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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* This file is part of libmount from util-linux project.
*
* Copyright (C) 2022 Karel Zak <kzak@redhat.com>
*
* libmount is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
*
* This is X-mount.owner=, X-mount.group= and X-mount.mode= implementation.
*
* Please, see the comment in libmount/src/hooks.c to understand how hooks work.
*/
#include <sched.h>
#include "mountP.h"
#include "fileutils.h"
struct hook_data {
uid_t owner;
gid_t group;
mode_t mode;
};
/* de-initiallize this module */
static int hookset_deinit(struct libmnt_context *cxt, const struct libmnt_hookset *hs)
{
void *data;
DBG(HOOK, ul_debugobj(hs, "deinit '%s'", hs->name));
/* remove all our hooks and free hook data */
while (mnt_context_remove_hook(cxt, hs, 0, &data) == 0) {
free(data);
data = NULL;
}
return 0;
}
static int hook_post(
struct libmnt_context *cxt,
const struct libmnt_hookset *hs __attribute__((__unused__)),
void *data)
{
struct hook_data *hd = (struct hook_data *) data;
const char *target;
int rc = 0;
assert(cxt);
if (!hd || !cxt->fs)
return 0;
target = mnt_fs_get_target(cxt->fs);
if (!target)
return 0;
if (hd->owner != (uid_t) -1 || hd->group != (uid_t) -1) {
DBG(CXT, ul_debugobj(cxt, " lchown(%s, %u, %u)", target, hd->owner, hd->group));
if (lchown(target, hd->owner, hd->group) == -1)
return -MNT_ERR_CHOWN;
}
if (hd->mode != (mode_t) -1) {
DBG(CXT, ul_debugobj(cxt, " chmod(%s, %04o)", target, hd->mode));
if (chmod(target, hd->mode) == -1)
return -MNT_ERR_CHMOD;
}
return rc;
}
static inline struct hook_data *new_hook_data(void)
{
struct hook_data *hd = calloc(1, sizeof(*hd));
if (!hd)
return NULL;
hd->owner = (uid_t) -1;
hd->group = (gid_t) -1;
hd->mode = (mode_t) -1;
return hd;
}
static int hook_prepare_options(
struct libmnt_context *cxt,
const struct libmnt_hookset *hs,
void *data __attribute__((__unused__)))
{
struct hook_data *hd = NULL;
struct libmnt_optlist *ol;
struct libmnt_opt *opt;
int rc = 0;
assert(cxt);
assert(cxt->map_userspace);
ol = mnt_context_get_optlist(cxt);
if (!ol)
return -ENOMEM;
opt = mnt_optlist_get_named(ol, "X-mount.owner", cxt->map_userspace);
if (opt) {
const char *value = mnt_opt_get_value(opt);
if (!value)
goto fail;
if (!hd) {
hd = new_hook_data();
if (!hd)
goto fail;
}
if (mnt_parse_uid(value, strlen(value), &hd->owner))
goto fail;
}
opt = mnt_optlist_get_named(ol, "X-mount.group", cxt->map_userspace);
if (opt) {
const char *value = mnt_opt_get_value(opt);
if (!value)
goto fail;
if (!hd) {
hd = new_hook_data();
if (!hd)
goto fail;
}
if (mnt_parse_gid(value, strlen(value), &hd->group))
goto fail;
}
opt = mnt_optlist_get_named(ol, "X-mount.mode", cxt->map_userspace);
if (opt) {
const char *value = mnt_opt_get_value(opt);
if (!value)
goto fail;
if (!hd) {
hd = new_hook_data();
if (!hd)
goto fail;
}
if (mnt_parse_mode(value, strlen(value), &hd->mode))
goto fail;
}
if (hd) {
DBG(CXT, ul_debugobj(cxt, " wanted ownership %d:%d, mode %04o",
hd->owner, hd->group, hd->mode));
rc = mnt_context_append_hook(cxt, hs,
MNT_STAGE_POST,
hd, hook_post);
if (rc < 0)
goto fail;
}
return 0;
fail:
if (rc == 0)
rc = -MNT_ERR_MOUNTOPT;
free(hd);
return rc;
}
const struct libmnt_hookset hookset_owner =
{
.name = "__owner",
.firststage = MNT_STAGE_PREP_OPTIONS,
.firstcall = hook_prepare_options,
.deinit = hookset_deinit
};
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