/* ----------------------------------------------------------------------- *
*
* mount_bind.c - module to mount a local filesystem if possible;
* otherwise create a symlink.
*
* Copyright 2000 Transmeta Corporation - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
* USA; either version 2 of the License, or (at your option) any later
* version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <stdlib.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/stat.h>
#define MODULE_MOUNT
#include "automount.h"
#define MODPREFIX "mount(bind): "
int mount_version = AUTOFS_MOUNT_VERSION; /* Required by protocol */
static int bind_works = 0;
int mount_init(void **context)
{
char tmp1[] = "/tmp/autoXXXXXX", *t1_dir;
char tmp2[] = "/tmp/autoXXXXXX", *t2_dir;
int err;
struct stat st1, st2;
t1_dir = mkdtemp(tmp1);
t2_dir = mkdtemp(tmp2);
if (t1_dir == NULL || t2_dir == NULL) {
if (t1_dir)
rmdir(t1_dir);
if (t2_dir)
rmdir(t2_dir);
return 0;
}
if (lstat(t1_dir, &st1) == -1)
goto out;
err = spawn_mount(LOGOPT_NONE, "-n", "--bind", t1_dir, t2_dir, NULL);
if (err == 0 &&
lstat(t2_dir, &st2) == 0 &&
st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino) {
bind_works = 1;
}
if (spawn_umount(LOGOPT_NONE, "-n", t2_dir, NULL) != 0)
debug(LOGOPT_ANY, MODPREFIX "umount failed for %s", t2_dir);
out:
rmdir(t1_dir);
rmdir(t2_dir);
return 0;
}
int mount_reinit(void **context)
{
return 0;
}
int mount_mount(struct autofs_point *ap, const char *root, const char *name, int name_len,
const char *what, const char *fstype, const char *options, void *context)
{
char fullpath[PATH_MAX];
char buf[MAX_ERR_BUF];
int err;
int i, len;
int symlnk = (*name != '/' && (ap->flags & MOUNT_FLAG_SYMLINK));
if (ap->flags & MOUNT_FLAG_REMOUNT)
return 0;
/* Extract "symlink" pseudo-option which forces local filesystems
* to be symlinked instead of bound.
*/
if (*name != '/' && !symlnk && options) {
const char *comma;
int o_len = strlen(options) + 1;
for (comma = options; *comma != '\0';) {
const char *cp;
const char *end;
while (*comma == ',')
comma++;
/* Skip leading white space */
while (*comma == ' ' || *comma == '\t')
comma++;
cp = comma;
while (*comma != '\0' && *comma != ',')
comma++;
/* Skip trailing white space */
end = comma - 1;
while (*comma == ' ' || *comma == '\t')
end--;
o_len = end - cp + 1;
if (_strncmp("symlink", cp, o_len) == 0)
symlnk = 1;
}
}
/* Root offset of multi-mount */
len = strlen(root);
if (root[len - 1] == '/') {
len = snprintf(fullpath, len, "%s", root);
} else if (*name == '/') {
/*
* Direct or offset mount, name is absolute path so
* don't use root (but with move mount changes root
* is now the same as name).
*/
len = sprintf(fullpath, "%s", root);
} else {
len = sprintf(fullpath, "%s/%s", root, name);
}
fullpath[len] = '\0';
i = len;
while (--i > 0 && fullpath[i] == '/')
fullpath[i] = '\0';
if (options == NULL || *options == '\0')
options = "defaults";
if (!strcmp(what, fullpath)) {
debug(ap->logopt, MODPREFIX
"cannot mount or symlink %s to itself", fullpath);
return 1;
}
if (!symlnk && bind_works) {
int status, existed = 1;
debug(ap->logopt, MODPREFIX "calling mkdir_path %s", fullpath);
status = mkdir_path(fullpath, 0555);
if (status && errno != EEXIST) {
char *estr = strerror_r(errno, buf, MAX_ERR_BUF);
error(ap->logopt,
MODPREFIX "mkdir_path %s failed: %s",
fullpath, estr);
return 1;
}
if (!status)
existed = 0;
debug(ap->logopt, MODPREFIX
"calling mount --bind -o %s %s %s",
options, what, fullpath);
err = spawn_bind_mount(ap->logopt, "-o",
options, what, fullpath, NULL);
if (err) {
if (ap->type != LKP_INDIRECT)
return 1;
if (!existed &&
(!(ap->flags & MOUNT_FLAG_GHOST) && name_len))
rmdir_path(ap, fullpath, ap->dev);
return err;
} else {
debug(ap->logopt,
MODPREFIX "mounted %s type %s on %s",
what, fstype, fullpath);
return 0;
}
} else {
char *cp;
char basepath[PATH_MAX];
int status;
struct stat st;
strcpy(basepath, fullpath);
cp = strrchr(basepath, '/');
if (cp != NULL && cp != basepath)
*cp = '\0';
if ((status = stat(fullpath, &st)) == 0) {
if (S_ISDIR(st.st_mode))
rmdir(fullpath);
} else {
debug(ap->logopt,
MODPREFIX "calling mkdir_path %s", basepath);
if (mkdir_path(basepath, 0555) && errno != EEXIST) {
char *estr;
estr = strerror_r(errno, buf, MAX_ERR_BUF);
error(ap->logopt,
MODPREFIX "mkdir_path %s failed: %s",
basepath, estr);
return 1;
}
}
if (symlink(what, fullpath) && errno != EEXIST) {
error(ap->logopt,
MODPREFIX
"failed to create symlink %s -> %s",
fullpath, what);
if ((ap->flags & MOUNT_FLAG_GHOST) && !status) {
if (mkdir_path(fullpath, 0555) && errno != EEXIST) {
char *estr = strerror_r(errno, buf, MAX_ERR_BUF);
error(ap->logopt,
MODPREFIX "mkdir_path %s failed: %s",
fullpath, estr);
}
} else {
if (ap->type == LKP_INDIRECT)
rmdir_path(ap, fullpath, ap->dev);
}
return 1;
} else {
debug(ap->logopt,
MODPREFIX "symlinked %s -> %s", fullpath, what);
return 0;
}
}
}
int mount_done(void *context)
{
return 0;
}