cosmopolitan/libc/sock/sendfile.c

102 lines
4.9 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/nt/winsock.h"
#include "libc/sock/internal.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
static textwindows ssize_t sendfile$linux2nt(int outfd, int infd,
int64_t *inout_opt_inoffset,
size_t uptobytes) {
struct NtOverlapped Overlapped;
struct NtOverlapped *lpOverlapped;
if (!isfdkind(outfd, kFdSocket) || !isfdkind(outfd, kFdFile)) return ebadf();
if (inout_opt_inoffset) {
memset(&Overlapped, 0, sizeof(Overlapped));
Overlapped.Pointer = (void *)(intptr_t)(*inout_opt_inoffset);
lpOverlapped = &Overlapped;
} else {
lpOverlapped = NULL;
}
/* TODO(jart): Fetch this on a per-socket basis via GUID. */
if (TransmitFile(g_fds.p[outfd].handle, g_fds.p[infd].handle, uptobytes, 0,
lpOverlapped, NULL, 0)) {
return uptobytes;
} else {
return winsockerr();
}
}
static ssize_t sendfile$linux2netflix(int outfd, int infd,
int64_t *inout_opt_inoffset,
size_t uptobytes) {
int sendfile$netflix(int32_t infd, int32_t outfd, int64_t offset,
size_t nbytes, const void *opt_hdtr,
int64_t *out_opt_sbytes,
int32_t flags) asm("sendfile$sysv") hidden;
int rc;
int64_t offset, sbytes;
if (inout_opt_inoffset) {
offset = *inout_opt_inoffset;
} else if ((offset = lseek$sysv(infd, 0, SEEK_CUR)) == -1) {
return -1;
}
if ((rc = sendfile$netflix(infd, outfd, offset, uptobytes, NULL, &sbytes,
0)) != -1) {
if (inout_opt_inoffset) *inout_opt_inoffset += sbytes;
return sbytes;
} else {
return -1;
}
}
/**
* Transfers data from file to network.
*
* @param outfd needs to be a socket
* @param infd needs to be a file
* @param inout_opt_inoffset may be specified for pread()-like behavior
* @param uptobytes is usually the number of bytes remaining in file; it
* can't exceed INT_MAX-1; some platforms block until everything's
* sent, whereas others won't; zero isn't allowed
* @return number of bytes transmitted which may be fewer than requested
* @see copy_file_range() for file ↔ file
* @see splice() for fd ↔ pipe
*/
ssize_t sendfile(int outfd, int infd, int64_t *inout_opt_inoffset,
size_t uptobytes) {
if (!uptobytes) return einval();
if (uptobytes > 0x7ffffffe /* Microsoft's off-by-one */) return eoverflow();
if (IsModeDbg() && uptobytes > 1) uptobytes >>= 1;
if (IsLinux()) {
return sendfile$sysv(outfd, infd, inout_opt_inoffset, uptobytes);
} else if (IsFreebsd() || IsXnu()) {
return sendfile$linux2netflix(outfd, infd, inout_opt_inoffset, uptobytes);
} else if (IsWindows()) {
return sendfile$linux2nt(outfd, infd, inout_opt_inoffset, uptobytes);
} else {
return copyfd(infd, inout_opt_inoffset, outfd, NULL, uptobytes, 0);
}
}