cosmopolitan/libc/calls/mkntpathat.c
Justine Tunney 39e7f24947
Fix handling of paths with dirfd on Windows
This change fixes an issue with all system calls ending with *at(), when
the caller passes `dirfd != AT_FDCWD` and an absolute path. It's because
the old code was turning paths like C:\bin\ls into \\C:\bin\ls\C:\bin\ls
after being converted from paths like /C/bin/ls. I noticed this when the
Emacs dired mode stopped working. It's unclear if it's a regression with
Cosmopolitan Libc or if this was introduced by the Emacs v29 upgrade. It
also impacted posix_spawn() for which a newly minted example now exists.
2024-09-01 17:52:30 -07:00

110 lines
4.6 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et 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/calls/syscall_support-nt.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/strace.h"
#include "libc/macros.h"
#include "libc/nt/enum/fileflagandattributes.h"
#include "libc/nt/files.h"
#include "libc/nt/thunk/msabi.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/errfuns.h"
static int IsAlpha(int c) {
return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
}
static bool IsAbsolutePathWin32(char16_t *path) {
if (path[0] == '\\')
return true;
if (IsAlpha(path[0]) && path[1] == ':')
return true;
return false;
}
static textwindows int __mkntpathath_impl(int64_t dirhand, const char *path,
int flags,
char16_t file[hasatleast PATH_MAX]) {
size_t n;
char16_t dir[PATH_MAX];
uint32_t dirlen, filelen;
if (!isutf8(path, -1))
return eilseq(); // thwart overlong nul in conversion
if ((filelen = __mkntpath2(path, file, flags)) == -1)
return -1;
if (!filelen)
return enoent();
if (dirhand != AT_FDCWD && !IsAbsolutePathWin32(file)) {
dirlen = GetFinalPathNameByHandle(dirhand, dir, ARRAYLEN(dir),
kNtFileNameNormalized | kNtVolumeNameDos);
if (!dirlen)
return __winerr();
if (dirlen + 1 + filelen + 1 > ARRAYLEN(dir))
return enametoolong();
dir[dirlen] = u'\\';
memcpy(dir + dirlen + 1, file, (filelen + 1) * sizeof(char16_t));
memcpy(file, dir, ((n = dirlen + 1 + filelen) + 1) * sizeof(char16_t));
int res = __normntpath(file, n);
return res;
} else {
return filelen;
}
}
textwindows int __mkntpathath(int64_t dirhand, const char *path, int flags,
char16_t file[hasatleast PATH_MAX]) {
// convert the path.
int len;
if ((len = __mkntpathath_impl(dirhand, path, flags, file)) == -1) {
return -1;
}
// if path ends with a slash, then we need to manually do what linux
// does and check to make sure it's a directory, and return ENOTDIR,
// since WIN32 will reject the path with EINVAL if we don't do this.
if (len && file[len - 1] == '\\') {
uint32_t fattr;
if (len > 1 && !(len == 3 && file[1] == ':')) {
file[--len] = 0;
}
if ((fattr = GetFileAttributes(file)) != -1u &&
!(fattr & kNtFileAttributeReparsePoint) &&
!(fattr & kNtFileAttributeDirectory)) {
return enotdir();
}
}
return len;
}
textwindows int __mkntpathat(int dirfd, const char *path, int flags,
char16_t file[hasatleast PATH_MAX]) {
int64_t dirhand;
if (dirfd == AT_FDCWD) {
dirhand = AT_FDCWD;
} else if (__isfdkind(dirfd, kFdFile)) {
dirhand = g_fds.p[dirfd].handle;
} else {
return ebadf();
}
return __mkntpathath(dirhand, path, flags, file);
}