From: Daan De Meyer Date: Fri, 24 Mar 2023 16:12:24 +0000 (+0100) Subject: copy: Add COPY_LOCK_BSD X-Git-Tag: v254-rc1~166^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=01428141ba42a06d22f2c0e0df26049e700f4098;p=thirdparty%2Fsystemd.git copy: Add COPY_LOCK_BSD When making ephemeral copies of files/directories whose cleanup depends on whether they're locked or not, it's necessary to have the lock from the very beginning, so let's support that with a new COPY_LOCK_BSD flag. --- diff --git a/src/shared/copy.c b/src/shared/copy.c index 9c221785618..db26945be8e 100644 --- a/src/shared/copy.c +++ b/src/shared/copy.c @@ -167,6 +167,7 @@ int copy_bytes_full( assert(fdf >= 0); assert(fdt >= 0); + assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); /* Tries to copy bytes from the file descriptor 'fdf' to 'fdt' in the smartest possible way. Copies a maximum * of 'max_bytes', which may be specified as UINT64_MAX, in which no maximum is applied. Returns negative on @@ -931,7 +932,7 @@ static int fd_copy_directory( _cleanup_close_ int fdf = -EBADF, fdt = -EBADF; _cleanup_closedir_ DIR *d = NULL; - bool exists, created; + bool exists; int r; assert(st); @@ -961,33 +962,22 @@ static int fd_copy_directory( if (!d) return -errno; - exists = false; - if (copy_flags & COPY_MERGE_EMPTY) { - r = dir_is_empty_at(dt, to, /* ignore_hidden_or_backup= */ false); - if (r < 0 && r != -ENOENT) - return r; - else if (r == 1) - exists = true; - } + r = dir_is_empty_at(dt, to, /* ignore_hidden_or_backup= */ false); + if (r < 0 && r != -ENOENT) + return r; + if ((r > 0 && !(copy_flags & (COPY_MERGE|COPY_MERGE_EMPTY))) || (r == 0 && !FLAGS_SET(copy_flags, COPY_MERGE))) + return -EEXIST; - if (exists) - created = false; - else { - if (copy_flags & COPY_MAC_CREATE) - r = mkdirat_label(dt, to, st->st_mode & 07777); - else - r = mkdirat(dt, to, st->st_mode & 07777); - if (r >= 0) - created = true; - else if (errno == EEXIST && (copy_flags & COPY_MERGE)) - created = false; - else - return -errno; - } + exists = r >= 0; - fdt = openat(dt, to, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); + fdt = xopenat_lock(dt, to, + O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|(exists ? 0 : O_CREAT|O_EXCL), + (copy_flags & COPY_MAC_CREATE ? XO_LABEL : 0), + st->st_mode & 07777, + copy_flags & COPY_LOCK_BSD ? LOCK_BSD : LOCK_NONE, + LOCK_EX); if (fdt < 0) - return -errno; + return fdt; r = 0; @@ -1063,9 +1053,9 @@ static int fd_copy_directory( } q = fd_copy_tree_generic(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, - depth_left-1, override_uid, override_gid, copy_flags, denylist, - hardlink_context, child_display_path, progress_path, progress_bytes, - userdata); + depth_left-1, override_uid, override_gid, copy_flags & ~COPY_LOCK_BSD, + denylist, hardlink_context, child_display_path, progress_path, + progress_bytes, userdata); if (q == -EINTR) /* Propagate SIGINT/SIGTERM up instantly */ return q; @@ -1076,7 +1066,7 @@ static int fd_copy_directory( } finish: - if (created) { + if (!exists) { if (fchown(fdt, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid) < 0) @@ -1094,7 +1084,7 @@ finish: return -errno; } - return r; + return copy_flags & COPY_LOCK_BSD ? TAKE_FD(fdt) : 0; } static int fd_copy_leaf( @@ -1188,6 +1178,7 @@ int copy_tree_at_full( assert(from); assert(to); + assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); if (fstatat(fdf, from, &st, AT_SYMLINK_NOFOLLOW) < 0) return -errno; @@ -1290,6 +1281,7 @@ int copy_file_fd_at_full( assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD); assert(from); assert(fdt >= 0); + assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); fdf = openat(dir_fdf, from, O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fdf < 0) @@ -1360,17 +1352,13 @@ int copy_file_at_full( return r; WITH_UMASK(0000) { - if (copy_flags & COPY_MAC_CREATE) { - r = mac_selinux_create_file_prepare_at(dir_fdt, to, S_IFREG); - if (r < 0) - return r; - } - fdt = openat(dir_fdt, to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, - mode != MODE_INVALID ? mode : st.st_mode); - if (copy_flags & COPY_MAC_CREATE) - mac_selinux_create_file_clear(); + fdt = xopenat_lock(dir_fdt, to, + flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, + (copy_flags & COPY_MAC_CREATE ? XO_LABEL : 0), + mode != MODE_INVALID ? mode : st.st_mode, + copy_flags & COPY_LOCK_BSD ? LOCK_BSD : LOCK_NONE, LOCK_EX); if (fdt < 0) - return -errno; + return fdt; } if (!FLAGS_SET(flags, O_EXCL)) { /* if O_EXCL was used we created the thing as regular file, no need to check again */ @@ -1382,7 +1370,7 @@ int copy_file_at_full( if (chattr_mask != 0) (void) chattr_fd(fdt, chattr_flags, chattr_mask & CHATTR_EARLY_FL, NULL); - r = copy_bytes_full(fdf, fdt, UINT64_MAX, copy_flags, NULL, NULL, progress_bytes, userdata); + r = copy_bytes_full(fdf, fdt, UINT64_MAX, copy_flags & ~COPY_LOCK_BSD, NULL, NULL, progress_bytes, userdata); if (r < 0) goto fail; @@ -1399,9 +1387,11 @@ int copy_file_at_full( } } - r = close_nointr(TAKE_FD(fdt)); /* even if this fails, the fd is now invalidated */ - if (r < 0) - goto fail; + if (!FLAGS_SET(copy_flags, COPY_LOCK_BSD)) { + r = close_nointr(TAKE_FD(fdt)); /* even if this fails, the fd is now invalidated */ + if (r < 0) + goto fail; + } if (copy_flags & COPY_FSYNC_FULL) { r = fsync_parent_at(dir_fdt, to); @@ -1409,7 +1399,7 @@ int copy_file_at_full( goto fail; } - return 0; + return copy_flags & COPY_LOCK_BSD ? TAKE_FD(fdt) : 0; fail: /* Only unlink if we definitely are the ones who created the file */ @@ -1437,6 +1427,7 @@ int copy_file_atomic_at_full( assert(from); assert(to); + assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dir_fdt, to, S_IFREG); diff --git a/src/shared/copy.h b/src/shared/copy.h index da084b66f29..3bf496e42bd 100644 --- a/src/shared/copy.h +++ b/src/shared/copy.h @@ -29,6 +29,7 @@ typedef enum CopyFlags { COPY_HOLES = 1 << 14, /* Copy holes */ COPY_GRACEFUL_WARN = 1 << 15, /* Skip copying file types that aren't supported by the target filesystem */ COPY_TRUNCATE = 1 << 16, /* Truncate to current file offset after copying */ + COPY_LOCK_BSD = 1 << 17, /* Return a BSD exclusively locked file descriptor referring to the copied image/directory. */ } CopyFlags; typedef enum DenyType { diff --git a/src/test/test-copy.c b/src/test/test-copy.c index f5bcb8756f9..72aea4efb6d 100644 --- a/src/test/test-copy.c +++ b/src/test/test-copy.c @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: LGPL-2.1-or-later */ +#include #include #include @@ -435,4 +436,24 @@ TEST_RET(copy_holes) { return 0; } +TEST(copy_lock) { + _cleanup_(rm_rf_physical_and_freep) char *t = NULL; + _cleanup_close_ int tfd = -EBADF, fd = -EBADF; + + assert_se((tfd = mkdtemp_open(NULL, 0, &t)) >= 0); + assert_se(mkdirat(tfd, "abc", 0755) >= 0); + assert_se(write_string_file_at(tfd, "abc/def", "abc", WRITE_STRING_FILE_CREATE) >= 0); + + assert_se((fd = copy_directory_at(tfd, "abc", tfd, "qed", COPY_LOCK_BSD)) >= 0); + assert_se(faccessat(tfd, "qed", F_OK, 0) >= 0); + assert_se(faccessat(tfd, "qed/def", F_OK, 0) >= 0); + assert_se(xopenat_lock(tfd, "qed", 0, 0, 0, LOCK_BSD, LOCK_EX|LOCK_NB) == -EAGAIN); + fd = safe_close(fd); + + assert_se((fd = copy_file_at(tfd, "abc/def", tfd, "poi", 0, 0644, COPY_LOCK_BSD))); + assert_se(read_file_at_and_streq(tfd, "poi", "abc\n")); + assert_se(xopenat_lock(tfd, "poi", 0, 0, 0, LOCK_BSD, LOCK_EX|LOCK_NB) == -EAGAIN); + fd = safe_close(fd); +} + DEFINE_TEST_MAIN(LOG_DEBUG);