cosmopolitan/libc/calls/fstatat.c
2024-07-19 19:38:00 -07:00

102 lines
5 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 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/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/struct/stat.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/fmt/itoa.h"
#include "libc/intrin/describeflags.h"
#include "libc/intrin/strace.h"
#include "libc/intrin/weaken.h"
#include "libc/log/log.h"
#include "libc/mem/alloca.h"
#include "libc/runtime/zipos.internal.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/at.h"
#include "libc/sysv/errfuns.h"
static inline const char *__strace_fstatat_flags(char buf[12], int flags) {
if (flags == AT_SYMLINK_NOFOLLOW)
return "AT_SYMLINK_NOFOLLOW";
FormatInt32(buf, flags);
return buf;
}
/**
* Returns information about thing.
*
* On Windows, this implementation always sets `st_uid` and `st_gid` to
* `getuid()` and `getgid()`. Anyone who relies upon the information to
* secure a multi-tenant personal computer should consider improving it
* and further note that the `st_mode` group / other bits will be clear
*
* @param dirfd is normally `AT_FDCWD` but if it's an open directory and
* file is a relative path, then `path` becomes relative to `dirfd`
* @param st is where the result is stored
* @param flags can have `AT_SYMLINK_NOFOLLOW`
* @raise EACCES if denied access to component in path prefix
* @raise EIO if i/o error occurred while reading from filesystem
* @raise ELOOP if a symbolic link loop exists in `path`
* @raise ENAMETOOLONG if a component in `path` exceeds `NAME_MAX`
* @raise ENOENT on empty string or if component in path doesn't exist
* @raise ENOTDIR if a parent component existed that wasn't a directory
* @raise EILSEQ if `path` contains illegal UTF-8 sequences (Windows/MacOS)
* @raise ENOTDIR if `path` is relative and `dirfd` isn't an open directory
* @raise ENOEXEC if `path` is a zip path and this executable isn't a zip file
* @raise EOVERFLOW shouldn't be possible on 64-bit systems
* @raise ELOOP may ahappen if `SYMLOOP_MAX` symlinks were dereferenced
* @raise ENAMETOOLONG may happen if `path` exceeded `PATH_MAX`
* @raise EFAULT if `path` or `st` point to invalid memory
* @raise EINVAL if `flags` has unsupported bits
* @return 0 on success, or -1 w/ errno
* @see S_ISDIR(st.st_mode), S_ISREG()
* @asyncsignalsafe
* @vforksafe
*/
int fstatat(int dirfd, const char *path, struct stat *st, int flags) {
// execve() depends on this
int rc;
struct ZiposUri zipname;
if (flags & ~AT_SYMLINK_NOFOLLOW) {
return einval();
} else if (__isfdkind(dirfd, kFdZip)) {
STRACE("zipos dirfd not supported yet");
rc = einval();
} else if (_weaken(__zipos_stat) &&
_weaken(__zipos_parseuri)(path, &zipname) != -1) {
if (!__vforked) {
rc = _weaken(__zipos_stat)(&zipname, st);
} else {
rc = enotsup();
}
} else if (IsLinux() || IsXnu() || IsFreebsd() || IsOpenbsd() || IsNetbsd()) {
rc = sys_fstatat(dirfd, path, st, flags);
} else if (IsWindows()) {
rc = sys_fstatat_nt(dirfd, path, st, flags);
} else {
rc = enosys();
}
STRACE("fstatat(%s, %#s, [%s], %s) → %d% m", DescribeDirfd(dirfd), path,
DescribeStat(rc, st), __strace_fstatat_flags(alloca(12), flags), rc);
return rc;
}
__weak_reference(fstatat, fstatat64);