tests/elfstrtab.c - platform/external/elfutils.git - Git at Google

 /* Test program for elf_strptr function.
    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 <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 #include ELFUTILS_HEADER(elf)
 #include <gelf.h>


 /* Index of last string added.  Returned by add_string ().  */
 static size_t stridx = 0;

 /* Some random strings.  */
 static char *str1;
 static size_t str1_off;
 static char *str2;
 static size_t str2_off;
 static char *str3;
 static size_t str3_off;

 /* First three strings we write out. They should always be there.  */
 static char *orig_str1;
 static size_t orig_str1_off;
 static char *orig_str2;
 static size_t orig_str2_off;
 static char *orig_str3;
 static size_t orig_str3_off;

 static void
 check_orig_strings (Elf *elf, int ndx, const char *msg)
 {
   printf ("checking orig strings: %s\n", msg);

   const char *str = elf_strptr (elf, ndx, 0);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp ("", str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, 1);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (".strings", str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, orig_str1_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (orig_str1, str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, orig_str2_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (orig_str2, str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, orig_str3_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (orig_str3, str) != 0)
     exit (1);
 }

 static void
 check_strings (Elf *elf, int ndx, const char *msg)
 {
   check_orig_strings (elf, ndx, msg);

   const char *str = elf_strptr (elf, ndx, str1_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (str1, str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, str2_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (str2, str) != 0)
     exit (1);

   str = elf_strptr (elf, ndx, str3_off);
   printf ("\t'%s'\n", str);
   if (str == NULL || strcmp (str3, str) != 0)
     exit (1);
 }

 /* Adds a string and returns the offset in the section.  */
 static size_t
 add_string (Elf_Scn *scn, char *str)
 {
   size_t lastidx = stridx;
   size_t size = strlen (str) + 1;

   Elf_Data *data = elf_newdata (scn);
   if (data == NULL)
     {
       printf ("cannot create data SHSTRTAB section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   data->d_buf = str;
   data->d_type = ELF_T_BYTE;
   data->d_size = size;
   data->d_align = 1;
   data->d_version = EV_CURRENT;

   stridx += size;
   printf ("add_string: '%s', stridx: %zd, lastidx: %zd\n",
 	  str, stridx, lastidx);
   return lastidx;
 }

 static void
 check_elf (const char *fname, int class, int use_mmap)
 {
   printf ("\nfname: %s\n", fname);
   stridx = 0;

   int fd = open (fname, O_RDWR | O_CREAT | O_TRUNC, 0666);
   if (fd == -1)
     {
       printf ("cannot open `%s': %s\n", fname, strerror (errno));
       exit (1);
     }

   Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL);
   if (elf == NULL)
     {
       printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Create an ELF header.
   if (gelf_newehdr (elf, class) == 0)
     {
       printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
       exit (1);
     }

   GElf_Ehdr ehdr_mem;
   GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
   if (ehdr == NULL)
     {
       printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Initialize header.
   ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB;
   ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
   ehdr->e_type = ET_NONE;
   ehdr->e_machine = EM_X86_64;
   ehdr->e_version = EV_CURRENT;

   // Create strings section.
   Elf_Scn *scn = elf_newscn (elf);
   if (scn == NULL)
     {
       printf ("cannot create strings section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Add an empty string to the table as NUL entry for section zero.
   add_string (scn, "");

   GElf_Shdr shdr_mem;
   GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
   if (shdr == NULL)
     {
       printf ("cannot get header for strings section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   shdr->sh_type = SHT_STRTAB;
   shdr->sh_flags = 0;
   shdr->sh_addr = 0;
   shdr->sh_link = SHN_UNDEF;
   shdr->sh_info = SHN_UNDEF;
   shdr->sh_addralign = 1;
   shdr->sh_entsize = 0;
   shdr->sh_name = add_string (scn, ".strings");

   // We have to store the section strtab index in the ELF header.
   // So sections have actual names.
   int ndx = elf_ndxscn (scn);
   ehdr->e_shstrndx = ndx;

   if (gelf_update_ehdr (elf, ehdr) == 0)
     {
       printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Add some random strings. These are the original ones. They should
   // always be there (together with the empty "" and .strings section
   // name strings.
   orig_str1 = "elfutils";
   orig_str1_off = add_string (scn, orig_str1);
   orig_str2 = "strtabelf";
   orig_str2_off = add_string (scn, orig_str2);
   orig_str3 = "three";
   orig_str3_off = add_string (scn, orig_str3);

