util: make creation time xattr logic more generic

src/journal/journal-file.c

@@ -26,7 +26,6 @@
 #include <sys/statvfs.h>
 #include <fcntl.h>
 #include <stddef.h>
-#include <sys/xattr.h>
 
 #include "journal-def.h"
 #include "journal-file.h"
@@ -2526,8 +2525,6 @@ int journal_file_open(
         }
 
         if (f->last_stat.st_size == 0 && f->writable) {
-                uint64_t crtime;
-
                 /* Let's attach the creation time to the journal file,
                  * so that the vacuuming code knows the age of this
                  * file even if the file might end up corrupted one
@@ -2538,8 +2535,7 @@ int journal_file_open(
                  * attributes are not supported we'll just skip this,
                  * and rely solely on mtime/atime/ctime of the file. */
 
-                crtime = htole64((uint64_t) now(CLOCK_REALTIME));
-                fsetxattr(f->fd, "user.crtime_usec", &crtime, sizeof(crtime), XATTR_CREATE);
+                fd_setcrtime(f->fd, now(CLOCK_REALTIME));
 
 #ifdef HAVE_GCRYPT
                 /* Try to load the FSPRG state, and if we can't, then

src/journal/journal-vacuum.c

@@ -75,9 +75,8 @@ static void patch_realtime(
                 const struct stat *st,
                 unsigned long long *realtime) {
 
-        usec_t x;
-        uint64_t crtime;
         _cleanup_free_ const char *path = NULL;
+        usec_t x, crtime;
 
         /* The timestamp was determined by the file name, but let's
          * see if the file might actually be older than the file name
@@ -112,10 +111,8 @@ static void patch_realtime(
         if (!path)
                 return;
 
-        if (getxattr(path, "user.crtime_usec", &crtime, sizeof(crtime)) == sizeof(crtime)) {
-                crtime = le64toh(crtime);
-
-                if (crtime > 0 && crtime != (uint64_t) -1 && crtime < *realtime)
+        if (path_getcrtime(path, &crtime) >= 0) {
+                if (crtime < *realtime)
                         *realtime = crtime;
         }
 }

src/shared/util.c

@@ -59,6 +59,7 @@
 #include <langinfo.h>
 #include <locale.h>
 #include <sys/personality.h>
+#include <sys/xattr.h>
 #include <libgen.h>
 #undef basename
 
@@ -84,6 +85,7 @@
 #include "gunicode.h"
 #include "virt.h"
 #include "def.h"
+#include "sparse-endian.h"
 
 int saved_argc = 0;
 char **saved_argv = NULL;
@@ -7558,3 +7560,62 @@ int openpt_in_namespace(pid_t pid, int flags) {
 
         return -EIO;
 }
+
+int fd_getcrtime(int fd, usec_t *usec) {
+        uint64_t u;
+        le64_t le;
+        ssize_t n;
+
+        assert(fd >= 0);
+        assert(usec);
+
+        /* Until Linux gets a real concept of birthtime/creation time,
+         * let's fake one with xattrs */
+
+        n = fgetxattr(fd, "user.crtime_usec", &le, sizeof(le));
+        if (n < 0)
+                return -errno;
+        if (n != sizeof(le))
+                return -EIO;
+
+        u = le64toh(le);
+        if (u == 0 || u == (uint64_t) -1)
+                return -EIO;
+
+        *usec = (usec_t) u;
+        return 0;
+}
+
+int path_getcrtime(const char *p, usec_t *usec) {
+        uint64_t u;
+        le64_t le;
+        ssize_t n;
+
+        assert(p);
+        assert(usec);
+
+        n = getxattr(p, "user.crtime_usec", &le, sizeof(le));
+        if (n < 0)
+                return -errno;
+        if (n != sizeof(le))
+                return -EIO;
+
+        u = le64toh(le);
+        if (u == 0 || u == (uint64_t) -1)
+                return -EIO;
+
+        *usec = (usec_t) u;
+        return 0;
+}
+
+int fd_setcrtime(int fd, usec_t usec) {
+        le64_t le;
+
+        assert(fd >= 0);
+
+        le = htole64((uint64_t) usec);
+        if (fsetxattr(fd, "user.crtime_usec", &le, sizeof(le), XATTR_CREATE) < 0)
+                return -errno;
+
+        return 0;
+}

src/shared/util.h

@@ -1062,3 +1062,7 @@ union inotify_event_buffer {
 int ptsname_malloc(int fd, char **ret);
 
 int openpt_in_namespace(pid_t pid, int flags);
+
+int fd_setcrtime(int fd, usec_t usec);
+int fd_getcrtime(int fd, usec_t *usec);
+int path_getcrtime(const char *p, usec_t *usec);