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authorRich Felker <dalias@aerifal.cx>2011-04-08 09:24:19 -0400
committerRich Felker <dalias@aerifal.cx>2011-04-08 09:24:19 -0400
commit7168790763cdeb794df52be6e3b39fbb021c5a64 (patch)
treefa302a8cb7f16d6201db3499082cc6b70012769a
parent5b8d81f706da0b7dc0abb5d0d74595d5b2f60d52 (diff)
downloadmusl-7168790763cdeb794df52be6e3b39fbb021c5a64.tar.gz
workaround broken msghdr struct on 64bit linux
POSIX clearly specifies the type of msg_iovlen and msg_controllen, and Linux ignores it and makes them both size_t instead. to work around this we add padding (instead of just using the wrong types like glibc does), but we also need to patch-up the struct before passing it to the kernel in case the caller did not zero-fill it. if i could trust the kernel to just ignore the upper 32 bits, this would not be necessary, but i don't think it will ignore them...
-rw-r--r--arch/x86_64/bits/socket.h4
-rw-r--r--src/network/recvmsg.c12
-rw-r--r--src/network/sendmsg.c9
3 files changed, 23 insertions, 2 deletions
diff --git a/arch/x86_64/bits/socket.h b/arch/x86_64/bits/socket.h
index b3230625..0e5ee1aa 100644
--- a/arch/x86_64/bits/socket.h
+++ b/arch/x86_64/bits/socket.h
@@ -3,9 +3,9 @@ struct msghdr
void *msg_name;
socklen_t msg_namelen;
struct iovec *msg_iov;
- int msg_iovlen;
+ int msg_iovlen, __pad1;
void *msg_control;
- socklen_t msg_controllen;
+ socklen_t msg_controllen, __pad2;
int msg_flags;
};
diff --git a/src/network/recvmsg.c b/src/network/recvmsg.c
index edc5f241..65094fc8 100644
--- a/src/network/recvmsg.c
+++ b/src/network/recvmsg.c
@@ -1,12 +1,24 @@
#include <sys/socket.h>
+#include <limits.h>
#include "syscall.h"
#include "libc.h"
ssize_t recvmsg(int fd, struct msghdr *msg, int flags)
{
ssize_t r;
+#if LONG_MAX > INT_MAX
+ struct msghdr h, *orig = msg;
+ if (msg) {
+ h = *msg;
+ h.__pad1 = h.__pad2 = 0;
+ msg = &h;
+ }
+#endif
CANCELPT_BEGIN;
r = socketcall(recvmsg, fd, msg, flags, 0, 0, 0);
CANCELPT_END;
+#if LONG_MAX > INT_MAX
+ if (orig) *orig = h;
+#endif
return r;
}
diff --git a/src/network/sendmsg.c b/src/network/sendmsg.c
index 5d1123f0..047c0eff 100644
--- a/src/network/sendmsg.c
+++ b/src/network/sendmsg.c
@@ -1,10 +1,19 @@
#include <sys/socket.h>
+#include <limits.h>
#include "syscall.h"
#include "libc.h"
ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
{
ssize_t r;
+#if LONG_MAX > INT_MAX
+ struct msghdr h;
+ if (msg) {
+ h = *msg;
+ h.__pad1 = h.__pad2 = 0;
+ msg = &h;
+ }
+#endif
CANCELPT_BEGIN;
r = socketcall(sendmsg, fd, msg, flags, 0, 0, 0);
CANCELPT_END;