From 4f74bb6059b54df31b9a6cdaf844112a7003b0ff Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <vda.linux@googlemail.com>
Date: Tue, 2 Apr 2019 14:39:56 +0200
Subject: [PATCH] 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>
---
 coreutils/fsync.c | 30 ++++++++++++++++--------------
 coreutils/sync.c  | 22 +++++++++-------------
 2 files changed, 25 insertions(+), 27 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;
 }
diff --git a/coreutils/sync.c b/coreutils/sync.c
index b93476aee..e60e553a3 100644
--- a/coreutils/sync.c
+++ b/coreutils/sync.c
@@ -20,6 +20,7 @@
 //config:	sync -d FILE... executes fdatasync() on each FILE.
 //config:	sync -f FILE... executes syncfs() on each FILE.
 
+//               APPLET_NOFORK:name  main  location    suid_type     help
 //applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))
 
 //kbuild:lib-$(CONFIG_SYNC) += sync.o
@@ -52,7 +53,7 @@ int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
 	return EXIT_SUCCESS;
 #else
 	unsigned opts;
-	int ret = EXIT_SUCCESS;
+	int ret;
 
 	enum {
 		OPT_DATASYNC = (1 << 0),
@@ -66,35 +67,30 @@ int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
 	if (!argv[0])
 		sync();
 
+	ret = EXIT_SUCCESS;
 	while (*argv) {
-		int fd = open_or_warn(*argv, 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 < 0) {
 			ret = EXIT_FAILURE;
 			goto next;
 		}
-		if (opts & OPT_DATASYNC) {
-			if (fdatasync(fd))
-				goto err;
-			goto do_close;
-		}
 		if (opts & OPT_SYNCFS) {
 			/*
 			 * syncfs is documented to only fail with EBADF,
 			 * which can't happen here. So, no error checks.
 			 */
 			syncfs(fd);
-			goto do_close;
-		}
-		if (fsync(fd)) {
- err:
+		} else
+		if (((opts & OPT_DATASYNC) ? fdatasync(fd) : fsync(fd)) != 0) {
 			bb_simple_perror_msg(*argv);
 			ret = EXIT_FAILURE;
 		}
- do_close:
 		close(fd);
  next:
-		++argv;
+		argv++;
 	}
 
 	return ret;