From 5c103d4734ef0dfa1fb2f3359d41505acd0478ca Mon Sep 17 00:00:00 2001
From: Gilad Arnold <garnold@google.com>
Date: Mon, 24 Aug 2015 18:19:18 -0700
Subject: Stop using preadv/pwritev.

These are non-standard functions that may not be supported in all
environments.  We replace them with pread/pwrite, which provide similar
atomicity and side-effect semantics, and are also simpler to use.

This also adds EINTR protection around pread.

Bug: 22373707
Change-Id: I78d813c14a958747ed5750e6d00c1ee8fe8031ad
---
 src/seccomp.c |  2 +-
 src/util.c    | 25 ++++---------------------
 2 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/src/seccomp.c b/src/seccomp.c
index fbc5a33..9f9a5fe 100644
--- a/src/seccomp.c
+++ b/src/seccomp.c
@@ -72,7 +72,7 @@ enable_setter_seccomp (void)
     /* Process ALLOWs as quickly as possible */
     SC_ALLOW (read),
     SC_ALLOW (write),
-    SC_ALLOW (pwritev),
+    SC_ALLOW (pwrite64),
 
     SC_ALLOW (settimeofday),
     SC_ALLOW (ioctl), /* TODO(wad) filter for fd and RTC_SET_TIME */
diff --git a/src/util.c b/src/util.c
index 6bb279c..71ed0d6 100644
--- a/src/util.c
+++ b/src/util.c
@@ -23,7 +23,6 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
-#include <sys/uio.h>
 #include <sys/wait.h>
 #include <syslog.h>
 #include <time.h>
@@ -286,16 +285,8 @@ int rtc_close(struct rtc_handle *handle)
 
 int file_write(int fd, void *buf, size_t sz)
 {
-	struct iovec iov[1];
-	ssize_t ret;
-	iov[0].iov_base = buf;
-	iov[0].iov_len = sz;
-	ret = IGNORE_EINTR (pwritev (fd, iov, 1, 0));
-	if (ret != sz)
-	{
-		return -1;
-	}
-	return 0;
+	ssize_t ret = IGNORE_EINTR (pwrite (fd, buf, sz, 0));
+	return (ret >= 0 && ((size_t) ret) == sz ? 0 : -1);
 }
 
 int file_open(const char *path, int write, int cloexec)
@@ -329,16 +320,8 @@ int file_close(int fd)
 
 int file_read(int fd, void *buf, size_t sz)
 {
-	struct iovec iov[1];
-	iov[0].iov_base = buf;
-	iov[0].iov_len = sz;
-	if (preadv (fd, iov, 1, 0) != sz)
-	{
-		/* Returns -1 on read failure */
-		return -1;
-	}
-	/* Returns 0 on a successful buffer fill. */
-	return 0;
+	ssize_t ret = IGNORE_EINTR (pread (fd, buf, sz, 0));
+	return (ret >= 0 && ((size_t) ret) == sz ? 0 : -1);
 }
 
 int time_get(struct timeval *tv)
-- 
cgit v1.2.3