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Improve system call documentation

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This change also introduces partial faccessat() support for zipos and
makes some slight breaking changes in errno results. close() is fixed
to use `EBADF` rather than `EINVAL` and we're now using `ENOTSUP` not
`EOPNOTSUPP` to indicate that zipos doesn't support a system call yet
This commit is contained in:
Justine Tunney 2022-10-02 07:42:44 -07:00
parent 0b5f84dd20
commit ad97775370
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GPG key ID: BE714B4575D6E328
18 changed files with 273 additions and 67 deletions
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34
libc/calls/faccessat.c
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@ -17,6 +17,7 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/syscall-nt.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
@ -35,33 +36,42 @@
* @param dirfd is normally AT_FDCWD but if it's an open directory and
* file is a relative path, then file is opened relative to dirfd
* @param path is a filename or directory
* @param mode can be R_OK, W_OK, X_OK, F_OK
* @param flags can have AT_EACCESS, AT_SYMLINK_NOFOLLOW
* @note on Linux flags is only supported on Linux 5.8+
* @param amode can be `R_OK`, `W_OK`, `X_OK`, or `F_OK`
* @param flags can have `AT_EACCESS` and/or `AT_SYMLINK_NOFOLLOW`
* @return 0 if ok, or -1 and sets errno
* @raise EINVAL if `mode` has bad value
* @raise EPERM if pledge() is in play without rpath promise
* @raise EACCES if access for requested `mode` would be denied
* @raise ENOTDIR if a directory component in `path` exists as non-directory
* @raise ENOENT if component of `path` doesn't exist or `path` is empty
* @raise ENOTSUP if `path` is a zip file and `dirfd` isn't `AT_FDCWD`
* @note on Linux `flags` is only supported on Linux 5.8+
* @asyncsignalsafe
*/
int faccessat(int dirfd, const char *path, int mode, uint32_t flags) {
int faccessat(int dirfd, const char *path, int amode, uint32_t flags) {
int e, rc;
if (IsAsan() && !__asan_is_valid(path, 1)) {
struct ZiposUri zipname;
if (!path || (IsAsan() && !__asan_is_valid(path, 1))) {
rc = efault();
} else if (_weaken(__zipos_notat) &&
_weaken(__zipos_notat)(dirfd, path) == -1) {
rc = -1; /* TODO(jart): implement me */
} else if (__isfdkind(dirfd, kFdZip)) {
rc = enotsup();
} else if (_weaken(__zipos_open) &&
_weaken(__zipos_parseuri)(path, &zipname) != -1) {
rc = _weaken(__zipos_access)(&zipname, amode);
} else if (!IsWindows()) {
e = errno;
if (!flags) goto NoFlags;
if ((rc = sys_faccessat2(dirfd, path, mode, flags)) == -1) {
if ((rc = sys_faccessat2(dirfd, path, amode, flags)) == -1) {
if (errno == ENOSYS) {
errno = e;
NoFlags:
rc = sys_faccessat(dirfd, path, mode, flags);
rc = sys_faccessat(dirfd, path, amode, flags);
}
}
} else {
rc = sys_faccessat_nt(dirfd, path, mode, flags);
rc = sys_faccessat_nt(dirfd, path, amode, flags);
}
STRACE("faccessat(%s, %#s, %#o, %#x) → %d% m", DescribeDirfd(dirfd), path,
mode, flags, rc);
amode, flags, rc);
return rc;
}