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rm-rf: introduce new flag REMOVE_MISSING_OK 

This new flag suppresses error if the top-level path specified doesn't
exist. This is useful since suppressing this on the caller side isn't
easy, since ENOENT migh be propagate for some reason from further inside
and we can't distuingish that.

While we are at it, also be a bit more careful witht the various
combinations of flags.

(Note that in some cases rm_rf() was already ignoring ENOENT from
unlink() or rmdir(), however that was pretty useless, since we always
open() the top-level path with O_DIRECTORY and if that hit ENOENT we
didn't ignore the failure).
This commit is contained in:
Lennart Poettering 2019-03-29 16:13:03 +01:00
parent 6b39223cd3
commit c0228b4fa3
2 changed files with 38 additions and 24 deletions
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53
src/basic/rm-rf.c
View File

@ -161,9 +161,8 @@ int rm_rf(const char *path, RemoveFlags flags) {
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
return -EINVAL;
/* We refuse to clean the root file system with this
* call. This is extra paranoia to never cause a really
* seriously broken system. */
/* We refuse to clean the root file system with this call. This is extra paranoia to never cause a
* really seriously broken system. */
if (path_equal_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
@ -175,6 +174,9 @@ int rm_rf(const char *path, RemoveFlags flags) {
if (r >= 0)
return r;
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && r == -ENOENT)
return 0;
if (!IN_SET(r, -ENOTTY, -EINVAL, -ENOTDIR))
return r;
@ -183,34 +185,45 @@ int rm_rf(const char *path, RemoveFlags flags) {
fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (fd < 0) {
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
if (!IN_SET(errno, ENOTDIR, ELOOP))
return -errno;
if (!(flags & REMOVE_PHYSICAL)) {
if (statfs(path, &s) < 0)
return -errno;
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES))
return 0;
if (is_physical_fs(&s))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove files from a disk file system under \"%s\", refusing.",
path);
if (FLAGS_SET(flags, REMOVE_ROOT)) {
if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) {
if (statfs(path, &s) < 0)
return -errno;
if (is_physical_fs(&s))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove files from a disk file system under \"%s\", refusing.",
path);
}
if (unlink(path) < 0) {
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
return -errno;
}
}
if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
if (unlink(path) < 0 && errno != ENOENT)
return -errno;
return 0;
}
r = rm_rf_children(fd, flags, NULL);
if (flags & REMOVE_ROOT) {
if (rmdir(path) < 0) {
if (r == 0 && errno != ENOENT)
r = -errno;
}
}
if (FLAGS_SET(flags, REMOVE_ROOT) &&
rmdir(path) < 0 &&
r >= 0 &&
(!FLAGS_SET(flags, REMOVE_MISSING_OK) || errno != ENOENT))
r = -errno;
return r;
}

9
src/basic/rm-rf.h
View File

@ -6,10 +6,11 @@
#include "errno-util.h"
typedef enum RemoveFlags {
REMOVE_ONLY_DIRECTORIES = 1 << 0,
REMOVE_ROOT = 1 << 1,
REMOVE_PHYSICAL = 1 << 2, /* if not set, only removes files on tmpfs, never physical file systems */
REMOVE_SUBVOLUME = 1 << 3,
REMOVE_ONLY_DIRECTORIES = 1 << 0, /* Only remove empty directories, no files */
REMOVE_ROOT = 1 << 1, /* Remove the specified directory itself too, not just the contents of it */
REMOVE_PHYSICAL = 1 << 2, /* If not set, only removes files on tmpfs, never physical file systems */
REMOVE_SUBVOLUME = 1 << 3, /* Drop btrfs subvolumes in the tree too */
REMOVE_MISSING_OK = 1 << 4, /* If the top-level directory is missing, ignore the ENOENT for it */
} RemoveFlags;
int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev);