commit 21c8d57fca6bad5c9573679c2f7b40e584bd597c (tree)
parent f4798297ded2d05f4e1919fb27a9cdb9981a5e11
Author: Andrew Kelley <andrew@ziglang.org>
Date: Sat, 4 May 2019 14:05:55 -0400
Merge pull request #2326 from daurnimator/sendmmsg
Add sendmmsg syscall wrapper
Diffstat:
5 files changed, 139 insertions(+), 17 deletions(-)
diff --git a/std/c/freebsd.zig b/std/c/freebsd.zig
@@ -42,14 +42,36 @@ pub const pthread_attr_t = extern struct {
};
pub const msghdr = extern struct {
- msg_name: *u8,
+ /// optional address
+ msg_name: ?*sockaddr,
+ /// size of address
msg_namelen: socklen_t,
- msg_iov: *iovec,
+ /// scatter/gather array
+ msg_iov: [*]iovec,
+ /// # elements in msg_iov
msg_iovlen: i32,
- __pad1: i32,
- msg_control: *u8,
+ /// ancillary data
+ msg_control: ?*c_void,
+ /// ancillary data buffer len
msg_controllen: socklen_t,
- __pad2: socklen_t,
+ /// flags on received message
+ msg_flags: i32,
+};
+
+pub const msghdr_const = extern struct {
+ /// optional address
+ msg_name: ?*const sockaddr,
+ /// size of address
+ msg_namelen: socklen_t,
+ /// scatter/gather array
+ msg_iov: [*]iovec_const,
+ /// # elements in msg_iov
+ msg_iovlen: i32,
+ /// ancillary data
+ msg_control: ?*c_void,
+ /// ancillary data buffer len
+ msg_controllen: socklen_t,
+ /// flags on received message
msg_flags: i32,
};
diff --git a/std/c/netbsd.zig b/std/c/netbsd.zig
@@ -42,14 +42,36 @@ pub const pthread_attr_t = extern struct {
};
pub const msghdr = extern struct {
- msg_name: *u8,
+ /// optional address
+ msg_name: ?*sockaddr,
+ /// size of address
msg_namelen: socklen_t,
- msg_iov: *iovec,
+ /// scatter/gather array
+ msg_iov: [*]iovec,
+ /// # elements in msg_iov
msg_iovlen: i32,
- __pad1: i32,
- msg_control: *u8,
+ /// ancillary data
+ msg_control: ?*c_void,
+ /// ancillary data buffer len
msg_controllen: socklen_t,
- __pad2: socklen_t,
+ /// flags on received message
+ msg_flags: i32,
+};
+
+pub const msghdr_const = extern struct {
+ /// optional address
+ msg_name: ?*const sockaddr,
+ /// size of address
+ msg_namelen: socklen_t,
+ /// scatter/gather array
+ msg_iov: [*]iovec_const,
+ /// # elements in msg_iov
+ msg_iovlen: i32,
+ /// ancillary data
+ msg_control: ?*c_void,
+ /// ancillary data buffer len
+ msg_controllen: socklen_t,
+ /// flags on received message
msg_flags: i32,
};
diff --git a/std/os/linux.zig b/std/os/linux.zig
@@ -12,6 +12,7 @@ pub use switch (builtin.arch) {
pub use @import("linux/errno.zig");
pub const PATH_MAX = 4096;
+pub const IOV_MAX = 1024;
pub const STDIN_FILENO = 0;
pub const STDOUT_FILENO = 1;
@@ -1193,6 +1194,16 @@ pub const iovec_const = extern struct {
iov_len: usize,
};
+pub const mmsghdr = extern struct {
+ msg_hdr: msghdr,
+ msg_len: u32,
+};
+
+pub const mmsghdr_const = extern struct {
+ msg_hdr: msghdr_const,
+ msg_len: u32,
+};
+
pub fn getsockname(fd: i32, noalias addr: *sockaddr, noalias len: *socklen_t) usize {
return syscall3(SYS_getsockname, @bitCast(usize, isize(fd)), @ptrToInt(addr), @ptrToInt(len));
}
@@ -1213,10 +1224,50 @@ pub fn getsockopt(fd: i32, level: u32, optname: u32, noalias optval: [*]u8, noal
return syscall5(SYS_getsockopt, @bitCast(usize, isize(fd)), level, optname, @ptrToInt(optval), @ptrToInt(optlen));
}
-pub fn sendmsg(fd: i32, msg: *const msghdr, flags: u32) usize {
+pub fn sendmsg(fd: i32, msg: *msghdr_const, flags: u32) usize {
return syscall3(SYS_sendmsg, @bitCast(usize, isize(fd)), @ptrToInt(msg), flags);
}
+pub fn sendmmsg(fd: i32, msgvec: [*]mmsghdr_const, vlen: u32, flags: u32) usize {
+ if (@typeInfo(usize).Int.bits > @typeInfo(@typeOf(mmsghdr(undefined).msg_len)).Int.bits) {
+ // workaround kernel brokenness:
+ // if adding up all iov_len overflows a i32 then split into multiple calls
+ // see https://www.openwall.com/lists/musl/2014/06/07/5
+ const kvlen = if (vlen > IOV_MAX) IOV_MAX else vlen; // matches kernel
+ var next_unsent: usize = 0;
+ for (msgvec[0..kvlen]) |*msg, i| {
+ var size: i32 = 0;
+ const msg_iovlen = @intCast(usize, msg.msg_hdr.msg_iovlen); // kernel side this is treated as unsigned
+ for (msg.msg_hdr.msg_iov[0..msg_iovlen]) |iov, j| {
+ if (iov.iov_len > std.math.maxInt(i32) or @addWithOverflow(i32, size, @intCast(i32, iov.iov_len), &size)) {
+ // batch-send all messages up to the current message
+ if (next_unsent < i) {
+ const batch_size = i - next_unsent;
+ const r = syscall4(SYS_sendmmsg, @bitCast(usize, isize(fd)), @ptrToInt(&msgvec[next_unsent]), batch_size, flags);
+ if (getErrno(r) != 0) return next_unsent;
+ if (r < batch_size) return next_unsent + r;
+ }
+ // send current message as own packet
+ const r = sendmsg(fd, &msg.msg_hdr, flags);
+ if (getErrno(r) != 0) return r;
+ // Linux limits the total bytes sent by sendmsg to INT_MAX, so this cast is safe.
