storage: constify where possible

This was made necessary by changes to the overlay driver.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Adrian Reber <areber@redhat.com>

src/lxc/conf.c

@@ -2735,7 +2735,7 @@ int chown_mapped_root_exec_wrapper(void *args)
  * root is privileged with respect to hostuid/hostgid X, allowing
  * him to do the chown.
  */
-int chown_mapped_root(char *path, struct lxc_conf *conf)
+int chown_mapped_root(const char *path, struct lxc_conf *conf)
 {
 	uid_t rootuid, rootgid;
 	unsigned long val;
@@ -2743,14 +2743,14 @@ int chown_mapped_root(char *path, struct lxc_conf *conf)
 	struct stat sb;
 	char map1[100], map2[100], map3[100], map4[100], map5[100];
 	char ugid[100];
-	char *args1[] = {"lxc-usernsexec",
+	const char *args1[] = {"lxc-usernsexec",
 			 "-m", map1,
 			 "-m", map2,
 			 "-m", map3,
 			 "-m", map5,
 			 "--", "chown", ugid, path,
 			 NULL};
-	char *args2[] = {"lxc-usernsexec",
+	const char *args2[] = {"lxc-usernsexec",
 			 "-m", map1,
 			 "-m", map2,
 			 "-m", map3,

src/lxc/conf.h

@@ -396,7 +396,7 @@ extern int setup_resource_limits(struct lxc_list *limits, pid_t pid);
 extern int find_unmapped_nsid(struct lxc_conf *conf, enum idtype idtype);
 extern int mapped_hostid(unsigned id, struct lxc_conf *conf,
 			 enum idtype idtype);
-extern int chown_mapped_root(char *path, struct lxc_conf *conf);
+extern int chown_mapped_root(const char *path, struct lxc_conf *conf);
 extern int lxc_ttys_shift_ids(struct lxc_conf *c);
 extern int userns_exec_1(struct lxc_conf *conf, int (*fn)(void *), void *data,
 			 const char *fn_name);

src/lxc/lxccontainer.c

@@ -1315,7 +1315,7 @@ static bool create_run_template(struct lxc_container *c, char *tpath, bool need_
 				}
 			}
 		} else { /* TODO come up with a better way here! */
-			char *src;
+			const char *src;
 			free(bdev->dest);
 			src = lxc_storage_get_path(bdev->src, bdev->type);
 			bdev->dest = strdup(src);

src/lxc/storage/btrfs.c

@@ -187,7 +187,8 @@ bool btrfs_detect(const char *path)
 int btrfs_mount(struct lxc_storage *bdev)
 {
 	unsigned long mntflags;
-	char *mntdata, *src;
+	char *mntdata;
+	const char *src;
 	int ret;
 
 	if (strcmp(bdev->type, "btrfs"))
@@ -348,7 +349,7 @@ out:
 
 int btrfs_snapshot_wrapper(void *data)
 {
-	char *src;
+	const char *src;
 	struct rsync_data_char *arg = data;
 
 	if (setgid(0) < 0) {
@@ -372,7 +373,7 @@ int btrfs_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 		     const char *oldpath, const char *lxcpath, int snap,
 		     uint64_t newsize, struct lxc_conf *conf)
 {
-	char *src;
+	const char *src;
 
 	if (!orig->dest || !orig->src)
 		return -1;
@@ -821,7 +822,7 @@ bool btrfs_try_remove_subvol(const char *path)
 
 int btrfs_destroy(struct lxc_storage *orig)
 {
-	char *src;
+	const char *src;
 
 	src = lxc_storage_get_path(orig->src, "btrfs");
 

src/lxc/storage/dir.c

@@ -39,7 +39,7 @@ int dir_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 		   const char *lxcpath, int snap, uint64_t newsize,
 		   struct lxc_conf *conf)
 {
-	char *src_no_prefix;
+	const char *src_no_prefix;
 	int ret;
 	size_t len;
 
