diff options
Diffstat (limited to 'libmount/src/context_mount.c')
| -rw-r--r-- | libmount/src/context_mount.c | 935 |
1 files changed, 935 insertions, 0 deletions
diff --git a/libmount/src/context_mount.c b/libmount/src/context_mount.c new file mode 100644 index 0000000..f3d8ff1 --- /dev/null +++ b/libmount/src/context_mount.c @@ -0,0 +1,935 @@ +/* + * Copyright (C) 2010 Karel Zak <kzak@redhat.com> + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ + +/** + * 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" + +/* + * this has to be called after mnt_context_evaluate_permissions() + */ +static int fix_optstr(struct libmnt_context *cxt) +{ + int rc = 0; + char *next; + char *name, *val; + size_t namesz, valsz; + struct libmnt_fs *fs; +#ifdef HAVE_LIBSELINUX + int se_fix = 0, se_rem = 0; +#endif + assert(cxt); + assert(cxt->fs); + assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED)); + + if (!cxt) + return -EINVAL; + if (!cxt->fs || (cxt->flags & MNT_FL_MOUNTOPTS_FIXED)) + return 0; + + DBG(CXT, mnt_debug_h(cxt, "mount: fixing optstr")); + + fs = cxt->fs; + + /* The propagation flags should not be used together with any other + * flags (except MS_REC and MS_SILENT) */ + if (cxt->mountflags & MS_PROPAGATION) + cxt->mountflags &= (MS_PROPAGATION | MS_REC | MS_SILENT); + + /* + * The "user" options is our business (so we can modify the option), + * but exception is command line for /sbin/mount.<type> helpers. Let's + * save the original user=<name> to call the helpers with unchanged + * "user" setting. + * + * Don't check for MNT_MS_USER in cxt->user_mountflags, the flag maybe + * removed by evaluate_permissions(). + */ + if (!mnt_optstr_get_option(fs->user_optstr, "user", &val, &valsz)) { + if (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, mnt_debug_h(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, mnt_debug_h(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; + } + + 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 allow to remount 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 we have translate the contexts */ + se_fix = 1; + + if (!se_rem) { + /* de-duplicate SELinux options */ + mnt_optstr_deduplicate_option(&fs->fs_optstr, "context"); + mnt_optstr_deduplicate_option(&fs->fs_optstr, "fscontext"); + mnt_optstr_deduplicate_option(&fs->fs_optstr, "defcontext"); + mnt_optstr_deduplicate_option(&fs->fs_optstr, "rootcontext"); + mnt_optstr_deduplicate_option(&fs->fs_optstr, "seclabel"); + } +#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) && + namesz >= 7 && (!strncmp(name, "context", 7) || + !strncmp(name, "fscontext", 9) || + !strncmp(name, "defcontext", 10) || + !strncmp(name, "rootcontext", 11) || + !strncmp(name, "seclabel", 8))) { + 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 + if (rc) + goto done; + } + + if (!rc && cxt->user_mountflags & MNT_MS_USER) + rc = mnt_optstr_fix_user(&fs->user_optstr); + + /* 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, mnt_debug_h(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 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[1]; + char *next, *name, *val; + size_t namesz, valsz; + int rc = 0; + + assert(cxt); + assert(cxt->fs); + assert(optstr); + + DBG(CXT, mnt_debug_h(cxt, "mount: generate helper mount options")); + + *optstr = mnt_fs_strdup_options(cxt->fs); + if (!*optstr) + return -ENOMEM; + + 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); + next = *optstr; + + while (!mnt_optstr_next_option(&next, &name, &namesz, &val, &valsz)) { + const struct libmnt_optmap *ent; + + mnt_optmap_get_entry(maps, 1, 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> maybe be used by some filesystems as 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->fs); + assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED)); + + if (!cxt) + return -EINVAL; + if (!cxt->fs) + return 0; + + DBG(CXT, mnt_debug_h(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; + cxt->user_mountflags &= ~MNT_MS_USER; + cxt->user_mountflags &= ~MNT_MS_USERS; + } else { + /* + * user mount + */ + if (!(cxt->flags & MNT_FL_TAB_APPLIED)) + { + DBG(CXT, mnt_debug_h(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, mnt_debug_h(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, mnt_debug_h(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, mnt_debug_h(cxt, "permissions evaluation ends with -EPERMS")); + return -EPERM; + } + } + + return 0; +} + +/* + * mnt_context_helper_setopt() backend + * + * This function applies 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; + default: + return 1; + break; + } + + return rc; +} + +static int exec_helper(struct libmnt_context *cxt) +{ + char *o = NULL; + int rc; + + assert(cxt); + assert(cxt->fs); + assert(cxt->helper); + assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED)); + + DBG(CXT, mnt_debug_h(cxt, "mount: executing helper %s", cxt->helper)); + + rc = generate_helper_optstr(cxt, &o); + if (rc) + return -EINVAL; + + DBG_FLUSH; + + switch (fork()) { + case 0: + { + const char *args[12], *type; + int i = 0; + + if (setgid(getgid()) < 0) + exit(EXIT_FAILURE); + + if (setuid(getuid()) < 0) + 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 */ + + /* + * TODO: remove the exception for "nfs", -s is documented + * for years should be usable everywhere. + */ + if (mnt_context_is_sloppy(cxt) && + type && startswith(type, "nfs")) + 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 && !endswith(cxt->helper, type)) { + args[i++] = "-t"; /* 10 */ + args[i++] = type; /* 11 */ + } + args[i] = NULL; /* 12 */ +#ifdef CONFIG_LIBMOUNT_DEBUG + for (i = 0; args[i]; i++) + DBG(CXT, mnt_debug_h(cxt, "argv[%d] = \"%s\"", + i, args[i])); +#endif + DBG_FLUSH; + execv(cxt->helper, (char * const *) args); + exit(EXIT_FAILURE); + } + default: + { + int st; + wait(&st); + cxt->helper_status = WIFEXITED(st) ? WEXITSTATUS(st) : -1; + + DBG(CXT, mnt_debug_h(cxt, "%s executed [status=%d]", + cxt->helper, cxt->helper_status)); + cxt->helper_exec_status = rc = 0; + break; + } + + case -1: + cxt->helper_exec_status = rc = -errno; + DBG(CXT, mnt_debug_h(cxt, "fork() failed")); + break; + } + + free(o); + return rc; +} + +/* + * The default is to use fstype from cxt->fs, this could be overwritten by + * @try_type argument. + * + * 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; + } + if (cxt->helper) + return exec_helper(cxt); + + flags = cxt->mountflags; + src = mnt_fs_get_srcpath(cxt->fs); + target = mnt_fs_get_target(cxt->fs); + + if (!target) + return -EINVAL; + if (!src) { + /* unnecessary, should be already resolved in + * mnt_context_prepare_srcpath(), but for sure... */ + DBG(CXT, mnt_debug_h(cxt, "WARNING: source is NULL -- using \"none\"!")); + src = "none"; + } + type = try_type ? : mnt_fs_get_fstype(cxt->fs); + + if (!(flags & MS_MGC_MSK)) + flags |= MS_MGC_VAL; + + DBG(CXT, mnt_debug_h(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)) + cxt->syscall_status = 0; + else { + if (mount(src, target, type, flags, cxt->mountdata)) { + cxt->syscall_status = -errno; + DBG(CXT, mnt_debug_h(cxt, "mount(2) failed [errno=%d %m]", + -cxt->syscall_status)); + return -cxt->syscall_status; + } + DBG(CXT, mnt_debug_h(cxt, "mount(2) success")); + cxt->syscall_status = 0; + } + + 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; +} + +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; + + assert(cxt); + assert((cxt->flags & MNT_FL_MOUNTFLAGS_MERGED)); + + if (!neg && pattern) { + /* + * try all types from the list + */ + char *p, *p0; + + DBG(CXT, mnt_debug_h(cxt, "trying to mount by FS pattern list")); + + p0 = p = strdup(pattern); + if (!p) + return -ENOMEM; + do { + char *end = strchr(p, ','); + if (end) + *end = '\0'; + rc = do_mount(cxt, p); + p = end ? end + 1 : NULL; + + } while (!mnt_context_get_status(cxt) && p); + + free(p0); + + if (mnt_context_get_status(cxt)) + return rc; + } + + /* + * try /etc/filesystems and /proc/filesystems + */ + DBG(CXT, mnt_debug_h(cxt, "trying to mount by filesystems lists")); + + rc = mnt_get_filesystems(&filesystems, neg ? pattern : NULL); + if (rc) + return rc; + + 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) + 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; + + assert(cxt); + assert(cxt->fs); + assert(cxt->helper_exec_status == 1); + assert(cxt->syscall_status == 1); + + 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; + + cxt->action = MNT_ACT_MOUNT; + + DBG(CXT, mnt_debug_h(cxt, "mount: preparing")); + + /* TODO: fstab is unnecessary for MS_{MOVE,BIND,STARED,...