1 files changed, 79 insertions, 0 deletions
diff --git a/libc-bottom-half/headers/public/wasi/libc-find-relpath.h b/libc-bottom-half/headers/public/wasi/libc-find-relpath.h
new file mode 100644
index 0000000..32dbb03
--- /dev/null
+++ b/libc-bottom-half/headers/public/wasi/libc-find-relpath.h
@@ -0,0 +1,79 @@
+#ifndef __wasi_libc_find_relpath_h
+#define __wasi_libc_find_relpath_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Look up the given `path`, relative to the cwd, in the preopened directory
+ * map. If a suitable entry is found, then the file descriptor for that entry
+ * is returned. Additionally the absolute path of the directory's file
+ * descriptor is returned in `abs_prefix` and the relative portion that needs
+ * to be opened is stored in `*relative_path`.
+ *
+ * The `relative_path` argument must be a pointer to a buffer valid  for
+ * `relative_path_len` bytes, and this may be used as storage for the relative
+ * portion of the path being returned through `*relative_path`.
+ *
+ * See documentation on `__wasilibc_find_abspath` for more info about what the
+ * paths look like.
+ *
+ * Returns -1 on failure. Errno is set to either:
+ *
+ *  * ENOMEM - failed to allocate memory for internal routines.
+ *  * ENOENT - the `path` could not be found relative to any preopened dir.
+ *  * ERANGE - the `relative_path` buffer is too small to hold the relative path.
+ */
+int __wasilibc_find_relpath(const char *path,
+                            const char **__restrict__ abs_prefix,
+                            char **relative_path,
+                            size_t relative_path_len);
+
+/**
+ * Look up the given `path`, which is interpreted as absolute, in the preopened
+ * directory map. If a suitable entry is found, then the file descriptor for
+ * that entry is returned. Additionally the relative portion of the path to
+ * where the fd is opened is returned through `relative_path`, the absolute
+ * prefix which was matched is stored to `abs_prefix`, and `relative_path` may
+ * be an interior pointer to the `abspath` string.
+ *
+ * The `abs_prefix` returned string will not contain a leading `/`. Note that
+ * this may be the empty string. Additionally the returned `relative_path` will
+ * not contain a leading `/`. The `relative_path` return will not return an
+ * empty string, it will return `"."` instead if it would otherwise do so.
+ *
+ * Returns -1 on failure. Errno is set to either:
+ *
+ *  * ENOMEM - failed to allocate memory for internal routines.
+ *  * ENOENT - the `path` could not be found relative to any preopened dir.
+ */
+int __wasilibc_find_abspath(const char *abspath,
+                            const char **__restrict__ abs_prefix,
+                            const char **__restrict__ relative_path);
+
+/**
+ * Same as `__wasilibc_find_relpath`, except that this function will interpret
+ * `relative` as a malloc'd buffer that will be `realloc`'d to the appropriate
+ * size to contain the relative path.
+ *
+ * Note that this is a weak symbol and if it's not defined you can use
+ * `__wasilibc_find_relpath`. The weak-nature of this symbols means that if it's
+ * not otherwise included in the compilation then `chdir` wasn't used an there's
+ * no need for this symbol.
+ *
+ * See documentation on `__wasilibc_find_relpath` for more information.
+ */
+int __wasilibc_find_relpath_alloc(
+    const char *path,
+    const char **abs,
+    char **relative,
+    size_t *relative_len,
+    int can_realloc
+) __attribute__((__weak__));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif