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Improve system call polyfills

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- Polyfill open() w/ O_CLOEXEC on RHEL5
- Remove old workaround from rmdir() on the New Technology
- preadv() and pwritev() are now smarter about demodernization
- preadv() and pwritev() are now available on the New Technology
This commit is contained in:
Justine Tunney
2021-03-08 10:07:02 -08:00
parent 816b0e1851
commit 0ad609268f
21 changed files with 260 additions and 117 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
libc/calls/getcwd-xnu.c
View File

@@ -31,7 +31,7 @@ char *sys_getcwd_xnu(char *res, size_t size) {
int fd;
struct stat st[2];
char buf[XNU_MAXPATHLEN], *ret = NULL;
if ((fd = sys_openat(AT_FDCWD, ".", O_RDONLY | O_DIRECTORY)) != -1) {
if ((fd = sys_openat(AT_FDCWD, ".", O_RDONLY | O_DIRECTORY, 0)) != -1) {
if (sys_fstat(fd, &st[0]) != -1) {
if (st[0].st_dev && st[0].st_ino) {
if (sys_fcntl(fd, XNU_F_GETPATH, buf) != -1) {

4
libc/calls/internal.h
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@@ -108,6 +108,7 @@ i32 __sys_dup3(i32, i32, i32) hidden;
i32 __sys_execve(const char *, char *const[], char *const[]) hidden;
i32 __sys_fstat(i32, struct stat *) hidden;
i32 __sys_fstatat(i32, const char *, struct stat *, i32) hidden;
i32 __sys_openat(i32, const char *, i32, u32) hidden;
i32 __sys_pipe2(i32[hasatleast 2], u32) hidden;
i32 __sys_utimensat(i32, const char *, const struct timespec *, i32) hidden;
i32 getdents(i32, char *, u32, i64 *) hidden;
@@ -153,7 +154,7 @@ i32 sys_mprotect(void *, u64, i32) hidden;
i32 sys_msync(void *, u64, i32) hidden;
i32 sys_munmap(void *, u64) hidden;
i32 sys_nanosleep(const struct timespec *, struct timespec *) hidden;
i32 sys_openat(i32, const char *, i32, ...) hidden;
i32 sys_openat(i32, const char *, i32, u32) hidden;
i32 sys_pause(void) hidden;
i32 sys_pipe(i32[hasatleast 2]) hidden;
i32 sys_pipe2(i32[hasatleast 2], u32) hidden;
@@ -218,6 +219,7 @@ void __sigenter_xnu(void *, i32, i32, struct __darwin_siginfo *,
int gethostname_linux(char *, size_t) hidden;
int gethostname_bsd(char *, size_t) hidden;
int gethostname_nt(char *, size_t) hidden;
size_t __iovec_size(const struct iovec *, size_t) hidden;
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § syscalls » windows nt » veneers ─╬─│┼

27
libc/calls/iovecsize.c Normal file
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@@ -0,0 +1,27 @@
/*-*- 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 2021 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/calls/internal.h"
size_t __iovec_size(const struct iovec *v, size_t n) {
size_t i, sum;
for (sum = i = 0; i < n; ++i) {
sum += v[i].iov_len;
}
return sum;
}

44
libc/calls/openat-sysv.c Normal file
View File

@@ -0,0 +1,44 @@
/*-*- 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 2021 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/calls/internal.h"
#include "libc/errno.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/sysv/consts/o.h"
int sys_openat(int dirfd, const char *file, int flags, unsigned mode) {
int fd, err;
err = errno;
fd = __sys_openat(dirfd, file, flags, mode);
/*
* RHEL5 doesn't support O_CLOEXEC
* What on earth is it doing here?
* It returns -530!
*/
if (IsLinux() && fd == -1 && errno > 255) {
errno = err;
fd = __sys_openat(dirfd, file, flags & ~O_CLOEXEC, mode);
if (fd != -1 && (flags & O_CLOEXEC)) {
sys_fcntl(fd, F_SETFD, FD_CLOEXEC);
}
}
return fd;
}

