utils-std

commit: c6b6d2ad7d5c2ad29d1958a22f6bd13c15757e39
parent 56a94bdfc264dfc1fe7bdd3f1913184fbfced974
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Wed, 18 Sep 2024 04:53:20 +0200

cmd/sync: add -f (syncfs) support

Diffstat:
M
cmd/sync.1
11
++++++++---
M
cmd/sync.c
55
+++++++++++++++++++++++++++++++------------------------
M
configure
2
++
A
configure.d/syncfs.c
15
+++++++++++++++

4 files changed, 56 insertions(+), 27 deletions(-)
diff --git a/cmd/sync.1 b/cmd/sync.1
@@ -9,24 +9,29 @@
 .Nd Schedule file system updates
 .Sh SYNOPSIS
 .Nm
-.Op Fl d
+.Op Fl df
 .Op Ar file...
 .Sh DESCRIPTION
 Schedule cached writes to filesystems.
 If any
 .Ar file
-is specified, only those files are scheduled, otherwise all filesystems are synchronized.
+is specified, only those files are scheduled,
+otherwise all filesystems are synchronized.
 .Sh OPTIONS
 .Bl -tag -width _d
 .It Fl d
 Sync only file data, not metadata.
+.It Fl f
+Sync entire filesystem. (Only available on systems with
+.Xr syncfs 2 )
 .El
 .Sh EXIT STATUS
 .Ex -std
 .Sh SEE ALSO
 .Xr fdatasync 2 ,
 .Xr fsync 2 ,
-.Xr sync 2
+.Xr sync 2 ,
+.Xr syncfs 2
 .Sh STANDARDS
 No applicable one known.
 .Sh AUTHORS
diff --git a/cmd/sync.c b/cmd/sync.c
@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: MPL-2.0
 
 #define _POSIX_C_SOURCE 200809L
+#define _GNU_SOURCE       // syncfs
 #define _XOPEN_SOURCE 700 // sync
 
 #include <errno.h>
@@ -11,23 +12,36 @@
 #include <stdio.h>  // fprintf
 #include <stdlib.h> // abort
 #include <string.h> // strerror
-#include <unistd.h> // fsync, sync, getopt
+#include <unistd.h> // fsync, sync, getopt, syncfs
 
 int
 main(int argc, char *argv[])
 {
-	bool optd = false;
+	int err = 0;
+	int (*sync_func)(int) = fsync;
 
 	int c = -1;
-	while((c = getopt(argc, argv, ":d")) != -1)
+	while((c = getopt(argc, argv, ":df")) != -1)
 	{
 		switch(c)
 		{
 		case 'd':
-			optd = true;
+			sync_func = fdatasync;
 			break;
+		case 'f':
+#ifdef HAS_SYNCFS
+			sync_func = syncfs;
+			break;
+#else
+			fprintf(stderr,
+			        "sync: System doesn't supports syncfs(3), continuing with error status set\n");
+			err = 1;
+			break;
+#endif
 		case '?':
-			fprintf(stderr, "sync: Unrecognized option '-%c'\n", optopt);
+			fprintf(
+			    stderr, "sync: Unrecognized option '-%c', continuing with error status set\n", optopt);
+			err = 1;
 			break;
 		default:
 			abort();
@@ -39,8 +53,12 @@ main(int argc, char *argv[])
 
 	if(argc == 0)
 	{
+#ifdef HAS_SYNCFS
+		if(sync_func == syncfs) fprintf(stderr, "sync: Warning -f passed without arguments\n");
+#endif
+
 		sync();
-		return 0;
+		return err;
 	}
 
 	for(int i = 0; i < argc; i++)
@@ -52,24 +70,13 @@ main(int argc, char *argv[])
 			return 1;
 		}
 
-		if(optd)
-		{
-			if(fdatasync(fd) < 0)
-			{
-				fprintf(stderr,
-				        "sync: Failed synchronizing data changes of file '%s': %s\n",
-				        argv[i],
-				        strerror(errno));
-				return 1;
-			}
-		}
-		else
+		if(sync_func(fd) < 0)
 		{
-			if(fsync(fd) < 0)
-			{
-				fprintf(stderr, "sync: Failed synchronizing file '%s': %s\n", argv[i], strerror(errno));
-				return 1;
-			}
+			fprintf(stderr,
+			        "sync: Failed synchronizing changes related to file '%s': %s\n",
+			        argv[i],
+			        strerror(errno));
+			return 1;
 		}
 
 		if(close(fd) < 0)
@@ -82,5 +89,5 @@ main(int argc, char *argv[])
 		}
 	}
 
-	return 0;
+	return err;
 }
diff --git a/configure b/configure
@@ -233,6 +233,8 @@ fi
 
 check_conftest configure.d/getopt_long.c && CFLAGS="${CFLAGS} -DHAS_GETOPT_LONG"
 
+check_conftest configure.d/syncfs.c && CFLAGS="${CFLAGS} -DHAS_SYNCFS"
+
 echo
 
 ## Configuration write
diff --git a/configure.d/syncfs.c b/configure.d/syncfs.c
@@ -0,0 +1,15 @@
+// utils-std: Collection of commonly available Unix tools
+// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
+// SPDX-License-Identifier: MPL-2.0
+
+// Because that's what our utilities will use :)
+#define _POSIX_C_SOURCE 200809L
+#define _GNU_SOURCE // for syncfs
+
+#include <unistd.h> // syncfs
+
+int
+test(int fd)
+{
+	return syncfs(fd);
+}