From f266297dbbc4a0278ca993946656fb664a674336 Mon Sep 17 00:00:00 2001
From: tanyifeng <tanyifeng1@huawei.com>
Date: Mon, 14 Jan 2019 17:02:02 +0800
Subject: [PATCH 022/131] support rootfs mount propagation

Signed-off-by: LiFeng <lifeng68@huawei.com>
---
 src/lxc/conf.c                  | 230 +++++++++++++++++++++-----------
 src/lxc/conf.h                  |   2 +-
 src/lxc/confile.c               |   8 +-
 src/lxc/criu.c                  |   4 +-
 src/lxc/storage/btrfs.c         |   4 +-
 src/lxc/storage/dir.c           |   9 +-
 src/lxc/storage/overlay.c       |   4 +-
 src/lxc/storage/storage_utils.c |   4 +-
 src/lxc/storage/zfs.c           |   4 +-
 9 files changed, 165 insertions(+), 104 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 8d8230fb..55d1e453 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1296,11 +1296,102 @@ static int lxc_fill_autodev(const struct lxc_rootfs *rootfs)
 	return 0;
 }
 
+static void null_endofword(char *word)
+{
+	while (*word && *word != ' ' && *word != '\t')
+		word++;
+	*word = '\0';
+}
+
+/* skip @nfields spaces in @src */
+static char *get_field(char *src, int nfields)
+{
+	int i;
+	char *p = src;
+
+	for (i = 0; i < nfields; i++) {
+		while (*p && *p != ' ' && *p != '\t')
+			p++;
+
+		if (!*p)
+			break;
+
+		p++;
+	}
+
+	return p;
+}
+
+static int rootfs_parent_mount_private(char *rootfs)
+{
+	/* walk /proc/self/mountinfo and change parent of rootfs to private */
+	FILE *f = fopen("/proc/self/mountinfo", "r");
+	char *line = NULL;
+	char *parent = NULL, *options = NULL;
+	size_t len = 0;
+	int ret = 0;
+
+	if (!f) {
+		SYSERROR("Failed to open /proc/self/mountinfo to make parent of rootfs to private");
+		return -1;
+	}
+
+	while (getline(&line, &len, f) != -1) {
+		char *target, *opts, *tmptarget;
+		target = get_field(line, 4);
+		if (!target)
+			continue;
+		tmptarget = strdup(target);
+		if (!tmptarget)
+			continue;
+		null_endofword(tmptarget);
+		if (!strstr(rootfs, tmptarget)) {
+			free(tmptarget);
+			continue;
+		}
+		if (!parent || strlen(tmptarget) > strlen(parent)) {
+			free(parent);
+			parent = tmptarget;
+		} else {
+			free(tmptarget);
+			continue;
+		}
+		opts = get_field(target, 2);
+		if (!opts)
+			continue;
+		null_endofword(opts);
+		free(options);
+		options = strdup(opts);
+		if (!options)
+			continue;
+	}
+
+	if (!parent || !options) {
+		ERROR("Could not find parent mount of %s", rootfs);
+		ret = -1;
+	} else {
+		if (strstr(options, "shared")) {
+			if (mount(NULL, parent, NULL, MS_PRIVATE, NULL)) {
+				SYSERROR("Failed to make %s private", parent);
+				ret = -1;
+			}
+			DEBUG("Mounted parent %s of rootfs %s to private", parent, rootfs);
+		}
+	}
+	free(parent);
+	free(options);
+	fclose(f);
+	free(line);
+	return ret;
+}
+
 static int lxc_mount_rootfs(struct lxc_conf *conf)
 {
 	int ret;
 	struct lxc_storage *bdev;
 	const struct lxc_rootfs *rootfs = &conf->rootfs;
+	unsigned long flags, mntflags, pflags;
+	char *mntdata;
 
 	if (!rootfs->path) {
 		ret = mount("", "/", NULL, MS_SLAVE | MS_REC, 0);
@@ -1319,6 +1410,44 @@ static int lxc_mount_rootfs(struct lxc_conf *conf)
 		return -1;
 	}
 