@@ -121,7 +121,7 @@ int dir_create(struct lxc_storage *bdev, const char *dest, const char *n,
 int dir_destroy(struct lxc_storage *orig)
 {
 	int ret;
-	char *src;
+	const char *src;
 
 	src = lxc_storage_get_path(orig->src, orig->src);
 
@@ -149,7 +149,8 @@ int dir_mount(struct lxc_storage *bdev)
 {
 	int ret;
 	unsigned long mflags, mntflags;
-	char *src, *mntdata;
+	char *mntdata;
+	const char *src;
 
 	if (strcmp(bdev->type, "dir"))
 		return -22;

src/lxc/storage/loop.c

@@ -235,7 +235,7 @@ int loop_mount(struct lxc_storage *bdev)
 {
 	int ret, loopfd;
 	char loname[MAXPATHLEN];
-	char *src;
+	const char *src;
 
 	if (strcmp(bdev->type, "loop"))
 		return -22;

src/lxc/storage/lvm.c

@@ -235,7 +235,7 @@ bool lvm_detect(const char *path)
 
 int lvm_mount(struct lxc_storage *bdev)
 {
-	char *src;
+	const char *src;
 
 	if (strcmp(bdev->type, "lvm"))
 		return -22;
@@ -330,11 +330,12 @@ static int lvm_snapshot_create_new_uuid_wrapper(void *data)
 static int lvm_snapshot(struct lxc_storage *orig, const char *path, uint64_t size)
 {
 	int ret;
-	char *origsrc, *pathdup, *lv;
+	char *lv, *pathdup;
 	char sz[24];
 	char fstype[100];
 	char cmd_output[MAXPATHLEN];
 	char repairchar;
+	const char *origsrc;
 	struct lvcreate_args cmd_args = {0};
 
 	ret = snprintf(sz, 24, "%" PRIu64 "b", size);
@@ -433,7 +434,8 @@ int lvm_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 		    (const char *[]){"lvm:", "dev", vg, cname, NULL},
 		    false);
 	} else {
-		char *dup, *slider, *src;
+		const char *src;
+		char *dup, *slider;
 
 		src = lxc_storage_get_path(orig->src, orig->type);
 
@@ -497,11 +499,11 @@ int lvm_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 bool lvm_create_clone(struct lxc_conf *conf, struct lxc_storage *orig,
 		      struct lxc_storage *new, uint64_t newsize)
 {
-	char *src;
-	const char *thinpool;
 	int ret;
+	const char *src;
+	const char *thinpool;
 	struct rsync_data data;
-	char *cmd_args[2];
+	const char *cmd_args[2];
 	char cmd_output[MAXPATHLEN] = {0};
 	char fstype[100] = "ext4";
 	uint64_t size = newsize;
@@ -560,7 +562,7 @@ bool lvm_create_snapshot(struct lxc_conf *conf, struct lxc_storage *orig,
 			 struct lxc_storage *new, uint64_t newsize)
 {
 	int ret;
-	char *newsrc;
+	const char *newsrc;
 	uint64_t size = newsize;
 
 	if (is_blktype(orig)) {

src/lxc/storage/nbd.c

@@ -118,7 +118,7 @@ bool nbd_detect(const char *path)
 int nbd_mount(struct lxc_storage *bdev)
 {
 	int ret = -1, partition;
-	char *src;
+	const char *src;
 	char path[50];
 
 	if (strcmp(bdev->type, "nbd"))

src/lxc/storage/overlay.c

@@ -54,7 +54,7 @@ int ovl_clonepaths(struct lxc_storage *orig, struct lxc_storage *new, const char
 		   int snap, uint64_t newsize, struct lxc_conf *conf)
 {
 	int ret;
-	char *src;
+	const char *src;
 
 	if (!snap) {
 		ERROR("The overlay storage driver can only be used for "
@@ -683,14 +683,14 @@ int ovl_umount(struct lxc_storage *bdev)
 	return ret;
 }
 
-char *ovl_get_lower(const char *rootfs_path)
+const char *ovl_get_lower(const char *rootfs_path)
 {
-	char *s1;
+	const char *s1 = rootfs_path;
 
