mirror of
https://github.com/jart/cosmopolitan.git
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104 lines
4.4 KiB
C
104 lines
4.4 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#include "libc/cosmo.h"
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#include "libc/errno.h"
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#include "libc/nt/enum/accessmask.h"
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#include "libc/nt/enum/fileflagandattributes.h"
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#include "libc/nt/enum/symboliclink.h"
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#include "libc/nt/enum/tokeninformationclass.h"
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#include "libc/nt/errors.h"
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#include "libc/nt/files.h"
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#include "libc/nt/privilege.h"
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#include "libc/nt/runtime.h"
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#include "libc/nt/struct/luid.h"
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#include "libc/nt/struct/tokenprivileges.h"
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#include "libc/nt/thunk/msabi.h"
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#include "libc/runtime/stack.h"
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#include "libc/sysv/errfuns.h"
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static struct {
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_Atomic(uint32_t) once;
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_Bool allowed;
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} g_winlink;
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static textwindows void InitializeWinlink(void) {
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int64_t tok;
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struct NtLuid id;
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struct NtTokenPrivileges tp;
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if (!OpenProcessToken(GetCurrentProcess(), kNtTokenAllAccess, &tok)) return;
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if (!LookupPrivilegeValue(0, u"SeCreateSymbolicLinkPrivilege", &id)) return;
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tp.PrivilegeCount = 1;
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tp.Privileges[0].Luid = id;
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tp.Privileges[0].Attributes = kNtSePrivilegeEnabled;
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if (!AdjustTokenPrivileges(tok, 0, &tp, sizeof(tp), 0, 0)) return;
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g_winlink.allowed = GetLastError() != kNtErrorNotAllAssigned;
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}
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textwindows int sys_symlinkat_nt(const char *target, int newdirfd,
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const char *linkpath) {
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#pragma GCC push_options
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#pragma GCC diagnostic ignored "-Wframe-larger-than="
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struct {
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char16_t target16[PATH_MAX];
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char16_t linkpath16[PATH_MAX];
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} M;
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CheckLargeStackAllocation(&M, sizeof(M));
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#pragma GCC pop_options
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int targetlen;
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uint32_t attrs, flags;
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// convert the paths
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if (__mkntpathat(newdirfd, linkpath, 0, M.linkpath16) == -1) return -1;
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if ((targetlen = __mkntpath(target, M.target16)) == -1) return -1;
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// determine if we need directory flag
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if ((attrs = GetFileAttributes(M.target16)) != -1u) {
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if (attrs & kNtFileAttributeDirectory) {
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flags = kNtSymbolicLinkFlagDirectory;
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} else {
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flags = 0;
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}
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} else {
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// win32 needs to know if it's a directory of a file symlink, but
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// that's hard to determine if we're creating a broken symlink so
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// we'll fall back to checking for trailing slash
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if (targetlen && M.target16[targetlen - 1] == '\\') {
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flags = kNtSymbolicLinkFlagDirectory;
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} else {
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flags = 0;
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}
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}
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// windows only lets administrators do this
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// even then we're required to ask for permission
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cosmo_once(&g_winlink.once, InitializeWinlink);
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if (!g_winlink.allowed) {
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return eperm();
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}
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// we can now proceed
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if (CreateSymbolicLink(M.linkpath16, M.target16, flags)) {
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return 0;
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} else {
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return __fix_enotdir(-1, M.linkpath16);
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}
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}
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