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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:30:35 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 14:30:35 +0000
commit378c18e5f024ac5a8aef4cb40d7c9aa9633d144c (patch)
tree44dfb6ca500d32cabd450649b322a42e70a30683 /libmount/src/context_mount.c
parentInitial commit. (diff)
downloadutil-linux-upstream.tar.xz
util-linux-upstream.zip
Adding upstream version 2.38.1.upstream/2.38.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'libmount/src/context_mount.c')
-rw-r--r--libmount/src/context_mount.c2018
1 files changed, 2018 insertions, 0 deletions
diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c
new file mode 100644
index 0000000..1fc3ff2
--- /dev/null
+++ b/libmount/src/context_mount.c
@@ -0,0 +1,2018 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * This file is part of libmount from util-linux project.
+ *
+ * Copyright (C) 2010-2018 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.
+ */
+
+/**
+ * SECTION: context-mount
+ * @title: Mount context
+ * @short_description: high-level API to mount operation.
+ */
+
+#ifdef HAVE_LIBSELINUX
+#include <selinux/selinux.h>
+#include <selinux/context.h>
+#endif
+
+#include <sys/wait.h>
+#include <sys/mount.h>
+
+#include "linux_version.h"
+#include "mountP.h"
+#include "strutils.h"
+
+/*
+ * Kernel supports only one MS_PROPAGATION flag change by one mount(2) syscall,
+ * to bypass this restriction we call mount(2) per flag. It's really not a perfect
+ * solution, but it's the same like to execute multiple mount(8) commands.
+ *
+ * We use cxt->addmounts (additional mounts) list to keep order of the requested
+ * flags changes.
+ */
+struct libmnt_addmount *mnt_new_addmount(void)
+{
+ struct libmnt_addmount *ad = calloc(1, sizeof(*ad));
+ if (!ad)
+ return NULL;
+
+ INIT_LIST_HEAD(&ad->mounts);
+ return ad;
+}
+
+void mnt_free_addmount(struct libmnt_addmount *ad)
+{
+ if (!ad)
+ return;
+ list_del(&ad->mounts);
+ free(ad);
+}
+
+static int mnt_context_append_additional_mount(struct libmnt_context *cxt,
+ struct libmnt_addmount *ad)
+{
+ assert(cxt);
+ assert(ad);
+
+ if (!list_empty(&ad->mounts))
+ return -EINVAL;
+
+ DBG(CXT, ul_debugobj(cxt,
+ "mount: add additional flag: 0x%08lx",
+ ad->mountflags));
+
+ list_add_tail(&ad->mounts, &cxt->addmounts);
+ return 0;
+}
+
+/*
+ * add additional mount(2) syscall requests when necessary to set propagation flags
+ * after regular mount(2).
+ */
+static int init_propagation(struct libmnt_context *cxt)
+{
+ char *name;
+ char *opts = (char *) mnt_fs_get_vfs_options(cxt->fs);
+ size_t namesz;
+ struct libmnt_optmap const *maps[1];
+ int rec_count = 0;
+
+ if (!opts)
+ return 0;
+
+ DBG(CXT, ul_debugobj(cxt, "mount: initialize additional propagation mounts"));
+
+ maps[0] = mnt_get_builtin_optmap(MNT_LINUX_MAP);
+
+ while (!mnt_optstr_next_option(&opts, &name, &namesz, NULL, NULL)) {
+ const struct libmnt_optmap *ent;
+ struct libmnt_addmount *ad;
+ int rc;
+
+ if (!mnt_optmap_get_entry(maps, 1, name, namesz, &ent) || !ent)
+ continue;
+
+ DBG(CXT, ul_debugobj(cxt, " checking %s", ent->name));
+
+ /* Note that MS_REC may be used for more flags, so we have to keep
+ * track about number of recursive options to keep the MS_REC in the
+ * mountflags if necessary.
+ */
+ if (ent->id & MS_REC)
+ rec_count++;
+
+ if (!(ent->id & MS_PROPAGATION))
+ continue;
+
+ ad = mnt_new_addmount();
+ if (!ad)
+ return -ENOMEM;
+
+ ad->mountflags = ent->id;
+ DBG(CXT, ul_debugobj(cxt, " adding extra mount(2) call for %s", ent->name));
+ rc = mnt_context_append_additional_mount(cxt, ad);
+ if (rc)
+ return rc;
+
+ DBG(CXT, ul_debugobj(cxt, " removing %s from primary mount(2) call", ent->name));
+ cxt->mountflags &= ~ent->id;
+
+ if (ent->id & MS_REC)
+ rec_count--;
+ }
+
+ if (rec_count)
+ cxt->mountflags |= MS_REC;
+
+ return 0;
+}
+
+/*
+ * add additional mount(2) syscall request to implement "bind,<flags>", the first regular
+ * mount(2) is the "bind" operation, the second is "remount,bind,<flags>" call.
+ */
+static int init_bind_remount(struct libmnt_context *cxt)
+{
+ struct libmnt_addmount *ad;
+ int rc;
+
+ assert(cxt);
+ assert(cxt->mountflags & MS_BIND);
+ assert(!(cxt->mountflags & MS_REMOUNT));
+
+ DBG(CXT, ul_debugobj(cxt, "mount: initialize additional ro,bind mount"));
+
+ ad = mnt_new_addmount();
+ if (!ad)
+ return -ENOMEM;
+
+ ad->mountflags = cxt->mountflags;
+ ad->mountflags |= (MS_REMOUNT | MS_BIND);
+
+ rc = mnt_context_append_additional_mount(cxt, ad);
+ if (rc)
+ return rc;
+
+ return 0;
+}
+
+#if defined(HAVE_LIBSELINUX) || defined(HAVE_SMACK)
+struct libmnt_optname {
+ const char *name;
+ size_t namesz;
+};
+
+#define DEF_OPTNAME(n) { .name = n, .namesz = sizeof(n) - 1 }
+#define DEF_OPTNAME_LAST { .name = NULL }
+
+static int is_option(const char *name, size_t namesz,
+ const struct libmnt_optname *names)
+{
+ const struct libmnt_optname *p;
+
+ for (p = names; p && p->name; p++) {
+ if (p->namesz == namesz
+ && strncmp(name, p->name, namesz) == 0)
+ return 1;
+ }
+
+ return 0;
+}
+#endif /* HAVE_LIBSELINUX || HAVE_SMACK */
+
+/*
+ * this has to be called after mnt_context_evaluate_permissions()
+ */
+static int fix_optstr(struct libmnt_context *cxt)
+{
+ int rc = 0;
+ struct libmnt_ns *ns_old;
+ char *next;
+ char *name, *val;
+ size_t namesz, valsz;
+ struct libmnt_fs *fs;
+#ifdef HAVE_LIBSELINUX
+ int se_fix = 0, se_rem = 0;
+ static const struct libmnt_optname selinux_options[] = {
+ DEF_OPTNAME("context"),
+ DEF_OPTNAME("fscontext"),
+ DEF_OPTNAME("defcontext"),
+ DEF_OPTNAME("rootcontext"),
+ DEF_OPTNAME("seclabel"),
+ DEF_OPTNAME_LAST
+ };
+#endif
+#ifdef HAVE_SMACK
+ int sm_rem = 0;
+ static const struct libmnt_optname smack_options[] = {
+ DEF_OPTNAME("smackfsdef"),
+ DEF_OPTNAME("smackfsfloor"),
+ DEF_OPTNAME("smackfshat"),
+ DEF_OPTNAME("smackfsroot"),
+ DEF_OPTNAME("smackfstransmute"),
+ DEF_OPTNAME_LAST
+ };
+#endif
+ assert(cxt);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ if (!cxt->fs || (cxt->flags & MNT_FL_MOUNTOPTS_FIXED))
+ return 0;
+
+ fs = cxt->fs;
+
+ DBG(CXT, ul_debugobj(cxt, "mount: fixing options, current "
+ "vfs: '%s' fs: '%s' user: '%s', optstr: '%s'",
+ fs->vfs_optstr, fs->fs_optstr, fs->user_optstr, fs->optstr));
+
+ /*
+ * The "user" options is our business (so we can modify the option),
+ * the exception is command line for /sbin/mount.<type> helpers. Let's
+ * save the original user=<name> to call the helpers with an unchanged
+ * "user" setting.