-	s1 = strstr(rootfs_path, ":/");
+	if (strncmp(rootfs_path, "overlay:", 8) == 0)
-	if (!s1)
+		s1 += 8;
-		return NULL;
+	else if (strncmp(rootfs_path, "overlayfs:", 10) == 0)
-	s1++;
+		s1 += 10;
 
 	s1 = strstr(s1, ":/");
 	if (!s1)
@@ -714,16 +714,20 @@ char *ovl_get_rootfs(const char *rootfs_path, size_t *rootfslen)
 	if (!s1)
 		return NULL;
 
-	s2 = strstr(s1, ":/");
+	s2 = s1;
-	if (s2) {
+	if (strncmp(rootfs_path, "overlay:", 8) == 0)
-		s2 = s2 + 1;
+		s2 += 8;
-		if ((s3 = strstr(s2, ":/")))
+	else if (strncmp(rootfs_path, "overlayfs:", 10) == 0)
-			*s3 = '\0';
+		s2 += 10;
-		rootfsdir = strdup(s2);
+
-		if (!rootfsdir) {
+	s3 = strstr(s2, ":/");
-			free(s1);
+	if (s3)
-			return NULL;
+		*s3 = '\0';
-		}
+
+	rootfsdir = strdup(s2);
+	if (!rootfsdir) {
+		free(s1);
+		return NULL;
 	}
 
 	if (!rootfsdir)

src/lxc/storage/overlay.h

@@ -66,7 +66,7 @@ extern int ovl_update_abs_paths(struct lxc_conf *lxc_conf, const char *lxc_path,
 /* To be called from functions in lxccontainer.c: Get lower directory for
  * overlay rootfs.
  */
-extern char *ovl_get_lower(const char *rootfs_path);
+extern const char *ovl_get_lower(const char *rootfs_path);
 
 /* Get rootfs path for overlay backed containers. Allocated memory must be freed
  * by caller.

src/lxc/storage/rbd.c

@@ -189,7 +189,7 @@ int rbd_create(struct lxc_storage *bdev, const char *dest, const char *n,
 int rbd_destroy(struct lxc_storage *orig)
 {
 	int ret;
-	char *src;
+	const char *src;
 	char *rbdfullname;
 	char cmd_output[MAXPATHLEN];
 	struct rbd_args args = {0};
@@ -233,7 +233,7 @@ bool rbd_detect(const char *path)
 
 int rbd_mount(struct lxc_storage *bdev)
 {
-	char *src;
+	const char *src;
 
 	if (strcmp(bdev->type, "rbd"))
 		return -22;

src/lxc/storage/rsync.c

@@ -86,7 +86,7 @@ int lxc_rsync_exec(const char *src, const char *dest)
 int lxc_rsync(struct rsync_data *data)
 {
 	int ret;
-	char *dest, *src;
+	const char *dest, *src;
 	struct lxc_storage *orig = data->orig, *new = data->new;
 
 	ret = unshare(CLONE_NEWNS);

src/lxc/storage/storage.c

@@ -338,7 +338,7 @@ struct lxc_storage *storage_copy(struct lxc_container *c, const char *cname,
 				 uint64_t newsize, bool *needs_rdep)
 {
 	int ret;
-	char *src_no_prefix;
+	const char *src_no_prefix;
 	struct lxc_storage *new, *orig;
 	bool snap = (flags & LXC_CLONE_SNAPSHOT);
 	bool maybe_snap = (flags & LXC_CLONE_MAYBE_SNAPSHOT);
@@ -718,7 +718,7 @@ bool rootfs_is_blockdev(struct lxc_conf *conf)
 	return false;
 }
 
-char *lxc_storage_get_path(char *src, const char *prefix)
+const char *lxc_storage_get_path(char *src, const char *prefix)
 {
 	size_t prefix_len;
 

src/lxc/storage/storage.h

@@ -137,6 +137,6 @@ extern struct lxc_storage *storage_create(const char *dest, const char *type,
 extern void storage_put(struct lxc_storage *bdev);
 extern bool storage_destroy(struct lxc_conf *conf);
 extern bool rootfs_is_blockdev(struct lxc_conf *conf);
-extern char *lxc_storage_get_path(char *src, const char *prefix);
+extern const char *lxc_storage_get_path(char *src, const char *prefix);
 