+	// isulad-start: support mount propagations of rootfs
+	//Get rootfs mnt propagation options, such as slave or shared
+	if (parse_mntopts(conf->rootfs.options, &mntflags, &pflags, &mntdata) < 0) {
+		free(mntdata);
+		return -1;
+	}
+	free(mntdata);
+
+	flags = MS_SLAVE | MS_REC;
+	if (pflags)
+		flags = pflags;
+
+	/* Mount propagation inside container can not greater than host.
+	* So we must change propagation of root according to flags, default is rslave.
+	* That means shared propagation inside container is disabled by default.
+	*/
+	ret = mount("", "/", NULL, flags, NULL);
+	if (ret < 0) {
+		SYSERROR("Failed to make / to propagation flags %lu.", flags);
+		return -1;
+	}
+
+	/* Make parent mount private to make sure following bind mount does
+	* not propagate in other namespaces. Also it will help with kernel
+	* check pass in pivot_root. (IS_SHARED(new_mnt->mnt_parent))
+	*/
+	ret = rootfs_parent_mount_private(conf->rootfs.mount);
+	if (ret != 0) {
+		ERROR("Failed to make parent of rootfs %s to private.", conf->rootfs.mount);
+		return -1;
+	}
+
+	ret = mount(conf->rootfs.mount, conf->rootfs.mount, "bind", MS_BIND | MS_REC, NULL);
+	if (ret < 0) {
+		SYSERROR("Failed to mount rootfs %s", conf->rootfs.mount);
+		return -1;
+	}// isulad-end: support mount propagations of rootfs
+
 	bdev = storage_init(conf);
 	if (!bdev) {
 		ERROR("Failed to mount rootfs \"%s\" onto \"%s\" with options \"%s\"",
@@ -1960,7 +2089,7 @@ static int lxc_setup_console(const struct lxc_rootfs *rootfs,
 	return lxc_setup_ttydir_console(rootfs, console, ttydir);
 }
 
-static void parse_mntopt(char *opt, unsigned long *flags, char **data, size_t size)
+static void parse_mntopt(char *opt, unsigned long *mflags, unsigned long *pflags, char **data, size_t size)
 {
 	struct mount_opt *mo;
 
@@ -1970,26 +2099,40 @@ static void parse_mntopt(char *opt, unsigned long *flags, char **data, size_t si
 	for (mo = &mount_opt[0]; mo->name != NULL; mo++) {
 		if (strncmp(opt, mo->name, strlen(mo->name)) == 0) {
 			if (mo->clear)
-				*flags &= ~mo->flag;
+				*mflags &= ~mo->flag;
 			else
-				*flags |= mo->flag;
+				*mflags |= mo->flag;
 			return;
 		}
 	}
 
+	/* If opt is found in propagation_opt, set or clear flags. */
+	for (mo = &propagation_opt[0]; mo->name != NULL; mo++) {
+		if (strncmp(opt, mo->name, strlen(mo->name)) != 0)
+			continue;
+
+		if (mo->clear)
+			*pflags &= ~mo->flag;
+		else
+			*pflags |= mo->flag;
+
+		return;
+	}
+
 	if (strlen(*data))
 		(void)strlcat(*data, ",", size);
 
 	(void)strlcat(*data, opt, size);
 }
 
-int parse_mntopts(const char *mntopts, unsigned long *mntflags, char **mntdata)
+int parse_mntopts(const char *mntopts, unsigned long *mntflags, unsigned long *pflags, char **mntdata)
 {
 	char *data, *p, *s;
 	size_t size;
 
 	*mntdata = NULL;
 	*mntflags = 0L;
+	*pflags = 0L;
 
 	if (!mntopts)
 		return 0;
@@ -2007,7 +2150,7 @@ int parse_mntopts(const char *mntopts, unsigned long *mntflags, char **mntdata)
 	*data = 0;
 
 	lxc_iterate_parts(p, s, ",")
-		parse_mntopt(p, mntflags, &data, size);
+		parse_mntopt(p, mntflags, pflags, &data, size);
 
 	if (*data)
 		*mntdata = data;
@@ -2018,71 +2161,6 @@ int parse_mntopts(const char *mntopts, unsigned long *mntflags, char **mntdata)
 	return 0;
 }
 
-static void parse_propagationopt(char *opt, unsigned long *flags)
-{
-	struct mount_opt *mo;
-
-	/* If opt is found in propagation_opt, set or clear flags. */
-	for (mo = &propagation_opt[0]; mo->name != NULL; mo++) {
-		if (strncmp(opt, mo->name, strlen(mo->name)) != 0)
-			continue;
-
-		if (mo->clear)
-			*flags &= ~mo->flag;
-		else
-			*flags |= mo->flag;
-
-		return;
-	}
-}
-
-int parse_propagationopts(const char *mntopts, unsigned long *pflags)
-{
-	char *p, *s;
-
-	if (!mntopts)
-		return 0;
-
-	s = strdup(mntopts);
-	if (!s) {
-		SYSERROR("Failed to allocate memory");
-		return -ENOMEM;
-	}
-
-	*pflags = 0L;
-	lxc_iterate_parts(p, s, ",")
-		parse_propagationopt(p, pflags);
-	free(s);
-
-	return 0;
-}
-
-static void null_endofword(char *word)
-{
-	while (*word && *word != ' ' && *word != '\t')
-		word++;
-	*word = '\0';
-}
-
-/* skip @nfields spaces in @src */
-static char *get_field(char *src, int nfields)
-{
-	int i;
-	char *p = src;
-
-	for (i = 0; i < nfields; i++) {
-		while (*p && *p != ' ' && *p != '\t')
-			p++;
-
-		if (!*p)
-			break;
-
-		p++;
-	}
-
-	return p;
-}
-
 static int mount_entry(const char *fsname, const char *target,
 		       const char *fstype, unsigned long mountflags,
 		       unsigned long pflags, const char *data, bool optional,
@@ -2289,10 +2367,9 @@ static inline int mount_entry_on_generic(struct mntent *mntent,
 					 const char *lxc_path)
 {
 	int ret;
-	unsigned long mntflags;
+	unsigned long mntflags, pflags;
 	char *mntdata;
 	bool dev, optional, relative;
-	unsigned long pflags = 0;
 	char *rootfs_path = NULL;
 