+ */
+ if (cxt->user_mountflags & MNT_MS_USER) {
+ if (!mnt_optstr_get_option(fs->user_optstr,
+ "user", &val, &valsz) && val) {
+ cxt->orig_user = strndup(val, valsz);
+ if (!cxt->orig_user) {
+ rc = -ENOMEM;
+ goto done;
+ }
+ }
+ cxt->flags |= MNT_FL_SAVED_USER;
+ }
+
+ /*
+ * Sync mount options with mount flags
+ */
+ DBG(CXT, ul_debugobj(cxt, "mount: fixing vfs optstr"));
+ rc = mnt_optstr_apply_flags(&fs->vfs_optstr, cxt->mountflags,
+ mnt_get_builtin_optmap(MNT_LINUX_MAP));
+ if (rc)
+ goto done;
+
+ DBG(CXT, ul_debugobj(cxt, "mount: fixing user optstr"));
+ rc = mnt_optstr_apply_flags(&fs->user_optstr, cxt->user_mountflags,
+ mnt_get_builtin_optmap(MNT_USERSPACE_MAP));
+ if (rc)
+ goto done;
+
+ if (fs->vfs_optstr && *fs->vfs_optstr == '\0') {
+ free(fs->vfs_optstr);
+ fs->vfs_optstr = NULL;
+ }
+ if (fs->user_optstr && *fs->user_optstr == '\0') {
+ free(fs->user_optstr);
+ fs->user_optstr = NULL;
+ }
+ if (cxt->mountflags & MS_PROPAGATION) {
+ rc = init_propagation(cxt);
+ if (rc)
+ return rc;
+ }
+ if ((cxt->mountflags & MS_BIND)
+ && (cxt->mountflags & MNT_BIND_SETTABLE)
+ && !(cxt->mountflags & MS_REMOUNT)) {
+ rc = init_bind_remount(cxt);
+ if (rc)
+ return rc;
+ }
+
+ next = fs->fs_optstr;
+
+#ifdef HAVE_LIBSELINUX
+ if (!is_selinux_enabled())
+ /* Always remove SELinux garbage if SELinux disabled */
+ se_rem = 1;
+ else if (cxt->mountflags & MS_REMOUNT)
+ /*
+ * Linux kernel < 2.6.39 does not support remount operation
+ * with any selinux specific mount options.
+ *
+ * Kernel 2.6.39 commits: ff36fe2c845cab2102e4826c1ffa0a6ebf487c65
+ * 026eb167ae77244458fa4b4b9fc171209c079ba7
+ * fix this odd behavior, so we don't have to care about it in
+ * userspace.
+ */
+ se_rem = get_linux_version() < KERNEL_VERSION(2, 6, 39);
+ else
+ /* For normal mount, contexts are translated */
+ se_fix = 1;
+
+ if (!se_rem) {
+ /* de-duplicate SELinux options */
+ const struct libmnt_optname *p;
+ for (p = selinux_options; p && p->name; p++)
+ mnt_optstr_deduplicate_option(&fs->fs_optstr, p->name);
+ }
+#endif
+#ifdef HAVE_SMACK
+ if (access("/sys/fs/smackfs", F_OK) != 0)
+ sm_rem = 1;
+#endif
+ while (!mnt_optstr_next_option(&next, &name, &namesz, &val, &valsz)) {
+
+ if (namesz == 3 && !strncmp(name, "uid", 3))
+ rc = mnt_optstr_fix_uid(&fs->fs_optstr, val, valsz, &next);
+ else if (namesz == 3 && !strncmp(name, "gid", 3))
+ rc = mnt_optstr_fix_gid(&fs->fs_optstr, val, valsz, &next);
+#ifdef HAVE_LIBSELINUX
+ else if ((se_rem || se_fix)
+ && is_option(name, namesz, selinux_options)) {
+
+ if (se_rem) {
+ /* remove context= option */
+ next = name;
+ rc = mnt_optstr_remove_option_at(&fs->fs_optstr,
+ name,
+ val ? val + valsz :
+ name + namesz);
+ } else if (se_fix && val && valsz)
+ /* translate selinux contexts */
+ rc = mnt_optstr_fix_secontext(&fs->fs_optstr,
+ val, valsz, &next);
+ }
+#endif
+#ifdef HAVE_SMACK
+ else if (sm_rem && is_option(name, namesz, smack_options)) {
+
+ next = name;
+ rc = mnt_optstr_remove_option_at(&fs->fs_optstr,
+ name,
+ val ? val + valsz : name + namesz);
+ }
+#endif
+ if (rc)
+ goto done;
+ }
+
+
+ if (!rc && mnt_context_is_restricted(cxt) && (cxt->user_mountflags & MNT_MS_USER)) {
+ ns_old = mnt_context_switch_origin_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+
+ rc = mnt_optstr_fix_user(&fs->user_optstr);
+
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+ }
+
+ /* refresh merged optstr */
+ free(fs->optstr);
+ fs->optstr = NULL;
+ fs->optstr = mnt_fs_strdup_options(fs);
+done:
+ cxt->flags |= MNT_FL_MOUNTOPTS_FIXED;
+
+ DBG(CXT, ul_debugobj(cxt, "fixed options [rc=%d]: "
+ "vfs: '%s' fs: '%s' user: '%s', optstr: '%s'", rc,
+ fs->vfs_optstr, fs->fs_optstr, fs->user_optstr, fs->optstr));
+
+ if (rc)
+ rc = -MNT_ERR_MOUNTOPT;
+ return rc;
+}
+
+/*
+ * Converts the already evaluated and fixed options to the form that is compatible
+ * with /sbin/mount.type helpers.
+ */
+static int generate_helper_optstr(struct libmnt_context *cxt, char **optstr)
+{
+ struct libmnt_optmap const *maps[2];
+ char *next, *name, *val;
+ size_t namesz, valsz;
+ int rc = 0;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert(optstr);
+
+ DBG(CXT, ul_debugobj(cxt, "mount: generate helper mount options"));
+
+ *optstr = mnt_fs_strdup_options(cxt->fs);
+ if (!*optstr)
+ return -ENOMEM;
+
+ if ((cxt->user_mountflags & MNT_MS_USER) ||
+ (cxt->user_mountflags & MNT_MS_USERS)) {
+ /*
+ * This is unnecessary for real user-mounts as mount.<type>
+ * helpers always have to follow fstab rather than mount
+ * options on the command line.
+ *
+ * However, if you call mount.<type> as root, then the helper follows
+ * the command line. If there is (for example) "user,exec" in fstab,
+ * then we have to manually append the "exec" back to the options
+ * string, because there is nothing like MS_EXEC (we only have
+ * MS_NOEXEC in mount flags and we don't care about the original
+ * mount string in libmount for VFS options).
+ *
+ * This use-case makes sense for MS_SECURE flags only (see
+ * mnt_optstr_get_flags() and mnt_context_merge_mflags()).
+ */
+ if (!(cxt->mountflags & MS_NOEXEC))
+ mnt_optstr_append_option(optstr, "exec", NULL);
+ if (!(cxt->mountflags & MS_NOSUID))
+ mnt_optstr_append_option(optstr, "suid", NULL);
+ if (!(cxt->mountflags & MS_NODEV))
+ mnt_optstr_append_option(optstr, "dev", NULL);
+ }
+
+ if (cxt->flags & MNT_FL_SAVED_USER)
+ rc = mnt_optstr_set_option(optstr, "user", cxt->orig_user);
+ if (rc)
+ goto err;
+
+ /* remove userspace options with MNT_NOHLPS flag */
+ maps[0] = mnt_get_builtin_optmap(MNT_USERSPACE_MAP);
+ maps[1] = mnt_get_builtin_optmap(MNT_LINUX_MAP);
+ next = *optstr;
+
+ while (!mnt_optstr_next_option(&next, &name, &namesz, &val, &valsz)) {
+ const struct libmnt_optmap *ent;
+
+ mnt_optmap_get_entry(maps, 2, name, namesz, &ent);
+ if (ent && ent->id && (ent->mask & MNT_NOHLPS)) {
+ next = name;
+ rc = mnt_optstr_remove_option_at(optstr, name,
+ val ? val + valsz : name + namesz);
+ if (rc)
+ goto err;
+ }
+ }
+
+ return rc;
+err:
+ free(*optstr);
+ *optstr = NULL;
+ return rc;
+}
+
+/*
+ * this has to be called before fix_optstr()
+ *
+ * Note that user=<name> may be used by some filesystems as a filesystem
+ * specific option (e.g. cifs). Yes, developers of such filesystems have
+ * allocated pretty hot place in hell...