   // Finished strings section, update the header.
   if (gelf_update_shdr (scn, shdr) == 0)
     {
       printf ("cannot update STRTAB section header: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Let the library compute the internal structure information.
   if (elf_update (elf, ELF_C_NULL) < 0)
     {
       printf ("failure in elf_update(NULL): %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Check our strings are there.
   check_orig_strings (elf, ndx, "first elf_update, before write");

   // Write everything to disk.
   if (elf_update (elf, ELF_C_WRITE) < 0)
     {
       printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Check out strings are there.
   check_orig_strings (elf, ndx, "first elf_update, after write");

   // Add some more random strings.  These will not be written to disk.
   scn = elf_getscn (elf, ndx);
   if (scn == NULL)
     {
       printf ("couldn't re-get strings section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   str1 = "elfutils2";
   str1_off = add_string (scn, str1);
   str2 = "strtabelf2";
   str2_off = add_string (scn, str2);
   str3 = "three2";
   str3_off = add_string (scn, str3);

   // Update internal structure information again.
   if (elf_update (elf, ELF_C_NULL) < 0)
     {
       printf ("failure in re-elf_update(NULL): %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Check our new strings are there.
   check_strings (elf, ndx, "first extra strings");

   if (elf_end (elf) != 0)
     {
       printf ("failure in elf_end: %s\n", elf_errmsg (-1));
       exit (1);
     }

   close (fd);

   /* Read the ELF from disk now.  */
   fd = open (fname, O_RDWR, 0666);
   if (fd == -1)
     {
       printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
       exit (1);
     }

   elf = elf_begin (fd, use_mmap ? ELF_C_RDWR_MMAP : ELF_C_RDWR, NULL);
   if (elf == NULL)
     {
       printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
       exit (1);
     }

   /* Are our strings there?  */
   check_orig_strings (elf, ndx, "read ELF file, orig strings");

   // Add some more random strings.
   scn = elf_getscn (elf, ndx);
   if (scn == NULL)
     {
       printf ("couldn't re-get strings section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   shdr = gelf_getshdr (scn, &shdr_mem);
   if (shdr == NULL)
     {
       printf ("cannot get header for strings section: %s\n", elf_errmsg (-1));
       exit (1);
     }

   // Reset stridx to end of section.
   printf ("sh_size: %" PRIu64 "\n", shdr->sh_size);
   stridx = shdr->sh_size;

   str1 = "0123456789";
   str1_off = add_string (scn, str1);
   str2 = "supercalifragilisticexpialidocious";
   str2_off = add_string (scn, str2);
   str3 = "forty-two";
   str3_off = add_string (scn, str3);

   // Update internal structure information.
   if (elf_update (elf, ELF_C_NULL) < 0)
     {
       printf ("failure in rw-elf_update(NULL): %s\n", elf_errmsg (-1));
       exit (1);
     }

   /* Check our new strings are there.  */
   check_strings (elf, ndx, "read file, added strings");

   // Write updated ELF file.
   if (elf_update (elf, ELF_C_WRITE) < 0)
     {
       printf ("failure in re-elf_update(NULL): %s\n", elf_errmsg (-1));
       exit (1);
     }

   if (elf_end (elf) != 0)
     {
       printf ("failure in elf_end: %s\n", elf_errmsg (-1));
       exit (1);
     }

   close (fd);

   // And read it in one last time.
   fd = open (fname, O_RDONLY, 0666);
   if (fd == -1)
     {
       printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
       exit (1);
     }

   elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
   if (elf == NULL)
     {
       printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
       exit (1);
     }

   /* Are all our strings there?  */
   check_strings (elf, ndx, "all together now");

   if (elf_end (elf) != 0)
     {
       printf ("failure in elf_end: %s\n", elf_errmsg (-1));
       exit (1);
     }

   close (fd);

   unlink (fname);
 }

 int
 main (int argc __attribute__ ((unused)), char *argv[] __attribute__ ((unused)))
 {
   elf_version (EV_CURRENT);

   // Fill holes with something non-zero to more easily spot
   // unterminated strings.
   elf_fill ('X');

   check_elf ("strtab.elf.32", ELFCLASS32, 0);
   check_elf ("strtab.elf.32.mmap", ELFCLASS32, 1);
   check_elf ("strtab.elf.64", ELFCLASS64, 0);
   check_elf ("strtab.elf.64.mmap", ELFCLASS64, 1);

   return 0;
 }
	/* Test program for elf_strptr function.
	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 <errno.h>
	#include <fcntl.h>
	#include <inttypes.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	#include ELFUTILS_HEADER(elf)
	#include <gelf.h>


