/*-*- 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/assert.h"
#include "libc/calls/createfileflags.internal.h"
#include "libc/calls/internal.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/syscall-nt.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/errno.h"
#include "libc/macros.internal.h"
#include "libc/nt/console.h"
#include "libc/nt/createfile.h"
#include "libc/nt/enum/accessmask.h"
#include "libc/nt/enum/creationdisposition.h"
#include "libc/nt/enum/fileflagandattributes.h"
#include "libc/nt/enum/filesharemode.h"
#include "libc/nt/enum/filetype.h"
#include "libc/nt/files.h"
#include "libc/nt/process.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/nt/thunk/msabi.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/fileno.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
__msabi extern typeof(GetFileAttributes) *const __imp_GetFileAttributesW;
static textwindows int64_t sys_open_nt_impl(int dirfd, const char *path,
uint32_t flags, int32_t mode,
uint32_t extra_attr) {
// join(topath(dirfd), path) and translate from utf-8 to utf-16
char16_t path16[PATH_MAX];
if (__mkntpathat(dirfd, path, flags, path16) == -1) {
return kNtInvalidHandleValue;
}
// implement no follow flag
// you can't open symlinks; use readlink
// this flag only applies to the final path component
// if _O_NOFOLLOW_ANY is passed (-1 on NT) it'll be rejected later
uint32_t fattr = GetFileAttributes(path16);
if (flags & _O_NOFOLLOW) {
if (fattr != -1u && (fattr & kNtFileAttributeReparsePoint)) {
return eloop();
}
flags &= ~_O_NOFOLLOW; // don't actually pass this to win32
}
// handle some obvious cases while we have the attributes
// we should ideally resolve symlinks ourself before doing this
if (fattr != -1u) {
if (fattr & kNtFileAttributeDirectory) {
if ((flags & O_ACCMODE) != O_RDONLY || (flags & _O_CREAT)) {
// tried to open directory for writing. note that our
// undocumented _O_TMPFILE support on windows requires that a
// filename be passed, rather than a directory like linux.
return eisdir();
}
// on posix, the o_directory flag is an advisory safeguard that
// isn't required. on windows, it's mandatory for opening a dir
flags |= _O_DIRECTORY;
} else if (!(fattr & kNtFileAttributeReparsePoint)) {
// we know for certain file isn't a directory
if (flags & _O_DIRECTORY) {
return enotdir();
}
}
}
// translate posix flags to win32 flags
uint32_t perm, share, disp, attr;
if (GetNtOpenFlags(flags, mode, &perm, &share, &disp, &attr) == -1) {
return kNtInvalidHandleValue;
}
if (fattr != -1u) {
// "We have been asked to create a read-only file. "If the file
// already exists, the semantics of the Unix open system call is to
// preserve the existing permissions. If we pass CREATE_ALWAYS and
// FILE_ATTRIBUTE_READONLY to CreateFile, and the file already
// exists, CreateFile will change the file permissions. Avoid that to
// preserve the Unix semantics." -Quoth GoLang syscall_windows.go
attr &= ~kNtFileAttributeReadonly;
}
// kNtTruncateExisting always returns kNtErrorInvalidParameter :'(
if (disp == kNtTruncateExisting) {
if (fattr != -1u) {
disp = kNtCreateAlways; // file exists (wish it could be more atomic)
} else {
return __fix_enotdir(enotdir(), path16);
}
}
// We optimistically request some write permissions in O_RDONLY mode.
// But that might prevent opening some files. So reactively back off.
int extra_perm = 0;
if ((flags & O_ACCMODE) == O_RDONLY) {
extra_perm = kNtFileWriteAttributes | kNtFileWriteEa;
}
// open the file, following symlinks
int e = errno;
int64_t hand = CreateFile(path16, perm | extra_perm, share, &kNtIsInheritable,
disp, attr | extra_attr, 0);
if (hand == -1 && errno == EACCES && (flags & O_ACCMODE) == O_RDONLY) {
errno = e;
hand = CreateFile(path16, perm, share, &kNtIsInheritable, disp,
attr | extra_attr, 0);
}
return __fix_enotdir(hand, path16);
}
static textwindows int sys_open_nt_file(int dirfd, const char *file,
uint32_t flags, int32_t mode,
size_t fd) {
int64_t handle;
if ((handle = sys_open_nt_impl(dirfd, file, flags, mode,
kNtFileFlagOverlapped)) != -1) {
g_fds.p[fd].handle = handle;
g_fds.p[fd].kind = kFdFile;
g_fds.p[fd].flags = flags;
g_fds.p[fd].mode = mode;
return fd;
} else {
return -1;
}
}
static textwindows int sys_open_nt_special(int fd, int flags, int mode,
int kind, const char16_t *name) {
g_fds.p[fd].kind = kind;
g_fds.p[fd].mode = mode;
g_fds.p[fd].flags = flags;
g_fds.p[fd].handle = CreateFile(name, kNtGenericRead | kNtGenericWrite,
kNtFileShareRead | kNtFileShareWrite,
&kNtIsInheritable, kNtOpenExisting, 0, 0);
return fd;
}
static textwindows int sys_open_nt_dup(int fd, int flags, int mode, int oldfd) {
int64_t handle;
if (!__isfdopen(oldfd)) {
return enoent();
}
if (DuplicateHandle(GetCurrentProcess(), g_fds.p[oldfd].handle,
GetCurrentProcess(), &handle, 0, true,
kNtDuplicateSameAccess)) {
g_fds.p[fd] = g_fds.p[oldfd];
g_fds.p[fd].handle = handle;
g_fds.p[fd].mode = mode;
if (!sys_fcntl_nt_setfl(fd, flags)) {
return fd;
} else {
CloseHandle(handle);
return -1;
}
} else {
return __winerr();
}
}
textwindows int sys_open_nt(int dirfd, const char *file, uint32_t flags,
int32_t mode) {
int fd;
ssize_t rc;
BLOCK_SIGNALS;
__fds_lock();
if (!(flags & _O_CREAT)) mode = 0;
if ((rc = fd = __reservefd_unlocked(-1)) != -1) {
if (startswith(file, "/dev/")) {
if (!strcmp(file + 5, "tty")) {
rc = sys_open_nt_special(fd, flags, mode, kFdConsole, u"CONIN$");
} else if (!strcmp(file + 5, "null")) {
rc = sys_open_nt_special(fd, flags, mode, kFdDevNull, u"NUL");
} else if (!strcmp(file + 5, "stdin")) {
rc = sys_open_nt_dup(fd, flags, mode, STDIN_FILENO);
} else if (!strcmp(file + 5, "stdout")) {
rc = sys_open_nt_dup(fd, flags, mode, STDOUT_FILENO);
} else if (!strcmp(file + 5, "stderr")) {
rc = sys_open_nt_dup(fd, flags, mode, STDERR_FILENO);
} else {
rc = enoent();
}
} else {
rc = sys_open_nt_file(dirfd, file, flags, mode, fd);
}
if (rc == -1) {
__releasefd(fd);
}
__fds_unlock();
}
ALLOW_SIGNALS;
return rc;
}