+ */
+static int evaluate_permissions(struct libmnt_context *cxt)
+{
+ unsigned long u_flags = 0;
+
+ assert(cxt);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ if (!cxt->fs)
+ return 0;
+
+ DBG(CXT, ul_debugobj(cxt, "mount: evaluating permissions"));
+
+ mnt_context_get_user_mflags(cxt, &u_flags);
+
+ if (!mnt_context_is_restricted(cxt)) {
+ /*
+ * superuser mount
+ */
+ cxt->user_mountflags &= ~MNT_MS_OWNER;
+ cxt->user_mountflags &= ~MNT_MS_GROUP;
+ } else {
+ /*
+ * user mount
+ */
+ if (!mnt_context_tab_applied(cxt))
+ {
+ DBG(CXT, ul_debugobj(cxt, "perms: fstab not applied, ignore user mount"));
+ return -EPERM;
+ }
+
+ /*
+ * MS_OWNERSECURE and MS_SECURE mount options are already
+ * applied by mnt_optstr_get_flags() in mnt_context_merge_mflags()
+ * if "user" (but no user=<name> !) options is set.
+ *
+ * Let's ignore all user=<name> (if <name> is set) requests.
+ */
+ if (cxt->user_mountflags & MNT_MS_USER) {
+ size_t valsz = 0;
+
+ if (!mnt_optstr_get_option(cxt->fs->user_optstr,
+ "user", NULL, &valsz) && valsz) {
+
+ DBG(CXT, ul_debugobj(cxt, "perms: user=<name> detected, ignore"));
+ cxt->user_mountflags &= ~MNT_MS_USER;
+ }
+ }
+
+ /*
+ * MS_OWNER: Allow owners to mount when fstab contains the
+ * owner option. Note that this should never be used in a high
+ * security environment, but may be useful to give people at
+ * the console the possibility of mounting a floppy. MS_GROUP:
+ * Allow members of device group to mount. (Martin Dickopp)
+ */
+ if (u_flags & (MNT_MS_OWNER | MNT_MS_GROUP)) {
+ struct stat sb;
+ struct libmnt_cache *cache = NULL;
+ char *xsrc = NULL;
+ const char *srcpath = mnt_fs_get_srcpath(cxt->fs);
+
+ if (!srcpath) { /* Ah... source is TAG */
+ cache = mnt_context_get_cache(cxt);
+ xsrc = mnt_resolve_spec(
+ mnt_context_get_source(cxt),
+ cache);
+ srcpath = xsrc;
+ }
+ if (!srcpath) {
+ DBG(CXT, ul_debugobj(cxt, "perms: src undefined"));
+ return -EPERM;
+ }
+
+ if (strncmp(srcpath, "/dev/", 5) == 0 &&
+ stat(srcpath, &sb) == 0 &&
+ (((u_flags & MNT_MS_OWNER) && getuid() == sb.st_uid) ||
+ ((u_flags & MNT_MS_GROUP) && mnt_in_group(sb.st_gid))))
+
+ cxt->user_mountflags |= MNT_MS_USER;
+
+ if (!cache)
+ free(xsrc);
+ }
+
+ if (!(cxt->user_mountflags & (MNT_MS_USER | MNT_MS_USERS))) {
+ DBG(CXT, ul_debugobj(cxt, "permissions evaluation ends with -EPERMS"));
+ return -EPERM;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * mnt_context_helper_setopt() backend
+ *
+ * This function applies the mount.type command line option (for example parsed
+ * by getopt() or getopt_long()) to @cxt. All unknown options are ignored and
+ * then 1 is returned.
+ *
+ * Returns: negative number on error, 1 if @c is unknown option, 0 on success.
+ */
+int mnt_context_mount_setopt(struct libmnt_context *cxt, int c, char *arg)
+{
+ int rc = -EINVAL;
+
+ assert(cxt);
+ assert(cxt->action == MNT_ACT_MOUNT);
+
+ switch(c) {
+ case 'f':
+ rc = mnt_context_enable_fake(cxt, TRUE);
+ break;
+ case 'n':
+ rc = mnt_context_disable_mtab(cxt, TRUE);
+ break;
+ case 'r':
+ rc = mnt_context_append_options(cxt, "ro");
+ break;
+ case 'v':
+ rc = mnt_context_enable_verbose(cxt, TRUE);
+ break;
+ case 'w':
+ rc = mnt_context_append_options(cxt, "rw");
+ break;
+ case 'o':
+ if (arg)
+ rc = mnt_context_append_options(cxt, arg);
+ break;
+ case 's':
+ rc = mnt_context_enable_sloppy(cxt, TRUE);
+ break;
+ case 't':
+ if (arg)
+ rc = mnt_context_set_fstype(cxt, arg);
+ break;
+ case 'N':
+ if (arg)
+ rc = mnt_context_set_target_ns(cxt, arg);
+ break;
+ default:
+ return 1;
+ }
+
+ return rc;
+}
+
+static int exec_helper(struct libmnt_context *cxt)
+{
+ char *o = NULL, *namespace = NULL;
+ struct libmnt_ns *ns_tgt = mnt_context_get_target_ns(cxt);
+ int rc;
+ pid_t pid;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert(cxt->helper);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ DBG(CXT, ul_debugobj(cxt, "mount: executing helper %s", cxt->helper));
+
+ rc = generate_helper_optstr(cxt, &o);
+ if (rc)
+ return -EINVAL;
+
+ if (ns_tgt->fd != -1
+ && asprintf(&namespace, "/proc/%i/fd/%i",
+ getpid(), ns_tgt->fd) == -1) {
+ free(o);
+ return -ENOMEM;
+ }
+
+ DBG_FLUSH;
+
+ pid = fork();
+ switch (pid) {
+ case 0:
+ {
+ const char *args[14], *type;
+ int i = 0;
+
+ if (drop_permissions() != 0)
+ _exit(EXIT_FAILURE);
+
+ if (!mnt_context_switch_origin_ns(cxt))
+ _exit(EXIT_FAILURE);
+
+ type = mnt_fs_get_fstype(cxt->fs);
+
+ args[i++] = cxt->helper; /* 1 */
+ args[i++] = mnt_fs_get_srcpath(cxt->fs);/* 2 */
+ args[i++] = mnt_fs_get_target(cxt->fs); /* 3 */
+
+ if (mnt_context_is_sloppy(cxt))
+ args[i++] = "-s"; /* 4 */
+ if (mnt_context_is_fake(cxt))
+ args[i++] = "-f"; /* 5 */
+ if (mnt_context_is_nomtab(cxt))
+ args[i++] = "-n"; /* 6 */
+ if (mnt_context_is_verbose(cxt))
+ args[i++] = "-v"; /* 7 */
+ if (o) {
+ args[i++] = "-o"; /* 8 */
+ args[i++] = o; /* 9 */
+ }
+ if (type
+ && strchr(type, '.')
+ && !endswith(cxt->helper, type)) {
+ args[i++] = "-t"; /* 10 */
+ args[i++] = type; /* 11 */
+ }
+ if (namespace) {
+ args[i++] = "-N"; /* 11 */
+ args[i++] = namespace; /* 12 */
+ }
+ args[i] = NULL; /* 13 */
+ for (i = 0; args[i]; i++)
+ DBG(CXT, ul_debugobj(cxt, "argv[%d] = \"%s\"",
+ i, args[i]));
+ DBG_FLUSH;
+ execv(cxt->helper, (char * const *) args);
+ _exit(EXIT_FAILURE);
+ }
+ default:
+ {
+ int st;
+
+ if (waitpid(pid, &st, 0) == (pid_t) -1) {
+ cxt->helper_status = -1;
+ rc = -errno;
+ } else {
+ cxt->helper_status = WIFEXITED(st) ? WEXITSTATUS(st) : -1;
+ cxt->helper_exec_status = rc = 0;
+ }
+ DBG(CXT, ul_debugobj(cxt, "%s executed [status=%d, rc=%d%s]",
+ cxt->helper,
+ cxt->helper_status, rc,
+ rc ? " waitpid failed" : ""));
+ break;
+ }
+
+ case -1:
+ cxt->helper_exec_status = rc = -errno;
+ DBG(CXT, ul_debugobj(cxt, "fork() failed"));
+ break;
+ }
+
+ free(o);
+ free(namespace);
+ return rc;
+}
+
+static int do_mount_additional(struct libmnt_context *cxt,
+ const char *target,
+ unsigned long flags,
+ int *syserr)
+{
+ struct list_head *p;
+
+ assert(cxt);
+ assert(target);
+
+ if (syserr)
+ *syserr = 0;
+
+ list_for_each(p, &cxt->addmounts) {
+ int rc;
+ struct libmnt_addmount *ad =
+ list_entry(p, struct libmnt_addmount, mounts);
+
+ DBG(CXT, ul_debugobj(cxt, "mount(2) changing flag: 0x%08lx %s",
+ ad->mountflags,
+ ad->mountflags & MS_REC ? " (recursive)" : ""));
+
+ rc = mount("none", target, NULL,
+ ad->mountflags | (flags & MS_SILENT), NULL);
+ if (rc) {
+ if (syserr)
+ *syserr = -errno;
+ DBG(CXT, ul_debugobj(cxt,
+ "mount(2) failed [errno=%d %m]",
+ errno));
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
+static int do_mount_subdir(struct libmnt_context *cxt,
+ const char *root,
+ const char *subdir,
+ const char *target)
+{
+ char *src = NULL;
+ int rc = 0;
+
+ if (asprintf(&src, "%s/%s", root, subdir) < 0)
+ return -ENOMEM;
+
+ DBG(CXT, ul_debugobj(cxt, "mount subdir %s to %s", src, target));
+ if (mount(src, target, NULL, MS_BIND | MS_REC, NULL) != 0)
+ rc = -MNT_ERR_APPLYFLAGS;
+
+ DBG(CXT, ul_debugobj(cxt, "umount old root %s", root));
+ if (umount(root) != 0)
+ rc = -MNT_ERR_APPLYFLAGS;
+
+ free(src);
+ return rc;
+}
+
+/*
+ * The default is to use fstype from cxt->fs, this could be overwritten by
+ * @try_type argument. If @try_type is specified then mount with MS_SILENT.
