Implement missing unistd readv()

system/lib/libc/musl/src/unistd/readv.c

@@ -4,5 +4,13 @@
 
 ssize_t readv(int fd, const struct iovec *iov, int count)
 {
+#if __EMSCRIPTEN__
+	size_t num;
+	if (__wasi_syscall_ret(__wasi_fd_read(fd, (struct __wasi_iovec_t*)iov, count, &num))) {
+		num = -1;
+	}
+	return num;
+#else
 	return syscall_cp(SYS_readv, fd, iov, count);
+#endif
 }

tests/other/metadce/hello_world_O3_MAIN_MODULE.sent

@@ -15,7 +15,6 @@ __syscall133
 __syscall14
 __syscall142
 __syscall144
-__syscall145
 __syscall147
 __syscall148
 __syscall15

tests/other/metadce/hello_world_fastcomp_O3_MAIN_MODULE.sent

@@ -299,7 +299,6 @@ ___syscall133
 ___syscall14
 ___syscall142
 ___syscall144
-___syscall145
 ___syscall147
 ___syscall148
 ___syscall15

tests/test_other.py

@@ -8087,7 +8087,7 @@ def test_binaryen_metadce_cxx_fastcomp(self, *args):
     # don't compare the # of functions in a main module, which changes a lot
     # TODO(sbc): Investivate why the number of exports is order of magnitude
     # larger for wasm backend.
-    'main_module_1': (['-O3', '-s', 'MAIN_MODULE=1'],  175, [], [], 517336, None, 1518, None), # noqa
+    'main_module_1': (['-O3', '-s', 'MAIN_MODULE=1'],  174, [], [], 517336, None, 1518, None), # noqa
     'main_module_2': (['-O3', '-s', 'MAIN_MODULE=2'],   12, [], [],  10770,   12,   10, None), # noqa
   })
   @no_fastcomp()
@@ -8107,7 +8107,7 @@ def test_binaryen_metadce_hello(self, *args):
                       4, [],        [],           8,   0,    0,  0), # noqa; totally empty!
     # we don't metadce with linkable code! other modules may want stuff
     # don't compare the # of functions in a main module, which changes a lot
-    'main_module_1': (['-O3', '-s', 'MAIN_MODULE=1'], 1611, [], [], 226403, None, 107, None), # noqa
+    'main_module_1': (['-O3', '-s', 'MAIN_MODULE=1'], 1610, [], [], 226403, None, 107, None), # noqa
     'main_module_2': (['-O3', '-s', 'MAIN_MODULE=2'],   13, [], [],  10017,   13,   9,   20), # noqa
   })
   @no_wasm_backend()

tests/unistd/io.c

@@ -10,6 +10,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
+#include <sys/uio.h>
 #include <emscripten.h>
 
 int main() {
@@ -188,5 +189,25 @@ int main() {
   }
   printf("\n");
 
+  // readv
+  printf("\n");
+  memset(readBuffer, 0, sizeof readBuffer);
+  struct iovec iov;
+  iov.iov_base = readBuffer;
+  iov.iov_len = sizeof readBuffer;
+  printf("seek: %d\n", lseek(f, 0, SEEK_SET));
+  printf("read after write: %d\n", bytesRead = readv(f, &iov, 1));
+  printf("errno: %d\n", errno);
+  errno = 0;
+  printf("final: ");
+  for (int i = 0; i < bytesRead; i++) {
+    if (readBuffer[i] == 0) {
+      printf("\\0");
+    } else {
+      printf("%c", readBuffer[i]);
+    }
+  }
+  printf("\n");
+
   return 0;
 }

tests/unistd/io.out

@@ -78,3 +78,8 @@ seek: 0
 read after write: 37
 errno: 0
 final: wri4567890wri\0\0\0\0ite\0\0\0writeme\0\0write
+
+seek: 0
+read after write: 37
+errno: 0
+final: wri4567890wri\0\0\0\0ite\0\0\0writeme\0\0write