/*-*- 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/calls/ntmagicpaths.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/dce.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/strace.internal.h"
#include "libc/macros.internal.h"
#include "libc/nt/systeminfo.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/errfuns.h"
static inline bool IsSlash(char c) {
return c == '/' || c == '\\';
}
static inline int IsAlpha(int c) {
return ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z');
}
textwindows static const char *FixNtMagicPath(const char *path,
unsigned flags) {
const struct NtMagicPaths *mp = &kNtMagicPaths;
asm("" : "+r"(mp));
if (!IsSlash(path[0])) return path;
if (strcmp(path, mp->devtty) == 0) {
if ((flags & O_ACCMODE) == O_RDONLY) {
return mp->conin;
} else if ((flags & O_ACCMODE) == O_WRONLY) {
return mp->conout;
}
}
if (strcmp(path, mp->devnull) == 0) return mp->nul;
if (strcmp(path, mp->devstdin) == 0) return mp->conin;
if (strcmp(path, mp->devstdout) == 0) return mp->conout;
return path;
}
textwindows int __mkntpath(const char *path,
char16_t path16[hasatleast PATH_MAX]) {
return __mkntpath2(path, path16, -1);
}
/**
* Copies path for Windows NT.
*
* This function does the following chores:
*
* 1. Converting UTF-8 to UTF-16
* 2. Replacing forward-slashes with backslashes
* 3. Fixing drive letter paths, e.g. `/c/` → `c:\`
* 4. Add `\\?\` prefix for paths exceeding 260 chars
* 5. Remapping well-known paths, e.g. `/dev/null` → `NUL`
*
* @param flags is used by open()
* @param path16 is shortened so caller can prefix, e.g. \\.\pipe\, and
* due to a plethora of special-cases throughout the Win32 API
* @return short count excluding NUL on success, or -1 w/ errno
* @error ENAMETOOLONG
*/
textwindows int __mkntpath2(const char *path,
char16_t path16[hasatleast PATH_MAX], int flags) {
// 1. Need +1 for NUL-terminator
// 2. Need +1 for UTF-16 overflow
// 3. Need ≥2 for SetCurrentDirectory trailing slash requirement
// 4. Need ≥13 for mkdir() i.e. 1+8+3+1, e.g. "\\ffffffff.xxx\0"
// which is an "8.3 filename" from the DOS days
if (!path || (IsAsan() && !__asan_is_valid_str(path))) {
return efault();
}
path = FixNtMagicPath(path, flags);
size_t x, z;
char16_t *p = path16;
const char *q = path;
if (IsSlash(q[0]) && IsAlpha(q[1]) && IsSlash(q[2])) {
z = MIN(32767, PATH_MAX);
// turn "\c\foo" into "\\?\c:\foo"
p[0] = '\\';
p[1] = '\\';
p[2] = '?';
p[3] = '\\';
p[4] = q[1];
p[5] = ':';
p[6] = '\\';
p += 7;
q += 3;
z -= 7;
x = 7;
} else if (IsSlash(q[0]) && IsAlpha(q[1]) && !q[2]) {
z = MIN(32767, PATH_MAX);
// turn "\c" into "\\?\c:\"
p[0] = '\\';
p[1] = '\\';
p[2] = '?';
p[3] = '\\';
p[4] = q[1];
p[5] = ':';
p[6] = '\\';
p += 7;
q += 2;
z -= 7;
x = 7;
} else if (IsAlpha(q[0]) && q[1] == ':' && IsSlash(q[2])) {
z = MIN(32767, PATH_MAX);
// turn "c:\foo" into "\\?\c:\foo"
p[0] = '\\';
p[1] = '\\';
p[2] = '?';
p[3] = '\\';
p[4] = q[0];
p[5] = ':';
p[6] = '\\';
p += 7;
q += 3;
z -= 7;
x = 7;
} else if (IsSlash(q[0]) && IsSlash(q[1]) && q[2] == '?' && IsSlash(q[3])) {
z = MIN(32767, PATH_MAX);
x = 0;
} else {
z = MIN(260, PATH_MAX);
x = 0;
}
// turn /tmp into GetTempPath()
size_t m;
if (!x && IsSlash(q[0]) && q[1] == 't' && q[2] == 'm' && q[3] == 'p' &&
(IsSlash(q[4]) || !q[4])) {
m = GetTempPath(z, p);
if (!q[4]) return m;
q += 5;
p += m;
z -= m;
} else {
m = 0;
}
// turn utf-8 into utf-16
size_t n = tprecode8to16(p, z, q).ax;
if (n >= z - 1) {
return enametoolong();
}
// normalize path
// we need it because \\?\... paths have to be normalized
// we don't remove the trailing slash since it is special
size_t i, j;
for (j = i = 0; i < n; ++i) {
int c = p[i];
if (c == '/') {
c = '\\';
}
if (j > 1 && c == '\\' && p[j - 1] == '\\') {
// matched "^/" or "//" but not "^//"
} else if ((j && p[j - 1] == '\\') && //
c == '.' && //
(i + 1 == n || IsSlash(p[i + 1]))) {
// matched "/./" or "/.$"
i += !(i + 1 == n);
} else if ((j && p[j - 1] == '\\') && //
c == '.' && //
(i + 1 < n && p[i + 1] == '.') && //
(i + 2 == n || IsSlash(p[i + 2]))) {
// matched "/../" or "/..$"
while (j && p[j - 1] == '\\') --j;
while (j && p[j - 1] != '\\') --j;
} else {
p[j++] = c;
}
}
p[j] = 0;
n = j;
// our path is now stored at `path16` with length `n`
n = x + m + n;
// To avoid toil like this:
//
// "CMD.EXE was started with the above path as the current
// directory. UNC paths are not supported. Defaulting to Windows
// directory. Access is denied." -Quoth CMD.EXE
//
// Remove \\?\ prefix if we're within the 260 character limit.
if (n > 4 && n < 260 && //
path16[0] == '\\' && //
path16[1] == '\\' && //
path16[2] == '?' && //
path16[3] == '\\') {
memmove(path16, path16 + 4, (n - 4 + 1) * sizeof(char16_t));
n -= 4;
}
return n;
}