+ *
+ * Returns: 0 on success,
+ * >0 in case of mount(2) error (returns syscall errno),
+ * <0 in case of other errors.
+ */
+static int do_mount(struct libmnt_context *cxt, const char *try_type)
+{
+ int rc = 0, old_ns_fd = -1;
+ const char *src, *target, *type;
+ unsigned long flags;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ if (try_type) {
+ rc = mnt_context_prepare_helper(cxt, "mount", try_type);
+ if (rc)
+ return rc;
+ }
+
+ flags = cxt->mountflags;
+ src = mnt_fs_get_srcpath(cxt->fs);
+ target = mnt_fs_get_target(cxt->fs);
+
+ if (cxt->helper) {
+ rc = exec_helper(cxt);
+
+ if (mnt_context_helper_executed(cxt)
+ && mnt_context_get_helper_status(cxt) == 0
+ && !list_empty(&cxt->addmounts)
+ && do_mount_additional(cxt, target, flags, NULL))
+
+ return -MNT_ERR_APPLYFLAGS;
+ return rc;
+ }
+
+ if (!target)
+ return -EINVAL;
+ if (!src) {
+ /* unnecessary, should be already resolved in
+ * mnt_context_prepare_srcpath(), but to be sure... */
+ DBG(CXT, ul_debugobj(cxt, "WARNING: source is NULL -- using \"none\"!"));
+ src = "none";
+ }
+ type = try_type ? : mnt_fs_get_fstype(cxt->fs);
+
+ if (try_type)
+ flags |= MS_SILENT;
+
+
+ if (mnt_context_is_fake(cxt)) {
+ /*
+ * fake
+ */
+ cxt->syscall_status = 0;
+
+ DBG(CXT, ul_debugobj(cxt, "FAKE mount(2) "
+ "[source=%s, target=%s, type=%s, "
+ " mountflags=0x%08lx, mountdata=%s]",
+ src, target, type,
+ flags, cxt->mountdata ? "yes" : "<none>"));
+
+ } else if (mnt_context_propagation_only(cxt)) {
+ /*
+ * propagation flags *only*
+ */
+ if (do_mount_additional(cxt, target, flags, &cxt->syscall_status))
+ return -MNT_ERR_APPLYFLAGS;
+ } else {
+ /*
+ * regular mount
+ */
+
+ /* create unhared temporary target */
+ if (cxt->subdir) {
+ rc = mnt_tmptgt_unshare(&old_ns_fd);
+ if (rc)
+ return rc;
+ target = MNT_PATH_TMPTGT;
+ }
+
+ DBG(CXT, ul_debugobj(cxt, "mount(2) "
+ "[source=%s, target=%s, type=%s, "
+ " mountflags=0x%08lx, mountdata=%s]",
+ src, target, type,
+ flags, cxt->mountdata ? "yes" : "<none>"));
+
+ if (mount(src, target, type, flags, cxt->mountdata)) {
+ cxt->syscall_status = -errno;
+ DBG(CXT, ul_debugobj(cxt, "mount(2) failed [errno=%d %m]",
+ -cxt->syscall_status));
+ rc = -cxt->syscall_status;
+ goto done;
+ }
+ DBG(CXT, ul_debugobj(cxt, " mount(2) success"));
+ cxt->syscall_status = 0;
+
+ /*
+ * additional mounts for extra propagation flags
+ */
+ if (!list_empty(&cxt->addmounts)
+ && do_mount_additional(cxt, target, flags, NULL)) {
+
+ /* TODO: call umount? */
+ rc = -MNT_ERR_APPLYFLAGS;
+ goto done;
+ }
+
+ /*
+ * bind subdir to the real target, umount temporary target
+ */
+ if (cxt->subdir) {
+ target = mnt_fs_get_target(cxt->fs);
+ rc = do_mount_subdir(cxt, MNT_PATH_TMPTGT, cxt->subdir, target);
+ if (rc)
+ goto done;
+ mnt_tmptgt_cleanup(old_ns_fd);
+ old_ns_fd = -1;
+ }
+ }
+
+ if (try_type && cxt->update) {
+ struct libmnt_fs *fs = mnt_update_get_fs(cxt->update);
+ if (fs)
+ rc = mnt_fs_set_fstype(fs, try_type);
+ }
+
+done:
+ if (old_ns_fd >= 0)
+ mnt_tmptgt_cleanup(old_ns_fd);
+
+ return rc;
+}
+
+static int is_success_status(struct libmnt_context *cxt)
+{
+ if (mnt_context_helper_executed(cxt))
+ return mnt_context_get_helper_status(cxt) == 0;
+
+ if (mnt_context_syscall_called(cxt))
+ return mnt_context_get_status(cxt) == 1;
+
+ return 0;
+}
+
+/* try mount(2) for all items in comma separated list of the filesystem @types */
+static int do_mount_by_types(struct libmnt_context *cxt, const char *types)
+{
+ int rc = -EINVAL;
+ char *p, *p0;
+
+ assert(cxt);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ DBG(CXT, ul_debugobj(cxt, "trying to mount by FS list '%s'", types));
+
+ p0 = p = strdup(types);
+ if (!p)
+ return -ENOMEM;
+ do {
+ char *autotype = NULL;
+ char *end = strchr(p, ',');
+
+ if (end)
+ *end = '\0';
+
+ DBG(CXT, ul_debugobj(cxt, "-->trying '%s'", p));
+
+ /* Let's support things like "udf,iso9660,auto" */
+ if (strcmp(p, "auto") == 0) {
+ rc = mnt_context_guess_srcpath_fstype(cxt, &autotype);
+ if (rc) {
+ DBG(CXT, ul_debugobj(cxt, "failed to guess FS type [rc=%d]", rc));
+ free(p0);
+ free(autotype);
+ return rc;
+ }
+ p = autotype;
+ DBG(CXT, ul_debugobj(cxt, " --> '%s'", p));
+ }
+
+ if (p)
+ rc = do_mount(cxt, p);
+ p = end ? end + 1 : NULL;
+ free(autotype);
+ } while (!is_success_status(cxt) && p);
+
+ free(p0);
+ return rc;
+}
+
+
+static int do_mount_by_pattern(struct libmnt_context *cxt, const char *pattern)
+{
+ int neg = pattern && strncmp(pattern, "no", 2) == 0;
+ int rc = -EINVAL;
+ char **filesystems, **fp;
+ struct libmnt_ns *ns_old;
+
+ assert(cxt);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+
+ /*
+ * Use the pattern as list of the filesystems
+ */
+ if (!neg && pattern) {
+ DBG(CXT, ul_debugobj(cxt, "use FS pattern as FS list"));
+ return do_mount_by_types(cxt, pattern);
+ }
+
+ DBG(CXT, ul_debugobj(cxt, "trying to mount by FS pattern '%s'", pattern));
+
+ /*
+ * Apply pattern to /etc/filesystems and /proc/filesystems
+ */
+ ns_old = mnt_context_switch_origin_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+ rc = mnt_get_filesystems(&filesystems, neg ? pattern : NULL);
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+ if (rc)
+ return rc;
+
+ if (filesystems == NULL)
+ return -MNT_ERR_NOFSTYPE;
+
+ for (fp = filesystems; *fp; fp++) {
+ DBG(CXT, ul_debugobj(cxt, " ##### trying '%s'", *fp));
+ rc = do_mount(cxt, *fp);
+ if (is_success_status(cxt))
+ break;
+ if (mnt_context_get_syscall_errno(cxt) != EINVAL &&
+ mnt_context_get_syscall_errno(cxt) != ENODEV)
+ break;
+ }
+ mnt_free_filesystems(filesystems);
+ return rc;
+}
+
+/**
+ * mnt_context_prepare_mount:
+ * @cxt: context
+ *
+ * Prepare context for mounting, unnecessary for mnt_context_mount().
+ *
+ * Returns: negative number on error, zero on success
+ */
+int mnt_context_prepare_mount(struct libmnt_context *cxt)
+{
+ int rc = -EINVAL;
+ struct libmnt_ns *ns_old;
+
+ if (!cxt || !cxt->fs || mnt_fs_is_swaparea(cxt->fs))
+ return -EINVAL;
+ if (!mnt_fs_get_source(cxt->fs) && !mnt_fs_get_target(cxt->fs))
+ return -EINVAL;
+ if (cxt->flags & MNT_FL_PREPARED)
+ return 0;
+
+ assert(cxt->helper_exec_status == 1);
+ assert(cxt->syscall_status == 1);
+
+ cxt->action = MNT_ACT_MOUNT;
+
+ ns_old = mnt_context_switch_target_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+
+ DBG(CXT, ul_debugobj(cxt, "mount: preparing"));
+
+ rc = mnt_context_apply_fstab(cxt);
+ if (!rc)
+ rc = mnt_context_merge_mflags(cxt);
+ if (!rc)
+ rc = evaluate_permissions(cxt);
+ if (!rc)
+ rc = fix_optstr(cxt);
+ if (!rc)
+ rc = mnt_context_prepare_srcpath(cxt);
+ if (!rc)
+ rc = mnt_context_guess_fstype(cxt);
+ if (!rc)
+ rc = mnt_context_prepare_target(cxt);
+ if (!rc)
+ rc = mnt_context_prepare_helper(cxt, "mount", NULL);
+ if (rc) {
+ DBG(CXT, ul_debugobj(cxt, "mount: preparing failed"));
+ goto end;
+ }
+ cxt->flags |= MNT_FL_PREPARED;
+
+end:
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+
+ return rc;
+}
+
+/**
+ * mnt_context_do_mount
+ * @cxt: context
+ *
+ * Call mount(2) or mount.type helper. Unnecessary for mnt_context_mount().
+ *
+ * Note that this function could be called only once. If you want to mount
+ * another source or target, then you have to call mnt_reset_context().
+ *
+ * If you want to call mount(2) for the same source and target with different
+ * mount flags or fstype, then call mnt_context_reset_status() and then try
+ * again mnt_context_do_mount().
+ *
+ * WARNING: non-zero return code does not mean that mount(2) syscall or
+ * mount.type helper wasn't successfully called.
+ *
+ * Check mnt_context_get_status() after error! See mnt_context_mount() for more
+ * details about errors and warnings.
+ *
+ * Returns: 0 on success;
+ * >0 in case of mount(2) error (returns syscall errno),
+ * <0 in case of other errors.
+ */
+int mnt_context_do_mount(struct libmnt_context *cxt)
+{
+ const char *type;
+ int res;
+ struct libmnt_ns *ns_old;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert(cxt->helper_exec_status == 1);
+ assert(cxt->syscall_status == 1);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+ assert((cxt->flags & MNT_FL_PREPARED));
+ assert((cxt->action == MNT_ACT_MOUNT));
+
+ DBG(CXT, ul_debugobj(cxt, "mount: do mount"));
+
+ if (!(cxt->flags & MNT_FL_MOUNTDATA))
+ cxt->mountdata = (char *) mnt_fs_get_fs_options(cxt->fs);
+
+ ns_old = mnt_context_switch_target_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+
+ type = mnt_fs_get_fstype(cxt->fs);
+ if (type) {
+ if (strchr(type, ','))
+ /* this only happens if fstab contains a list of filesystems */
+ res = do_mount_by_types(cxt, type);
+ else
+ res = do_mount(cxt, NULL);
+ } else
+ res = do_mount_by_pattern(cxt, cxt->fstype_pattern);
+
+#ifdef USE_LIBMOUNT_SUPPORT_MTAB
+ if (mnt_context_get_status(cxt)
+ && !mnt_context_is_fake(cxt)
+ && !cxt->helper
+ && mnt_context_mtab_writable(cxt)) {
+
+ int is_rdonly = -1;
+
+ DBG(CXT, ul_debugobj(cxt, "checking for RDONLY mismatch"));
+
+ /*
+ * Mounted by mount(2), do some post-mount checks
+ *
+ * Kernel can be used to use MS_RDONLY for bind mounts, but the
+ * read-only request could be silently ignored. Check it to
+ * avoid 'ro' in mtab and 'rw' in /proc/mounts.
+ */
+ if ((cxt->mountflags & MS_BIND)
+ && (cxt->mountflags & MS_RDONLY)) {
+
+ if (is_rdonly < 0)
+ is_rdonly = mnt_is_readonly(mnt_context_get_target(cxt));
+ if (!is_rdonly)
+ mnt_context_set_mflags(cxt, cxt->mountflags & ~MS_RDONLY);
+ }
+
+
+ /* Kernel can silently add MS_RDONLY flag when mounting file
+ * system that does not have write support. Check this to avoid
+ * 'ro' in /proc/mounts and 'rw' in mtab.
+ */
+ if (!(cxt->mountflags & (MS_RDONLY | MS_MOVE))
+ && !mnt_context_propagation_only(cxt)) {
+
+ if (is_rdonly < 0)
+ is_rdonly = mnt_is_readonly(mnt_context_get_target(cxt));
+ if (is_rdonly)
+ mnt_context_set_mflags(cxt, cxt->mountflags | MS_RDONLY);
+ }
+ }
+#endif
+
+ /* Cleanup will be immediate on failure, and deferred to umount on success */
+ if (mnt_context_is_veritydev(cxt))
+ mnt_context_deferred_delete_veritydev(cxt);
+
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+
+ return res;
+}
+
+/*
+ * Returns mountinfo FS entry of context source patch if the source is already
+ * mounted. This function is used for "already mounted" message or to get FS of
+ * re-used loop device.
+ */
+static struct libmnt_fs *get_already_mounted_source(struct libmnt_context *cxt)
+{
+ const char *src;
+ struct libmnt_table *tb;
+
+ assert(cxt);
+
+ src = mnt_fs_get_srcpath(cxt->fs);
+
+ if (src && mnt_context_get_mtab(cxt, &tb) == 0) {
+ struct libmnt_iter itr;
+ struct libmnt_fs *fs;
+
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+ while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+ const char *s = mnt_fs_get_srcpath(fs),
+ *t = mnt_fs_get_target(fs);
+
+ if (t && s && mnt_fs_streq_srcpath(fs, src))
+ return fs;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * Checks if source filesystem superblock is already ro-mounted. Note that we
+ * care about FS superblock as VFS node is irrelevant here.
+ */
+static int is_source_already_rdonly(struct libmnt_context *cxt)
+{
+ struct libmnt_fs *fs = get_already_mounted_source(cxt);
+ const char *opts = fs ? mnt_fs_get_fs_options(fs) : NULL;
+
+ return opts && mnt_optstr_get_option(opts, "ro", NULL, NULL) == 0;
+}
+
+/**
+ * mnt_context_finalize_mount:
+ * @cxt: context
+ *
+ * Mtab update, etc. Unnecessary for mnt_context_mount(), but should be called
+ * after mnt_context_do_mount(). See also mnt_context_set_syscall_status().
+ *
+ * Returns: negative number on error, 0 on success.
+ */
+int mnt_context_finalize_mount(struct libmnt_context *cxt)
+{
+ int rc;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED));
+ assert((cxt->flags & MNT_FL_PREPARED));
+
+ rc = mnt_context_prepare_update(cxt);
+ if (!rc)
+ rc = mnt_context_update_tabs(cxt);
+ return rc;
+}
+
+/**
+ * mnt_context_mount:
+ * @cxt: mount context
+ *
+ * High-level, mounts the filesystem by mount(2) or fork()+exec(/sbin/mount.type).
+ *
+ * This is similar to:
+ *
+ * mnt_context_prepare_mount(cxt);
+ * mnt_context_do_mount(cxt);
+ * mnt_context_finalize_mount(cxt);
+ *
+ * See also mnt_context_disable_helpers().
+ *
+ * Note that this function should be called only once. If you want to mount with
+ * different settings, then you have to call mnt_reset_context(). It's NOT enough
+ * to call mnt_context_reset_status(). If you want to call this function more than
+ * once, the whole context has to be reset.
+ *
+ * WARNING: non-zero return code does not mean that mount(2) syscall or
+ * mount.type helper wasn't successfully called.