+ msg.msg_len = @intCast(u32, r);
+ next_unsent = i + 1;
+ break;
+ }
+ }
+ }
+ if (next_unsent < kvlen or next_unsent == 0) { // want to make sure at least one syscall occurs (e.g. to trigger MSG_EOR)
+ const batch_size = kvlen - next_unsent;
+ const r = syscall4(SYS_sendmmsg, @bitCast(usize, isize(fd)), @ptrToInt(&msgvec[next_unsent]), batch_size, flags);
+ if (getErrno(r) != 0) return r;
+ return next_unsent + r;
+ }
+ return kvlen;
+ }
+ return syscall4(SYS_sendmmsg, @bitCast(usize, isize(fd)), @ptrToInt(msgvec), vlen, flags);
+}
+
pub fn connect(fd: i32, addr: *const c_void, len: socklen_t) usize {
return syscall3(SYS_connect, @bitCast(usize, isize(fd)), @ptrToInt(addr), len);
}
diff --git a/std/os/linux/arm64.zig b/std/os/linux/arm64.zig
@@ -2,6 +2,7 @@ const std = @import("../../std.zig");
const linux = std.os.linux;
const socklen_t = linux.socklen_t;
const iovec = linux.iovec;
+const iovec_const = linux.iovec_const;
pub const SYS_io_setup = 0;
pub const SYS_io_destroy = 1;
@@ -415,12 +416,24 @@ pub fn syscall6(
pub extern fn clone(func: extern fn (arg: usize) u8, stack: usize, flags: u32, arg: usize, ptid: *i32, tls: usize, ctid: *i32) usize;
pub const msghdr = extern struct {
- msg_name: *u8,
+ msg_name: ?*sockaddr,
msg_namelen: socklen_t,
- msg_iov: *iovec,
+ msg_iov: [*]iovec,
msg_iovlen: i32,
__pad1: i32,
- msg_control: *u8,
+ msg_control: ?*c_void,
+ msg_controllen: socklen_t,
+ __pad2: socklen_t,
+ msg_flags: i32,
+};
+
+pub const msghdr_const = extern struct {
+ msg_name: ?*const sockaddr,
+ msg_namelen: socklen_t,
+ msg_iov: [*]iovec_const,
+ msg_iovlen: i32,
+ __pad1: i32,
+ msg_control: ?*c_void,
msg_controllen: socklen_t,
__pad2: socklen_t,
msg_flags: i32,
diff --git a/std/os/linux/x86_64.zig b/std/os/linux/x86_64.zig
@@ -1,7 +1,9 @@
const std = @import("../../std.zig");
const linux = std.os.linux;
+const sockaddr = linux.sockaddr;
const socklen_t = linux.socklen_t;
const iovec = linux.iovec;
+const iovec_const = linux.iovec_const;
pub const SYS_read = 0;
pub const SYS_write = 1;
@@ -483,12 +485,24 @@ pub nakedcc fn restore_rt() void {
}
pub const msghdr = extern struct {
- msg_name: *u8,
+ msg_name: ?*sockaddr,
msg_namelen: socklen_t,
- msg_iov: *iovec,
+ msg_iov: [*]iovec,
msg_iovlen: i32,
__pad1: i32,
- msg_control: *u8,
+ msg_control: ?*c_void,
+ msg_controllen: socklen_t,
+ __pad2: socklen_t,
+ msg_flags: i32,
+};
+
+pub const msghdr_const = extern struct {
+ msg_name: ?*const sockaddr,
+ msg_namelen: socklen_t,
+ msg_iov: [*]iovec_const,
+ msg_iovlen: i32,
+ __pad1: i32,
+ msg_control: ?*c_void,
msg_controllen: socklen_t,
__pad2: socklen_t,
msg_flags: i32,
