utils-std

commit: a993092bcd87f3f1c636d3667fcaf9411b106a4e
parent b27b9ab570f546ba313ec35f5c22af23d68af000
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Sat, 27 Jul 2024 23:59:17 +0200

cmd/sync: Add hook to fsync() and fdatasync()

Diffstat:
M
cmd/sync.1
19
+++++++++++++++----
M
cmd/sync.c
82
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----

2 files changed, 92 insertions(+), 9 deletions(-)
diff --git a/cmd/sync.1 b/cmd/sync.1
@@ -1,7 +1,7 @@
 .\" utils-std: Collection of commonly available Unix tools
 .\" Copyright 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
 .\" SPDX-License-Identifier: MPL-2.0
-.Dd 2021-12-27
+.Dd 2024-07-28
 .Dt SYNC 1
 .Os
 .Sh NAME
@@ -9,13 +9,24 @@
 .Nd Schedule file system updates
 .Sh SYNOPSIS
 .Nm
+.Op Fl d
+.Op Ar file...
 .Sh DESCRIPTION
-.Nm
-shall cause all information in memory that updates file systems to be scheduled for writing out to all file systems.
+Schedule cached writes to filesystems.
+If any
+.Ar file
+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.
+.El
 .Sh EXIT STATUS
 .Ex -std
 .Sh SEE ALSO
-.Xr sync 2
+.Xr sync 2 ,
+.Xr fdatasync 2 ,
+.Xr fsync 2 .
 .Sh STANDARDS
 No applicable one known.
 .Sh AUTHORS
diff --git a/cmd/sync.c b/cmd/sync.c
@@ -2,13 +2,85 @@
 // SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
 // SPDX-License-Identifier: MPL-2.0
 
-#define _XOPEN_SOURCE 700 // XSI but not mere POSIX
-#include <unistd.h>       // sync()
+#define _POSIX_C_SOURCE 200809L
+#define _XOPEN_SOURCE 700 // sync
+
+#include <errno.h>
+#include <fcntl.h> // open, O_*
+#include <stdbool.h>
+#include <stdio.h>  // fprintf
+#include <stdlib.h> // abort
+#include <string.h> // strerror
+#include <unistd.h> // fsync, sync, getopt
 
 int
-main(void)
+main(int argc, char *argv[])
 {
-	// Maybe consider hooking up to fsync(3p)
-	sync();
+	bool optd = false;
+
+	int c = -1;
+	while((c = getopt(argc, argv, ":d")) != -1)
+	{
+		switch(c)
+		{
+		case 'd':
+			optd = true;
+			break;
+		case '?':
+			fprintf(stderr, "sync: Unrecognized option '-%c'\n", optopt);
+			break;
+		default:
+			abort();
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if(argc == 0)
+	{
+		sync();
+		return 0;
+	}
+
+	for(int i = 0; i < argc; i++)
+	{
+		int fd = open(argv[i], O_RDONLY);
+		if(fd < 0)
+		{
+			fprintf(stderr, "sync: Failed opening file '%s': %s\n", argv[i], strerror(errno));
+			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(fsync(fd) < 0)
+			{
+				fprintf(stderr, "sync: Failed synchronizing file '%s': %s\n", argv[i], strerror(errno));
+				return 1;
+			}
+		}
+
+		if(close(fd) < 0)
+		{
+			fprintf(stderr,
+			        "sync: Failed closing file-descriptor of file '%s': %s\n",
+			        argv[i],
+			        strerror(errno));
+			return 1;
+		}
+	}
+
 	return 0;
 }