AT_FDCWD support.

Makefile

@@ -188,6 +188,10 @@ CFLAGS = $(WASM_CFLAGS) --target=$(TARGET_TRIPLE)
 # WebAssembly floating-point match doesn't trap.
 # TODO: Add -fno-signaling-nans when the compiler supports it.
 CFLAGS += -fno-trapping-math
+# We should have proper declarations for everything.
+CFLAGS += \
+    -Werror=missing-declarations \
+    -Werror=implicit-function-declaration \
 
 # Configure support for threads.
 ifeq ($(THREAD_MODEL), single)

expected/wasm32-wasi/defined-symbols.txt

@@ -249,6 +249,7 @@ __uflow
 __unlist_locked_file
 __uselocale
 __utc
+__wasilibc_access
 __wasilibc_cwd
 __wasilibc_ensure_environ
 __wasilibc_environ
@@ -258,12 +259,31 @@ __wasilibc_find_abspath
 __wasilibc_find_relpath
 __wasilibc_find_relpath_alloc
 __wasilibc_initialize_environ
+__wasilibc_link
+__wasilibc_link_newat
+__wasilibc_link_oldat
+__wasilibc_nocwd___wasilibc_rmdirat
+__wasilibc_nocwd___wasilibc_unlinkat
+__wasilibc_nocwd_faccessat
+__wasilibc_nocwd_fstatat
+__wasilibc_nocwd_linkat
+__wasilibc_nocwd_mkdirat
+__wasilibc_nocwd_openat_nomode
+__wasilibc_nocwd_opendirat
+__wasilibc_nocwd_readlinkat
+__wasilibc_nocwd_renameat
+__wasilibc_nocwd_scandirat
+__wasilibc_nocwd_symlinkat
+__wasilibc_nocwd_utimensat
 __wasilibc_open_nomode
-__wasilibc_openat_nomode
 __wasilibc_register_preopened_fd
+__wasilibc_rename_newat
+__wasilibc_rename_oldat
 __wasilibc_rmdirat
+__wasilibc_stat
 __wasilibc_tell
 __wasilibc_unlinkat
+__wasilibc_utimens
 __wasm_call_dtors
 __wcscoll_l
 __wcsftime_l

expected/wasm32-wasi/include-all.c

@@ -166,6 +166,7 @@
 #include <wasi/api.h>
 #include <wasi/libc-environ.h>
 #include <wasi/libc-find-relpath.h>
+#include <wasi/libc-nocwd.h>
 #include <wasi/libc.h>
 #include <wchar.h>
 #include <wctype.h>

expected/wasm32-wasi/predefined-macros.txt

@@ -46,6 +46,7 @@
 #define ARG_MAX 131072
 #define ARMAG "!<arch>\n"
 #define AT_EACCESS (0x0)
+#define AT_FDCWD (-2)
 #define AT_REMOVEDIR (0x4)
 #define AT_SYMLINK_FOLLOW (0x2)
 #define AT_SYMLINK_NOFOLLOW (0x1)
@@ -3021,6 +3022,7 @@
 #define __wasi_libc_environ_h 
 #define __wasi_libc_find_relpath_h 
 #define __wasi_libc_h 
+#define __wasi_libc_nocwd_h 
 #define __wasilibc___errno_h 
 #define __wasilibc___errno_values_h 
 #define __wasilibc___fd_set_h 

libc-bottom-half/cloudlibc/src/libc/dirent/opendirat.c

@@ -3,18 +3,15 @@
 // SPDX-License-Identifier: BSD-2-Clause
 
 #include <wasi/libc.h>
+#include <wasi/libc-nocwd.h>
 #include <dirent.h>
 #include <fcntl.h>
 #include <stddef.h>
 #include <unistd.h>
 
-DIR *opendirat(int dir, const char *dirname) {
+DIR *__wasilibc_nocwd_opendirat(int dir, const char *dirname) {
   // Open directory.
-#ifdef __wasilibc_unmodified_upstream // avoid making a varargs call
-  int fd = openat(dir, dirname, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
-#else
-  int fd = __wasilibc_openat_nomode(dir, dirname, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
-#endif
+  int fd = __wasilibc_nocwd_openat_nomode(dir, dirname, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
   if (fd == -1)
     return NULL;
 

libc-bottom-half/cloudlibc/src/libc/dirent/scandirat.c

@@ -4,6 +4,7 @@
 
 #include <wasi/api.h>
 #include <wasi/libc.h>
+#include <wasi/libc-nocwd.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -17,19 +18,15 @@ static int sel_true(const struct dirent *de) {
   return 1;
 }
 
-int scandirat(int dirfd, const char *dir, struct dirent ***namelist,
-              int (*sel)(const struct dirent *),
-              int (*compar)(const struct dirent **, const struct dirent **)) {
+int __wasilibc_nocwd_scandirat(int dirfd, const char *dir, struct dirent ***namelist,
+                               int (*sel)(const struct dirent *),
+                               int (*compar)(const struct dirent **, const struct dirent **)) {
   // Match all files if no select function is provided.
   if (sel == NULL)
     sel = sel_true;
 
   // Open the directory.
-#ifdef __wasilibc_unmodified_upstream // avoid making a varargs call
-  int fd = openat(dirfd, dir, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
-#else
-  int fd = __wasilibc_openat_nomode(dirfd, dir, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
-#endif
+  int fd = __wasilibc_nocwd_openat_nomode(dirfd, dir, O_RDONLY | O_NONBLOCK | O_DIRECTORY);
   if (fd == -1)
     return -1;
 
@@ -119,12 +116,8 @@ int scandirat(int dirfd, const char *dir, struct dirent ***namelist,
 
   read_entries:;
     // Load more directory entries and continue.
-#ifdef __wasilibc_unmodified_upstream
-    __wasi_errno_t error = __wasi_file_readdir(fd, buffer, buffer_size,
-#else
     // TODO: Remove the cast on `buffer` once the witx is updated with char8 support.
     __wasi_errno_t error = __wasi_fd_readdir(fd, (uint8_t *)buffer, buffer_size,
-#endif
                                                        cookie, &buffer_used);
     if (error != 0) {
       errno = error;

libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c

@@ -11,156 +11,61 @@
 #include <fcntl.h>
 #include <string.h>
 
-#ifdef __wasilibc_unmodified_upstream // fstat
-static_assert(O_APPEND == __WASI_FDFLAG_APPEND, "Value mismatch");
-static_assert(O_DSYNC == __WASI_FDFLAG_DSYNC, "Value mismatch");
-static_assert(O_NONBLOCK == __WASI_FDFLAG_NONBLOCK, "Value mismatch");
-static_assert(O_RSYNC == __WASI_FDFLAG_RSYNC, "Value mismatch");
-static_assert(O_SYNC == __WASI_FDFLAG_SYNC, "Value mismatch");
-#else
 static_assert(O_APPEND == __WASI_FDFLAGS_APPEND, "Value mismatch");
 static_assert(O_DSYNC == __WASI_FDFLAGS_DSYNC, "Value mismatch");
 static_assert(O_NONBLOCK == __WASI_FDFLAGS_NONBLOCK, "Value mismatch");
 static_assert(O_RSYNC == __WASI_FDFLAGS_RSYNC, "Value mismatch");
 static_assert(O_SYNC == __WASI_FDFLAGS_SYNC, "Value mismatch");
-#endif
 
-#ifdef __wasilibc_unmodified_upstream // fstat
-static_assert(O_CREAT >> 12 == __WASI_O_CREAT, "Value mismatch");
-static_assert(O_DIRECTORY >> 12 == __WASI_O_DIRECTORY, "Value mismatch");
-static_assert(O_EXCL >> 12 == __WASI_O_EXCL, "Value mismatch");
-static_assert(O_TRUNC >> 12 == __WASI_O_TRUNC, "Value mismatch");
-#else
 static_assert(O_CREAT >> 12 == __WASI_OFLAGS_CREAT, "Value mismatch");
 static_assert(O_DIRECTORY >> 12 == __WASI_OFLAGS_DIRECTORY, "Value mismatch");
 static_assert(O_EXCL >> 12 == __WASI_OFLAGS_EXCL, "Value mismatch");
 static_assert(O_TRUNC >> 12 == __WASI_OFLAGS_TRUNC, "Value mismatch");
-#endif
 