} */ + 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_prepare_target(cxt); + if (!rc) + rc = mnt_context_guess_fstype(cxt); + if (!rc) + rc = mnt_context_prepare_helper(cxt, "mount", NULL); + if (rc) { + DBG(CXT, mnt_debug_h(cxt, "mount: preparing failed")); + return rc; + } + cxt->flags |= MNT_FL_PREPARED; + 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 than you have to call mnt_reset_context(). + * + * If you want to call mount(2) for the same source and target with a 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! +* + * 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; + + 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, mnt_debug_h(cxt, "mount: do mount")); + + if (!(cxt->flags & MNT_FL_MOUNTDATA)) + cxt->mountdata = (char *) mnt_fs_get_fs_options(cxt->fs); + + type = mnt_fs_get_fstype(cxt->fs); + if (type) + res = do_mount(cxt, NULL); + else + res = do_mount_by_pattern(cxt, cxt->fstype_pattern); + + if (mnt_context_get_status(cxt) + && !mnt_context_is_fake(cxt) + && !cxt->helper) { + /* + * Mounted by mount(2), do some post-mount checks + * + * Kernel allows 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) + && !mnt_is_readonly(mnt_context_get_target(cxt))) + + 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_PROPAGATION | MS_MOVE)) + && mnt_is_readonly(mnt_context_get_target(cxt))) + + mnt_context_set_mflags(cxt, + cxt->mountflags | MS_RDONLY); + } + + return res; +} + +/** + * 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 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 could be called only once. If you want to mount with + * different setting than you have to call mnt_reset_context(). It's NOT enough + * to call mnt_context_reset_status() if you want call this function more than + * once, whole context has to be reseted. + * + * 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! + * + * 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; + + assert(cxt); + assert(cxt->fs); + assert(cxt->helper_exec_status == 1); + assert(cxt->syscall_status == 1); + + rc = mnt_context_prepare_mount(cxt); + if (!rc) + rc = mnt_context_prepare_update(cxt); + if (!rc) + rc = mnt_context_do_mount(cxt); + + /* TODO: if mtab update is expected then check if the + * target is really mounted read-write to avoid 'ro' in + * mtab and 'rw' in /proc/mounts. + */ + if (!rc) + rc = mnt_context_update_tabs(cxt); + 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 not 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. + * + * 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; + + mtab = cxt->mtab; + cxt->mtab = NULL; /* do not reset mtab */ + mnt_reset_context(cxt); + cxt->mtab = mtab; + + 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, mnt_debug_h(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 not match with options patterns */ + (cxt->fstype_pattern && !mnt_fs_match_fstype(*fs, + cxt->fstype_pattern)) || + + /* ignore filesystems not match with type patterns */ + (cxt->optstr_pattern && !mnt_fs_match_options(*fs, + cxt->optstr_pattern))) { + if (ignored) + *ignored = 1; + DBG(CXT, mnt_debug_h(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; + } + + 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 */ + + rc = mnt_context_set_fs(cxt, *fs); + if (!rc) { + rc = mnt_context_mount(cxt); + if (mntrc) + *mntrc = rc; + } + + if (mnt_context_is_child(cxt)) { + DBG(CXT, mnt_debug_h(cxt, "next-mount: child exit [rc=%d]", rc)); + DBG_FLUSH; + exit(rc); + } + return 0; +} + |