[PATCH v2] xfs_io: implement 'utimes' command

[Deepa Dinamani <deepa.kernel@gmail.com>]

Add the utimes command to provide a way to utilize
the futimens C library call. This is the
interface to the utimensat system call, which updates
the mtime and atime of a file.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
Changes since v1:
* changed error return values
* removed redundant roff formatting directive
* removed unneeded argument count check

 include/input.h   |  1 +
 io/Makefile       |  2 +-
 io/init.c         |  1 +
 io/io.h           |  1 +
 io/utimes.c       | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 libxcmd/input.c   | 22 +++++++++++++++
 man/man8/xfs_io.8 | 11 ++++++++
 7 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100755 io/utimes.c
 mode change 100644 => 100755 libxcmd/input.c

diff --git a/include/input.h b/include/input.h
index d02170f..221678e 100644
--- a/include/input.h
+++ b/include/input.h
@@ -48,6 +48,7 @@ extern uid_t	uid_from_string(char *user);
 extern gid_t	gid_from_string(char *group);
 extern prid_t	prid_from_string(char *project);
 extern bool	isdigits_only(const char *str);
+extern int	timespec_from_string(const char *sec, const char *nsec, struct timespec *ts);
 
 #define HAVE_FTW_H 1	/* TODO: configure me */
 
diff --git a/io/Makefile b/io/Makefile
index 62bc03b..392e02a 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -11,7 +11,7 @@ HFILES = init.h io.h
 CFILES = init.c \
 	attr.c bmap.c file.c freeze.c fsync.c getrusage.c imap.c link.c \
 	mmap.c open.c parent.c pread.c prealloc.c pwrite.c seek.c shutdown.c \
-	sync.c truncate.c reflink.c
+	sync.c truncate.c reflink.c utimes.c
 
 LLDLIBS = $(LIBXCMD) $(LIBHANDLE)
 LTDEPENDENCIES = $(LIBXCMD) $(LIBHANDLE)
diff --git a/io/init.c b/io/init.c
index efe7390..6319aeb 100644
--- a/io/init.c
+++ b/io/init.c
@@ -85,6 +85,7 @@ init_commands(void)
 	sync_range_init();
 	truncate_init();
 	reflink_init();
+	utimes_init();
 }
 
 static int
diff --git a/io/io.h b/io/io.h
index 2bc7ac4..fddd7a3 100644
--- a/io/io.h
+++ b/io/io.h
@@ -113,6 +113,7 @@ extern void		seek_init(void);
 extern void		shutdown_init(void);
 extern void		sync_init(void);
 extern void		truncate_init(void);
+extern void		utimes_init(void);
 
 #ifdef HAVE_FADVISE
 extern void		fadvise_init(void);
diff --git a/io/utimes.c b/io/utimes.c
new file mode 100755
index 0000000..faf9b8d
--- /dev/null
+++ b/io/utimes.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2016 Deepa Dinamani
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "command.h"
+#include "input.h"
+#include "init.h"
+#include "io.h"
+
+static cmdinfo_t utimes_cmd;
+
+static void
+utimes_help(void)
+{
+	printf(_(
+"\n"
+" Update file atime and mtime of the current file with nansecond precision.\n"
+"\n"
+" Usage: utimes atime_sec atime_nsec mtime_sec mtime_nsec.\n"
+" *_sec: Seconds elapsed since 1970-01-01 00:00:00 UTC.\n"
+" *_nsec: Nanoseconds since the corresponding *_sec.\n"
+"\n"));
+}
+
+static int
+utimes_f(
+	int		argc,
+	char		**argv)
+{
+	struct timespec t[2];
+	int result;
+
+	/* Get the timestamps */
+	result = timespec_from_string(argv[1], argv[2], &t[0]);
+	if (result) {
+		fprintf(stderr, "Bad value for atime\n");
+		return 0;
+	}
+	result = timespec_from_string(argv[3], argv[4], &t[1]);
+	if (result) {
+		fprintf(stderr, "Bad value for mtime\n");
+		return 0;
+	}
+
+	/* Call futimens to update time. */
+	if (futimens(file->fd, t)) {
+		perror("futimens");
+		return 0;
+	}
+
+	return 0;
+}
+
+void
+utimes_init(void)
+{
+	utimes_cmd.name = "utimes";
+	utimes_cmd.cfunc = utimes_f;
+	utimes_cmd.argmin = 4;
+	utimes_cmd.argmax = 4;
+	utimes_cmd.flags = CMD_NOMAP_OK | CMD_FOREIGN_OK;
+	utimes_cmd.args = _("atime_sec atime_nsec mtime_sec mtime_nsec");
+	utimes_cmd.oneline = _("Update file times of the current file");
+	utimes_cmd.help = utimes_help;
+
+	add_command(&utimes_cmd);
+}
diff --git a/libxcmd/input.c b/libxcmd/input.c
old mode 100644
new mode 100755
index 5a7dce3..8aeb3b0
--- a/libxcmd/input.c
+++ b/libxcmd/input.c
@@ -327,6 +327,28 @@ timestr(
 }
 
 /*
+ * Convert from a pair of arbitrary user strings into a timespec.
+ */
+
+int
+timespec_from_string(
+	const char	* secs,
+	const char	* nsecs,
+	struct timespec	* ts)
+{
+	char* p;
+	if (!secs || !nsecs || !ts)
+		return 1;
+	ts->tv_sec = strtoull(secs, &p, 0);
+	if (*p)
+		return 1;
+	ts->tv_nsec = strtoull(nsecs, &p, 0);
+	if (*p)
+		return 1;
+	return 0;
+}
+
+/*
  * Convert from arbitrary user strings into a numeric ID.
  * If it's all numeric, we convert that inplace, else we do
  * the name lookup, and return the found identifier.
diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
index 2c56f09..9efb7b2 100644
--- a/man/man8/xfs_io.8
+++ b/man/man8/xfs_io.8
@@ -589,6 +589,16 @@ Copy data into the open file beginning at
 Copy up to
 .I length
 bytes of data.
+.RE
+.PD
+.TP
+.BI utimes " atime_sec atime_nsec mtime_sec mtime_nsec"
+The utimes command changes the atime and mtime of the current file.
+sec uses UNIX timestamp notation and is the seconds elapsed since
+1970-01-01 00:00:00 UTC.
+nsec is the nanoseconds since the sec. This value needs to be in
+the range 0-999999999 with UTIME_NOW and UTIME_OMIT being exceptions.
+Each (sec, nsec) pair constitutes a single timestamp value.
 
 .SH MEMORY MAPPED I/O COMMANDS
 .TP
@@ -875,6 +885,7 @@ verbose output will be printed.
 .BR fstatfs (2),
 .BR fsync (2),
 .BR ftruncate (2),
+.BR futimens (3),
 .BR mmap (2),
 .BR msync (2),
 .BR open (2),
-- 
2.7.4