tag 627325 + patch thanks OoO En cette matinée pluvieuse du vendredi 20 mai 2011, vers 10:52, Modestas Vainius <mo...@debian.org> disait :
>> Package: eatmydata >> Version: 26-2 >> Severity: wishlist >> >> Hi! >> >> eatmydata would be useful on laptops when they are put on battery. We >> would put eatmydata in /etc/ld.so.preload and let it know when we want >> sync() or not. For example, if /var/run/eatmydata.on exists, we want >> sync() disabled. >> >> Would you accept a patch which does something like this? > Sure I would accept it. eatmydata.c already has similar code but it's > disabled > iirc. If you polished it, made file path configurable via environment > variable > (which would also serve as ON/OFF switch of this functionality) and added > appropriate documentation, I would consider applying it. Hi! Here is the patch against the current package. If EATMYDATA environment variable is present, eatmydata will check the file defined by this variable. If the file exists, any sync() call is suppressed.
From f340e0fd04576331a9dd33f2d612e1c9126c5a81 Mon Sep 17 00:00:00 2001
From: Vincent Bernat <ber...@luffy.cx>
Date: Sat, 21 May 2011 10:46:12 +0200
Subject: [PATCH] Presence of EATMYDATA environment variable will alter
eatmydata behavior.
If the variable environment exists and point to a file that exists,
eatmydata will suppress all sync() and related calls. However, when
the file does not exist, eatmydata will keep them.
---
debian/eatmydata.1 | 6 ++++++
eatmydata.c | 18 ++++++------------
eatmydatatest.c | 5 +++++
3 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/debian/eatmydata.1 b/debian/eatmydata.1
index b192755..c72cf4d 100644
--- a/debian/eatmydata.1
+++ b/debian/eatmydata.1
@@ -18,6 +18,12 @@ command line. In order to use symlink mode, create a symlink to
in the PATH and execute \fBeatmydata\fR via that symlink. Then \fBeatmydata\fR
will find that program in the PATH and run it in the libeatmydata environment
repassing all command line options.
+.P
+\fBeathmydata\fR also looks for \fIEATMYDATA\fR environment
+variable. If it does exist, it should point to a file that will enable
+\fBeatmydata\fR if present or disable it if absent. This way,
+\fBeatmydata\fR can be enabled dynamically depending on some external
+condition.
.SH OPTIONS
.P
Please note that \fBeatmydata\fR does not process any command line options in
diff --git a/eatmydata.c b/eatmydata.c
index ab943c3..0579616 100644
--- a/eatmydata.c
+++ b/eatmydata.c
@@ -13,16 +13,13 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-/*
-#define CHECK_FILE "/tmp/eatmydata"
-*/
-
#ifndef RTLD_NEXT
# define _GNU_SOURCE
#endif
#include <sys/types.h>
#include <unistd.h>
+#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
@@ -59,20 +56,17 @@ int eatmydata_is_hungry(void)
if(!libc_open)
eatmydata_init();
-#ifdef CHECK_FILE
static struct stat buf;
int old_errno, stat_ret;
+ char *check_file;
old_errno= errno;
- stat_ret= stat(CHECK_FILE, &buf);
+ if (check_file= getenv("EATMYDATA"))
+ stat_ret= stat(check_file, &buf);
errno= old_errno;
- /* Treat any error as if file doesn't exist, for safety */
- return !stat_ret;
-#else
- /* Always hungry! */
- return 1;
-#endif
+ /* Hungry when no variable environment or when the file does exist */
+ return (!check_file || !stat_ret);
}
int fsync(int fd)
diff --git a/eatmydatatest.c b/eatmydatatest.c
index 82303fa..4e149f0 100644
--- a/eatmydatatest.c
+++ b/eatmydatatest.c
@@ -76,6 +76,11 @@ int main(int argc, char** argv)
TESTCASE(fdatasync(fd), 0, "system fdatasync() was not overriden");
TESTCASE(msync(0, 1, 1), 0, "system msync() was not overriden");
+ // Test with inexistent EATMYDATA variable
+ setenv("EATMYDATA", "/empty/doesnotexist", 1);
+ TESTCASE(fsync(fd), -1, "system fsync() was overriden despite EATMYDATA check file");
+ setenv("EATMYDATA", "/etc/passwd", 1);
+ TESTCASE(fsync(fd), 0, "system fsync() was not overriden with EATMYDATA inexistent env");
if (failed_tests > 0) {
fprintf(stderr, "%d test cases failed\n", failed_tests);
return 2;
--
1.7.5.1
-- Vincent Bernat http://www.luffy.cx
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