linux: do not write twice errors

if the error was sent correctly to the sync socket, then do not
attempt to print it again from the container process.

Signed-off-by: Giuseppe Scrivano <[email protected]>

src/libcrun/linux.c

@@ -3535,11 +3535,13 @@ read_error_from_sync_socket (int sync_socket_fd, int *error, char **str)
   int code;
   int ret;
 
-  ret = TEMP_FAILURE_RETRY (read (sync_socket_fd, &code, sizeof (code)));
-  if (UNLIKELY (ret < 0))
-    return false;
-
-  *error = code;
+  if (*error == 0)
+    {
+      ret = TEMP_FAILURE_RETRY (read (sync_socket_fd, &code, sizeof (code)));
+      if (UNLIKELY (ret < 0))
+        return false;
+      *error = code;
+    }
 
   ret = TEMP_FAILURE_RETRY (read (sync_socket_fd, &size, sizeof (size)));
   if (UNLIKELY (ret < 0))
@@ -3566,9 +3568,9 @@ read_error_from_sync_socket (int sync_socket_fd, int *error, char **str)
 static bool
 send_error_to_sync_socket (int sync_socket_fd, bool has_fd, libcrun_error_t *err)
 {
+  size_t size;
   int ret;
   int code;
-  size_t size;
   char *msg;
 
   if (err == NULL || *err == NULL)
@@ -3604,10 +3606,10 @@ send_error_to_sync_socket (int sync_socket_fd, bool has_fd, libcrun_error_t *err
 static inline int
 send_success_to_sync_socket (int sync_socket, libcrun_error_t *err)
 {
-  const char success = 0;
+  const int success = 0;
   int ret;
 
-  ret = TEMP_FAILURE_RETRY (write (sync_socket, &success, 1));
+  ret = TEMP_FAILURE_RETRY (write (sync_socket, &success, sizeof (success)));
   if (UNLIKELY (ret < 0))
     return crun_make_error (err, errno, "write to sync socket");
 
@@ -3622,32 +3624,31 @@ send_error_to_sync_socket_and_die (int sync_socket_fd, bool has_terminal, libcru
   if (err == NULL || *err == NULL)
     _exit (EXIT_FAILURE);
 
-  if (send_error_to_sync_socket (sync_socket_fd, has_terminal, err))
-    _exit (EXIT_FAILURE);
-
-  errno = crun_error_get_errno (err);
-  msg = (*err)->msg;
-  libcrun_fail_with_error (errno, "%s", msg);
+  if (! send_error_to_sync_socket (sync_socket_fd, has_terminal, err))
+    {
+      errno = crun_error_get_errno (err);
+      msg = (*err)->msg;
+      libcrun_fail_with_error (errno, "%s", msg);
+    }
   _exit (EXIT_FAILURE);
 }
 
 static int
 expect_success_from_sync_socket (int sync_fd, libcrun_error_t *err)
 {
-  int err_code;
   cleanup_free char *err_str = NULL;
-  char res = 1;
+  int res = 1;
   int ret;
 
-  ret = TEMP_FAILURE_RETRY (read (sync_fd, &res, 1));
-  if (UNLIKELY (ret != 1))
+  ret = TEMP_FAILURE_RETRY (read (sync_fd, &res, sizeof (res)));
+  if (UNLIKELY (ret != sizeof (res)))
     return crun_make_error (err, errno, "read status from sync socket");
 
   if (res == 0)
     return 0;
 
-  if (read_error_from_sync_socket (sync_fd, &err_code, &err_str))
-    return crun_make_error (err, err_code, "%s", err_str);
+  if (read_error_from_sync_socket (sync_fd, &res, &err_str))
+    return crun_make_error (err, res, "%s", err_str);
 
   return crun_make_error (err, 0, "read from sync socket");
 }
@@ -4806,7 +4807,7 @@ join_process_parent_helper (runtime_spec_schema_config_schema_process *process,
       ret = receive_fd_from_socket (sync_fd, err);
       if (UNLIKELY (ret < 0))
         {
-          int err_code;
+          int err_code = 0;
           cleanup_free char *err_str = NULL;
 
           if (read_error_from_sync_socket (sync_fd, &err_code, &err_str))