+ *
+ * Always use mnt_context_get_status():
+ *
+ * <informalexample>
+ * <programlisting>
+ * rc = mnt_context_mount(cxt);
+ *
+ * if (mnt_context_helper_executed(cxt))
+ * return mnt_context_get_helper_status(cxt);
+ * if (rc == 0 && mnt_context_get_status(cxt) == 1)
+ * return MNT_EX_SUCCESS;
+ * return MNT_EX_FAIL;
+ * </programlisting>
+ * </informalexample>
+ *
+ * or mnt_context_get_excode() to generate mount(8) compatible error
+ * or warning message:
+ *
+ * <informalexample>
+ * <programlisting>
+ * rc = mnt_context_mount(cxt);
+ * rc = mnt_context_get_excode(cxt, rc, buf, sizeof(buf));
+ * if (buf)
+ * warnx(_("%s: %s"), mnt_context_get_target(cxt), buf);
+ * return rc; // MNT_EX_*
+ * </programlisting>
+ * </informalexample>
+ *
+ * Returns: 0 on success;
+ * >0 in case of mount(2) error (returns syscall errno),
+ * <0 in case of other errors.
+ */
+int mnt_context_mount(struct libmnt_context *cxt)
+{
+ int rc;
+ struct libmnt_ns *ns_old;
+
+ assert(cxt);
+ assert(cxt->fs);
+ assert(cxt->helper_exec_status == 1);
+ assert(cxt->syscall_status == 1);
+
+ ns_old = mnt_context_switch_target_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+
+again:
+ rc = mnt_context_prepare_mount(cxt);
+ if (!rc)
+ rc = mnt_context_prepare_update(cxt);
+ if (!rc)
+ rc = mnt_context_do_mount(cxt);
+ if (!rc)
+ rc = mnt_context_update_tabs(cxt);
+
+ /*
+ * Read-only device or already read-only mounted FS.
+ * Try mount the filesystem read-only.
+ */
+ if ((rc == -EROFS && !mnt_context_syscall_called(cxt)) /* before syscall; rdonly loopdev */
+ || mnt_context_get_syscall_errno(cxt) == EROFS /* syscall failed with EROFS */
+ || mnt_context_get_syscall_errno(cxt) == EACCES /* syscall failed with EACCES */
+ || (mnt_context_get_syscall_errno(cxt) == EBUSY /* already ro-mounted FS */
+ && is_source_already_rdonly(cxt)))
+ {
+ unsigned long mflags = 0;
+
+ mnt_context_get_mflags(cxt, &mflags);
+
+ if (!(mflags & MS_RDONLY) /* not yet RDONLY */
+ && !(mflags & MS_REMOUNT) /* not remount */
+ && !(mflags & MS_BIND) /* not bin mount */
+ && !mnt_context_is_rwonly_mount(cxt)) { /* no explicit read-write */
+
+ assert(!(cxt->flags & MNT_FL_FORCED_RDONLY));
+ DBG(CXT, ul_debugobj(cxt, "write-protected source, trying RDONLY."));
+
+ mnt_context_reset_status(cxt);
+ mnt_context_set_mflags(cxt, mflags | MS_RDONLY);
+ cxt->flags |= MNT_FL_FORCED_RDONLY;
+ goto again;
+ }
+ }
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+ return rc;
+}
+
+/**
+ * mnt_context_next_mount:
+ * @cxt: context
+ * @itr: iterator
+ * @fs: returns the current filesystem
+ * @mntrc: returns the return code from mnt_context_mount()
+ * @ignored: returns 1 for non-matching and 2 for already mounted filesystems
+ *
+ * This function tries to mount the next filesystem from fstab (as returned by
+ * mnt_context_get_fstab()). See also mnt_context_set_fstab().
+ *
+ * You can filter out filesystems by:
+ * mnt_context_set_options_pattern() to simulate mount -a -O pattern
+ * mnt_context_set_fstype_pattern() to simulate mount -a -t pattern
+ *
+ * If the filesystem is already mounted or does not match defined criteria,
+ * then the mnt_context_next_mount() function returns zero, but the @ignored is
+ * non-zero. Note that the root filesystem and filesystems with "noauto" option
+ * are always ignored.
+ *
+ * If mount(2) syscall or mount.type helper failed, then the
+ * mnt_context_next_mount() function returns zero, but the @mntrc is non-zero.
+ * Use also mnt_context_get_status() to check if the filesystem was
+ * successfully mounted.
+ *
+ * See mnt_context_mount() for more details about errors and warnings.
+ *
+ * Returns: 0 on success,
+ * <0 in case of error (!= mount(2) errors)
+ * 1 at the end of the list.
+ */
+int mnt_context_next_mount(struct libmnt_context *cxt,
+ struct libmnt_iter *itr,
+ struct libmnt_fs **fs,
+ int *mntrc,
+ int *ignored)
+{
+ struct libmnt_table *fstab, *mtab;
+ const char *o, *tgt;
+ int rc, mounted = 0;
+
+ if (ignored)
+ *ignored = 0;
+ if (mntrc)
+ *mntrc = 0;
+
+ if (!cxt || !fs || !itr)
+ return -EINVAL;
+
+ rc = mnt_context_get_fstab(cxt, &fstab);
+ if (rc)
+ return rc;
+
+ rc = mnt_table_next_fs(fstab, itr, fs);
+ if (rc != 0)
+ return rc; /* more filesystems (or error) */
+
+ o = mnt_fs_get_user_options(*fs);
+ tgt = mnt_fs_get_target(*fs);
+
+ DBG(CXT, ul_debugobj(cxt, "next-mount: trying %s", tgt));
+
+ /* ignore swap */
+ if (mnt_fs_is_swaparea(*fs) ||
+
+ /* ignore root filesystem */
+ (tgt && (strcmp(tgt, "/") == 0 || strcmp(tgt, "root") == 0)) ||
+
+ /* ignore noauto filesystems */
+ (o && mnt_optstr_get_option(o, "noauto", NULL, NULL) == 0) ||
+
+ /* ignore filesystems which don't match options patterns */
+ (cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
+ cxt->fstype_pattern)) ||
+
+ /* ignore filesystems which don't match type patterns */
+ (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
+ cxt->optstr_pattern))) {
+ if (ignored)
+ *ignored = 1;
+ DBG(CXT, ul_debugobj(cxt, "next-mount: not-match "
+ "[fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]",
+ mnt_fs_get_fstype(*fs),
+ cxt->fstype_pattern,
+ mnt_fs_get_options(*fs),
+ cxt->optstr_pattern));
+ return 0;
+ }
+
+ /* ignore already mounted filesystems */
+ rc = mnt_context_is_fs_mounted(cxt, *fs, &mounted);
+ if (rc) {
+ if (mnt_table_is_empty(cxt->mtab)) {
+ DBG(CXT, ul_debugobj(cxt, "next-mount: no mount table [rc=%d], ignore", rc));
+ rc = 0;
+ if (ignored)
+ *ignored = 1;
+ }
+ return rc;
+ }
+ if (mounted) {
+ if (ignored)
+ *ignored = 2;
+ return 0;
+ }
+
+ /* Save mount options, etc. -- this is effective for the first
+ * mnt_context_next_mount() call only. Make sure that cxt has not set
+ * source, target or fstype.
+ */
+ if (!mnt_context_has_template(cxt)) {
+ mnt_context_set_source(cxt, NULL);
+ mnt_context_set_target(cxt, NULL);
+ mnt_context_set_fstype(cxt, NULL);
+ mnt_context_save_template(cxt);
+ }
+
+ /* reset context, but protect mtab */
+ mtab = cxt->mtab;
+ cxt->mtab = NULL;
+ mnt_reset_context(cxt);
+ cxt->mtab = mtab;
+
+ if (mnt_context_is_fork(cxt)) {
+ rc = mnt_fork_context(cxt);
+ if (rc)
+ return rc; /* fork error */
+
+ if (mnt_context_is_parent(cxt)) {
+ return 0; /* parent */
+ }
+ }
+
+ /*
+ * child or non-forked
+ */
+
+ /* copy stuff from fstab to context */
+ rc = mnt_context_apply_fs(cxt, *fs);
+ if (!rc) {
+ /*
+ * "-t <pattern>" is used to filter out fstab entries, but for ordinary
+ * mount operation -t means "-t <type>". We have to zeroize the pattern
+ * to avoid misinterpretation.
+ */
+ char *pattern = cxt->fstype_pattern;
+ cxt->fstype_pattern = NULL;
+
+ rc = mnt_context_mount(cxt);
+
+ cxt->fstype_pattern = pattern;
+
+ if (mntrc)
+ *mntrc = rc;
+ }
+
+ if (mnt_context_is_child(cxt)) {
+ DBG(CXT, ul_debugobj(cxt, "next-mount: child exit [rc=%d]", rc));
+ DBG_FLUSH;
+ _exit(rc);
+ }
+ return 0;
+}
+
+
+/**
+ * mnt_context_next_remount:
+ * @cxt: context
+ * @itr: iterator
+ * @fs: returns the current filesystem
+ * @mntrc: returns the return code from mnt_context_mount()
+ * @ignored: returns 1 for non-matching
+ *
+ * This function tries to remount the next mounted filesystem (as returned by
+ * mnt_context_get_mtab()).
