Fix resource leaks and minor issues

- Close pipe fds on fork failure in ExecFile::execute
- Add exception-safe fclose in cmd_file_append via try/catch
- Add overflow guards before K/M/G bit shifts in parse_whole_value
- Fix %u format for int* in sscanf (change to %d)
- Fix typo "atter"→"after" in error message

src/command_local.cc

@@ -173,9 +173,13 @@ cmd_file_append(const torrent::Object::list_type& args) {
   if (output == nullptr)
     throw torrent::input_error("Could not append to file '" + args.front().as_string() + "': " + std::strerror(errno));
 
-  file_print_list(++args.begin(), args.end(), output, file_print_delim_space);
-
-  fprintf(output, "\n");
+  try {
+    file_print_list(++args.begin(), args.end(), output, file_print_delim_space);
+    fprintf(output, "\n");
+  } catch (...) {
+    fclose(output);
+    throw;
+  }
   fclose(output);
   return torrent::Object();
 }

src/core/download.cc

@@ -137,7 +137,7 @@ Download::set_root_directory(const std::string& path) {
     rpc::call_command("d.state.set", (int64_t)0, rpc::make_target(this));
     control->core()->download_list()->close_directly(this);
 
-    throw torrent::input_error("Cannot change the directory of an open download atter the files have been moved.");
+    throw torrent::input_error("Cannot change the directory of an open download after the files have been moved.");
   }
 
   control->core()->download_list()->close_directly(this);

src/option_parser.cc

@@ -137,7 +137,7 @@ void
 OptionParser::call_int_pair(slot_int_pair slot, const std::string& arg) {
   int a, b;
 
-  if (std::sscanf(arg.c_str(), "%u-%u", &a, &b) != 2)
+  if (std::sscanf(arg.c_str(), "%d-%d", &a, &b) != 2)
     throw std::runtime_error("Invalid argument, \"" + arg + "\" should be \"a-b\"");
 
   slot(a, b);

src/rpc/exec_file.cc

@@ -41,8 +41,13 @@ ExecFile::execute(const char* file, char* const* argv, int flags) {
 
   pid_t childPid = fork();
 
-  if (childPid == -1)
+  if (childPid == -1) {
+    if (flags & flag_capture) {
+      ::close(pipeFd[0]);
+      ::close(pipeFd[1]);
+    }
     throw torrent::input_error("ExecFile::execute(...) Fork failed.");
+  }
 
   if (childPid == 0) {
     if (flags & flag_background) {

src/rpc/parse.cc

@@ -120,11 +120,17 @@ parse_value_nothrow(const char* src, int64_t* value, int base, int unit) {
   case 'b':
   case 'B': ++last; break;
   case 'k':
-  case 'K': *value = *value << 10; ++last; break;
+  case 'K':
+    if (*value > (int64_t)0x1FFFFFFFFFFFFF) return src; // overflow guard
+    *value = *value << 10; ++last; break;
   case 'm':
-  case 'M': *value = *value << 20; ++last; break;
+  case 'M':
+    if (*value > (int64_t)0x7FFFFFFFFFF) return src; // overflow guard
+    *value = *value << 20; ++last; break;
   case 'g':
-  case 'G': *value = *value << 30; ++last; break;
+  case 'G':
+    if (*value > (int64_t)0x1FFFFFFFF) return src; // overflow guard
+    *value = *value << 30; ++last; break;
 //   case ' ':
 //   case '\0': *value = *value * unit; break;
 //   default: throw torrent::input_error("Could not parse value.");