 	optional = hasmntopt(mntent, "optional") != NULL;
@@ -2312,11 +2389,7 @@ static inline int mount_entry_on_generic(struct mntent *mntent,
 	}
 	cull_mntent_opt(mntent);
 
-	ret = parse_propagationopts(mntent->mnt_opts, &pflags);
-	if (ret < 0)
-		return -1;
-
-	ret = parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata);
+	ret = parse_mntopts(mntent->mnt_opts, &mntflags, &pflags, &mntdata);
 	if (ret < 0)
 		return -1;
 
@@ -3544,7 +3617,8 @@ int lxc_setup_rootfs_prepare_root(struct lxc_conf *conf, const char *name,
 		return 0;
 	}
 
-	remount_all_slave();
+	if (!conf->rootfs.options)
+		remount_all_slave();
 
 	ret = run_lxc_hooks(name, "pre-mount", conf, NULL);
 	if (ret < 0) {
diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index db474e11..7393dbfe 100644
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -463,7 +463,7 @@ extern int userns_exec_1(struct lxc_conf *conf, int (*fn)(void *), void *data,
 extern int userns_exec_full(struct lxc_conf *conf, int (*fn)(void *),
 			    void *data, const char *fn_name);
 extern int parse_mntopts(const char *mntopts, unsigned long *mntflags,
-			 char **mntdata);
+			 unsigned long *pflags, char **mntdata);
 extern int parse_propagationopts(const char *mntopts, unsigned long *pflags);
 extern void tmp_proc_unmount(struct lxc_conf *lxc_conf);
 extern void remount_all_slave(void);
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index e1999656..db63b550 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -2065,16 +2065,10 @@ static int set_config_rootfs_options(const char *key, const char *value,
 	char *mdata = NULL, *opts = NULL;
 	struct lxc_rootfs *rootfs = &lxc_conf->rootfs;
 
-	ret = parse_mntopts(value, &mflags, &mdata);
+	ret = parse_mntopts(value, &mflags, &pflags, &mdata);
 	if (ret < 0)
 		return -EINVAL;
 
-	ret = parse_propagationopts(value, &pflags);
-	if (ret < 0) {
-		free(mdata);
-		return -EINVAL;
-	}
-
 	ret = set_config_string_item(&opts, value);
 	if (ret < 0) {
 		free(mdata);
diff --git a/src/lxc/criu.c b/src/lxc/criu.c
index 31c19407..bb97859b 100644
--- a/src/lxc/criu.c
+++ b/src/lxc/criu.c
@@ -389,9 +389,9 @@ static void exec_criu(struct cgroup_ops *cgroup_ops, struct lxc_conf *conf,
 	while (getmntent_r(mnts, &mntent, buf, sizeof(buf))) {
 		char *fmt, *key, *val, *mntdata;
 		char arg[2 * PATH_MAX + 2];
-		unsigned long flags;
+		unsigned long flags, pflags;
 
-		if (parse_mntopts(mntent.mnt_opts, &flags, &mntdata) < 0)
+		if (parse_mntopts(mntent.mnt_opts, &flags, &pflags, &mntdata) < 0)
 			goto err;
 
 		free(mntdata);
diff --git a/src/lxc/storage/btrfs.c b/src/lxc/storage/btrfs.c
index bbfce61b..a02c2150 100644
--- a/src/lxc/storage/btrfs.c
+++ b/src/lxc/storage/btrfs.c
@@ -212,7 +212,7 @@ bool btrfs_detect(const char *path)
 
 int btrfs_mount(struct lxc_storage *bdev)
 {
-	unsigned long mntflags;
+	unsigned long mntflags, pflags;
 	char *mntdata;
 	const char *src;
 	int ret;
@@ -223,7 +223,7 @@ int btrfs_mount(struct lxc_storage *bdev)
 	if (!bdev->src || !bdev->dest)
 		return -22;
 
