libmount: add mount(8) sample

This code is going to be used as mount(8) replacement in the next
major release (2.20). For now this mount(8) implementation does not
support loopdevs initialization.

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 422 insertions, 0 deletions

diff --git a/shlibs/mount/samples/mount.c b/shlibs/mount/samples/mount.c
new file mode 100644
index 000000000..1d032a621
--- /dev/null
+++ b/shlibs/mount/samples/mount.c
@@ -0,0 +1,422 @@
+/*
+ * mount(8) -- mount a filesystem
+ *
+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
+ * Written by Karel Zak <kzak@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <getopt.h>
+#include <err.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "mount.h"
+#include "nls.h"
+#include "c.h"
+
+/*** TODO: DOCS:
+ *
+ *  -p, --pass-fd	is unsupported
+ *  --guess-fstype	is unsupported
+ *  -c =                --no-canonicalize
+ */
+
+/* exit status */
+#define EX_SUCCESS	0
+#define EX_USAGE	1	/* incorrect invocation or permission */
+#define EX_SYSERR	2	/* out of memory, cannot fork, ... */
+#define EX_SOFTWARE	4	/* internal mount bug or wrong version */
+#define EX_USER		8	/* user interrupt */
+#define EX_FILEIO      16	/* problems writing, locking, ... mtab/fstab */
+#define EX_FAIL	       32	/* mount failure */
+#define EX_SOMEOK      64	/* some mount succeeded */
+
+static mnt_lock *lock;
+
+static void lock_atexit_cleanup(void)
+{
+	if (lock)
+		mnt_unlock_file(lock);
+}
+
+static void __attribute__((__noreturn__)) exit_non_root(const char *option)
+{
+	const uid_t ruid = getuid();
+	const uid_t euid = geteuid();
+
+	if (ruid == 0 && euid != 0) {
+		/* user is root, but setuid to non-root */
+		if (option)
+			errx(EX_USAGE, _("only root can use \"--%s\" option "
+					 "(effective UID is %u)"),
+					option, euid);
+		errx(EX_USAGE, _("only root can do that "
+				 "(effective UID is %u)"), euid);
+	}
+	if (option)
+		errx(EX_USAGE, _("only root can use \"--%s\" option"), option);
+	errx(EX_USAGE, _("only root can do that"));
+}
+
+static void __attribute__((__noreturn__)) print_version(void)
+{
+	const char *ver = NULL;
+
+	mnt_get_library_version(&ver);
+
+	printf("%s from %s (libmount %s)\n",
+			program_invocation_short_name, PACKAGE_STRING, ver);
+	exit(EX_SUCCESS);
+}
+
+static const char *opt_to_longopt(int c, const struct option *opts)
+{
+	const struct option *o;
+
+	for (o = opts; o->name; o++)
+		if (o->val == c)
+			return o->name;
+	return NULL;
+}
+
+static int print_all(mnt_context *cxt, char *pattern, int show_label)
+{
+	int rc = 0;
+	mnt_tab *tb;
+	mnt_iter *itr;
+	mnt_fs *fs;
+	mnt_cache *cache = NULL;
+
+	rc = mnt_context_get_mtab(cxt, &tb);
+	if (rc)
+		goto done;
+
+	itr = mnt_new_iter(MNT_ITER_FORWARD);
+	if (!itr)
+		goto done;
+
+	if (show_label)
+		cache = mnt_new_cache();
+
+	while(mnt_tab_next_fs(tb, itr, &fs) == 0) {
+		const char *type = mnt_fs_get_fstype(fs);
+		const char *src = mnt_fs_get_source(fs);
+		char *optstr = mnt_fs_strdup_options(fs);
+
+		if (type && pattern && !mnt_match_fstype(type, pattern))
+			continue;
+
+		/* TODO: print loop backing file instead of device name */
+
+		printf ("%s on %s", src ? : "none", mnt_fs_get_target(fs));
+		if (type)
+			printf (" type %s", type);
+		if (optstr)
+			printf (" (%s)", optstr);
+		if (show_label && src) {
+			char *lb = mnt_cache_find_tag_value(cache, src, "LABEL");
+			if (lb)
+				printf (" [%s]", lb);
+		}
+		fputc('\n', stdout);
+	}
+done:
+	mnt_free_cache(cache);
+	return rc;
+}
+
+static void __attribute__((__noreturn__)) usage(FILE *out)
+{
+	fprintf(out, _("Usage:\n"
+		" %1$s [-lhV]\n"
+		" %1$s -a [options]\n"
+		" %1$s [options] <source> | <directory>\n"
+		" %1$s [options] <source> <directory>\n"
+		" %1$s <operation> <mountpoint> [<target>]\n"),
+		program_invocation_short_name);
+
+	fprintf(out, _(
+	"\nOptions:\n"
+	" -a, --all               mount all filesystems mentioned in fstab\n"
+	" -f, --fake              dry run, skip mount(2) syscall\n"
+	" -F, --fork              fork off for each device (use with -a)\n"
+	" -h, --help              this help\n"
+	" -n, --no-mtab           don't write to /etc/mtab\n"
+	" -r, --read-only         mount the filesystem read-only (same as -o ro)\n"
+	" -v, --verbose           verbose mode\n"
+	" -V, --version           print version string\n"
+	" -w, --read-write        mount the filesystem read-write (default)\n"
+	" -o, --options <list>    comma separated string of mount options\n"
+	" -O, --test-opts <list>  limit the set of filesystems (use with -a)\n"
+	" -t, --types <list>      indicate the filesystem type\n"
+	" -c, --no-canonicalize   don't canonicalize paths\n"
+	" -i, --internal-only     don't call the mount.<type> helpers\n"
+	" -l, --show-labels       lists all mounts with LABELs\n"
+
+	"\nSource:\n"
+	" -L, --label <label>     synonym for LABEL=<label>\n"
+	" -U, --uuid <uuid>       synonym for UUID=<uuid>\n"
+	" LABEL=<label>           specifies device by filesystem label\n"
+	" UUID=<uuid>             specifies device by filesystem UUID\n"
+	" <device>                specifies device by path\n"
+	" <directory>             mountpoint for bind mounts (see --bind/rbind)\n"
+	" <file>                  regular file for loopdev setup\n"
+
+	"\nOperations:\n"
+	" -B, --bind              mount a subtree somewhere else (same as -o bind)\n"
+	" -M, --move              move a subtree to some other place\n"
+	" -R, --rbind             mount a subtree and all submounts somewhere else\n"
+	" --make-shared           mark a subtree as shared\n"
+	" --make-slave            mark a subtree as slave\n"
+	" --make-private          mark a subtree as private\n"
+	" --make-unbindable       mark a subtree as unbindable\n"
+	" --make-rshared          recursively mark a whole subtree as shared\n"
+	" --make-rslave           recursively mark a whole subtree as slave\n"
+	" --make-rprivate         recursively mark a whole subtree as private\n"
+	" --make-runbindable      recursively mark a whole subtree as unbindable\n"
+	));
+
+	fprintf(out, _("\nFor more information see mount(8).\n"));
+
+	exit(out == stderr ? EX_USAGE : EX_SUCCESS);
+}
+
+int main(int argc, char **argv)
+{
+	int c, rc = EXIT_FAILURE, all = 0, show_labels = 0;
+	mnt_context *cxt;
+	char *source = NULL, *srcbuf = NULL;
+	char *types = NULL;
+	unsigned long oper = 0;
+
+	struct option longopts[] = {
+		{ "all", 0, 0, 'a' },
+		{ "fake", 0, 0, 'f' },
+		{ "fork", 0, 0, 'F' },
+		{ "help", 0, 0, 'h' },
+		{ "no-mtab", 0, 0, 'n' },
+		{ "read-only", 0, 0, 'r' },
+		{ "ro", 0, 0, 'r' },
+		{ "verbose", 0, 0, 'v' },
+		{ "version", 0, 0, 'V' },
+		{ "read-write", 0, 0, 'w' },
+		{ "rw", 0, 0, 'w' },
+		{ "options", 1, 0, 'o' },
+		{ "test-opts", 1, 0, 'O' },
+		{ "types", 1, 0, 't' },
+		{ "uuid", 1, 0, 'U' },
+		{ "label", 1, 0, 'L'},
+		{ "bind", 0, 0, 'B' },
+		{ "move", 0, 0, 'M' },
+		{ "rbind", 0, 0, 'R' },
+		{ "make-shared", 0, 0, 136 },
+		{ "make-slave", 0, 0, 137 },
+		{ "make-private", 0, 0, 138 },
+		{ "make-unbindable", 0, 0, 139 },
+		{ "make-rshared", 0, 0, 140 },
+		{ "make-rslave", 0, 0, 141 },
+		{ "make-rprivate", 0, 0, 142 },
+		{ "make-runbindable", 0, 0, 143 },
+		{ "no-canonicalize", 0, 0, 'c' },
+		{ "internal-only", 0, 0, 'i' },
+		{ "show-labels", 0, 0, 'l' },
+		{ NULL, 0, 0, 0 }
+	};
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+
+	mnt_init_debug(0);
+	cxt = mnt_new_context();
+	if (!cxt)
+		err(EX_SYSERR, _("libmount context allocation failed"));
+
+	while ((c = getopt_long(argc, argv, "aBcfFhilL:Mno:O:rRsU:vVwt:",
+					longopts, NULL)) != -1) {
+
+		/* only few options are allowed for non-root users */
+		if (mnt_context_is_restricted(cxt) && !strchr("hlLUVv", c))
+			exit_non_root(opt_to_longopt(c, longopts));
+
+		switch(c) {
+		case 'a':
+			all = 1;
+			err(EX_FAIL, "-a not implemented yet");	/* TODO */
+			break;
+		case 'c':
+			mnt_context_disable_canonicalize(cxt, TRUE);
+			break;
+		case 'f':
+			mnt_context_enable_fake(cxt, TRUE);
+			break;
+		case 'F':
+			err(EX_FAIL, "-F not implemented yet");	/* TODO */
+			break;
+		case 'h':
+			usage(stdout);
+			break;
+		case 'i':
+			mnt_context_disable_helpers(cxt, TRUE);
+			break;
+		case 'n':
+			mnt_context_disable_mtab(cxt, TRUE);
+			break;
+		case 'r':
+			if (mnt_context_append_options(cxt, "ro"))
+				err(EX_SYSERR, _("failed to append options"));
+			break;
+		case 'v':
+			mnt_context_enable_verbose(cxt, TRUE);
+			break;
+		case 'V':
+			print_version();
+			break;
+		case 'w':
+			if (mnt_context_append_options(cxt, "rw"))
+				err(EX_SYSERR, _("failed to append options"));
+			break;
+		case 'o':
+			if (mnt_context_append_options(cxt, optarg))
+				err(EX_SYSERR, _("failed to append options"));
+			break;
+		case 'O':
+			if (mnt_context_set_options_pattern(cxt, optarg))
+				err(EX_SYSERR, _("failed to set options pattern"));
+			break;
+		case 'L':
+		case 'U':
+			if (source)
+				errx(EX_USAGE, _("only one <source> could be specified"));
+			if (asprintf(&srcbuf, "%s=\"%s\"",
+				     c == 'L' ? "LABEL" : "UUID", optarg) <= 0)
+				err(EX_SYSERR, _("failed to allocate source buffer"));
+			source = srcbuf;
+			break;
+		case 'l':
+			show_labels = 1;
+			break;
+		case 't':
+			types = optarg;
+			break;
+		case 's':
+			mnt_context_enable_sloppy(cxt, TRUE);
+			break;
+		case 'B':
+			oper = MS_BIND;
+			break;
+		case 'M':
+			oper = MS_MOVE;
+			break;
+		case 'R':
+			oper = (MS_BIND | MS_REC);
+			break;
+		case 136:
+			oper = MS_SHARED;
+			break;
+		case 137:
+			oper = MS_SLAVE;
+			break;
+		case 138:
+			oper = MS_PRIVATE;
+			break;
+		case 139:
+			oper = MS_UNBINDABLE;
+			break;
+		case 140:
+			oper = (MS_SHARED | MS_REC);
+			break;
+		case 141:
+			oper = (MS_SLAVE | MS_REC);
+			break;
+		case 142:
+			oper = (MS_PRIVATE | MS_REC);
+			break;
+		case 143:
+			oper = (MS_UNBINDABLE | MS_REC);
+			break;
+		default:
+			usage(stderr);
+			break;
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (!source && !argc && !all) {
+		if (oper)
+			usage(stderr);
+		if (!print_all(cxt, types, show_labels))
+			rc = EX_SUCCESS;
+		goto done;
+	}
+
+	if (oper && (types || all || source))
+		usage(stderr);
+
+	if (types && (strchr(types, ',') || strncmp(types, "no", 2) == 0))
+		mnt_context_set_fstype_pattern(cxt, types);
+	else if (types)
+		mnt_context_set_fstype(cxt, types);
+
+	if (argc == 0 && source) {
+		/* mount -L|-U */
+		mnt_context_set_source(cxt, source);
+
+	} else if (argc == 1) {
+		/* mount [-L|-U] <target>
+		 * mount <source|target> */
+		if (source) {
+			if (mnt_context_is_restricted(cxt))
+				exit_non_root(NULL);
+			 mnt_context_set_source(cxt, source);
+		}
+		mnt_context_set_target(cxt, argv[0]);
+
+	} else if (argc == 2 && !source) {
+		/* mount <source> <target> */
+		if (mnt_context_is_restricted(cxt))
+			exit_non_root(NULL);
+		mnt_context_set_source(cxt, argv[0]);
+		mnt_context_set_target(cxt, argv[1]);
+	} else
+		usage(stderr);
+
+	if (oper)
+		mnt_context_set_mountflags(cxt, oper);
+
+	lock = mnt_context_get_lock(cxt);
+	if (lock)
+		atexit(lock_atexit_cleanup);
+
+	rc = mnt_context_do_mount(cxt);
+	if (rc) {
+		/* TODO: call mnt_context_strerror() */
+		rc = EX_FAIL;
+	} else
+		rc = EX_SUCCESS;
+done:
+	free(srcbuf);
+	mnt_free_context(cxt);
+	return rc;
+}
+