By using new ioctl (BTRFS_IOC_GET_SUBVOL_INFO), this commit allows
non-privileged user to call util_subvolume_info() as long as @id is zero
(user can only get the information of the subvolume which he can open).
Signed-off-by: Tomohiro Misono <misono.tomoh...@jp.fujitsu.com>
---
libbtrfsutil/btrfsutil.h | 7 +++++-
libbtrfsutil/errors.c | 4 ++++
libbtrfsutil/subvolume.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
index 6d655f49..5fe798c5 100644
--- a/libbtrfsutil/btrfsutil.h
+++ b/libbtrfsutil/btrfsutil.h
@@ -63,6 +63,8 @@ enum btrfs_util_error {
BTRFS_UTIL_ERROR_SYNC_FAILED,
BTRFS_UTIL_ERROR_START_SYNC_FAILED,
BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED,
+ BTRFS_UTIL_ERROR_INVALID_ARGUMENT_FOR_USER,
+ BTRFS_UTIL_ERROR_GET_SUBVOL_INFO_FAILED,
};
/**
@@ -266,7 +268,10 @@ struct btrfs_util_subvolume_info {
* to check whether the subvolume exists; %BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND
* will be returned if it does not.
*
- * This requires appropriate privilege (CAP_SYS_ADMIN).
+ * This requires appropriate privilege (CAP_SYS_ADMIN) for older kernel.
+ * For newer kernel which supports BTRFS_IOC_GET_SUGBVOL_INFO,
+ * non-privileged user with appropriate permission for @path can use this too
+ * (in that case @id must be zero).
*
* Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
*/
diff --git a/libbtrfsutil/errors.c b/libbtrfsutil/errors.c
index 634edc65..f196fa71 100644
--- a/libbtrfsutil/errors.c
+++ b/libbtrfsutil/errors.c
@@ -45,6 +45,10 @@ static const char * const error_messages[] = {
[BTRFS_UTIL_ERROR_SYNC_FAILED] = "Could not sync filesystem",
[BTRFS_UTIL_ERROR_START_SYNC_FAILED] = "Could not start filesystem
sync",
[BTRFS_UTIL_ERROR_WAIT_SYNC_FAILED] = "Could not wait for filesystem
sync",
+ [BTRFS_UTIL_ERROR_INVALID_ARGUMENT_FOR_USER] =
+ "Non-root user cannot specify subvolume id",
+ [BTRFS_UTIL_ERROR_GET_SUBVOL_INFO_FAILED] =
+ "Could not get subvolume information by BTRFS_IOC_GET_SUBVOL_INFO",
};
PUBLIC const char *btrfs_util_strerror(enum btrfs_util_error err)
diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
index 0d7ef5bf..3ce6e0a6 100644
--- a/libbtrfsutil/subvolume.c
+++ b/libbtrfsutil/subvolume.c
@@ -31,6 +31,14 @@
#include "btrfsutil_internal.h"
+static bool is_root(void)
+{
+ uid_t uid;
+
+ uid = geteuid();
+ return (uid == 0);
+}
+
/*
* This intentionally duplicates btrfs_util_is_subvolume_fd() instead of
opening
* a file descriptor and calling it, because fstat() and fstatfs() don't accept
@@ -383,11 +391,61 @@ static enum btrfs_util_error get_subvolume_info_root(int
fd, uint64_t id,
return BTRFS_UTIL_OK;
}
+static enum btrfs_util_error get_subvolume_info_user(int fd,
+ struct
btrfs_util_subvolume_info *subvol)
+{
+ struct btrfs_ioctl_get_subvol_info_args info;
+ int ret;
+
+ ret = ioctl(fd, BTRFS_IOC_GET_SUBVOL_INFO, &info);
+ if (ret < 0)
+ return BTRFS_UTIL_ERROR_GET_SUBVOL_INFO_FAILED;
+
+ subvol->id = info.id;
+ subvol->parent_id = info.parent_id;
+ subvol->dir_id = info.dirid;
+ subvol->flags = info.flags;
+ subvol->generation = info.generation;
+
+ memcpy(subvol->uuid, info.uuid, sizeof(subvol->uuid));
+ memcpy(subvol->parent_uuid, info.parent_uuid,
+ sizeof(subvol->parent_uuid));
+ memcpy(subvol->received_uuid, info.received_uuid,
+ sizeof(subvol->received_uuid));
+
+ subvol->ctransid = info.ctransid;
+ subvol->otransid = info.otransid;
+ subvol->stransid = info.stransid;
+ subvol->rtransid = info.rtransid;
+
+ subvol->ctime.tv_sec = info.ctime.sec;
+ subvol->ctime.tv_nsec = info.ctime.nsec;
+ subvol->otime.tv_sec = info.otime.sec;
+ subvol->otime.tv_nsec = info.otime.nsec;
+ subvol->stime.tv_sec = info.stime.sec;
+ subvol->stime.tv_nsec = info.stime.nsec;
+ subvol->rtime.tv_sec = info.rtime.sec;
+ subvol->rtime.tv_nsec = info.rtime.nsec;
+
+ return BTRFS_UTIL_OK;
+}
+
PUBLIC enum btrfs_util_error btrfs_util_subvolume_info_fd(int fd, uint64_t id,
struct
btrfs_util_subvolume_info *subvol)
{
enum btrfs_util_error err;
+ if (!is_root()) {
+ if (id != 0)
+ return BTRFS_UTIL_ERROR_INVALID_ARGUMENT_FOR_USER;
+
+ err = btrfs_util_is_subvolume_fd(fd);
+ if (err)
+ return err;
+
+ return get_subvolume_info_user(fd, subvol);
+ }
+
if (id == 0) {
err = btrfs_util_is_subvolume_fd(fd);
if (err)
--
2.14.3
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