fsync,sync: make them similar

sync: add O_NOCTTY
fsync: drop O_NOATIME, add O_NONBLOCK, set exitcode to 1 if fsync() fails,
    update --help message to be similar to sync.
both: reformat code to minimize "diff -u sync.c fsync.c":
    in particular, they use same open() flags now

function                                             old     new   delta
fsync_main                                           126     130      +4
packed_usage                                       33316   33317      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 5/0)                 Total: 5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 16 insertions, 14 deletions

diff --git a/coreutils/fsync.c b/coreutils/fsync.c
index c7cba9f61..216cbcf41 100644
--- a/coreutils/fsync.c
+++ b/coreutils/fsync.c
@@ -12,6 +12,7 @@
 //config:       help
 //config:       fsync is used to flush file-related cached blocks to disk.
 
+//                APPLET_NOFORK:name   main   location    suid_type     help
 //applet:IF_FSYNC(APPLET_NOFORK(fsync, fsync, BB_DIR_BIN, BB_SUID_DROP, fsync))
 
 //kbuild:lib-$(CONFIG_FSYNC) += fsync.o
@@ -19,20 +20,17 @@
 //usage:#define fsync_trivial_usage
 //usage:       "[-d] FILE..."
 //usage:#define fsync_full_usage "\n\n"
-//usage:       "Write files' buffered blocks to disk\n"
+//usage:       "Write all buffered blocks in FILEs to disk\n"
 //usage:     "\n        -d      Avoid syncing metadata"
 
 #include "libbb.h"
-#ifndef O_NOATIME
-# define O_NOATIME 0
-#endif
 
 /* This is a NOFORK applet. Be very careful! */
 
 int fsync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int fsync_main(int argc UNUSED_PARAM, char **argv)
 {
-        int status;
+        int ret;
         int opts;
 
         opts = getopt32(argv, "d"); /* fdatasync */
@@ -41,20 +39,24 @@ int fsync_main(int argc UNUSED_PARAM, char **argv)
                 bb_show_usage();
         }
 
-        status = EXIT_SUCCESS;
+        ret = EXIT_SUCCESS;
         do {
-                int fd = open_or_warn(*argv, O_NOATIME | O_NOCTTY | O_RDONLY);
+                /* GNU "sync FILE" uses O_NONBLOCK open */
+                int fd = open_or_warn(*argv, /*O_NOATIME |*/ O_NOCTTY | O_RDONLY | O_NONBLOCK);
+                /* open(NOATIME) can only be used by owner or root, don't use NOATIME here */
 
-                if (fd == -1) {
-                        status = EXIT_FAILURE;
-                        continue;
+                if (fd < 0) {
+                        ret = EXIT_FAILURE;
+                        goto next;
                 }
-                if ((opts ? fdatasync(fd) : fsync(fd))) {
-                        //status = EXIT_FAILURE; - do we want this?
+                if ((opts ? fdatasync(fd) : fsync(fd)) != 0) {
                         bb_simple_perror_msg(*argv);
+                        ret = EXIT_FAILURE;
                 }
                 close(fd);
-        } while (*++argv);
+ next:
+                argv++;
+        } while (*argv);
 
-        return status;
+        return ret;
 }