+ *
+ * You can filter out filesystems by:
+ * mnt_context_set_options_pattern() to simulate mount -a -O pattern
+ * mnt_context_set_fstype_pattern() to simulate mount -a -t pattern
+ *
+ * If the filesystem does not match defined criteria, then the
+ * mnt_context_next_remount() function returns zero, but the @ignored is
+ * non-zero.
+ *
+ * IMPORTANT -- the mount operation is performed in the current context.
+ * The context is reset before the next mount (see mnt_reset_context()).
+ * The context setting related to the filesystem (e.g. mount options,
+ * etc.) are protected.
+
+ * If mount(2) syscall or mount.type helper failed, then the
+ * mnt_context_next_mount() function returns zero, but the @mntrc is non-zero.
+ * Use also mnt_context_get_status() to check if the filesystem was
+ * successfully mounted.
+ *
+ * See mnt_context_mount() for more details about errors and warnings.
+ *
+ * Returns: 0 on success,
+ * <0 in case of error (!= mount(2) errors)
+ * 1 at the end of the list.
+ *
+ * Since: 2.34
+ */
+int mnt_context_next_remount(struct libmnt_context *cxt,
+ struct libmnt_iter *itr,
+ struct libmnt_fs **fs,
+ int *mntrc,
+ int *ignored)
+{
+ struct libmnt_table *mtab;
+ const char *tgt;
+ int rc;
+
+ if (ignored)
+ *ignored = 0;
+ if (mntrc)
+ *mntrc = 0;
+
+ if (!cxt || !fs || !itr)
+ return -EINVAL;
+
+ rc = mnt_context_get_mtab(cxt, &mtab);
+ if (rc)
+ return rc;
+
+ rc = mnt_table_next_fs(mtab, itr, fs);
+ if (rc != 0)
+ return rc; /* more filesystems (or error) */
+
+ tgt = mnt_fs_get_target(*fs);
+
+ DBG(CXT, ul_debugobj(cxt, "next-remount: trying %s", tgt));
+
+ /* ignore filesystems which don't match options patterns */
+ if ((cxt->fstype_pattern && !mnt_fs_match_fstype(*fs,
+ cxt->fstype_pattern)) ||
+
+ /* ignore filesystems which don't match type patterns */
+ (cxt->optstr_pattern && !mnt_fs_match_options(*fs,
+ cxt->optstr_pattern))) {
+ if (ignored)
+ *ignored = 1;
+ DBG(CXT, ul_debugobj(cxt, "next-remount: not-match "
+ "[fstype: %s, t-pattern: %s, options: %s, O-pattern: %s]",
+ mnt_fs_get_fstype(*fs),
+ cxt->fstype_pattern,
+ mnt_fs_get_options(*fs),
+ cxt->optstr_pattern));
+ return 0;
+ }
+
+ /* Save mount options, etc. -- this is effective for the first
+ * mnt_context_next_remount() call only. Make sure that cxt has not set
+ * source, target or fstype.
+ */
+ if (!mnt_context_has_template(cxt)) {
+ mnt_context_set_source(cxt, NULL);
+ mnt_context_set_target(cxt, NULL);
+ mnt_context_set_fstype(cxt, NULL);
+ mnt_context_save_template(cxt);
+ }
+
+ /* restore original, but protect mtab */
+ cxt->mtab = NULL;
+ mnt_reset_context(cxt);
+ cxt->mtab = mtab;
+
+ rc = mnt_context_set_target(cxt, tgt);
+ if (!rc) {
+ /*
+ * "-t <pattern>" is used to filter out fstab entries, but for ordinary
+ * mount operation -t means "-t <type>". We have to zeroize the pattern
+ * to avoid misinterpretation.
+ */
+ char *pattern = cxt->fstype_pattern;
+ cxt->fstype_pattern = NULL;
+
+ rc = mnt_context_mount(cxt);
+
+ cxt->fstype_pattern = pattern;
+
+ if (mntrc)
+ *mntrc = rc;
+ rc = 0;
+ }
+
+ return rc;
+}
+
+/*
+ * Returns 1 if @dir parent is shared
+ */
+static int is_shared_tree(struct libmnt_context *cxt, const char *dir)
+{
+ struct libmnt_table *tb = NULL;
+ struct libmnt_fs *fs;
+ unsigned long mflags = 0;
+ char *mnt = NULL, *p;
+ int rc = 0;
+ struct libmnt_ns *ns_old;
+
+ ns_old = mnt_context_switch_target_ns(cxt);
+ if (!ns_old)
+ return -MNT_ERR_NAMESPACE;
+
+ if (!dir)
+ return 0;
+ if (mnt_context_get_mtab(cxt, &tb) || !tb)
+ goto done;
+
+ mnt = strdup(dir);
+ if (!mnt)
+ goto done;
+ p = strrchr(mnt, '/');
+ if (!p)
+ goto done;
+ if (p > mnt)
+ *p = '\0';
+ fs = mnt_table_find_mountpoint(tb, mnt, MNT_ITER_BACKWARD);
+
+ rc = fs && mnt_fs_is_kernel(fs)
+ && mnt_fs_get_propagation(fs, &mflags) == 0
+ && (mflags & MS_SHARED);
+done:
+ free(mnt);
+ if (!mnt_context_switch_ns(cxt, ns_old))
+ return -MNT_ERR_NAMESPACE;
+ return rc;
+}
+
+int mnt_context_get_mount_excode(
+ struct libmnt_context *cxt,
+ int rc,
+ char *buf,
+ size_t bufsz)
+{
+ int syserr;
+ struct stat st;
+ unsigned long uflags = 0, mflags = 0;
+
+ int restricted = mnt_context_is_restricted(cxt);
+ const char *tgt = mnt_context_get_target(cxt);
+ const char *src = mnt_context_get_source(cxt);
+
+ if (mnt_context_helper_executed(cxt)) {
+ /*
+ * /sbin/mount.<type> called, return status
+ */
+ if (rc == -MNT_ERR_APPLYFLAGS && buf)
+ snprintf(buf, bufsz, _("WARNING: failed to apply propagation flags"));
+
+ return mnt_context_get_helper_status(cxt);
+ }
+
+ if (rc == 0 && mnt_context_get_status(cxt) == 1) {
+ /*
+ * Libmount success && syscall success.
+ */
+ if (buf && mnt_context_forced_rdonly(cxt))
+ snprintf(buf, bufsz, _("WARNING: source write-protected, mounted read-only"));
+ return MNT_EX_SUCCESS;
+ }
+
+ mnt_context_get_mflags(cxt, &mflags); /* mount(2) flags */
+ mnt_context_get_user_mflags(cxt, &uflags); /* userspace flags */
+
+ if (!mnt_context_syscall_called(cxt)) {
+ /*
+ * libmount errors (extra library checks)
+ */
+ switch (rc) {
+ case -EPERM:
+ if (buf)
+ snprintf(buf, bufsz, _("operation permitted for root only"));
+ return MNT_EX_USAGE;
+ case -EBUSY:
+ if (buf)
+ snprintf(buf, bufsz, _("%s is already mounted"), src);
+ return MNT_EX_USAGE;
+ case -MNT_ERR_NOFSTAB:
+ if (!buf)
+ return MNT_EX_USAGE;
+ if (mnt_context_is_swapmatch(cxt))
+ snprintf(buf, bufsz, _("can't find in %s"),
+ mnt_get_fstab_path());
+ else if (tgt)
+ snprintf(buf, bufsz, _("can't find mount point in %s"),
+ mnt_get_fstab_path());
+ else if (src)
+ snprintf(buf, bufsz, _("can't find mount source %s in %s"),
+ src, mnt_get_fstab_path());
+ return MNT_EX_USAGE;
+ case -MNT_ERR_AMBIFS:
+ if (buf)
+ snprintf(buf, bufsz, _("more filesystems detected on %s; use -t <type> or wipefs(8)"), src);
+ return MNT_EX_USAGE;
+ case -MNT_ERR_NOFSTYPE:
+ if (buf)
+ snprintf(buf, bufsz, restricted ?
