[PATCH] D62718: [llvm-objcopy] Change handling of output file permissions

[Fangrui Song via Phabricator via llvm-commits]

MaskRay requested changes to this revision.
MaskRay added a comment.
This revision now requires changes to proceed.

I believe GNU objcopy has the following logic:

    if (i_ehdrp->e_type == ET_EXEC)
      abfd->flags |= EXEC_P;
    else if (i_ehdrp->e_type == ET_DYN)
      abfd->flags |= DYNAMIC;
  
  // bfd/opncls.c
  static inline void
  _maybe_make_executable (bfd * abfd)
  {
    /* If the file was open for writing and is now executable,
       make it so.  */
    if (abfd->direction == write_direction
        && (abfd->flags & (EXEC_P | DYNAMIC)) != 0)
      {
        struct stat buf;
  
        if (stat (abfd->filename, &buf) == 0
  	  /* Do not attempt to change non-regular files.  This is
  	     here especially for configure scripts and kernel builds
  	     which run tests with "ld [...] -o /dev/null".  */
  	  && S_ISREG(buf.st_mode))
  	{
  	  unsigned int mask = umask (0);
  
  	  umask (mask);
  	  chmod (abfd->filename,
  		 (0777
  		  & (buf.st_mode | ((S_IXUSR | S_IXGRP | S_IXOTH) &~ mask))));
  	}
      }
  }

I would not suggest copying this behavior (if ET_EXEC or ET_DYN, chmod +x).
Instead, mirroring the input file's permissions is much more reasonable and gives the least surprise.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62718/new/

https://reviews.llvm.org/D62718