Route rmdir/unlink directly to wasi's file_unlink_{directory,file}.

This way, if an application calls rmdir, it will only link in the
file_unlink_directory, and not file_unlink_file too.

Also, re-implement remove in terms of these new utilities.

Author: sunfishcode

Makefile

@@ -121,6 +121,7 @@ LIBC_TOP_HALF_MUSL_SOURCES = \
                  %/rename.c \
                  %/tmpnam.c %/tmpfile.c %/tempnam.c \
                  %/popen.c %/pclose.c \
+                 %/remove.c \
                  %/gets.c, \
                  $(wildcard $(LIBC_TOP_HALF_MUSL_SRC_DIR)/stdio/*.c)) \
     $(filter-out %/strsignal.c, \

expected/wasm32-wasi/defined-symbols.txt

@@ -243,6 +243,8 @@ __uselocale
 __utc
 __wasilibc_fd_renumber
 __wasilibc_register_preopened_fd
+__wasilibc_rmdirat
+__wasilibc_rmfileat
 __wcscoll_l
 __wcsftime_l
 __wcsxfrm_l

libc-bottom-half/cloudlibc/src/libc/unistd/__wasilibc_rmdirat.c

@@ -0,0 +1,14 @@
+#include <common/errno.h>
+#include <wasi/core.h>
+#include <errno.h>
+#include <string.h>
+
+int __wasilibc_rmdirat(int fd, const char *path) {
+    size_t path_len = strlen(path);
+    __wasi_errno_t error = __wasi_file_unlink_directory(fd, path, path_len);
+    if (error != 0) {
+        errno = errno_fixup_directory(fd, error);
+        return -1;
+    }
+    return 0;
+}

libc-bottom-half/cloudlibc/src/libc/unistd/__wasilibc_rmfileat.c

@@ -0,0 +1,14 @@
+#include <common/errno.h>
+#include <wasi/core.h>
+#include <errno.h>
+#include <string.h>
+
+int __wasilibc_rmfileat(int fd, const char *path) {
+    size_t path_len = strlen(path);
+    __wasi_errno_t error = __wasi_file_unlink_file(fd, path, path_len);
+    if (error != 0) {
+        errno = error;
+        return -1;
+    }
+    return 0;
+}

libc-bottom-half/cloudlibc/src/libc/unistd/unlinkat.c

@@ -5,6 +5,10 @@
 #include <common/errno.h>
 
 #include <wasi/core.h>
+#ifdef __wasilibc_unmodified_upstream // unlink
+#else
+#include <wasi/libc.h>
+#endif
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
@@ -21,22 +25,11 @@ int unlinkat(int fd, const char *path, int flag) {
     errno = errno_fixup_directory(fd, error);
     return -1;
   }
+  return 0;
 #else
-  __wasi_errno_t error;
-  size_t path_len = strlen(path);
   if ((flag & AT_REMOVEDIR) != 0) {
-    error = __wasi_file_unlink_directory(fd, path, path_len);
-    if (error != 0) {
-      errno = errno_fixup_directory(fd, error);
-      return -1;
-    }
-  } else {
-    error = __wasi_file_unlink_file(fd, path, path_len);
-    if (error != 0) {
-      errno = error;
-      return -1;
-    }
+    return __wasilibc_rmdirat(fd, path);
   }
+  return __wasilibc_rmfileat(fd, path);
 #endif
-  return 0;
 }

libc-bottom-half/headers/public/wasi/libc.h

@@ -7,6 +7,8 @@ extern "C" {
 
 int __wasilibc_register_preopened_fd(int fd, const char *path);
 int __wasilibc_fd_renumber(int fd, int newfd);
+int __wasilibc_rmfileat(int fd, const char *path);
+int __wasilibc_rmdirat(int fd, const char *path);
 
 #ifdef __cplusplus
 }

libc-bottom-half/libpreopen/lib/po_libc_wrappers.c

@@ -51,6 +51,7 @@
 #ifdef __wasilibc_unmodified_upstream
 #else
 #include <errno.h>
+#include <wasi/libc.h>
 #endif
 
 #include "internal.h"
@@ -318,15 +319,26 @@ unlink(const char *pathname)
 {
 	struct po_relpath rel_pathname = find_relative(pathname, NULL);
 
-	return unlinkat(rel_pathname.dirfd, rel_pathname.relative_path, 0);
+	return __wasilibc_rmfileat(rel_pathname.dirfd, rel_pathname.relative_path);
 }
 
 int
 rmdir(const char *pathname)
 {
 	struct po_relpath rel_pathname = find_relative(pathname, NULL);
 
-	return unlinkat(rel_pathname.dirfd, rel_pathname.relative_path, AT_REMOVEDIR);
+	return __wasilibc_rmdirat(rel_pathname.dirfd, rel_pathname.relative_path);
+}
+
+int
+remove(const char *pathname)
+{
+	struct po_relpath rel_pathname = find_relative(pathname, NULL);
+
+	int r = __wasilibc_rmfileat(rel_pathname.dirfd, rel_pathname.relative_path);
+	if (r != 0 && errno == EISDIR)
+		r = __wasilibc_rmdirat(rel_pathname.dirfd, rel_pathname.relative_path);
+	return r;
 }
 
 int

libc-top-half/musl/src/stdio/remove.c

@@ -1,15 +1,10 @@
-#ifdef __wasilibc_unmodified_upstream
-#else
-#include <unistd.h>
-#endif
 #include <stdio.h>
 #include <errno.h>
 #include <fcntl.h>
 #include "syscall.h"
 
 int remove(const char *path)
 {
-#ifdef __wasilibc_unmodified_upstream
 #ifdef SYS_unlink
 	int r = __syscall(SYS_unlink, path);
 #else
@@ -21,9 +16,4 @@ int remove(const char *path)
 	if (r==-EISDIR) r = __syscall(SYS_unlinkat, AT_FDCWD, path, AT_REMOVEDIR);
 #endif
 	return __syscall_ret(r);
-#else
-	int r = unlink(path);
-	if (r != 0 && errno==EISDIR) r = rmdir(path);
-	return r;
-#endif
 }