/*
* XXX - Serialize calls to fsgetmntlist, so that threads can get consistent
* snapshots of the in-kernel mnttab. This function should be removed
* once getextmntent is made MT-safe and callers can invoke fsgetmntlist
* directly.
*/
struct mntlist *
getmntlist()
{
struct mntlist *mntl;
(void) mutex_lock(&mnttab_lock);
mntl = fsgetmntlist();
(void) mutex_unlock(&mnttab_lock);
return (mntl);
}
/*
* find_lofsentry() searches for the real path which this requested LOFS path
* (rpath) shadows. If found, it will return the sharetab entry of
* the real path that corresponds to the LOFS path.
* We first search mnttab to see if the requested path is an automounted
* path. If it is an automounted path, it will trigger the mount by stat()ing
* the requested path. Note that it is important to check that this path is
* actually an automounted path, otherwise we would stat() a path which may
* turn out to be NFS and block indefinitely on a dead server. The automounter
* times-out if the server is dead, so there's no risk of hanging this
* thread waiting for stat().
* After the mount has been triggered (if necessary), we look for a
* mountpoint of type LOFS (by searching /etc/mnttab again) which
* is a substring of the rpath. If found, we construct a new path by
* concatenating the mnt_special and the remaining of rpath, call findentry()
* to make sure the 'real path' is shared.
*/
static struct share *
find_lofsentry(char *rpath, int *done_flag)
{
struct stat r_stbuf;
mntlist_t *ml, *mntl, *mntpnt = NULL;
struct share *retcode = NULL;
char tmp_path[MAXPATHLEN];
int mntpnt_len = 0, tmp;
char *p1, *p2;
if ((*done_flag)++)
return (retcode);
/*
* While fsgetmntlist() uses lockf() to
* lock the mnttab before reading it in,
* the lock ignores threads in the same process.
* Read in the mnttab with the protection of a mutex.
*/
(void) mutex_lock(&mnttab_lock);
mntl = fsgetmntlist();
(void) mutex_unlock(&mnttab_lock);
/*
* Obtain the mountpoint for the requested path.
*/
for (ml = mntl; ml; ml = ml->mntl_next) {
for (p1 = ml->mntl_mnt->mnt_mountp, p2 = rpath;
*p1 == *p2 && *p1; p1++, p2++);
if (is_substring(&p1, &p2) &&
(tmp = strlen(ml->mntl_mnt->mnt_mountp)) >= mntpnt_len) {
mntpnt = ml;
mntpnt_len = tmp;
}
}
/*
* If the path needs to be autoFS mounted, trigger the mount by
* stat()ing it. This is determined by checking whether the
* mountpoint we just found is of type autofs.
*/
if (mntpnt != NULL &&
strcmp(mntpnt->mntl_mnt->mnt_fstype, "autofs") == 0) {
/*
* The requested path is a substring of an autoFS filesystem.
* Trigger the mount.
*/
if (stat(rpath, &r_stbuf) < 0) {
if (verbose)
syslog(LOG_NOTICE, "%s: %m", rpath);
goto done;
}
if ((r_stbuf.st_mode & S_IFMT) == S_IFDIR) {
/*
* The requested path is a directory, stat(2) it
* again with a trailing '.' to force the autoFS
* module to trigger the mount of indirect
* automount entries, such as /net/jurassic/.
*/
if (strlen(rpath) + 2 > MAXPATHLEN) {
if (verbose) {
syslog(LOG_NOTICE,
"%s/.: exceeds MAXPATHLEN %d",
rpath, MAXPATHLEN);
}
goto done;
}
(void) strcpy(tmp_path, rpath);
(void) strcat(tmp_path, "/.");
if (stat(tmp_path, &r_stbuf) < 0) {
if (verbose)
syslog(LOG_NOTICE, "%s: %m", tmp_path);
goto done;
}
}
/*
* The mount has been triggered, re-read mnttab to pick up
* the changes made by autoFS.
*/
fsfreemntlist(mntl);
(void) mutex_lock(&mnttab_lock);
mntl = fsgetmntlist();
(void) mutex_unlock(&mnttab_lock);
}
/*
* The autoFS mountpoint has been triggered if necessary,
* now search mnttab again to determine if the requested path
* is an LOFS mount of a shared path.
*/
mntpnt_len = 0;
for (ml = mntl; ml; ml = ml->mntl_next) {
if (strcmp(ml->mntl_mnt->mnt_fstype, "lofs"))
continue;
for (p1 = ml->mntl_mnt->mnt_mountp, p2 = rpath;
*p1 == *p2 && *p1; p1++, p2++);
if (is_substring(&p1, &p2) &&
((tmp = strlen(ml->mntl_mnt->mnt_mountp)) >= mntpnt_len)) {
mntpnt_len = tmp;
if ((strlen(ml->mntl_mnt->mnt_special) + strlen(p2)) >
MAXPATHLEN) {
if (verbose) {
syslog(LOG_NOTICE, "%s%s: exceeds %d",
ml->mntl_mnt->mnt_special, p2,
MAXPATHLEN);
}
if (retcode)
sharefree(retcode);
retcode = NULL;
goto done;
}
(void) strcpy(tmp_path, ml->mntl_mnt->mnt_special);
(void) strcat(tmp_path, p2);
if (retcode)
sharefree(retcode);
retcode = findentry(tmp_path);
}
}
if (retcode) {
assert(strlen(tmp_path) > 0);
(void) strcpy(rpath, tmp_path);
}
done:
fsfreemntlist(mntl);
return (retcode);
}
