musl/src/network/recvmsg.c

#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
	r = socketcall_cp(recvmsg, fd, msg, flags, 0, 0, 0);
#if LONG_MAX > INT_MAX
	if (orig) *orig = h;
#endif
	return r;
}
initial check-in, version 0.5.0 2011-02-12 00:22:29 -05:00			`#include <sys/socket.h>`
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... 2011-04-08 09:24:19 -04:00			`#include <limits.h>`
initial check-in, version 0.5.0 2011-02-12 00:22:29 -05:00			`#include "syscall.h"`
			`#include "libc.h"`

			`ssize_t recvmsg(int fd, struct msghdr *msg, int flags)`
			`{`
			`ssize_t r;`
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... 2011-04-08 09:24:19 -04:00			`#if LONG_MAX > INT_MAX`
			`struct msghdr h, *orig = msg;`
			`if (msg) {`
			`h = *msg;`
			`h.__pad1 = h.__pad2 = 0;`
			`msg = &h;`
			`}`
			`#endif`
overhaul pthread cancellation this patch improves the correctness, simplicity, and size of cancellation-related code. modulo any small errors, it should now be completely conformant, safe, and resource-leak free. the notion of entering and exiting cancellation-point context has been completely eliminated and replaced with alternative syscall assembly code for cancellable syscalls. the assembly is responsible for setting up execution context information (stack pointer and address of the syscall instruction) which the cancellation signal handler can use to determine whether the interrupted code was in a cancellable state. these changes eliminate race conditions in the previous generation of cancellation handling code (whereby a cancellation request received just prior to the syscall would not be processed, leaving the syscall to block, potentially indefinitely), and remedy an issue where non-cancellable syscalls made from signal handlers became cancellable if the signal handler interrupted a cancellation point. x86_64 asm is untested and may need a second try to get it right. 2011-04-17 11:43:03 -04:00			`r = socketcall_cp(recvmsg, fd, msg, flags, 0, 0, 0);`
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... 2011-04-08 09:24:19 -04:00			`#if LONG_MAX > INT_MAX`
			`if (orig) *orig = h;`
			`#endif`
initial check-in, version 0.5.0 2011-02-12 00:22:29 -05:00			`return r;`
			`}`