-	if (parse_mntopts(bdev->mntopts, &mntflags, &mntdata) < 0) {
+	if (parse_mntopts(bdev->mntopts, &mntflags, &pflags, &mntdata) < 0) {
 		free(mntdata);
 		return -22;
 	}
diff --git a/src/lxc/storage/dir.c b/src/lxc/storage/dir.c
index 79b64696..c7b5ee27 100644
--- a/src/lxc/storage/dir.c
+++ b/src/lxc/storage/dir.c
@@ -170,20 +170,13 @@ int dir_mount(struct lxc_storage *bdev)
 	if (!bdev->src || !bdev->dest)
 		return -22;
 
-	ret = parse_mntopts(bdev->mntopts, &mntflags, &mntdata);
+	ret = parse_mntopts(bdev->mntopts, &mntflags, &pflags, &mntdata);
 	if (ret < 0) {
 		ERROR("Failed to parse mount options \"%s\"", bdev->mntopts);
 		free(mntdata);
 		return -EINVAL;
 	}
 
-	ret = parse_propagationopts(bdev->mntopts, &pflags);
-	if (ret < 0) {
-		ERROR("Failed to parse propagation options \"%s\"", bdev->mntopts);
-		free(mntdata);
-		return -EINVAL;
-	}
-
 	src = lxc_storage_get_path(bdev->src, bdev->type);
 
 	ret = mount(src, bdev->dest, "bind", MS_BIND | MS_REC | mntflags | pflags, mntdata);
diff --git a/src/lxc/storage/overlay.c b/src/lxc/storage/overlay.c
index 01546b1b..90408a3b 100644
--- a/src/lxc/storage/overlay.c
+++ b/src/lxc/storage/overlay.c
@@ -495,7 +495,7 @@ int ovl_mount(struct lxc_storage *bdev)
 	char *options_work, *work, *lastslash;
 	int lastslashidx;
 	size_t len, len2;
-	unsigned long mntflags;
+	unsigned long mntflags, pflags;
 	char *mntdata;
 	int ret, ret2;
 
@@ -575,7 +575,7 @@ int ovl_mount(struct lxc_storage *bdev)
 	memcpy(work + lastslashidx, "olwork", STRLITERALLEN("olwork"));
 	work[lastslashidx + STRLITERALLEN("olwork")] = '\0';
 
-	ret = parse_mntopts(bdev->mntopts, &mntflags, &mntdata);
+	ret = parse_mntopts(bdev->mntopts, &mntflags, &pflags, &mntdata);
 	if (ret < 0) {
 		ERROR("Failed to parse mount options");
 		free(mntdata);
diff --git a/src/lxc/storage/storage_utils.c b/src/lxc/storage/storage_utils.c
index fa4e7270..46e08a35 100644
--- a/src/lxc/storage/storage_utils.c
+++ b/src/lxc/storage/storage_utils.c
@@ -396,7 +396,7 @@ int find_fstype_cb(char *buffer, void *data)
 		const char *options;
 	} *cbarg = data;
 
-	unsigned long mntflags;
+	unsigned long mntflags, pflags;
 	char *mntdata;
 	char *fstype;
 
@@ -411,7 +411,7 @@ int find_fstype_cb(char *buffer, void *data)
 	DEBUG("Trying to mount \"%s\"->\"%s\" with FSType \"%s\"", cbarg->rootfs,
 	      cbarg->target, fstype);
 
-	if (parse_mntopts(cbarg->options, &mntflags, &mntdata) < 0) {
+	if (parse_mntopts(cbarg->options, &mntflags, &pflags, &mntdata) < 0) {
 		free(mntdata);
 		return 0;
 	}
diff --git a/src/lxc/storage/zfs.c b/src/lxc/storage/zfs.c
index ba104da5..752b0c50 100644
--- a/src/lxc/storage/zfs.c
+++ b/src/lxc/storage/zfs.c
@@ -184,7 +184,7 @@ int zfs_mount(struct lxc_storage *bdev)
 	size_t oldlen, newlen, totallen;
 	char *mntdata, *tmp;
 	const char *src;
-	unsigned long mntflags;
+	unsigned long mntflags, pflags;
 	char cmd_output[PATH_MAX] = {0};
 
 	if (strcmp(bdev->type, "zfs"))
@@ -193,7 +193,7 @@ int zfs_mount(struct lxc_storage *bdev)
 	if (!bdev->src || !bdev->dest)
 		return -22;
 
-	ret = parse_mntopts(bdev->mntopts, &mntflags, &mntdata);
+	ret = parse_mntopts(bdev->mntopts, &mntflags, &pflags, &mntdata);
 	if (ret < 0) {
 		ERROR("Failed to parse mount options");
 		free(mntdata);
-- 
2.23.0