81
libc/calls/preadv.c
View File

@@ -17,6 +17,7 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/bits.h"
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/iovec.h"
@@ -25,54 +26,84 @@
#include "libc/macros.internal.h"
#include "libc/sysv/consts/iov.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.internal.h"
#define __NR_preadv_linux 0x0127
/**
* Reads data from multiple buffers from file descriptor at offset.
* Reads with maximum generality.
*
* @param count is recommended to be 16 or fewer; if it exceeds IOV_MAX
* then the extra buffers are simply ignored
* @return number of bytes actually read, or -1 w/ errno
* @asyncsignalsafe
* @vforksafe
*/
ssize_t preadv(int fd, struct iovec *iovec, int count, int64_t off) {
ssize_t preadv(int fd, struct iovec *iov, int iovlen, int64_t off) {
static bool once, demodernize;
int olderr;
int i, err;
ssize_t rc;
if (!count) return 0;
if ((count = MIN(count, IOV_MAX)) < 0) return einval();
size_t got, toto;
if (fd < 0) return einval();
if (iovlen < 0) return einval();
if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
return weaken(__zipos_read)(
(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, off);
} else if (IsWindows()) {
if (fd < g_fds.n) {
return sys_read_nt(g_fds.p + fd, iov, iovlen, off);
} else {
return ebadf();
}
} else if (IsMetal()) {
return enosys();
}
/*
* NT, XNU, and 2007-era Linux don't support this system call.
*/
if (!once) {
once = true;
if (IsModeDbg() || (IsLinux() && iovec->iov_len >= __NR_preadv_linux)) {
/*
* Read size is too large to detect older kernels safely without
* introducing nontrivial mechanics. We'll try again later.
*/
once = false;
err = errno;
rc = sys_preadv(fd, iov, iovlen, off, off);
if (rc == -1 && errno == ENOSYS) {
errno = err;
once = true;
demodernize = true;
} else {
olderr = errno;
rc = sys_preadv(fd, iovec, count, off, off);
if (rc == -1 && errno == ENOSYS) {
errno = olderr;
demodernize = true;
} else if (IsLinux() && rc == __NR_preadv_linux /*RHEL5:CVE-2010-3301*/) {
demodernize = true;
} else if (IsLinux() && rc == __NR_preadv_linux) {
if (__iovec_size(iov, iovlen) < __NR_preadv_linux) {
demodernize = true; /*RHEL5:CVE-2010-3301*/
once = true;
} else {
return rc;
}
} else {
once = true;
return rc;
}
}
if (!demodernize) {
return sys_preadv(fd, iovec, count, off, off);
} else {
return pread(fd, iovec[0].iov_base, iovec[0].iov_len, off);
return sys_preadv(fd, iov, iovlen, off, off);
}
if (!iovlen) {
return sys_pread(fd, NULL, 0, off, off);
}
for (toto = i = 0; i < iovlen; ++i) {
rc = sys_pread(fd, iov[i].iov_base, iov[i].iov_len, off, off);
if (rc == -1) {
if (toto && (errno == EINTR || errno == EAGAIN)) {
return toto;
} else {
return -1;
}
}
got = rc;
toto += got;
if (got != iov[i].iov_len) {
break;
}
}
return toto;
}

