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/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Mount and unmount overlayfs mountpoints (linux only)
*/
#include "private-lib-core.h"
#include <unistd.h>
#include <libmount/libmount.h>
#include <string.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
static int
rm_rf_cb(const char *dirpath, void *user, struct lws_dir_entry *lde)
{
char path[384];
if (!strcmp(lde->name, ".") || !strcmp(lde->name, ".."))
return 0;
lws_snprintf(path, sizeof(path), "%s/%s", dirpath, lde->name);
if (lde->type == LDOT_DIR) {
lws_dir(path, NULL, rm_rf_cb);
rmdir(path);
} else
unlink(path);
return 0;
}
int
lws_fsmount_mount(struct lws_fsmount *fsm)
{
struct libmnt_context *ctx;
char opts[512], c;
int n, m;
/*
* For robustness, there are a couple of sticky situations caused by
* previous mounts not cleaning up... 1) still mounted on the mountpoint
* and 2) junk in the session dir from the dead session.
*
* For 1), do a gratuitous umount attempts until it feels nothing to
* umount...
*/
c = fsm->mp[0];
while (!lws_fsmount_unmount(fsm))
fsm->mp[0] = c;
fsm->mp[0] = c;
/*
* ... for 2), generate the session dir basepath and destroy everything
* in it... it's less dangerous than it sounds because there are
* hardcoded unusual dir names in the base path, so it can't go wild
* even if the overlay path is empty or /
*/
lws_snprintf(opts, sizeof(opts), "%s/overlays/%s/session",
fsm->overlay_path, fsm->ovname);
lwsl_info("%s: emptying session dir %s\n", __func__, opts);
lws_dir(opts, NULL, rm_rf_cb);
/*
* Piece together the options for the overlay mount...
*/
n = lws_snprintf(opts, sizeof(opts), "lowerdir=");
for (m = LWS_ARRAY_SIZE(fsm->layers) - 1; m >= 0; m--)
if (fsm->layers[m]) {
if (n != 9)
opts[n++] = ':';
n += lws_snprintf(&opts[n], (size_t)(sizeof(opts) - (unsigned int)n),
"%s/%s/%s", fsm->layers_path,
fsm->distro, fsm->layers[m]);
}
n += lws_snprintf(&opts[n], (size_t)(sizeof(opts) - (unsigned int)n),
",upperdir=%s/overlays/%s/session",
fsm->overlay_path, fsm->ovname);
n += lws_snprintf(&opts[n], (size_t)(sizeof(opts) - (unsigned int)n),
",workdir=%s/overlays/%s/work",
fsm->overlay_path, fsm->ovname);
ctx = mnt_new_context();
if (!ctx)
return 1;
mnt_context_set_fstype(ctx, "overlay");
mnt_context_set_options(ctx, opts);
mnt_context_set_mflags(ctx, MS_NOATIME /* |MS_NOEXEC */);
mnt_context_set_target(ctx, fsm->mp);
mnt_context_set_source(ctx, "none");
lwsl_notice("%s: mount opts %s\n", __func__, opts);
puts(opts);
m = mnt_context_mount(ctx);
lwsl_notice("%s: mountpoint %s: %d\n", __func__, fsm->mp, m);
mnt_free_context(ctx);
return m;
}
int
lws_fsmount_unmount(struct lws_fsmount *fsm)
{
struct libmnt_context *ctx;
int m;
lwsl_notice("%s: %s\n", __func__, fsm->mp);
ctx = mnt_new_context();
if (!ctx)
return 1;
mnt_context_set_target(ctx, fsm->mp);
m = mnt_context_umount(ctx);
mnt_free_context(ctx);
fsm->mp[0] = '\0';
return m;
}
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