text: /* Copyright (C) 2015 Red Hat, Inc.
     This file is part of elfutils.
  
     This file is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     elfutils is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #ifdef HAVE_CONFIG_H
  # include <config.h>
  #endif
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <inttypes.h>
  #include <libelf.h>
  #include <gelf.h>
  #include <stdbool.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  
  int
  main (int argc, char *argv[])
  {
    int result = 0;
    int cnt;
  
    if (argc < 3
        || (strcmp (argv[1], "elf") != 0
  	  && strcmp (argv[1], "gnu") != 0))
      {
        printf ("Usage: (elf|gnu) files...\n");
        return -1;
      }
  
    int gnu;
    if (strcmp (argv[1], "gnu") == 0)
      gnu = 1;
    else
      gnu = 0;
  
    elf_version (EV_CURRENT);
  
    for (cnt = 2; cnt < argc; ++cnt)
      {
        int fd = open (argv[cnt], O_RDONLY);
  
        Elf *elf = elf_begin (fd, ELF_C_READ, NULL);
        if (elf == NULL)
  	{
  	  printf ("%s not usable %s\n", argv[cnt], elf_errmsg (-1));
  	  result = 1;
  	  close (fd);
  	  continue;
  	}
  
        /* To get the section names.  */
        size_t strndx;
        elf_getshdrstrndx (elf, &strndx);
  
        Elf_Scn *scn = NULL;
        while ((scn = elf_nextscn (elf, scn)) != NULL)
  	{
  	  size_t idx = elf_ndxscn (scn);
  	  GElf_Shdr mem;
  	  GElf_Shdr *shdr = gelf_getshdr (scn, &mem);
  	  const char *name = elf_strptr (elf, strndx, shdr->sh_name);
  	  if (shdr->sh_type == SHT_NOBITS
  	      || (shdr->sh_flags & SHF_ALLOC) != 0)
  	    {
  	      printf ("Cannot compress %zd %s\n", idx, name);
  	    }
  	  else if ((shdr->sh_flags & SHF_COMPRESSED) != 0
  		   || strncmp (name, ".zdebug", strlen (".zdebug")) == 0)
  	    {
  	      printf ("Already compressed %zd %s\n", idx, name);
  	    }
  	  else
  	    {
  	      size_t orig_size = shdr->sh_size;
  	      printf ("Lets compress %zd %s, size: %" PRId64 "\n",
  		      idx, name, shdr->sh_size);
  	      Elf_Data *d = elf_getdata (scn, NULL);
  	      if (d == NULL)
  		{
  		  printf ("Couldn't get orig data for section %zd\n", idx);
  		  return -1;
  		}
  	      /* Make a copy so we can compare after
  		 compression/decompression.  */
  	      if (d->d_size != orig_size)
  		{
  		  printf ("Unexpected data size for orig section %zd\n", idx);
  		  return -1;
  		}
  	      char *orig_buf = malloc (d->d_size);
  	      if (orig_size > 0 && orig_buf == NULL)
  		{
  		  printf ("No memory to copy section %zd data\n", idx);
  		  return -1;
  		}
  	      if (orig_size > 0)
  		memcpy (orig_buf, d->d_buf, orig_size);
  
  	      bool forced = false;
  	      if (gnu)
  		{
  		  int res = elf_compress_gnu (scn, 1, 0);
  		  if (res == 0)
  		    {
  		      forced = true;
  		      res = elf_compress_gnu (scn, 1, ELF_CHF_FORCE);
  		    }
  		  if (res < 0)
  		    {
  		      printf ("elf_compress_gnu%sfailed for section %zd: %s\n",
  			      forced ? " (forced) " : " ",
  			      idx, elf_errmsg (-1));
  		      return -1;
  		    }
  		}
  	      else
  		{
  		  int res = elf_compress (scn, ELFCOMPRESS_ZLIB, 0);
  		  if (res == 0)
  		    {
  		      forced = true;
  		      res = elf_compress (scn, ELFCOMPRESS_ZLIB, ELF_CHF_FORCE);
  		    }
  		  if (res < 0)
  		    {
  		      printf ("elf_compress%sfailed for section %zd: %s\n",
  			      forced ? " (forced) " : " ",
  			      idx, elf_errmsg (-1));
  		      return -1;
  		    }
  		}
  	      GElf_Shdr newmem;
  	      GElf_Shdr *newshdr = gelf_getshdr (scn, &newmem);
  	      size_t new_size = newshdr->sh_size;
  	      d = elf_getdata (scn, NULL);
  	      // Don't check this, might depend on zlib implementation.
  	      // fprintf (stderr, "  new_size: %zd\n", new_size);
  	      if (d->d_size != new_size)
  		{
  		  printf ("Unexpected data size for compressed section %zd\n",
  			  idx);
  		  return -1;
  		}
  
  	      if (forced && new_size < orig_size)
  		{
  		  printf ("section %zd forced to compress, but size smaller\n",
  			  idx);
  		  return -1;
  		}
  
  	      if (! forced && new_size >= orig_size)
  		{
  		  printf ("section %zd compressed to bigger size\n",
  			  idx);
  		  return -1;
  		}
  
  	      if (new_size == orig_size
  		  && memcmp (orig_buf, d->d_buf, orig_size) == 0)
  		{
  		  printf ("section %zd didn't compress\n", idx);
  		  return -1;
  		}
  
  	      if (gnu)
  		{
  		  if (elf_compress_gnu (scn, 0, 0) < 0)
  		    {
  		      printf ("elf_[un]compress_gnu failed for section %zd: %s\n",
  			      idx, elf_errmsg (-1));
  		      return -1;
  		    }
  		}
  	      else
  		{
  		  if (elf_compress (scn, 0, 0) < 0)
  		    {
  		      printf ("elf_[un]compress failed for section %zd: %s\n",
  			      idx, elf_errmsg (-1));
  		      return -1;
  		    }
  		}
  	      GElf_Shdr newermem;
  	      GElf_Shdr *newershdr = gelf_getshdr (scn, &newermem);
  	      size_t newer_size = newershdr->sh_size;
  	      d = elf_getdata (scn, NULL);
  	      // fprintf (stderr, "  newer_size: %zd\n", newer_size);
  	      if (d->d_size != newer_size)
  		{
  		  printf ("Unexpected data size for compressed section %zd\n",
  			  idx);
  		  return -1;
  		}
  	      if (newer_size != orig_size
  		  && memcmp (orig_buf, d->d_buf, orig_size) != 0)
  		{
  		  printf ("section %zd didn't correctly uncompress\n", idx);
  		  return -1;
  		}
  	      free (orig_buf);
  	      // Recompress the string table, just to make sure
  	      // everything keeps working. See elf_strptr above.
  	      if (! gnu && idx == strndx
  		  && elf_compress (scn, ELFCOMPRESS_ZLIB, 0) < 0)
  		{
  		  printf ("couldn't recompress section header strings: %s\n",
  			  elf_errmsg (-1));
  		  return -1;
  		}
  	    }
  	}
  
        elf_end (elf);
        close (fd);
      }
  
    return result;
  }
  