+ _("failed to determine filesystem type") :
+ _("no filesystem type specified"));
+ return MNT_EX_USAGE;
+ case -MNT_ERR_NOSOURCE:
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (buf) {
+ if (src)
+ snprintf(buf, bufsz, _("can't find %s"), src);
+ else
+ snprintf(buf, bufsz, _("no mount source specified"));
+ }
+ return MNT_EX_USAGE;
+ case -MNT_ERR_MOUNTOPT:
+ if (buf) {
+ const char *opts = mnt_context_get_options(cxt);
+
+ if (!opts)
+ opts = "";
+ if (opts)
+ snprintf(buf, bufsz, errno ?
+ _("failed to parse mount options '%s': %m") :
+ _("failed to parse mount options '%s'"), opts);
+ else
+ snprintf(buf, bufsz, errno ?
+ _("failed to parse mount options: %m") :
+ _("failed to parse mount options"));
+ }
+ return MNT_EX_USAGE;
+ case -MNT_ERR_LOOPDEV:
+ if (buf)
+ snprintf(buf, bufsz, _("failed to setup loop device for %s"), src);
+ return MNT_EX_FAIL;
+ case -MNT_ERR_LOOPOVERLAP:
+ if (buf)
+ snprintf(buf, bufsz, _("overlapping loop device exists for %s"), src);
+ return MNT_EX_FAIL;
+ case -MNT_ERR_LOCK:
+ if (buf)
+ snprintf(buf, bufsz, _("locking failed"));
+ return MNT_EX_FILEIO;
+ case -MNT_ERR_NAMESPACE:
+ if (buf)
+ snprintf(buf, bufsz, _("failed to switch namespace"));
+ return MNT_EX_SYSERR;
+ default:
+ return mnt_context_get_generic_excode(rc, buf, bufsz, _("mount failed: %m"));
+ }
+
+ } else if (mnt_context_get_syscall_errno(cxt) == 0) {
+ /*
+ * mount(2) syscall success, but something else failed
+ * (probably error in mtab processing).
+ */
+ if (rc == -MNT_ERR_LOCK) {
+ if (buf)
+ snprintf(buf, bufsz, _("filesystem was mounted, but failed to update userspace mount table"));
+ return MNT_EX_FILEIO;
+ }
+
+ if (rc == -MNT_ERR_NAMESPACE) {
+ if (buf)
+ snprintf(buf, bufsz, _("filesystem was mounted, but failed to switch namespace back"));
+ return MNT_EX_SYSERR;
+
+ }
+
+ if (rc < 0)
+ return mnt_context_get_generic_excode(rc, buf, bufsz,
+ _("filesystem was mounted, but any subsequent operation failed: %m"));
+
+ return MNT_EX_SOFTWARE; /* internal error */
+
+ }
+
+ /*
+ * mount(2) errors
+ */
+ syserr = mnt_context_get_syscall_errno(cxt);
+
+
+ switch(syserr) {
+ case EPERM:
+ if (!buf)
+ break;
+ if (geteuid() == 0) {
+ if (mnt_stat_mountpoint(tgt, &st) || !S_ISDIR(st.st_mode))
+ snprintf(buf, bufsz, _("mount point is not a directory"));
+ else
+ snprintf(buf, bufsz, _("permission denied"));
+ } else
+ snprintf(buf, bufsz, _("must be superuser to use mount"));
+ break;
+
+ case EBUSY:
+ if (!buf)
+ break;
+ if (mflags & MS_REMOUNT) {
+ snprintf(buf, bufsz, _("mount point is busy"));
+ break;
+ }
+ if (src) {
+ struct libmnt_fs *fs = get_already_mounted_source(cxt);
+
+ if (fs && mnt_fs_get_target(fs))
+ snprintf(buf, bufsz, _("%s already mounted on %s"),
+ src, mnt_fs_get_target(fs));
+ }
+ if (!*buf)
+ snprintf(buf, bufsz, _("%s already mounted or mount point busy"), src);
+ break;
+ case ENOENT:
+ if (tgt && mnt_lstat_mountpoint(tgt, &st)) {
+ if (buf)
+ snprintf(buf, bufsz, _("mount point does not exist"));
+ } else if (tgt && mnt_stat_mountpoint(tgt, &st)) {
+ if (buf)
+ snprintf(buf, bufsz, _("mount point is a symbolic link to nowhere"));
+ } else if (src && stat(src, &st)) {
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (buf)
+ snprintf(buf, bufsz, _("special device %s does not exist"), src);
+ } else if (buf) {
+ errno = syserr;
+ snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+ }
+ break;
+
+ case ENOTDIR:
+ if (mnt_stat_mountpoint(tgt, &st) || ! S_ISDIR(st.st_mode)) {
+ if (buf)
+ snprintf(buf, bufsz, _("mount point is not a directory"));
+ } else if (src && stat(src, &st) && errno == ENOTDIR) {
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (buf)
+ snprintf(buf, bufsz, _("special device %s does not exist "
+ "(a path prefix is not a directory)"), src);
+ } else if (buf) {
+ errno = syserr;
+ snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+ }
+ break;
+
+ case EINVAL:
+ if (!buf)
+ break;
+ if (mflags & MS_REMOUNT)
+ snprintf(buf, bufsz, _("mount point not mounted or bad option"));
+ else if (rc == -MNT_ERR_APPLYFLAGS)
+ snprintf(buf, bufsz, _("not mount point or bad option"));
+ else if ((mflags & MS_MOVE) && is_shared_tree(cxt, src))
+ snprintf(buf, bufsz,
+ _("bad option; moving a mount "
+ "residing under a shared mount is unsupported"));
+ else if (mnt_fs_is_netfs(mnt_context_get_fs(cxt)))
+ snprintf(buf, bufsz,
+ _("bad option; for several filesystems (e.g. nfs, cifs) "
+ "you might need a /sbin/mount.<type> helper program"));
+ else
+ snprintf(buf, bufsz,
+ _("wrong fs type, bad option, bad superblock on %s, "
+ "missing codepage or helper program, or other error"),
+ src);
+ break;
+
+ case EMFILE:
+ if (buf)
+ snprintf(buf, bufsz, _("mount table full"));
+ break;
+
+ case EIO:
+ if (buf)
+ snprintf(buf, bufsz, _("can't read superblock on %s"), src);
+ break;
+
+ case ENODEV:
+ if (!buf)
+ break;
+ if (mnt_context_get_fstype(cxt))
+ snprintf(buf, bufsz, _("unknown filesystem type '%s'"),
+ mnt_context_get_fstype(cxt));
+ else
+ snprintf(buf, bufsz, _("unknown filesystem type"));
+ break;
+
+ case ENOTBLK:
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (!buf)
+ break;
+ if (src && stat(src, &st))
+ snprintf(buf, bufsz, _("%s is not a block device, and stat(2) fails?"), src);
+ else if (src && S_ISBLK(st.st_mode))
+ snprintf(buf, bufsz,
+ _("the kernel does not recognize %s as a block device; "
+ "maybe \"modprobe driver\" is necessary"), src);
+ else if (src && S_ISREG(st.st_mode))
+ snprintf(buf, bufsz, _("%s is not a block device; try \"-o loop\""), src);
+ else
+ snprintf(buf, bufsz, _("%s is not a block device"), src);
+ break;
+
+ case ENXIO:
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (buf)
+ snprintf(buf, bufsz, _("%s is not a valid block device"), src);
+ break;
+
+ case EACCES:
+ case EROFS:
+ if (!buf)
+ break;
+ if (mflags & MS_RDONLY)
+ snprintf(buf, bufsz, _("cannot mount %s read-only"), src);
+ else if (mnt_context_is_rwonly_mount(cxt))
+ snprintf(buf, bufsz, _("%s is write-protected but explicit read-write mode requested"), src);
+ else if (mflags & MS_REMOUNT)
+ snprintf(buf, bufsz, _("cannot remount %s read-write, is write-protected"), src);
+ else if (mflags & MS_BIND)
+ snprintf(buf, bufsz, _("bind %s failed"), src);
+ else {
+ errno = syserr;
+ snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+ }
+ break;
+
+ case ENOMEDIUM:
+ if (uflags & MNT_MS_NOFAIL)
+ return MNT_EX_SUCCESS;
+ if (buf)
+ snprintf(buf, bufsz, _("no medium found on %s"), src);
+ break;
+
+ case EBADMSG:
+ /* Bad CRC for classic filesystems (e.g. extN or XFS) */
+ if (buf && src && stat(src, &st) == 0
+ && (S_ISBLK(st.st_mode) || S_ISREG(st.st_mode))) {
+ snprintf(buf, bufsz, _("cannot mount; probably corrupted filesystem on %s"), src);
+ break;
+ }
+ /* fallthrough */
+
+ default:
+ if (buf) {
+ errno = syserr;
+ snprintf(buf, bufsz, _("mount(2) system call failed: %m"));
+ }
+ break;
+ }
+
+ return MNT_EX_FAIL;
+}
+