 #endif /* #define __LXC_STORAGE_H */

src/lxc/storage/storage_utils.c

@@ -133,7 +133,7 @@ bool attach_block_device(struct lxc_conf *conf)
 int blk_getsize(struct lxc_storage *bdev, uint64_t *size)
 {
 	int fd, ret;
-	char *src;
+	const char *src;
 
 	src = lxc_storage_get_path(bdev->src, bdev->type);
 	fd = open(src, O_RDONLY);
@@ -162,11 +162,15 @@ void detach_block_device(struct lxc_conf *conf)
  */
 int detect_fs(struct lxc_storage *bdev, char *type, int len)
 {
-	int p[2], ret;
+	int ret;
+	int p[2];
 	size_t linelen;
 	pid_t pid;
 	FILE *f;
-	char *sp1, *sp2, *sp3, *srcdev, *line = NULL;
+	char *sp1, *sp2, *sp3;
+	const char *l, *srcdev;
+	char devpath[MAXPATHLEN];
+	char *line = NULL;
 
 	if (!bdev || !bdev->src || !bdev->dest)
 		return -1;
@@ -218,9 +222,7 @@ int detect_fs(struct lxc_storage *bdev, char *type, int len)
 		exit(1);
 	}
 
-	/* if symlink, get the real dev name */
+	l = linkderef(srcdev, devpath);
-	char devpath[MAXPATHLEN];
-	char *l = linkderef(srcdev, devpath);
 	if (!l)
 		exit(1);
 	f = fopen("/proc/self/mounts", "r");
@@ -383,7 +385,7 @@ int find_fstype_cb(char *buffer, void *data)
 	return 1;
 }
 
-char *linkderef(char *path, char *dest)
+const char *linkderef(const char *path, char *dest)
 {
 	struct stat sbuf;
 	ssize_t ret;

src/lxc/storage/storage_utils.h

@@ -45,7 +45,7 @@ extern int is_blktype(struct lxc_storage *b);
 extern int mount_unknown_fs(const char *rootfs, const char *target,
 			    const char *options);
 extern int find_fstype_cb(char *buffer, void *data);
-extern char *linkderef(char *path, char *dest);
+extern const char *linkderef(const char *path, char *dest);
 extern bool unpriv_snap_allowed(struct lxc_storage *b, const char *t, bool snap,
 				bool maybesnap);
 extern bool is_valid_storage_type(const char *type);

src/lxc/storage/zfs.c

@@ -180,7 +180,8 @@ int zfs_mount(struct lxc_storage *bdev)
 {
 	int ret;
 	size_t oldlen, newlen, totallen;
-	char *mntdata, *src, *tmp;
+	char *mntdata, *tmp;
+	const char *src;
 	unsigned long mntflags;
 	char cmd_output[MAXPATHLEN] = {0};
 
@@ -287,13 +288,13 @@ bool zfs_copy(struct lxc_conf *conf, struct lxc_storage *orig,
 	char cmd_output[MAXPATHLEN], option[MAXPATHLEN];
 	struct rsync_data data = {0, 0};
 	struct zfs_args cmd_args = {0};
-	char *argv[] = {"zfs",			     /* 0    */
+	const char *argv[] = {"zfs",			   /* 0    */
-			"create",		     /* 1    */
+			      "create",			   /* 1    */
-			"-o",     "",		     /* 2, 3 */
+			      "-o",     "",		   /* 2, 3 */
-			"-o",     "canmount=noauto", /* 4, 5 */
+			      "-o",     "canmount=noauto", /* 4, 5 */
-			"-p",			     /* 6    */
+			      "-p",			   /* 6    */
-			"",			     /* 7    */
+			      "",			   /* 7    */
-			NULL};
+			      NULL};
 
