[dart:io,fuchsia] Change namespace setup failure from ASSERTs to FATALs

To help investigate FLK-221.

Change-Id: I8c2fafac232bff8cac1d2acac14a2a765d267975
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/103360
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Zach Anderson <[email protected]>

Author: zanderso

runtime/bin/file_fuchsia.cc

@@ -255,24 +255,26 @@ bool File::Exists(Namespace* namespc, const char* name) {
   if (NO_RETRY_EXPECTED(fstatat(ns.fd(), ns.path(), &st, 0)) == 0) {
     // Everything but a directory and a link is a file to Dart.
     return !S_ISDIR(st.st_mode) && !S_ISLNK(st.st_mode);
-  } else {
-    return false;
   }
+  return false;
 }
 
 bool File::Create(Namespace* namespc, const char* name) {
   NamespaceScope ns(namespc, name);
   const int fd = NO_RETRY_EXPECTED(
       openat(ns.fd(), ns.path(), O_RDONLY | O_CREAT | O_CLOEXEC, 0666));
   if (fd < 0) {
+    Syslog::PrintErr("File::Create() openat(%ld, %s) failed: %s\n", ns.fd(),
+                     ns.path(), strerror(errno));
     return false;
   }
   // File.create returns a File, so we shouldn't be giving the illusion that the
   // call has created a file or that a file already exists if there is already
   // an entity at the same path that is a directory or a link.
-  bool is_file = true;
+  bool is_file = false;
   struct stat st;
   if (NO_RETRY_EXPECTED(fstat(fd, &st)) == 0) {
+    is_file = true;
     if (S_ISDIR(st.st_mode)) {
       errno = EISDIR;
       is_file = false;

runtime/bin/namespace_fuchsia.cc

@@ -22,20 +22,32 @@ namespace bin {
 
 NamespaceImpl::NamespaceImpl(fdio_ns_t* fdio_ns)
       : fdio_ns_(fdio_ns),
-        rootfd_(fdio_ns_opendir(fdio_ns)),
         cwd_(strdup("/")) {
-  ASSERT(rootfd_ > 0);
+  rootfd_ = fdio_ns_opendir(fdio_ns);
+  if (rootfd_ < 0) {
+    FATAL2("Failed to open file descriptor for namespace: errno=%d: %s", errno,
+           strerror(errno));
+  }
   cwdfd_ = dup(rootfd_);
-  ASSERT(cwdfd_ > 0);
+  if (cwdfd_ < 0) {
+    FATAL2("Failed to dup() namespace file descriptor: errno=%d: %s", errno,
+           strerror(errno));
+  }
 }
 
 NamespaceImpl::NamespaceImpl(const char* path)
       : fdio_ns_(NULL),
-        rootfd_(TEMP_FAILURE_RETRY(open(path, O_DIRECTORY))),
         cwd_(strdup("/")) {
-  ASSERT(rootfd_ > 0);
+  rootfd_ = TEMP_FAILURE_RETRY(open(path, O_DIRECTORY));
+  if (rootfd_ < 0) {
+    FATAL2("Failed to open file descriptor for namespace: errno=%d: %s", errno,
+           strerror(errno));
+  }
   cwdfd_ = dup(rootfd_);
-  ASSERT(cwdfd_ > 0);
+  if (cwdfd_ < 0) {
+    FATAL2("Failed to dup() namespace file descriptor: errno=%d: %s", errno,
+           strerror(errno));
+  }
 }
 
 NamespaceImpl::~NamespaceImpl() {
@@ -54,7 +66,7 @@ bool NamespaceImpl::SetCwd(Namespace* namespc, const char* new_path) {
   NamespaceScope ns(namespc, new_path);
   const intptr_t new_cwdfd =
       TEMP_FAILURE_RETRY(openat(ns.fd(), ns.path(), O_DIRECTORY));
-  if (new_cwdfd != 0) {
+  if (new_cwdfd < 0) {
     return false;
   }