cosmopolitan/libc/calls/readv.c
Justine Tunney 5a132f9652 Add seccomp bpf sandboxing to redbean
It's now possible to pass the `-S` or `-SS` flags to sandbox redbean
worker proecsses after they've been forked. The first `-S` flag is
intended to be a permissive builtin policy that limits system calls to
only that which the various parts of redbean serving need. The second
`-SS` flag is intended to be more restrictive, preventing things like
the Lua extensions you download off the web from using the HTTP client
or sockets APIs. In upcoming changes you'll be able to implement your
own Berkeley Packet Filter sandbox programs and load them via Lua.
2022-04-18 08:54:42 -07:00

80 lines
3.8 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 │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/strace.internal.h"
#include "libc/calls/struct/iovec.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/sock/internal.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.internal.h"
/**
* Reads data to multiple buffers.
*
* This is the same thing as read() except it has multiple buffers.
* This yields a performance boost in situations where it'd be expensive
* to stitch data together using memcpy() or issuing multiple syscalls.
* This wrapper is implemented so that readv() calls where iovlen<2 may
* be passed to the kernel as read() instead. This yields a 100 cycle
* performance boost in the case of a single small iovec.
*
* @return number of bytes actually read, or -1 w/ errno
* @restartable
*/
ssize_t readv(int fd, const struct iovec *iov, int iovlen) {
int i;
ssize_t rc;
if (fd >= 0 && iovlen >= 0) {
if (IsAsan() && !__asan_is_valid_iov(iov, iovlen)) {
rc = efault();
} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
rc = weaken(__zipos_read)(
(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, -1);
} else if (!IsWindows() && !IsMetal()) {
if (iovlen == 1) {
rc = sys_read(fd, iov[0].iov_base, iov[0].iov_len);
} else {
rc = sys_readv(fd, iov, iovlen);
}
} else if (fd >= g_fds.n) {
rc = ebadf();
} else if (IsMetal()) {
rc = sys_readv_metal(g_fds.p + fd, iov, iovlen);
} else {
rc = sys_readv_nt(g_fds.p + fd, iov, iovlen);
}
} else {
rc = einval();
}
#if defined(SYSDEBUG) && _DATATRACE
if (__strace > 0) {
if (rc == -1 && errno == EFAULT) {
STRACE("readv(%d, %p, %d) → %'zd% m", fd, iov, iovlen, rc);
} else {
kprintf(STRACE_PROLOGUE "readv(%d, [", fd);
__strace_iov(iov, iovlen, rc != -1 ? rc : 0);
kprintf("], %d) → %'ld% m%n", iovlen, rc);
}
}
#endif
return rc;
}