/*
* Get a linked list of all the shares on the system from /etc/dfs/dfstab
*/
fs_sharelist_t *
fs_get_share_list(int *errp)
{
fs_sharelist_t *newp;
fs_sharelist_t *headp;
fs_sharelist_t *tailp;
FILE *fp;
headp = NULL;
tailp = NULL;
if ((fp = fopen(SHARETAB, "r")) != NULL) {
struct share *sharetab_entry;
(void) mutex_lock(&sharetab_lock);
while (getshare(fp, &sharetab_entry) > 0) {
newp = create_sharelist_entry(sharetab_entry, errp);
if (newp == NULL) {
/*
* Out of memory
*/
fs_free_share_list(headp);
(void) mutex_unlock(&sharetab_lock);
(void) fclose(fp);
return (NULL);
}
if (headp == NULL) {
headp = newp;
tailp = newp;
} else {
tailp->next = newp;
tailp = newp;
}
} /* while (getshare(fp, &sharetab_entry) != 0) */
(void) mutex_unlock(&sharetab_lock);
(void) fclose(fp);
} else {
*errp = errno;
} /* if ((fp = fopen(SHARETAB, "r")) != NULL) */
/*
* Caller must free the mount list
*/
return (headp);
} /* fs_get_share_list */
void
check_sharetab()
{
FILE *f;
struct stat st;
static timestruc_t last_sharetab_time;
timestruc_t prev_sharetab_time;
struct share *sh;
struct sh_list *shp, *shp_prev;
int res, c = 0;
/*
* read in /etc/dfs/sharetab if it has changed
*/
if (stat(SHARETAB, &st) != 0) {
syslog(LOG_ERR, "Cannot stat %s: %m", SHARETAB);
return;
}
if (st.st_mtim.tv_sec == last_sharetab_time.tv_sec &&
st.st_mtim.tv_nsec == last_sharetab_time.tv_nsec) {
/*
* No change.
*/
return;
}
/*
* Remember the mod time, then after getting the
* write lock check again. If another thread
* already did the update, then there's no
* work to do.
*/
prev_sharetab_time = last_sharetab_time;
(void) rw_wrlock(&sharetab_lock);
if (prev_sharetab_time.tv_sec != last_sharetab_time.tv_sec ||
prev_sharetab_time.tv_nsec != last_sharetab_time.tv_nsec) {
(void) rw_unlock(&sharetab_lock);
return;
}
f = fopen(SHARETAB, "r+");
if (f == NULL) {
syslog(LOG_ERR, "Cannot open %s: %m", SHARETAB);
(void) rw_unlock(&sharetab_lock);
return;
}
/*
* Lock the file so that unshare can't
* truncate it while we're reading
*/
if (lockf(fileno(f), F_LOCK, 0L) < 0) {
syslog(LOG_ERR, "Cannot lock %s: %m", SHARETAB);
(void) rw_unlock(&sharetab_lock);
(void) fclose(f);
return;
}
/*
* Once we are sure /etc/dfs/sharetab has been
* modified, flush netgroup cache entries.
*/
netgrp_cache_flush();
sh_free(share_list); /* free old list */
share_list = NULL;
while ((res = getshare(f, &sh)) > 0) {
c++;
if (strcmp(sh->sh_fstype, "nfs") != 0)
continue;
shp = malloc(sizeof (*shp));
if (shp == NULL)
goto alloc_failed;
if (share_list == NULL)
share_list = shp;
else
/* LINTED not used before set */
shp_prev->shl_next = shp;
shp_prev = shp;
shp->shl_next = NULL;
shp->shl_sh = sharedup(sh);
if (shp->shl_sh == NULL)
goto alloc_failed;
}
if (res < 0)
syslog(LOG_ERR, "%s: invalid at line %d\n",
SHARETAB, c + 1);
if (stat(SHARETAB, &st) != 0) {
syslog(LOG_ERR, "Cannot stat %s: %m", SHARETAB);
(void) rw_unlock(&sharetab_lock);
return;
}
last_sharetab_time = st.st_mtim;
(void) fclose(f);
(void) rw_unlock(&sharetab_lock);
return;
alloc_failed:
syslog(LOG_ERR, "check_sharetab: no memory");
sh_free(share_list);
share_list = NULL;
(void) fclose(f);
(void) rw_unlock(&sharetab_lock);
}
