support passing stdio descriptors

This commit requires the stdio file descriptors to be explicitly
defined. This allows embedders to run multiple WASI applications
in the same process (assuming they also monkey patch the
uvwasi_proc_exit() functionality to not force the process to
exit).

README.md

@@ -27,6 +27,9 @@ int main(void) {
   uvwasi_errno_t err;
 
   /* Setup the initialization options. */
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 3;
   init_options.argv = calloc(3, sizeof(char*));
@@ -38,6 +41,7 @@ int main(void) {
   init_options.preopens = calloc(1, sizeof(uvwasi_preopen_t));
   init_options.preopens[0].mapped_path = "/var";
   init_options.preopens[0].real_path = ".";
+  init_options.allocator = NULL;
 
   /* Initialize the sandbox. */
   err = uvwasi_init(&uvwasi, &init_options);
@@ -146,6 +150,10 @@ typedef struct uvwasi_options_s {
   size_t argc;
   char** argv;
   char** envp;
+  uvwasi_fd_t stdin;
+  uvwasi_fd_t stdout;
+  uvwasi_fd_t stderr;
+  const uvwasi_mem_t* allocator;
 } uvwasi_options_t;
 ```
 

include/uvwasi.h

@@ -60,6 +60,9 @@ typedef struct uvwasi_options_s {
   size_t argc;
   char** argv;
   char** envp;
+  uvwasi_fd_t stdin;
+  uvwasi_fd_t stdout;
+  uvwasi_fd_t stderr;
   const uvwasi_mem_t* allocator;
 } uvwasi_options_t;
 

src/fd_table.c

@@ -16,7 +16,7 @@
 
 static uvwasi_errno_t uvwasi__insert_stdio(uvwasi_t* uvwasi,
                                            struct uvwasi_fd_table_t* table,
-                                           const uv_file fd,
+                                           const uvwasi_fd_t fd,
                                            const uvwasi_fd_t expected,
                                            const char* name) {
   struct uvwasi_fd_wrap_t* wrap;
@@ -190,15 +190,15 @@ uvwasi_errno_t uvwasi_fd_table_init(uvwasi_t* uvwasi,
   }
 
   /* Create the stdio FDs. */
-  err = uvwasi__insert_stdio(uvwasi, table, 0, 0, "<stdin>");
+  err = uvwasi__insert_stdio(uvwasi, table, options->stdin, 0, "<stdin>");
   if (err != UVWASI_ESUCCESS)
     goto error_exit;
 
-  err = uvwasi__insert_stdio(uvwasi, table, 1, 1, "<stdout>");
+  err = uvwasi__insert_stdio(uvwasi, table, options->stdout, 1, "<stdout>");
   if (err != UVWASI_ESUCCESS)
     goto error_exit;
 
-  err = uvwasi__insert_stdio(uvwasi, table, 2, 2, "<stderr>");
+  err = uvwasi__insert_stdio(uvwasi, table, options->stderr, 2, "<stderr>");
   if (err != UVWASI_ESUCCESS)
     goto error_exit;
 

test/test-args-get.c

@@ -12,6 +12,9 @@ int main(void) {
   char** args_get_argv;
   char* buf;
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 3;
   init_options.argv = calloc(3, sizeof(char*));

test/test-basic-file-io.c

@@ -29,6 +29,9 @@ int main(void) {
   uv_fs_req_cleanup(&req);
   assert(r == 0 || r == UV_EEXIST);
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-ebadf-input-validation.c

@@ -22,6 +22,9 @@ int main(void) {
 
   test_void = (void*) &test_fdstat;
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-environ-get.c

@@ -20,6 +20,9 @@ int main(void) {
   char* buf;
   size_t i;
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-fd-prestat-dir-name.c

@@ -19,6 +19,9 @@ int main(void) {
   uv_fs_req_cleanup(&req);
   assert(r == 0 || r == UV_EEXIST);
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-multiple-wasi-destroys.c

@@ -8,6 +8,9 @@ int main(void) {
   uvwasi_options_t init_options;
   uvwasi_errno_t err;
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-path-create-remove-directory.c

@@ -21,6 +21,9 @@ int main(void) {
   uv_fs_req_cleanup(&req);
   assert(r == 0 || r == UV_ENOENT);
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;

test/test-random-get.c

@@ -13,6 +13,9 @@ int main(void) {
   int success;
   int i;
 
+  init_options.stdin = 0;
+  init_options.stdout = 1;
+  init_options.stderr = 2;
   init_options.fd_table_size = 3;
   init_options.argc = 0;
   init_options.argv = NULL;