80
libc/calls/pwritev.c
View File

@@ -16,6 +16,7 @@
│ 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/struct/iovec.h"
@@ -24,6 +25,7 @@
#include "libc/macros.internal.h"
#include "libc/sysv/consts/iov.h"
#include "libc/sysv/errfuns.h"
#include "libc/zipos/zipos.internal.h"
#define __NR_pwritev_linux 0x0128
@@ -35,49 +37,77 @@
* been committed. It can also happen if we need to polyfill this system
* call using pwrite().
*
* @param count is recommended to be 16 or fewer; if it exceeds IOV_MAX
* then the extra buffers are simply ignored
* @return number of bytes actually sent, or -1 w/ errno
* @asyncsignalsafe
* @vforksafe
*/
ssize_t pwritev(int fd, const struct iovec *iovec, int count, int64_t off) {
ssize_t pwritev(int fd, const struct iovec *iov, int iovlen, int64_t off) {
static bool once, demodernize;
int olderr;
int i, err;
ssize_t rc;
if (!count) return 0;
if ((count = MIN(count, IOV_MAX)) < 0) return einval();
size_t sent, toto;
if (fd < 0) return einval();
if (iovlen < 0) return einval();
if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
return weaken(__zipos_write)(
(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, iov, iovlen, off);
} else if (IsWindows()) {
if (fd < g_fds.n) {
return sys_write_nt(g_fds.p + fd, iov, iovlen, off);
} else {
return ebadf();
}
} else if (IsMetal()) {
return enosys();
}
/*
* NT, XNU, and 2007-era Linux don't support this system call.
*/
if (!once) {
once = true;
if (IsModeDbg() || (IsLinux() && iovec->iov_len >= __NR_pwritev_linux)) {
/*
* Write size is too large to detect older kernels safely without
* introducing nontrivial mechanics. We'll try again later.
*/
once = false;
err = errno;
rc = sys_pwritev(fd, iov, iovlen, off, off);
if (rc == -1 && errno == ENOSYS) {
errno = err;
once = true;
demodernize = true;
} else {
olderr = errno;
rc = sys_pwritev(fd, iovec, count, off, off);
if (rc == -1 && errno == ENOSYS) {
errno = olderr;
demodernize = true;
} else if (IsLinux() &&
rc == __NR_pwritev_linux /*RHEL5:CVE-2010-3301*/) {
demodernize = true;
} else if (IsLinux() && rc == __NR_pwritev_linux) {
if (__iovec_size(iov, iovlen) < __NR_pwritev_linux) {
demodernize = true; /*RHEL5:CVE-2010-3301*/
once = true;
} else {
return rc;
}
} else {
once = true;
return rc;
}
}
if (!demodernize) {
return sys_pwritev(fd, iovec, count, off, off);
} else {
return pwrite(fd, iovec[0].iov_base, iovec[0].iov_len, off);
return sys_pwritev(fd, iov, iovlen, off, off);
}
if (!iovlen) {
return sys_pwrite(fd, NULL, 0, off, off);
}
for (toto = i = 0; i < iovlen; ++i) {
rc = sys_pwrite(fd, iov[i].iov_base, iov[i].iov_len, off, off);
if (rc == -1) {
if (toto && (errno == EINTR || errno == EAGAIN)) {
return toto;
} else {
return -1;
}
}
sent = rc;
toto += sent;
if (sent != iov[i].iov_len) {
break;
}
}
return toto;
}

22
libc/calls/unlinkat-nt.c
View File

@@ -33,25 +33,11 @@ static textwindows int sys_unlink_nt(const char16_t *path) {
}
static textwindows int sys_rmdir_nt(const char16_t *path) {
int e, ms;
for (ms = 1;; ms *= 2) {
if (RemoveDirectory(path)) return 0;
/*
* Files can linger, for absolutely no reason.
* Possibly some Windows Defender bug on Win7.
* Sleep for up to one second w/ expo backoff.
* Alternative is use Microsoft internal APIs.
* Never could have imagined it'd be this bad.
*/
if ((e = GetLastError()) == kNtErrorDirNotEmpty && ms <= 512) {
Sleep(ms);
continue;
} else {
break;
}
if (RemoveDirectory(path)) {
return 0;
} else {
return __winerr();
}
errno = e;
return -1;
}
textwindows int sys_unlinkat_nt(int dirfd, const char *path, int flags) {

10
libc/calls/write-nt.c
View File

@@ -25,14 +25,6 @@
#include "libc/nt/struct/overlapped.h"
#include "libc/sysv/errfuns.h"
static textwindows size_t SumIovecLen(const struct iovec *v, size_t n) {
size_t i, sum;
for (sum = i = 0; i < n; ++i) {
sum += v[i].iov_len;
}
return sum;
}
textwindows ssize_t sys_write_nt(struct Fd *fd, const struct iovec *iov,
size_t iovlen, ssize_t opt_offset) {
size_t i, total;
@@ -52,7 +44,7 @@ textwindows ssize_t sys_write_nt(struct Fd *fd, const struct iovec *iov,
return __winerr();
}
}
if (!total) assert(!SumIovecLen(iov, iovlen));
if (!total) assert(!__iovec_size(iov, iovlen));
return total;
} else {
if (WriteFile(fd->handle, NULL, 0, &wrote,