[PATCH] File name too long causing failure to open temporary head file in dlltool

[Alan Modra]

On Tue, Aug 13, 2024 at 10:31:21AM +0800, jiaying.song.cn@windriver.com wrote:
> From: Jiaying Song <jiaying.song.cn@windriver.com>
> 
> During the execution of the command: i686-w64-mingw32-dlltool
> --input-def $def_filepath --output-delaylib $filepath --dllname qemu.exe
> An error occurred:
> i686-w64-mingw32-dlltool: failed to open temporary head file: ..._w64_mingw32_nativesdk_qemu_8_2_2_build_plugins_libqemu_plugin_api_a_h.s
> 
> Due to the path length exceeding the Linux system's file name length
> limit (NAME_MAX=255), the temporary file name generated by the
> i686-w64-mingw32-dlltool command becomes too long to open. To address
> this, a new temporary file name prefix is generated using tmp_prefix =
> prefix_encode ("d", getpid()), ensuring that the file name does not
> exceed the system's length limit.
> 
> Signed-off-by: Jiaying Song <jiaying.song.cn@windriver.com>
> ---
>  binutils/dlltool.c | 17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/binutils/dlltool.c b/binutils/dlltool.c
> index 066c99a4..acaeb5a7 100644
> --- a/binutils/dlltool.c
> +++ b/binutils/dlltool.c
> @@ -4099,11 +4099,18 @@ main (int ac, char **av)
>        if (imp_name || delayimp_name)
>          {
>            const char *input = imp_name ? imp_name : delayimp_name;
> -          tmp_prefix = xmalloc (strlen (input) + 2);
> -          sprintf (tmp_prefix, "%s_", input);
> -          for (i = 0; tmp_prefix[i]; i++)
> -            if (!ISALNUM (tmp_prefix[i]))
> -              tmp_prefix[i] = '_';
> +          if ((strlen(input) + 2) > NAME_MAX)
> +            {
> +              tmp_prefix = prefix_encode ("d", getpid ());
> +            }
> +          else
> +            {
> +              tmp_prefix = xmalloc (strlen (input) + 2);
> +              sprintf (tmp_prefix, "%s_", input);
> +              for (i = 0; tmp_prefix[i]; i++)
> +              if (!ISALNUM (tmp_prefix[i]))
> +                tmp_prefix[i] = '_';
> +            }
>          }
>        else
>          {
> -- 
> 2.25.1

Thanks, I'm committing a slightly changed version.

diff --git a/binutils/dlltool.c b/binutils/dlltool.c
index d75a99d8b3d..6dc16a9ed84 100644
--- a/binutils/dlltool.c
+++ b/binutils/dlltool.c
@@ -4068,9 +4068,9 @@ main (int ac, char **av)
   if (tmp_prefix == NULL)
     {
       /* If possible use a deterministic prefix.  */
-      if (imp_name || delayimp_name)
+      const char *input = imp_name ? imp_name : delayimp_name;
+      if (input && strlen (input) + 2 <= NAME_MAX)
 	{
-	  const char *input = imp_name ? imp_name : delayimp_name;
 	  tmp_prefix = xmalloc (strlen (input) + 2);
 	  sprintf (tmp_prefix, "%s_", input);
 	  for (i = 0; tmp_prefix[i]; i++)
@@ -4078,9 +4078,7 @@ main (int ac, char **av)
 	      tmp_prefix[i] = '_';
 	}
       else
-	{
-	  tmp_prefix = prefix_encode ("d", getpid ());
-	}
+	tmp_prefix = prefix_encode ("d", getpid ());
     }
 
   mangle_defs ();


-- 
Alan Modra