-int openat(int fd, const char *path, int oflag, ...) {
-#ifdef __wasilibc_unmodified_upstream // fstat
-#else
-    return __wasilibc_openat_nomode(fd, path, oflag);
-}
-
-int __wasilibc_openat_nomode(int fd, const char *path, int oflag) {
-#endif
+int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) {
   // Compute rights corresponding with the access modes provided.
   // Attempt to obtain all rights, except the ones that contradict the
   // access mode provided to openat().
-#ifdef __wasilibc_unmodified_upstream // Let the WASI implementation check this instead.
-  __wasi_rights_t min = 0;
-#endif
   __wasi_rights_t max =
-#ifdef __wasilibc_unmodified_upstream // fstat
-      ~(__WASI_RIGHT_FD_DATASYNC | __WASI_RIGHT_FD_READ |
-        __WASI_RIGHT_FD_WRITE | __WASI_RIGHT_FILE_ALLOCATE |
-        __WASI_RIGHT_FILE_READDIR | __WASI_RIGHT_FILE_STAT_FPUT_SIZE |
-#else
       ~(__WASI_RIGHTS_FD_DATASYNC | __WASI_RIGHTS_FD_READ |
         __WASI_RIGHTS_FD_WRITE | __WASI_RIGHTS_FD_ALLOCATE |
-        __WASI_RIGHTS_FD_READDIR | __WASI_RIGHTS_FD_FILESTAT_SET_SIZE |
-#endif
-#ifdef __wasilibc_unmodified_upstream // RIGHT_MEM_MAP_EXEC
-        __WASI_RIGHT_MEM_MAP_EXEC);
-#else
-        0);
-#endif
+        __WASI_RIGHTS_FD_READDIR | __WASI_RIGHTS_FD_FILESTAT_SET_SIZE);
   switch (oflag & O_ACCMODE) {
     case O_RDONLY:
     case O_RDWR:
     case O_WRONLY:
       if ((oflag & O_RDONLY) != 0) {
-#ifdef __wasilibc_unmodified_upstream // Let the WASI implementation check this instead.
-        min |= (oflag & O_DIRECTORY) == 0 ? __WASI_RIGHT_FD_READ
-                                          : __WASI_RIGHT_FILE_READDIR;
-#endif
-#ifdef __wasilibc_unmodified_upstream // RIGHT_MEM_MAP_EXEC
-        max |= __WASI_RIGHT_FD_READ | __WASI_RIGHT_FILE_READDIR |
-               __WASI_RIGHT_MEM_MAP_EXEC;
-#else
         max |= __WASI_RIGHTS_FD_READ | __WASI_RIGHTS_FD_READDIR;
-#endif
       }
       if ((oflag & O_WRONLY) != 0) {
-#ifdef __wasilibc_unmodified_upstream // Let the WASI implementation check this instead.
-        min |= __WASI_RIGHT_FD_WRITE;
-        if ((oflag & O_APPEND) == 0)
-          min |= __WASI_RIGHT_FD_SEEK;
-#endif
-#ifdef __wasilibc_unmodified_upstream // fstat
-        max |= __WASI_RIGHT_FD_DATASYNC | __WASI_RIGHT_FD_WRITE |
-               __WASI_RIGHT_FILE_ALLOCATE |
-               __WASI_RIGHT_FILE_STAT_FPUT_SIZE;
-#else
         max |= __WASI_RIGHTS_FD_DATASYNC | __WASI_RIGHTS_FD_WRITE |
                __WASI_RIGHTS_FD_ALLOCATE |
                __WASI_RIGHTS_FD_FILESTAT_SET_SIZE;
-#endif
       }
       break;
     case O_EXEC:
-#ifdef __wasilibc_unmodified_upstream // RIGHT_PROC_EXEC
-      min |= __WASI_RIGHT_PROC_EXEC;
-#endif
       break;
     case O_SEARCH:
       break;
     default:
       errno = EINVAL;
       return -1;
   }
-#ifdef __wasilibc_unmodified_upstream // Let the WASI implementation check this instead.
-  assert((min & max) == min &&
-         "Minimal rights should be a subset of the maximum");
-#endif
 
   // Ensure that we can actually obtain the minimal rights needed.
   __wasi_fdstat_t fsb_cur;
-#ifdef __wasilibc_unmodified_upstream
-  __wasi_errno_t error = __wasi_fd_stat_get(fd, &fsb_cur);
-#else
   __wasi_errno_t error = __wasi_fd_fdstat_get(fd, &fsb_cur);
-#endif
   if (error != 0) {
     errno = error;
     return -1;
   }
-#ifdef __wasilibc_unmodified_upstream // Let the WASI implementation check this instead.
-  if (fsb_cur.fs_filetype != __WASI_FILETYPE_DIRECTORY) {
-    errno = ENOTDIR;
-    return -1;
-  }
-  if ((min & fsb_cur.fs_rights_inheriting) != min) {
-    errno = ENOTCAPABLE;
-    return -1;
-  }
-#endif
 
   // Path lookup properties.
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-  __wasi_lookup_t lookup = {.fd = fd, .flags = 0};
-#else
   __wasi_lookupflags_t lookup_flags = 0;
-#endif
   if ((oflag & O_NOFOLLOW) == 0)
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-    lookup.flags |= __WASI_LOOKUP_SYMLINK_FOLLOW;
-#else
     lookup_flags |= __WASI_LOOKUPFLAGS_SYMLINK_FOLLOW;
-#endif
 
   // Open file with appropriate rights.
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t and __wasi_fdstat_t
-  __wasi_fdstat_t fsb_new = {
-      .fs_flags = oflag & 0xfff,
-      .fs_rights_base = max & fsb_cur.fs_rights_inheriting,
-      .fs_rights_inheriting = fsb_cur.fs_rights_inheriting,
-  };
-  __wasi_fd_t newfd;
-  error = __wasi_file_open(lookup, path, strlen(path),
-                                 (oflag >> 12) & 0xfff, &fsb_new, &newfd);
-#else
   __wasi_fdflags_t fs_flags = oflag & 0xfff;
   __wasi_rights_t fs_rights_base = max & fsb_cur.fs_rights_inheriting;
   __wasi_rights_t fs_rights_inheriting = fsb_cur.fs_rights_inheriting;
@@ -169,13 +74,8 @@ int __wasilibc_openat_nomode(int fd, const char *path, int oflag) {
                                  (oflag >> 12) & 0xfff,
                                  fs_rights_base, fs_rights_inheriting, fs_flags,
                                  &newfd);
-#endif
   if (error != 0) {
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-    errno = errno_fixup_directory(lookup.fd, error);
-#else
     errno = errno_fixup_directory(fd, error);
-#endif
     return -1;
   }
   return newfd;

libc-bottom-half/cloudlibc/src/libc/stdio/renameat.c

@@ -9,13 +9,9 @@
 #include <stdio.h>
 #include <string.h>
 
-int renameat(int oldfd, const char *old, int newfd, const char *new) {
-#ifdef __wasilibc_unmodified_upstream
-  __wasi_errno_t error = __wasi_file_rename(oldfd, old, strlen(old),
-#else
+int __wasilibc_nocwd_renameat(int oldfd, const char *old, int newfd, const char *new) {
   __wasi_errno_t error = __wasi_path_rename(oldfd, old, strlen(old),
-#endif
-                                                    newfd, new, strlen(new));
+                                            newfd, new, strlen(new));
   if (error != 0) {
     errno = errno_fixup_directory(oldfd, errno_fixup_directory(newfd, error));
     return -1;

libc-bottom-half/cloudlibc/src/libc/sys/stat/fstatat.c

@@ -13,29 +13,17 @@
 
 #include "stat_impl.h"
 
-int fstatat(int fd, const char *restrict path, struct stat *restrict buf,
-            int flag) {
+int __wasilibc_nocwd_fstatat(int fd, const char *restrict path, struct stat *restrict buf,
+                             int flag) {
   // Create lookup properties.
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-  __wasi_lookup_t lookup = {.fd = fd, .flags = 0};
-#else
   __wasi_lookupflags_t lookup_flags = 0;
-#endif
   if ((flag & AT_SYMLINK_NOFOLLOW) == 0)
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-    lookup.flags |= __WASI_LOOKUP_SYMLINK_FOLLOW;
-#else
     lookup_flags |= __WASI_LOOKUPFLAGS_SYMLINK_FOLLOW;
-#endif
 
   // Perform system call.
   __wasi_filestat_t internal_stat;
   __wasi_errno_t error =
-#ifdef __wasilibc_unmodified_upstream // split out __wasi_lookup_t
-      __wasi_file_stat_get(lookup, path, strlen(path), &internal_stat);
-#else
       __wasi_path_filestat_get(fd, lookup_flags, path, strlen(path), &internal_stat);
-#endif
   if (error != 0) {
     errno = errno_fixup_directory(fd, error);
     return -1;

libc-bottom-half/cloudlibc/src/libc/sys/stat/mkdirat.c

@@ -10,18 +10,9 @@
 #include <errno.h>
 #include <string.h>
 
-#ifdef __wasilibc_unmodified_upstream
-int mkdirat(int fd, const char *path, ...) {
-#else
-int mkdirat(int fd, const char *path, mode_t mode) {
-#endif
-#ifdef __wasilibc_unmodified_upstream // __wasi_path_create_directory
-  __wasi_errno_t error = __wasi_file_create(
-      fd, path, strlen(path), __WASI_FILETYPE_DIRECTORY);
-#else
+int __wasilibc_nocwd_mkdirat(int fd, const char *path, mode_t mode) {
   __wasi_errno_t error = __wasi_path_create_directory(
       fd, path, strlen(path));
-#endif
   if (error != 0) {
     errno = errno_fixup_directory(fd, error);
     return -1;