From: Tiago Salem Herrmann <therrmann@suse.com>
Date: Tue, 12 Dec 2017 15:52:45 +0000 (-0200)
Subject: sysctl: disable buffer while writing to /proc
X-Git-Tag: v236~15^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=12ec9c309967d663e93254e3fca835f9a240e26f;p=thirdparty%2Fsystemd.git

sysctl: disable buffer while writing to /proc

fputs() writes only first 2048 bytes and fails
to write to /proc when values are larger than that.
This patch adds a new flag to WriteStringFileFlags
that make it possible to disable the buffer under
specific cases.
---

diff --git a/src/basic/fileio.c b/src/basic/fileio.c
index 12d6d06fa29..76c9333d261 100644
--- a/src/basic/fileio.c
+++ b/src/basic/fileio.c
@@ -167,6 +167,9 @@ int write_string_file_ts(
                 }
         }
 
+        if (flags & WRITE_STRING_FILE_DISABLE_BUFFER)
+                setvbuf(f, NULL, _IONBF, 0);
+
         r = write_string_stream_ts(f, line, flags, ts);
         if (r < 0)
                 goto fail;
diff --git a/src/basic/fileio.h b/src/basic/fileio.h
index c283f41f09b..da5d5c66b51 100644
--- a/src/basic/fileio.h
+++ b/src/basic/fileio.h
@@ -35,6 +35,7 @@ typedef enum {
         WRITE_STRING_FILE_AVOID_NEWLINE     = 1<<2,
         WRITE_STRING_FILE_VERIFY_ON_FAILURE = 1<<3,
         WRITE_STRING_FILE_SYNC              = 1<<4,
+        WRITE_STRING_FILE_DISABLE_BUFFER    = 1<<5,
 
         /* And before you wonder, why write_string_file_atomic_label_ts() is a separate function instead of just one
            more flag here: it's about linking: we don't want to pull -lselinux into all users of write_string_file()
diff --git a/src/shared/sysctl-util.c b/src/shared/sysctl-util.c
index 391065d804a..189580e3ed2 100644
--- a/src/shared/sysctl-util.c
+++ b/src/shared/sysctl-util.c
@@ -60,7 +60,7 @@ int sysctl_write(const char *property, const char *value) {
         log_debug("Setting '%s' to '%s'", property, value);
 
         p = strjoina("/proc/sys/", property);
-        return write_string_file(p, value, 0);
+        return write_string_file(p, value, WRITE_STRING_FILE_DISABLE_BUFFER);
 }
 
 int sysctl_read(const char *property, char **content) {