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author | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2018-06-14 11:19:22 +0200 |
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committer | GitHub <noreply@github.com> | 2018-06-14 11:19:22 +0200 |
commit | 36ee2ececcb6c66259a44a3dbbbf6f6db545fdff (patch) | |
tree | a35e26d3aa13bc5c9ad039e12f51eaf1afe56c2a | |
parent | 0722b359342d2a9f9e0d453875624387a0ba1be2 (diff) | |
parent | ec6bdf72597937c0fb981f5b1e04bbbe15000cc5 (diff) | |
download | systemd-36ee2ececcb6c66259a44a3dbbbf6f6db545fdff.tar.gz |
Merge pull request #9199 from poettering/copy-file-atomic
make copy_file_atomic() use O_TMPFILE to create the destination file
-rw-r--r-- | TODO | 4 | ||||
-rw-r--r-- | src/basic/copy.c | 48 | ||||
-rw-r--r-- | src/basic/fileio.c | 22 | ||||
-rw-r--r-- | src/test/test-copy.c | 21 |
4 files changed, 74 insertions, 21 deletions
@@ -14,6 +14,8 @@ Janitorial Clean-ups: * Rearrange tests so that the various test-xyz.c match a specific src/basic/xyz.c again +* copy.c: set the right chattrs before copying files and others after + * rework mount.c and swap.c to follow proper state enumeration/deserialization semantics, like we do for device.c now @@ -25,8 +27,6 @@ Features: * Add OnTimezoneChange= and OnTimeChange= stanzas to .timer units in order to schedule events based on time and timezone changes. -* add O_TMPFILE support to copy_file_atomic() - * nspawn: greater control over selinux label? * cgroups: figure out if we can somehow communicate in a cleaner way whether a diff --git a/src/basic/copy.c b/src/basic/copy.c index 1921047714..2b4a481c25 100644 --- a/src/basic/copy.c +++ b/src/basic/copy.c @@ -718,31 +718,55 @@ int copy_file(const char *from, const char *to, int flags, mode_t mode, unsigned } int copy_file_atomic(const char *from, const char *to, mode_t mode, unsigned chattr_flags, CopyFlags copy_flags) { - _cleanup_free_ char *t = NULL; + _cleanup_(unlink_and_freep) char *t = NULL; + _cleanup_close_ int fdt = -1; int r; assert(from); assert(to); - r = tempfn_random(to, NULL, &t); - if (r < 0) - return r; + /* We try to use O_TMPFILE here to create the file if we can. Note that that only works if COPY_REPLACE is not + * set though as we need to use linkat() for linking the O_TMPFILE file into the file system but that system + * call can't replace existing files. Hence, if COPY_REPLACE is set we create a temporary name in the file + * system right-away and unconditionally which we then can renameat() to the right name after we completed + * writing it. */ + + if (copy_flags & COPY_REPLACE) { + r = tempfn_random(to, NULL, &t); + if (r < 0) + return r; + + fdt = open(t, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|O_WRONLY|O_CLOEXEC, 0600); + if (fdt < 0) { + t = mfree(t); + return -errno; + } + } else { + fdt = open_tmpfile_linkable(to, O_WRONLY|O_CLOEXEC, &t); + if (fdt < 0) + return fdt; + } - r = copy_file(from, t, O_NOFOLLOW|O_EXCL, mode, chattr_flags, copy_flags); + if (chattr_flags != 0) + (void) chattr_fd(fdt, chattr_flags, (unsigned) -1); + + r = copy_file_fd(from, fdt, copy_flags); if (r < 0) return r; + if (fchmod(fdt, mode) < 0) + return -errno; + if (copy_flags & COPY_REPLACE) { - r = renameat(AT_FDCWD, t, AT_FDCWD, to); + if (renameat(AT_FDCWD, t, AT_FDCWD, to) < 0) + return -errno; + } else { + r = link_tmpfile(fdt, t, to); if (r < 0) - r = -errno; - } else - r = rename_noreplace(AT_FDCWD, t, AT_FDCWD, to); - if (r < 0) { - (void) unlink(t); - return r; + return r; } + t = mfree(t); return 0; } diff --git a/src/basic/fileio.c b/src/basic/fileio.c index 5837163fed..11223d5db8 100644 --- a/src/basic/fileio.c +++ b/src/basic/fileio.c @@ -1560,21 +1560,29 @@ int read_nul_string(FILE *f, char **ret) { } int mkdtemp_malloc(const char *template, char **ret) { - char *p; + _cleanup_free_ char *p = NULL; + int r; - assert(template); assert(ret); - p = strdup(template); + if (template) + p = strdup(template); + else { + const char *tmp; + + r = tmp_dir(&tmp); + if (r < 0) + return r; + + p = strjoin(tmp, "/XXXXXX"); + } if (!p) return -ENOMEM; - if (!mkdtemp(p)) { - free(p); + if (!mkdtemp(p)) return -errno; - } - *ret = p; + *ret = TAKE_PTR(p); return 0; } diff --git a/src/test/test-copy.c b/src/test/test-copy.c index a02746c76d..dcac5f15f7 100644 --- a/src/test/test-copy.c +++ b/src/test/test-copy.c @@ -240,7 +240,27 @@ static void test_copy_bytes_regular_file(const char *src, bool try_reflink, uint unlink(fn3); } +static void test_copy_atomic(void) { + _cleanup_(rm_rf_physical_and_freep) char *p = NULL; + const char *q; + int r; + + assert_se(mkdtemp_malloc(NULL, &p) >= 0); + + q = strjoina(p, "/fstab"); + + r = copy_file_atomic("/etc/fstab", q, 0644, 0, COPY_REFLINK); + if (r == -ENOENT) + return; + + assert_se(copy_file_atomic("/etc/fstab", q, 0644, 0, COPY_REFLINK) == -EEXIST); + + assert_se(copy_file_atomic("/etc/fstab", q, 0644, 0, COPY_REPLACE) >= 0); +} + int main(int argc, char *argv[]) { + log_set_max_level(LOG_DEBUG); + test_copy_file(); test_copy_file_fd(); test_copy_tree(); @@ -251,6 +271,7 @@ int main(int argc, char *argv[]) { test_copy_bytes_regular_file(argv[0], true, 1000); test_copy_bytes_regular_file(argv[0], false, 32000); /* larger than copy buffer size */ test_copy_bytes_regular_file(argv[0], true, 32000); + test_copy_atomic(); return 0; } |