[llvm] r187208 - Extend the lifetime of the strings passed to posix_spawn_file_actions_addopen.

[Hal Finkel]

----- Original Message -----
> Author: rafael
> Date: Fri Jul 26 11:21:31 2013
> New Revision: 187208
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=187208&view=rev
> Log:
> Extend the lifetime of the strings passed to
> posix_spawn_file_actions_addopen.
> 
> Thanks to Hal Finkel for finding the bug and for the initial patch.
> 
> Modified:
>     llvm/trunk/lib/Support/Unix/Program.inc
> 
> Modified: llvm/trunk/lib/Support/Unix/Program.inc
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Program.inc?rev=187208&r1=187207&r2=187208&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Support/Unix/Program.inc (original)
> +++ llvm/trunk/lib/Support/Unix/Program.inc Fri Jul 26 11:21:31 2013
> @@ -122,19 +122,19 @@ static bool RedirectIO(const StringRef *
>  }
>  
>  #ifdef HAVE_POSIX_SPAWN
> -static bool RedirectIO_PS(const StringRef *Path, int FD, std::string
> *ErrMsg,
> +static bool RedirectIO_PS(const std::string *Path, int FD,
> std::string *ErrMsg,
>                            posix_spawn_file_actions_t *FileActions) {
>    if (Path == 0) // Noop
>      return false;
> -  std::string File;
> +  const char *File;
>    if (Path->empty())
>      // Redirect empty paths to /dev/null
>      File = "/dev/null";
>    else
> -    File = *Path;
> +    File = Path->c_str();
>  
>    if (int Err = posix_spawn_file_actions_addopen(
> -          FileActions, FD, File.c_str(),
> +          FileActions, FD, File,
>            FD == 0 ? O_RDONLY : O_WRONLY | O_CREAT, 0666))
>      return MakeErrMsg(ErrMsg, "Cannot dup2", Err);
>    return false;
> @@ -185,18 +185,32 @@ static bool Execute(void **Data, StringR
>      posix_spawn_file_actions_t FileActionsStore;
>      posix_spawn_file_actions_t *FileActions = 0;
>  
> +    // If we call posix_spawn_file_actions_addopen we have to make
> sure the
> +    // c strings we pass to it stay alive until the call to
> posix_spaw,

Typo: posix_spaw (missing 'n').

Thanks again,
Hal

> +    // so we copy any StringRefs into this variable.
> +    std::string RedirectsStorage[3];
> +
>      if (redirects) {
> +      std::string *RedirectsStr[3] = {0, 0, 0};
> +      for (int I = 0; I < 3; ++I) {
> +        if (redirects[I]) {
> +          RedirectsStorage[I] = *redirects[I];
> +          RedirectsStr[I] = &RedirectsStorage[I];
> +        }
> +      }
> +
>        FileActions = &FileActionsStore;
>        posix_spawn_file_actions_init(FileActions);
>  
>        // Redirect stdin/stdout.
> -      if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) ||
> -          RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions))
> +      if (RedirectIO_PS(RedirectsStr[0], 0, ErrMsg, FileActions) ||
> +          RedirectIO_PS(RedirectsStr[1], 1, ErrMsg, FileActions))
>          return false;
>        if (redirects[1] == 0 || redirects[2] == 0 ||
>            *redirects[1] != *redirects[2]) {
>          // Just redirect stderr
> -        if (RedirectIO_PS(redirects[2], 2, ErrMsg, FileActions))
> return false;
> +        if (RedirectIO_PS(RedirectsStr[2], 2, ErrMsg, FileActions))
> +          return false;
>        } else {
>          // If stdout and stderr should go to the same place,
>          redirect stderr
>          // to the FD already open for stdout.
> 
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory