd" + ":rest of line" */
fprintf(new_fp, "%s%s%s\n", name_colon, new_passwd, cp);
}
changed_lines++;
} /* else delete user or group: skip the line */
next:
free(line);
}
if (changed_lines == 0) {
#if ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP
if (member) {
if (ENABLE_ADDGROUP && applet_name[0] == 'a')
bb_error_msg("can't find %s in %s", name, filename);
if (ENABLE_DELGROUP && applet_name[0] == 'd')
bb_error_msg("can't find %s in %s", member, filename);
}
#endif
if ((ENABLE_ADDUSER || ENABLE_ADDGROUP)
&& applet_name[0] == 'a' && !member
) {
/* add user or group */
fprintf(new_fp, "%s%s\n", name_colon, new_passwd);
changed_lines++;
}
}
fcntl(old_fd, F_SETLK, &lock);
/* We do want all of them to execute, thus | instead of || */
errno = 0;
if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp))
|| rename(fnamesfx, filename)
) {
/* At least one of those failed */
bb_perror_nomsg();
goto unlink_new;
}
/* Success: ret >= 0 */
ret = changed_lines;
unlink_new:
if (ret < 0)
unlink(fnamesfx);
close_old_fp:
fclose(old_fp);
free_mem:
free(fnamesfx);
free((char *)filename);
free(name_colon);
return ret;
}
/* if fn is NULL then input is stdin and output is stdout */
static int convert(char *fn, int ConvType)
{
int c, fd;
FILE *in, *out;
if (fn != NULL) {
in = bb_xfopen(fn, "rw");
/*
The file is then created with mode read/write and
permissions 0666 for glibc 2.0.6 and earlier or
0600 for glibc 2.0.7 and later.
*/
snprintf(tempFn, sizeof(tempFn), "%sXXXXXX", fn);
/*
sizeof tempFn is 4096, so it should be big enough to hold the full
path. however if the output is truncated the subsequent call to
mkstemp would fail.
*/
if ((fd = mkstemp(&tempFn[0])) == -1 || chmod(tempFn, 0600) == -1) {
bb_perror_nomsg_and_die();
}
out = fdopen(fd, "w+");
if (!out) {
close(fd);
remove(tempFn);
}
} else {
in = stdin;
out = stdout;
}
while ((c = fgetc(in)) != EOF) {
if (c == '\r')
continue;
if (c == '\n') {
if (ConvType == CT_UNIX2DOS)
fputc('\r', out);
fputc('\n', out);
continue;
}
fputc(c, out);
}
if (fn != NULL) {
if (fclose(in) < 0 || fclose(out) < 0) {
bb_perror_nomsg();
remove(tempFn);
return -2;
}
/* Assume they are both on the same filesystem (which
* should be true since we put them into the same directory
* so we _should_ be ok, but you never know... */
if (rename(tempFn, fn) < 0) {
bb_perror_msg("cannot rename '%s' as '%s'", tempFn, fn);
return -1;
}
}
return 0;
}
// if fn is NULL then input is stdin and output is stdout
static int convert(char *fn, int ConvType)
{
int c, fd;
struct timeval tv;
char tempFn[BUFSIZ];
static bb_uint64_t value=0;
FILE *in = stdin, *out = stdout;
if (fn != NULL) {
in = bb_xfopen(fn, "rw");
safe_strncpy(tempFn, fn, sizeof(tempFn));
c = strlen(tempFn);
tempFn[c] = '.';
while(1) {
/* tempFn is BUFSIZ so the last addressable spot it BUFSIZ-1.
* The loop increments by 2. So this must check for BUFSIZ-3. */
if (c >=BUFSIZ-3)
bb_error_msg_and_die("unique name not found");
/* Get some semi random stuff to try and make a
* random filename based (and in the same dir as)
* the input file... */
gettimeofday (&tv, NULL);
value += ((bb_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
tempFn[++c] = letters[value % 62];
tempFn[c+1] = '\0';
value /= 62;
if ((fd = open(tempFn, O_RDWR | O_CREAT | O_EXCL, 0600)) < 0 ) {
continue;
}
out = fdopen(fd, "w+");
if (!out) {
close(fd);
remove(tempFn);
continue;
}
break;
}
}
while ((c = fgetc(in)) != EOF) {
if (c == '\r') {
if ((ConvType == CT_UNIX2DOS) && (fn != NULL)) {
// file is alredy in DOS format so it is not necessery to touch it
remove(tempFn);
if (fclose(in) < 0 || fclose(out) < 0) {
bb_perror_nomsg();
return -2;
}
return 0;
}
if (!ConvType)
ConvType = CT_DOS2UNIX;
break;
}
if (c == '\n') {
if ((ConvType == CT_DOS2UNIX) && (fn != NULL)) {
// file is alredy in UNIX format so it is not necessery to touch it
remove(tempFn);
if ((fclose(in) < 0) || (fclose(out) < 0)) {
bb_perror_nomsg();
return -2;
}
return 0;
}
if (!ConvType) {
ConvType = CT_UNIX2DOS;
}
if (ConvType == CT_UNIX2DOS) {
fputc('\r', out);
}
fputc('\n', out);
break;
}
fputc(c, out);
}
if (c != EOF)
while ((c = fgetc(in)) != EOF) {
if (c == '\r')
continue;
if (c == '\n') {
if (ConvType == CT_UNIX2DOS)
fputc('\r', out);
fputc('\n', out);
continue;
}
fputc(c, out);
}
if (fn != NULL) {
if (fclose(in) < 0 || fclose(out) < 0) {
bb_perror_nomsg();
remove(tempFn);
return -2;
}
/* Assume they are both on the same filesystem (which
* should be true since we put them into the same directory
* so we _should_ be ok, but you never know... */
if (rename(tempFn, fn) < 0) {
bb_perror_msg("unable to rename '%s' as '%s'", tempFn, fn);
return -1;
}
}
return 0;
}