	/* Index of last string added. Returned by add_string (). */
	static size_t stridx = 0;

	/* Some random strings. */
	static char *str1;
	static size_t str1_off;
	static char *str2;
	static size_t str2_off;
	static char *str3;
	static size_t str3_off;

	/* First three strings we write out. They should always be there. */
	static char *orig_str1;
	static size_t orig_str1_off;
	static char *orig_str2;
	static size_t orig_str2_off;
	static char *orig_str3;
	static size_t orig_str3_off;

	static void
	check_orig_strings (Elf elf, int ndx, const char msg)
	{
	printf ("checking orig strings: %s\n", msg);

	const char *str = elf_strptr (elf, ndx, 0);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp ("", str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, 1);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (".strings", str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, orig_str1_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (orig_str1, str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, orig_str2_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (orig_str2, str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, orig_str3_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (orig_str3, str) != 0)
	exit (1);
	}

	static void
	check_strings (Elf elf, int ndx, const char msg)
	{
	check_orig_strings (elf, ndx, msg);

	const char *str = elf_strptr (elf, ndx, str1_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (str1, str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, str2_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (str2, str) != 0)
	exit (1);

	str = elf_strptr (elf, ndx, str3_off);
	printf ("\t'%s'\n", str);
	if (str == NULL \|\| strcmp (str3, str) != 0)
	exit (1);
	}

	/* Adds a string and returns the offset in the section. */
	static size_t
	add_string (Elf_Scn scn, char str)
	{
	size_t lastidx = stridx;
	size_t size = strlen (str) + 1;

	Elf_Data *data = elf_newdata (scn);
	if (data == NULL)
	{
	printf ("cannot create data SHSTRTAB section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	data->d_buf = str;
	data->d_type = ELF_T_BYTE;
	data->d_size = size;
	data->d_align = 1;
	data->d_version = EV_CURRENT;

	stridx += size;
	printf ("add_string: '%s', stridx: %zd, lastidx: %zd\n",
	str, stridx, lastidx);
	return lastidx;
	}

	static void
	check_elf (const char *fname, int class, int use_mmap)
	{
	printf ("\nfname: %s\n", fname);
	stridx = 0;

	int fd = open (fname, O_RDWR \| O_CREAT \| O_TRUNC, 0666);
	if (fd == -1)
	{
	printf ("cannot open `%s': %s\n", fname, strerror (errno));
	exit (1);
	}

	Elf *elf = elf_begin (fd, use_mmap ? ELF_C_WRITE_MMAP : ELF_C_WRITE, NULL);
	if (elf == NULL)
	{
	printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Create an ELF header.
	if (gelf_newehdr (elf, class) == 0)
	{
	printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
	exit (1);
	}

	GElf_Ehdr ehdr_mem;
	GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
	if (ehdr == NULL)
	{
	printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Initialize header.
	ehdr->e_ident[EI_DATA] = class == ELFCLASS64 ? ELFDATA2LSB : ELFDATA2MSB;
	ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
	ehdr->e_type = ET_NONE;
	ehdr->e_machine = EM_X86_64;
	ehdr->e_version = EV_CURRENT;

	// Create strings section.
	Elf_Scn *scn = elf_newscn (elf);
	if (scn == NULL)
	{
	printf ("cannot create strings section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Add an empty string to the table as NUL entry for section zero.
	add_string (scn, "");

	GElf_Shdr shdr_mem;
	GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
	if (shdr == NULL)
	{
	printf ("cannot get header for strings section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	shdr->sh_type = SHT_STRTAB;
	shdr->sh_flags = 0;
	shdr->sh_addr = 0;
	shdr->sh_link = SHN_UNDEF;
	shdr->sh_info = SHN_UNDEF;
	shdr->sh_addralign = 1;
	shdr->sh_entsize = 0;
	shdr->sh_name = add_string (scn, ".strings");

	// We have to store the section strtab index in the ELF header.
	// So sections have actual names.
	int ndx = elf_ndxscn (scn);
	ehdr->e_shstrndx = ndx;

	if (gelf_update_ehdr (elf, ehdr) == 0)
	{
	printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Add some random strings. These are the original ones. They should
	// always be there (together with the empty "" and .strings section
	// name strings.
	orig_str1 = "elfutils";
	orig_str1_off = add_string (scn, orig_str1);
	orig_str2 = "strtabelf";
	orig_str2_off = add_string (scn, orig_str2);
	orig_str3 = "three";
	orig_str3_off = add_string (scn, orig_str3);

	// Finished strings section, update the header.
	if (gelf_update_shdr (scn, shdr) == 0)
	{
	printf ("cannot update STRTAB section header: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Let the library compute the internal structure information.
	if (elf_update (elf, ELF_C_NULL) < 0)
	{
	printf ("failure in elf_update(NULL): %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Check our strings are there.
	check_orig_strings (elf, ndx, "first elf_update, before write");

	// Write everything to disk.
	if (elf_update (elf, ELF_C_WRITE) < 0)
	{
	printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Check out strings are there.
	check_orig_strings (elf, ndx, "first elf_update, after write");

	// Add some more random strings. These will not be written to disk.
	scn = elf_getscn (elf, ndx);
	if (scn == NULL)
	{
	printf ("couldn't re-get strings section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	str1 = "elfutils2";
	str1_off = add_string (scn, str1);
	str2 = "strtabelf2";
	str2_off = add_string (scn, str2);
	str3 = "three2";
	str3_off = add_string (scn, str3);

	// Update internal structure information again.
	if (elf_update (elf, ELF_C_NULL) < 0)
	{
	printf ("failure in re-elf_update(NULL): %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Check our new strings are there.
	check_strings (elf, ndx, "first extra strings");

	if (elf_end (elf) != 0)
	{
	printf ("failure in elf_end: %s\n", elf_errmsg (-1));
	exit (1);
	}

	close (fd);

	/* Read the ELF from disk now. */
	fd = open (fname, O_RDWR, 0666);
	if (fd == -1)
	{
	printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
	exit (1);
	}

	elf = elf_begin (fd, use_mmap ? ELF_C_RDWR_MMAP : ELF_C_RDWR, NULL);
	if (elf == NULL)
	{
	printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
	exit (1);
	}

	/* Are our strings there? */
	check_orig_strings (elf, ndx, "read ELF file, orig strings");

	// Add some more random strings.
	scn = elf_getscn (elf, ndx);
	if (scn == NULL)
	{
	printf ("couldn't re-get strings section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	shdr = gelf_getshdr (scn, &shdr_mem);
	if (shdr == NULL)
	{
	printf ("cannot get header for strings section: %s\n", elf_errmsg (-1));
	exit (1);
	}

	// Reset stridx to end of section.
	printf ("sh_size: %" PRIu64 "\n", shdr->sh_size);
	stridx = shdr->sh_size;

	str1 = "0123456789";
	str1_off = add_string (scn, str1);
	str2 = "supercalifragilisticexpialidocious";
	str2_off = add_string (scn, str2);
	str3 = "forty-two";
	str3_off = add_string (scn, str3);

	// Update internal structure information.
	if (elf_update (elf, ELF_C_NULL) < 0)
	{
	printf ("failure in rw-elf_update(NULL): %s\n", elf_errmsg (-1));
	exit (1);
	}

	/* Check our new strings are there. */
	check_strings (elf, ndx, "read file, added strings");

	// Write updated ELF file.
	if (elf_update (elf, ELF_C_WRITE) < 0)
	{
	printf ("failure in re-elf_update(NULL): %s\n", elf_errmsg (-1));
	exit (1);
	}

	if (elf_end (elf) != 0)
	{
	printf ("failure in elf_end: %s\n", elf_errmsg (-1));
	exit (1);
	}

	close (fd);

	// And read it in one last time.
	fd = open (fname, O_RDONLY, 0666);
	if (fd == -1)
	{
	printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
	exit (1);
	}

	elf = elf_begin (fd, use_mmap ? ELF_C_READ_MMAP : ELF_C_READ, NULL);
	if (elf == NULL)
	{
	printf ("cannot create ELF descriptor read-only: %s\n", elf_errmsg (-1));
	exit (1);
	}

	/* Are all our strings there? */
	check_strings (elf, ndx, "all together now");

	if (elf_end (elf) != 0)
	{
	printf ("failure in elf_end: %s\n", elf_errmsg (-1));
	exit (1);
	}

	close (fd);

	unlink (fname);
	}

	int
	main (int argc __attribute__ ((unused)), char *argv[] __attribute__ ((unused)))
	{
	elf_version (EV_CURRENT);

	// Fill holes with something non-zero to more easily spot
	// unterminated strings.
	elf_fill ('X');

	check_elf ("strtab.elf.32", ELFCLASS32, 0);
	check_elf ("strtab.elf.32.mmap", ELFCLASS32, 1);
	check_elf ("strtab.elf.64", ELFCLASS64, 0);
	check_elf ("strtab.elf.64.mmap", ELFCLASS64, 1);

	return 0;
	}