dwelf: Add string table functions from ebl.

Move the strtab functions from libebl to libdw. Programs often want to
create ELF/DWARF string tables. We don't want (static) linking against
ebl since those are internal functions that might change.

This introduces dwelf_strtab_init, dwelf_strtab_add,
dwelf_strtab_add_len, dwelf_strtab_finalize, dwelf_strent_off,
dwelf_strent_str and dwelf_strtab_free. Documentation for each has
been added to libdwelf.h. The add fucntion got a variant that takes
the length explicitly and finalize was changed to return NULL on
out of memory instead of aborting. All code and tests now uses the
new functions.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

5 files changed, 69 insertions, 46 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index d8de529a..e5a3fce3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2016-07-08  Mark Wielaard  <mjw@redhat.com>
+
+	* Makefile.am (strip_LDADD): Add libdw.
+	* elfcompress.c (process_file): Use dwelf_strtab functions instead of
+	ebl_strtab.
+	* strip.c (handle_elf): Likewise.
+	* unstrip.c (new_shstrtab): Likewise.
+
 2016-07-06  Mark Wielaard  <mjw@redhat.com>
 
 	* elf32-i386.script, i386_ld.c, ld.c, ld.h, ldgeneric.c, ldlex.l,
diff --git a/src/Makefile.am b/src/Makefile.am
index 6f796b33..9bb47651 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -71,7 +71,7 @@ readelf_LDADD = $(libdw) $(libebl) $(libelf) $(libeu) $(argp_LDADD) -ldl
 nm_LDADD = $(libdw) $(libebl) $(libelf) $(libeu) $(argp_LDADD) -ldl \
 	   $(demanglelib)
 size_LDADD = $(libelf) $(libeu) $(argp_LDADD)
-strip_LDADD = $(libebl) $(libelf) $(libeu) $(argp_LDADD) -ldl
+strip_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD) -ldl
 elflint_LDADD  = $(libebl) $(libelf) $(libeu) $(argp_LDADD) -ldl
 findtextrel_LDADD = $(libdw) $(libelf) $(argp_LDADD)
 addr2line_LDADD = $(libdw) $(libelf) $(argp_LDADD) $(demanglelib)
diff --git a/src/elfcompress.c b/src/elfcompress.c
index d0ca469c..86cc7165 100644
--- a/src/elfcompress.c
+++ b/src/elfcompress.c
@@ -32,6 +32,7 @@
 #include <unistd.h>
 #include ELFUTILS_HEADER(elf)
 #include ELFUTILS_HEADER(ebl)
+#include ELFUTILS_HEADER(dwelf)
 #include <gelf.h>
 #include "system.h"
 
@@ -265,9 +266,9 @@ process_file (const char *fname)
   char *snamebuf = NULL;
 
   /* String table (and symbol table), if section names need adjusting.  */
-  struct Ebl_Strtab *names = NULL;
-  struct Ebl_Strent **scnstrents = NULL;
-  struct Ebl_Strent **symstrents = NULL;
+  Dwelf_Strtab *names = NULL;
+  Dwelf_Strent **scnstrents = NULL;
+  Dwelf_Strent **symstrents = NULL;
   char **scnnames = NULL;
 
   /* Section data from names.  */
@@ -308,7 +309,7 @@ process_file (const char *fname)
     free (snamebuf);
     if (names != NULL)
       {
-	ebl_strtabfree (names);
+	dwelf_strtab_free (names);
 	free (scnstrents);
 	free (symstrents);
 	free (namesbuf);
@@ -524,14 +525,14 @@ process_file (const char *fname)
 
   if (adjust_names)
     {
-      names = ebl_strtabinit (true);
+      names = dwelf_strtab_init (true);
       if (names == NULL)
 	{
 	  error (0, 0, "Not enough memory for new strtab");
 	  return cleanup (-1);
 	}
       scnstrents = xmalloc (shnum
-			    * sizeof (struct Ebl_Strent *));
+			    * sizeof (Dwelf_Strent *));
       scnnames = xcalloc (shnum, sizeof (char *));
     }
 
@@ -870,7 +871,7 @@ process_file (const char *fname)
 
 	  /* We need to keep a copy of the name till the strtab is done.  */
 	  name = scnnames[ndx] = xstrdup (name);
-	  if ((scnstrents[ndx] = ebl_strtabadd (names, name, 0)) == NULL)
+	  if ((scnstrents[ndx] = dwelf_strtab_add (names, name)) == NULL)
 	    {
 	      error (0, 0, "No memory to add section name string table");
 	      return cleanup (-1);
@@ -916,7 +917,7 @@ process_file (const char *fname)
 		}
 	      size_t elsize = gelf_fsize (elfnew, ELF_T_SYM, 1, EV_CURRENT);
 	      size_t syms = symd->d_size / elsize;
-	      symstrents = xmalloc (syms * sizeof (struct Ebl_Strent *));
+	      symstrents = xmalloc (syms * sizeof (Dwelf_Strent *));
 	      for (size_t i = 0; i < syms; i++)
 		{
 		  GElf_Sym sym_mem;
@@ -938,7 +939,7 @@ process_file (const char *fname)
 			  error (0, 0, "Couldn't get symbol %zd name", i);
 			  return cleanup (-1);
 			}
-		      symstrents[i] = ebl_strtabadd (names, symname, 0);
+		      symstrents[i] = dwelf_strtab_add (names, symname);
 		      if (symstrents[i] == NULL)
 			{
 			  error (0, 0, "No memory to add to symbol name");
@@ -970,7 +971,11 @@ process_file (const char *fname)
 	  error (0, 0, "Couldn't create new section header string table data");
 	  return cleanup (-1);
 	}
-      ebl_strtabfinalize (names, data);
+      if (dwelf_strtab_finalize (names, data) == NULL)
+	{
+	  error (0, 0, "Not enough memory to create string table");
+	  return cleanup (-1);
+	}
       namesbuf = data->d_buf;
 
       GElf_Shdr shdr_mem;
@@ -984,7 +989,7 @@ process_file (const char *fname)
 
       /* Note that we also might have to compress and possibly set
 	 sh_off below */
-      shdr->sh_name = ebl_strtaboffset (scnstrents[shdrstrndx]);
+      shdr->sh_name = dwelf_strent_off (scnstrents[shdrstrndx]);
       shdr->sh_type = SHT_STRTAB;
       shdr->sh_flags = 0;
       shdr->sh_addr = 0;
@@ -1099,7 +1104,7 @@ process_file (const char *fname)
 	    }
 
 	  if (adjust_names)
-	    shdr->sh_name = ebl_strtaboffset (scnstrents[ndx]);
+	    shdr->sh_name = dwelf_strent_off (scnstrents[ndx]);
 
 	  if (gelf_update_shdr (scn, shdr) == 0)
 	    {
@@ -1133,7 +1138,7 @@ process_file (const char *fname)
 
 		  if (sym->st_name != 0)
 		    {
-		      sym->st_name = ebl_strtaboffset (symstrents[i]);
+		      sym->st_name = dwelf_strent_off (symstrents[i]);
 
 		      if (gelf_update_sym (symd, i, sym) == 0)
 			{
diff --git a/src/strip.c b/src/strip.c
index a6042445..23d3d51b 100644
--- a/src/strip.c
+++ b/src/strip.c
@@ -42,6 +42,7 @@
 
 #include <elf-knowledge.h>
 #include <libebl.h>
+#include "libdwelf.h"
 #include <system.h>
 
 typedef uint8_t GElf_Byte;
@@ -432,7 +433,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
     Elf32_Word group_idx;
     Elf32_Word group_cnt;
     Elf_Scn *newscn;
-    struct Ebl_Strent *se;
+    Dwelf_Strent *se;
     Elf32_Word *newsymidx;
   } *shdr_info = NULL;
   Elf_Scn *scn;
@@ -443,7 +444,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
   GElf_Ehdr *newehdr;
   GElf_Ehdr debugehdr_mem;
   GElf_Ehdr *debugehdr;
-  struct Ebl_Strtab *shst = NULL;
+  Dwelf_Strtab *shst = NULL;
   Elf_Data debuglink_crc_data;
   bool any_symtab_changes = false;
   Elf_Data *shstrtab_data = NULL;
@@ -1043,7 +1044,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
      will already be marked as unused.  */
 
   /* We need a string table for the section headers.  */
-  shst = ebl_strtabinit (true);
+  shst = dwelf_strtab_init (true);
   if (shst == NULL)
     {
       cleanup_debug ();
@@ -1071,7 +1072,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
 	elf_assert (elf_ndxscn (shdr_info[cnt].newscn) == shdr_info[cnt].idx);
 
 	/* Add this name to the section header string table.  */
-	shdr_info[cnt].se = ebl_strtabadd (shst, shdr_info[cnt].name, 0);
+	shdr_info[cnt].se = dwelf_strtab_add (shst, shdr_info[cnt].name);
       }
 
   /* Test whether we are doing anything at all.  */
@@ -1083,7 +1084,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
   if (debug_fname != NULL && !remove_shdrs)
     {
       /* Add the section header string table section name.  */
-      shdr_info[cnt].se = ebl_strtabadd (shst, ".gnu_debuglink", 15);
+      shdr_info[cnt].se = dwelf_strtab_add_len (shst, ".gnu_debuglink", 15);
       shdr_info[cnt].idx = idx++;
 
       /* Create the section header.  */
@@ -1146,7 +1147,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
   shdridx = cnt;
 
   /* Add the section header string table section name.  */
-  shdr_info[cnt].se = ebl_strtabadd (shst, ".shstrtab", 10);
+  shdr_info[cnt].se = dwelf_strtab_add_len (shst, ".shstrtab", 10);
   shdr_info[cnt].idx = idx;
 
   /* Create the section header.  */
@@ -1183,7 +1184,12 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
 	     gettext ("while create section header string table: %s"),
 	     elf_errmsg (-1));
     }
-  ebl_strtabfinalize (shst, shstrtab_data);
+  if (dwelf_strtab_finalize (shst, shstrtab_data) == NULL)
+    {
+      cleanup_debug ();
+      error (EXIT_FAILURE, 0,
+	     gettext ("no memory to create section header string table"));
+    }
 
   /* We have to set the section size.  */
   shdr_info[cnt].shdr.sh_size = shstrtab_data->d_size;
@@ -1199,7 +1205,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
 	elf_assert (scn != NULL);
 
 	/* Update the name.  */
-	shdr_info[cnt].shdr.sh_name = ebl_strtaboffset (shdr_info[cnt].se);
+	shdr_info[cnt].shdr.sh_name = dwelf_strent_off (shdr_info[cnt].se);
 
 	/* Update the section header from the input file.  Some fields
 	   might be section indeces which now have to be adjusted.  */
@@ -2171,7 +2177,7 @@ while computing checksum for debug information"));
   if (shstrtab_data != NULL)
     free (shstrtab_data->d_buf);
   if (shst != NULL)
-    ebl_strtabfree (shst);
+    dwelf_strtab_free (shst);
 
   /* That was it.  Close the descriptors.  */
   if (elf_end (newelf) != 0)
diff --git a/src/unstrip.c b/src/unstrip.c
index adeb5991..46737381 100644
--- a/src/unstrip.c
+++ b/src/unstrip.c
@@ -48,6 +48,7 @@
 #include <gelf.h>
 #include <libebl.h>
 #include <libdwfl.h>
+#include "libdwelf.h"
 #include "system.h"
 
 #ifndef _
@@ -686,7 +687,7 @@ struct section
   Elf_Scn *scn;
   const char *name;
   Elf_Scn *outscn;
-  struct Ebl_Strent *strent;
+  Dwelf_Strent *strent;
   GElf_Shdr shdr;
 };
 
@@ -757,7 +758,7 @@ struct symbol
   union
   {
     const char *name;
-    struct Ebl_Strent *strent;
+    Dwelf_Strent *strent;
   };
   union
   {
@@ -1214,12 +1215,12 @@ static Elf_Data *
 new_shstrtab (Elf *unstripped, size_t unstripped_shnum,
 	      Elf_Data *shstrtab, size_t unstripped_shstrndx,
 	      struct section *sections, size_t stripped_shnum,
-	      struct Ebl_Strtab *strtab)
+	      Dwelf_Strtab *strtab)
 {
   if (strtab == NULL)
     return NULL;
 
-  struct Ebl_Strent *unstripped_strent[unstripped_shnum - 1];
+  Dwelf_Strent *unstripped_strent[unstripped_shnum - 1];
   memset (unstripped_strent, 0, sizeof unstripped_strent);
   for (struct section *sec = sections;
        sec < &sections[stripped_shnum - 1];
@@ -1228,7 +1229,7 @@ new_shstrtab (Elf *unstripped, size_t unstripped_shnum,
       {
 	if (sec->strent == NULL)
 	  {
-	    sec->strent = ebl_strtabadd (strtab, sec->name, 0);
+	    sec->strent = dwelf_strtab_add (strtab, sec->name);
 	    ELF_CHECK (sec->strent != NULL,
 		       _("cannot add section name to string table: %s"));
 	  }
@@ -1243,7 +1244,7 @@ new_shstrtab (Elf *unstripped, size_t unstripped_shnum,
 	GElf_Shdr shdr_mem;
 	GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
 	const char *name = get_section_name (i + 1, shdr, shstrtab);
-	unstripped_strent[i] = ebl_strtabadd (strtab, name, 0);
+	unstripped_strent[i] = dwelf_strtab_add (strtab, name);
 	ELF_CHECK (unstripped_strent[i] != NULL,
 		   _("cannot add section name to string table: %s"));
       }
@@ -1255,7 +1256,8 @@ new_shstrtab (Elf *unstripped, size_t unstripped_shnum,
 						   unstripped_shstrndx), NULL);
   ELF_CHECK (elf_flagdata (strtab_data, ELF_C_SET, ELF_F_DIRTY),
 	     _("cannot update section header string table data: %s"));
-  ebl_strtabfinalize (strtab, strtab_data);
+  if (dwelf_strtab_finalize (strtab, strtab_data) == NULL)
+    error (EXIT_FAILURE, 0, "Not enough memory to create string table");
 
   /* Update the sh_name fields of sections we aren't modifying later.  */
   for (size_t i = 0; i < unstripped_shnum - 1; ++i)
@@ -1264,7 +1266,7 @@ new_shstrtab (Elf *unstripped, size_t unstripped_shnum,
 	Elf_Scn *scn = elf_getscn (unstripped, i + 1);
 	GElf_Shdr shdr_mem;
 	GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
-	shdr->sh_name = ebl_strtaboffset (unstripped_strent[i]);
+	shdr->sh_name = dwelf_strent_off (unstripped_strent[i]);
 	if (i + 1 == unstripped_shstrndx)
 	  shdr->sh_size = strtab_data->d_size;
 	update_shdr (scn, shdr);
@@ -1456,7 +1458,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
   const struct section *stripped_dynsym = NULL;
   size_t debuglink = SHN_UNDEF;
   size_t ndx_section[stripped_shnum - 1];
-  struct Ebl_Strtab *strtab = NULL;
+  Dwelf_Strtab *strtab = NULL;
   for (struct section *sec = sections;
        sec < &sections[stripped_shnum - 1];
        ++sec)
@@ -1508,8 +1510,8 @@ more sections in stripped file than debug file -- arguments reversed?"));
 		     _("cannot add new section: %s"));
 
 	  if (strtab == NULL)
-	    strtab = ebl_strtabinit (true);
-	  sec->strent = ebl_strtabadd (strtab, sec->name, 0);
+	    strtab = dwelf_strtab_init (true);
+	  sec->strent = dwelf_strtab_add (strtab, sec->name);
 	  ELF_CHECK (sec->strent != NULL,
 		     _("cannot add section name to string table: %s"));
 	}
@@ -1570,7 +1572,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
 	  shdr_mem.sh_info = ndx_section[sec->shdr.sh_info - 1];
 
 	if (strtab != NULL)
-	  shdr_mem.sh_name = ebl_strtaboffset (sec->strent);
+	  shdr_mem.sh_name = dwelf_strent_off (sec->strent);
 
 	Elf_Data *indata = elf_getdata (sec->scn, NULL);
 	ELF_CHECK (indata != NULL, _("cannot get section data: %s"));
@@ -1641,7 +1643,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
 
   /* We may need to update the symbol table.  */
   Elf_Data *symdata = NULL;
-  struct Ebl_Strtab *symstrtab = NULL;
+  Dwelf_Strtab *symstrtab = NULL;
   Elf_Data *symstrdata = NULL;
   if (unstripped_symtab != NULL && (stripped_symtab != NULL
 				    || check_prelink /* Section adjustments. */
@@ -1721,13 +1723,13 @@ more sections in stripped file than debug file -- arguments reversed?"));
 
       /* Now a final pass updates the map with the final order,
 	 and builds up the new string table.  */
-      symstrtab = ebl_strtabinit (true);
+      symstrtab = dwelf_strtab_init (true);
       for (size_t i = 0; i < nsym; ++i)
 	{
 	  assert (symbols[i].name != NULL);
 	  assert (*symbols[i].map != 0);
 	  *symbols[i].map = 1 + i;
-	  symbols[i].strent = ebl_strtabadd (symstrtab, symbols[i].name, 0);
+	  symbols[i].strent = dwelf_strtab_add (symstrtab, symbols[i].name);
 	}
 
       /* Scan the discarded symbols too, just to update their slots
@@ -1752,7 +1754,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
       /* If symtab and the section header table share the string table
 	 add the section names to the strtab and then (after finalizing)
 	 fixup the section header sh_names.  Also dispose of the old data.  */
-      struct Ebl_Strent *unstripped_strent[unstripped_shnum - 1];
+      Dwelf_Strent *unstripped_strent[unstripped_shnum - 1];
       if (unstripped_shstrndx == elf_ndxscn (unstripped_strtab))
 	{
 	  for (size_t i = 0; i < unstripped_shnum - 1; ++i)
@@ -1761,20 +1763,22 @@ more sections in stripped file than debug file -- arguments reversed?"));
 	      GElf_Shdr mem;
 	      GElf_Shdr *hdr = gelf_getshdr (sec, &mem);
 	      const char *name = get_section_name (i + 1, hdr, shstrtab);
-	      unstripped_strent[i] = ebl_strtabadd (symstrtab, name, 0);
+	      unstripped_strent[i] = dwelf_strtab_add (symstrtab, name);
 	      ELF_CHECK (unstripped_strent[i] != NULL,
 			 _("cannot add section name to string table: %s"));
 	    }
 
 	  if (strtab != NULL)
 	    {
-	      ebl_strtabfree (strtab);
+	      dwelf_strtab_free (strtab);
 	      free (strtab_data->d_buf);
 	      strtab = NULL;
 	    }
 	}
 
-      ebl_strtabfinalize (symstrtab, symstrdata);
+      if (dwelf_strtab_finalize (symstrtab, symstrdata) == NULL)
+	error (EXIT_FAILURE, 0, "Not enough memory to create symbol table");
+
       elf_flagdata (symstrdata, ELF_C_SET, ELF_F_DIRTY);
 
       /* And update the section header names if necessary.  */
@@ -1785,7 +1789,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
 	      Elf_Scn *sec = elf_getscn (unstripped, i + 1);
 	      GElf_Shdr mem;
 	      GElf_Shdr *hdr = gelf_getshdr (sec, &mem);
-	      shdr->sh_name = ebl_strtaboffset (unstripped_strent[i]);
+	      shdr->sh_name = dwelf_strent_off (unstripped_strent[i]);
 	      update_shdr (sec, hdr);
 	    }
 	}
@@ -1810,7 +1814,7 @@ more sections in stripped file than debug file -- arguments reversed?"));
 	  struct symbol *s = &symbols[i];
 
 	  /* Fill in the symbol details.  */
-	  sym.st_name = ebl_strtaboffset (s->strent);
+	  sym.st_name = dwelf_strent_off (s->strent);
 	  sym.st_value = s->value; /* Already biased to output address.  */
 	  sym.st_size = s->size;
 	  sym.st_shndx = s->shndx; /* Already mapped to output index.  */
@@ -1959,13 +1963,13 @@ more sections in stripped file than debug file -- arguments reversed?"));
 
   if (strtab != NULL)
     {
-      ebl_strtabfree (strtab);
+      dwelf_strtab_free (strtab);
       free (strtab_data->d_buf);
     }
 
   if (symstrtab != NULL)
     {
-      ebl_strtabfree (symstrtab);
+      dwelf_strtab_free (symstrtab);
       free (symstrdata->d_buf);
     }
   free_new_data ();