 	/* mountpoint */
 	ret = snprintf(option, MAXPATHLEN, "mountpoint=%s", new->dest);
@@ -342,7 +343,8 @@ bool zfs_snapshot(struct lxc_conf *conf, struct lxc_storage *orig,
 {
 	int ret;
 	size_t snapshot_len, len;
-	char *orig_src, *tmp, *snap_name, *snapshot;
+	char *tmp, *snap_name, *snapshot;
+	const char *orig_src;
 	struct zfs_args cmd_args = {0};
 	char cmd_output[MAXPATHLEN] = {0}, option[MAXPATHLEN];
 
@@ -447,8 +449,9 @@ int zfs_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 		   const char *lxcpath, int snap, uint64_t newsize,
 		   struct lxc_conf *conf)
 {
-	char *dataset, *orig_src, *tmp;
 	int ret;
+	char *dataset, *tmp;
+	const char *orig_src;
 	size_t dataset_len, len;
 	char cmd_output[MAXPATHLEN] = {0};
 
@@ -576,7 +579,8 @@ int zfs_clonepaths(struct lxc_storage *orig, struct lxc_storage *new,
 int zfs_destroy(struct lxc_storage *orig)
 {
 	int ret;
-	char *dataset, *src, *tmp;
+	char *dataset, *tmp;
+	const char *src;
 	bool found;
 	char *parent_snapshot = NULL;
 	struct zfs_args cmd_args = {0};
@@ -709,13 +713,13 @@ int zfs_create(struct lxc_storage *bdev, const char *dest, const char *n,
 	size_t len;
 	struct zfs_args cmd_args = {0};
 	char cmd_output[MAXPATHLEN], option[MAXPATHLEN];
-	char *argv[] = {"zfs",                    /* 0    */
+	const char *argv[] = {"zfs",			   /* 0    */
-			 "create",                /* 1    */
+			      "create",			   /* 1    */
-			 "-o", "",                /* 2, 3 */
+			      "-o",     "",		   /* 2, 3 */
-			 "-o", "canmount=noauto", /* 4, 5 */
+			      "-o",     "canmount=noauto", /* 4, 5 */
-			 "-p",                    /* 6    */
+			      "-p",			   /* 6    */
-			 "",                      /* 7    */
+			      "",			   /* 7    */
-			 NULL};
+			      NULL};
 
 	if (!specs || !specs->zfs.zfsroot)
 		zfsroot = lxc_global_config_value("lxc.bdev.zfs.root");

src/lxc/utils.c

@@ -65,7 +65,7 @@ lxc_log_define(lxc_utils, lxc);
  */
 extern bool btrfs_try_remove_subvol(const char *path);
 
-static int _recursive_rmdir(char *dirname, dev_t pdev,
+static int _recursive_rmdir(const char *dirname, dev_t pdev,
 			    const char *exclude, int level, bool onedev)
 {
 	struct dirent *direntp;
@@ -180,18 +180,18 @@ static bool is_native_overlayfs(const char *path)
 }
 
 /* returns 0 on success, -1 if there were any failures */
-extern int lxc_rmdir_onedev(char *path, const char *exclude)
+extern int lxc_rmdir_onedev(const char *path, const char *exclude)
 {
 	struct stat mystat;
 	bool onedev = true;
 
-	if (is_native_overlayfs(path)) {
+	if (is_native_overlayfs(path))
 		onedev = false;
-	}
 
 	if (lstat(path, &mystat) < 0) {
 		if (errno == ENOENT)
 			return 0;
+
 		ERROR("Failed to stat %s", path);
 		return -1;
 	}

src/lxc/utils.h

@@ -93,7 +93,7 @@
 #define LXC_IDMAPLEN 4096
 
 /* returns 1 on success, 0 if there were any failures */
-extern int lxc_rmdir_onedev(char *path, const char *exclude);
+extern int lxc_rmdir_onedev(const char *path, const char *exclude);
 extern int get_u16(unsigned short *val, const char *arg, int base);
 extern int mkdir_p(const char *dir, mode_t mode);
 extern char *get_rundir(void);