From: Alban Crequy <al...@endocode.com> renameat2() exists since Linux 3.15 but btrfs support for the flag RENAME_NOREPLACE was added later.
This patch implements a fallback when renameat2() returns EINVAL. EINVAL is the error returned when the filesystem does not support one of the flags. --- src/import/import-raw.c | 2 +- src/import/import-tar.c | 2 +- src/import/pull-raw.c | 2 +- src/import/pull-tar.c | 2 +- src/shared/copy.c | 7 ++++++- src/shared/machine-image.c | 2 +- src/shared/machine-pool.c | 2 +- src/shared/util.c | 32 ++++++++++++++++++++++++++++++++ src/shared/util.h | 2 ++ 9 files changed, 46 insertions(+), 7 deletions(-) diff --git a/src/import/import-raw.c b/src/import/import-raw.c index 15e5eb2..e354023 100644 --- a/src/import/import-raw.c +++ b/src/import/import-raw.c @@ -245,7 +245,7 @@ static int raw_import_finish(RawImport *i) { (void) rm_rf_dangerous(i->final_path, false, true, false); } - if (renameat2(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path, RENAME_NOREPLACE) < 0) + if (rename_noreplace(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path) < 0) return log_error_errno(errno, "Failed to move image into place: %m"); free(i->temp_path); diff --git a/src/import/import-tar.c b/src/import/import-tar.c index d5b6dad..dcbe721 100644 --- a/src/import/import-tar.c +++ b/src/import/import-tar.c @@ -201,7 +201,7 @@ static int tar_import_finish(TarImport *i) { (void) rm_rf_dangerous(i->final_path, false, true, false); } - if (renameat2(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path, RENAME_NOREPLACE) < 0) + if (rename_noreplace(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path) < 0) return log_error_errno(errno, "Failed to move image into place: %m"); free(i->temp_path); diff --git a/src/import/pull-raw.c b/src/import/pull-raw.c index d1d77d5..d4b17e7 100644 --- a/src/import/pull-raw.c +++ b/src/import/pull-raw.c @@ -384,7 +384,7 @@ static void raw_pull_job_on_finished(PullJob *j) { if (r < 0) goto finish; - r = renameat2(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path, RENAME_NOREPLACE); + r = rename_noreplace(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path); if (r < 0) { r = log_error_errno(errno, "Failed to move RAW file into place: %m"); goto finish; diff --git a/src/import/pull-tar.c b/src/import/pull-tar.c index 504642f..69df7af 100644 --- a/src/import/pull-tar.c +++ b/src/import/pull-tar.c @@ -281,7 +281,7 @@ static void tar_pull_job_on_finished(PullJob *j) { if (r < 0) goto finish; - if (renameat2(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path, RENAME_NOREPLACE) < 0) { + if (rename_noreplace(AT_FDCWD, i->temp_path, AT_FDCWD, i->final_path) < 0) { r = log_error_errno(errno, "Failed to rename to final image name: %m"); goto finish; } diff --git a/src/shared/copy.c b/src/shared/copy.c index 0239a58..e578d03 100644 --- a/src/shared/copy.c +++ b/src/shared/copy.c @@ -404,7 +404,12 @@ int copy_file_atomic(const char *from, const char *to, mode_t mode, bool replace if (r < 0) return r; - if (renameat2(AT_FDCWD, t, AT_FDCWD, to, replace ? 0 : RENAME_NOREPLACE) < 0) { + if (replace) { + r = renameat(AT_FDCWD, t, AT_FDCWD, to); + } else { + r = rename_noreplace(AT_FDCWD, t, AT_FDCWD, to); + } + if (r < 0) { unlink_noerrno(t); return -errno; } diff --git a/src/shared/machine-image.c b/src/shared/machine-image.c index c6d2850..ad5bff4 100644 --- a/src/shared/machine-image.c +++ b/src/shared/machine-image.c @@ -440,7 +440,7 @@ int image_rename(Image *i, const char *new_name) { if (!nn) return -ENOMEM; - if (renameat2(AT_FDCWD, i->path, AT_FDCWD, new_path, RENAME_NOREPLACE) < 0) + if (rename_noreplace(AT_FDCWD, i->path, AT_FDCWD, new_path) < 0) return -errno; /* Restore the immutable bit, if it was set before */ diff --git a/src/shared/machine-pool.c b/src/shared/machine-pool.c index e7671a3..7e902a3 100644 --- a/src/shared/machine-pool.c +++ b/src/shared/machine-pool.c @@ -140,7 +140,7 @@ static int setup_machine_raw(uint64_t size, sd_bus_error *error) { goto fail; } - if (renameat2(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw", RENAME_NOREPLACE) < 0) { + if (rename_noreplace(AT_FDCWD, tmp, AT_FDCWD, "/var/lib/machines.raw") < 0) { r = sd_bus_error_set_errnof(error, errno, "Failed to move /var/lib/machines.raw into place: %m"); goto fail; } diff --git a/src/shared/util.c b/src/shared/util.c index 74f2994..2ab7270 100644 --- a/src/shared/util.c +++ b/src/shared/util.c @@ -8118,3 +8118,35 @@ void cmsg_close_all(struct msghdr *mh) { if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int)); } + +int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) { + struct stat buf; + int ret; + + ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE); + + /* Even though renameat2() exists since Linux 3.15, btrfs added + * support for it later. If it is not implemented, fallback to another + * method. */ + if (ret == 0 || errno != EINVAL) + return ret; + + /* The link()/unlink() fallback does not work on directories. But + * renameat() without RENAME_NOREPLACE gives the same semantics on + * directories, except when newpath is an *empty* directory. This is + * good enough. */ + ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW); + if (ret == 0 && S_ISDIR(buf.st_mode)) + return renameat(olddirfd, oldpath, newdirfd, newpath); + + /* If it is not a directory, use the link()/unlink() fallback. */ + ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0); + if (ret < 0) + return ret; + + ret = unlinkat(olddirfd, oldpath, 0); + if (ret < 0) + unlinkat(newdirfd, newpath, 0); + + return ret; +} diff --git a/src/shared/util.h b/src/shared/util.h index 2de654f..45a8d37 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -1080,3 +1080,5 @@ void sigkill_wait(pid_t *pid); int syslog_parse_priority(const char **p, int *priority, bool with_facility); void cmsg_close_all(struct msghdr *mh); + +int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath); -- 2.1.4 _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel