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| author | Rich Felker <dalias@aerifal.cx> | 2011-04-08 09:24:19 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2011-04-08 09:24:19 -0400 |
| commit | 7168790763cdeb794df52be6e3b39fbb021c5a64 (patch) | |
| tree | fa302a8cb7f16d6201db3499082cc6b70012769a | |
| parent | 5b8d81f706da0b7dc0abb5d0d74595d5b2f60d52 (diff) | |
| download | musl-7168790763cdeb794df52be6e3b39fbb021c5a64.tar.gz musl-7168790763cdeb794df52be6e3b39fbb021c5a64.tar.xz musl-7168790763cdeb794df52be6e3b39fbb021c5a64.zip | |
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.h | 4 | ||||
| -rw-r--r-- | src/network/recvmsg.c | 12 | ||||
| -rw-r--r-- | src/network/sendmsg.c | 9 |
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; |