From e0452f1052e69dc838ab77e40f10e1949a382156 Mon Sep 17 00:00:00 2001
From: Alex Nikiforov <nika@gentoo>
Date: Thu, 21 Jul 2011 13:26:28 +0400
Subject: [PATCH 2/2] api: replace read/write with readv/writev
Put the pid and flags into iovec structure for processing via
writev/readv according to manual. Vector read/write syscall process
multiple iovec buffers in array order (man 2 writev). It's reduce the
number of syscalls and make code more clear (less read/write if pairs)
Signed-off-by: Alex Nikiforov <a.nikifo...@samsung.com>
---
src/api.c | 11 ++++++++---
src/daemon/cgrulesengd.c | 25 +++++++++++++++----------
2 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/src/api.c b/src/api.c
index d5022c2..8c6dd1e 100644
--- a/src/api.c
+++ b/src/api.c
@@ -43,6 +43,7 @@
#include <sys/socket.h>
#include <fcntl.h>
#include <sys/syscall.h>
+#include <sys/uio.h>
#include <unistd.h>
#include <fts.h>
#include <ctype.h>
@@ -3704,6 +3705,7 @@ int cgroup_register_unchanged_process(pid_t pid,
int flags)
int ret = 1;
char buff[sizeof(CGRULE_SUCCESS_STORE_PID)];
struct sockaddr_un addr;
+ struct iovec iov[2] = {};
sk = socket(PF_UNIX, SOCK_STREAM, 0);
if (sk < 0)
@@ -3720,10 +3722,13 @@ int cgroup_register_unchanged_process(pid_t pid,
int flags)
ret = 0;
goto close;
}
- if (write(sk, &pid, sizeof(pid)) < 0)
- goto close;
- if (write(sk, &flags, sizeof(flags)) < 0)
+ iov[0].iov_base = &pid;
+ iov[0].iov_len = sizeof(pid);
+ iov[1].iov_base = &flags;
+ iov[1].iov_len = sizeof(flags);
+
+ if (writev(sk, iov, 2) < 0)
goto close;
if (read(sk, buff, sizeof(buff)) < 0)
diff --git a/src/daemon/cgrulesengd.c b/src/daemon/cgrulesengd.c
index 2f42a57..14887bb 100644
--- a/src/daemon/cgrulesengd.c
+++ b/src/daemon/cgrulesengd.c
@@ -40,6 +40,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
+#include <sys/uio.h>
#include <sys/syslog.h>
#include <string.h>
#include <linux/netlink.h>
@@ -552,6 +553,7 @@ static void cgre_receive_unix_domain_msg(int sk_unix)
socklen_t caddr_len;
struct stat buff_stat;
char path[FILENAME_MAX];
+ struct iovec iov[2] = {};
caddr_len = sizeof(caddr);
fd_client = accept(sk_unix, (struct sockaddr *)&caddr, &caddr_len);
@@ -559,16 +561,19 @@ static void cgre_receive_unix_domain_msg(int sk_unix)
cgroup_dbg("accept error: %s\n", strerror(errno));
return;
}
- if (read(fd_client, &pid, sizeof(pid)) < 0) {
- cgroup_dbg("read error: %s\n", strerror(errno));
- goto close;
- }
- sprintf(path, "/proc/%d", pid);
- if (stat(path, &buff_stat)) {
- cgroup_dbg("There is not such process (PID: %d)", pid);
- goto close;
- }
- if (read(fd_client, &flags, sizeof(flags)) < 0) {
+
+ iov[0].iov_base = &pid;
+ iov[0].iov_len = sizeof(pid);
+ iov[1].iov_base = &flags;
+ iov[1].iov_len = sizeof(flags);
+
+ if (readv(fd_client, iov, 2) < 0) {
+ sprintf(path, "/proc/%d", pid);
+ if (stat(path, &buff_stat)) {
+ cgroup_dbg("There is not such process (PID: %d)", pid);
+ goto close;
+ }
+
cgroup_dbg("read error: %s\n", strerror(errno));
goto close;
}
--
1.7.4.1
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