diff options
Diffstat (limited to '')
| -rw-r--r-- | libmount/src/context_mount.c | 1935 |
1 files changed, 1935 insertions, 0 deletions
diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c new file mode 100644 index 0000000..8c394c1 --- /dev/null +++ b/libmount/src/context_mount.c @@ -0,0 +1,1935 @@ +/* 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). + */ + 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->mountflags & MS_NOSYMFOLLOW)) + mnt_optstr_append_option(optstr, "symfollow", 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 (setgid(getgid()) < 0) + _exit(EXIT_FAILURE); + + if (setuid(getuid()) < 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); + 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; +} + +/* + * 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; + const char *src, *target, *type; + unsigned long flags; + + assert(cxt); + assert(cxt->fs); + assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED)); + + if (try_type && !cxt->helper) { + 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; + + DBG(CXT, ul_debugobj(cxt, "%smount(2) " + "[source=%s, target=%s, type=%s, " + " mountflags=0x%08lx, mountdata=%s]", + mnt_context_is_fake(cxt) ? "(FAKE) " : "", + src, target, type, + flags, cxt->mountdata ? "yes" : "<none>")); + + if (mnt_context_is_fake(cxt)) { + /* + * fake + */ + cxt->syscall_status = 0; + + } 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 + */ + 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)); + return -cxt->syscall_status; + } + DBG(CXT, ul_debugobj(cxt, " 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? */ + return -MNT_ERR_APPLYFLAGS; + } + } + + 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); + } + + return rc; +} + +/* 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 (!mnt_context_get_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++) { + rc = do_mount(cxt, *fp); + if (mnt_context_get_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) + 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) + 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; +} + |