1 /* Copyright (C) 2015 Red Hat, Inc.
2    This file is part of elfutils.
3 
4    This file is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 3 of the License, or
7    (at your option) any later version.
8 
9    elfutils is distributed in the hope that it will be useful, but
10    WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12    GNU General Public License for more details.
13 
14    You should have received a copy of the GNU General Public License
15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
16 
17 #ifdef HAVE_CONFIG_H
18 # include <config.h>
19 #endif
20 
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <fcntl.h>
24 #include <inttypes.h>
25 #include <libelf.h>
26 #include <gelf.h>
27 #include <stdbool.h>
28 #include <stdio.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 
33 int
main(int argc,char * argv[])34 main (int argc, char *argv[])
35 {
36   int result = 0;
37   int cnt;
38 
39   if (argc < 3
40       || (strcmp (argv[1], "read") != 0
41           && strcmp (argv[1], "mmap") != 0))
42     {
43       printf ("Usage: (read|mmap) files...\n");
44       return -1;
45     }
46 
47   bool mmap = strcmp (argv[1], "mmap") == 0;
48 
49   elf_version (EV_CURRENT);
50 
51   for (cnt = 2; cnt < argc; ++cnt)
52     {
53       int fd = open (argv[cnt], O_RDONLY);
54 
55       Elf *elf = elf_begin (fd, mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
56       if (elf == NULL)
57 	{
58 	  printf ("%s not usable %s\n", argv[cnt], elf_errmsg (-1));
59 	  result = 1;
60 	  close (fd);
61 	  continue;
62 	}
63 
64       /* To get the section names.  */
65       size_t strndx;
66       elf_getshdrstrndx (elf, &strndx);
67 
68       Elf_Scn *scn = NULL;
69       while ((scn = elf_nextscn (elf, scn)) != NULL)
70 	{
71 	  size_t idx = elf_ndxscn (scn);
72 	  GElf_Shdr mem;
73 	  GElf_Shdr *shdr = gelf_getshdr (scn, &mem);
74 	  const char *name = elf_strptr (elf, strndx, shdr->sh_name);
75 	  if ((shdr->sh_flags & SHF_COMPRESSED) != 0)
76 	    {
77 	      /* Real compressed section.  */
78 	      if (elf_compress (scn, 0, 0) < 0)
79 		{
80 		  printf ("elf_compress failed for section %zd: %s\n",
81 			  idx, elf_errmsg (-1));
82 		  return -1;
83 		}
84 	      Elf_Data *d = elf_getdata (scn, NULL);
85 	      printf ("%zd: %s, ELF compressed, size: %zx\n",
86 		      idx, name, d->d_size);
87 	    }
88 	  else
89 	    {
90 	      /* Maybe an old GNU compressed .z section?  */
91 	      if (name[0] == '.' && name[1] == 'z')
92 		{
93 		  if (elf_compress_gnu (scn, 0, 0) < 0)
94 		    {
95 		      printf ("elf_compress_gnu failed for section %zd: %s\n",
96 			      idx, elf_errmsg (-1));
97 		      return -1;
98 		    }
99 		  Elf_Data *d = elf_getdata (scn, NULL);
100 		  printf ("%zd: %s, GNU compressed, size: %zx\n",
101 			  idx, name, d->d_size);
102 		}
103 	      else
104 		printf ("%zd: %s, NOT compressed\n", idx, name);
105 	    }
106 	}
107 
108       elf_end (elf);
109       close (fd);
110     }
111 
112   return result;
113 }
114