Support reading .zdebug_* DWARF sections compressed via zlib.

7 files changed, 195 insertions, 38 deletions

diff --git a/NEWS b/NEWS
index 115261e7..e4b2402f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,7 @@
+Version 0.153
+
+libdw: Support reading .zdebug_* DWARF sections compressed via zlib.
+
 Version 0.152
 
 Various build and warning nits fixed for newest GCC and Autoconf.
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 8ec74857..b0ba7e00 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,14 @@
+2011-02-23  Roland McGrath  <[email protected]>
+
+	* libdwP.h (struct Dwarf) [USE_ZLIB]: New member sectiondata_gzip_mask.
+	Declare __libdw_free_zdata.
+	* dwarf_end.c [USE_ZLIB] (__libdw_free_zdata): New function.
+	(dwarf_end): Call it.
+
+	* dwarf_begin_elf.c (valid_p): Likewise.
+	(check_section, scngrp_read): Likewise.
+	(check_section) [USE_ZLIB]: Grok .z* flavors of sections.
+
 2010-10-13  Roland McGrath  <[email protected]>
 
 	* dwarf.h: Add DW_LANG_Go.
diff --git a/libdw/dwarf_begin_elf.c b/libdw/dwarf_begin_elf.c
index b5fb7c91..9ec7d51f 100644
--- a/libdw/dwarf_begin_elf.c
+++ b/libdw/dwarf_begin_elf.c
@@ -1,5 +1,5 @@
 /* Create descriptor from ELF descriptor for processing file.
-   Copyright (C) 2002-2010 Red Hat, Inc.
+   Copyright (C) 2002-2011 Red Hat, Inc.
    This file is part of Red Hat elfutils.
    Written by Ulrich Drepper <[email protected]>, 2002.
 
@@ -61,6 +61,13 @@
 
 #include "libdwP.h"
 
+#if USE_ZLIB
+# include <endian.h>
+# define crc32		loser_crc32
+# include <zlib.h>
+# undef crc32
+#endif
+
 
 /* Section names.  */
 static const char dwarf_scnnames[IDX_last][17] =
@@ -117,6 +124,7 @@ check_section (Dwarf *result, GElf_Ehdr *ehdr, Elf_Scn *scn, bool inscngrp)
     {
       /* The section name must be valid.  Otherwise is the ELF file
 	 invalid.  */
+      __libdw_free_zdata (result);
       __libdw_seterrno (DWARF_E_INVALID_ELF);
       free (result);
       return NULL;
@@ -141,6 +149,76 @@ check_section (Dwarf *result, GElf_Ehdr *ehdr, Elf_Scn *scn, bool inscngrp)
 
 	break;
       }
+#if USE_ZLIB
+    else if (scnname[0] == '.' && scnname[1] == 'z'
+	     && strcmp (&scnname[2], &dwarf_scnnames[cnt][1]) == 0)
+      {
+	/* A compressed section.  */
+
+	if (unlikely (result->sectiondata[cnt] != NULL))
+	  /* A section appears twice.  That's bad.  We ignore the section.  */
+	  break;
+
+	/* Get the section data.  */
+	Elf_Data *data = elf_getdata (scn, NULL);
+	if (data != NULL && data->d_size != 0)
+	  {
+	    /* There is a 12-byte header of "ZLIB" followed by
+	       an 8-byte big-endian size.  */
+
+	    if (unlikely (data->d_size < 4 + 8)
+		|| unlikely (memcmp (data->d_buf, "ZLIB", 4) != 0))
+	      break;
+
+	    uint64_t size;
+	    memcpy (&size, data->d_buf + 4, sizeof size);
+	    size = be64toh (size);
+
+	    Elf_Data *zdata = malloc (sizeof (Elf_Data) + size);
+	    if (unlikely (zdata == NULL))
+	      break;
+
+	    zdata->d_buf = &zdata[1];
+	    zdata->d_type = ELF_T_BYTE;
+	    zdata->d_version = EV_CURRENT;
+	    zdata->d_size = size;
+	    zdata->d_off = 0;
+	    zdata->d_align = 1;
+
+	    z_stream z =
+	      {
+		.next_in = data->d_buf + 4 + 8,
+		.avail_in = data->d_size - 4 - 8,
+		.next_out = zdata->d_buf,
+		.avail_out = zdata->d_size
+	      };
+	    int zrc = inflateInit (&z);
+	    while (z.avail_in > 0 && likely (zrc == Z_OK))
+	      {
+		z.next_out = zdata->d_buf + (zdata->d_size - z.avail_out);
+		zrc = inflate (&z, Z_FINISH);
+		if (unlikely (zrc != Z_STREAM_END))
+		  {
+		    zrc = Z_DATA_ERROR;
+		    break;
+		  }
+		zrc = inflateReset (&z);
+	      }
+	    if (likely (zrc == Z_OK))
+	      zrc = inflateEnd (&z);
+
+	    if (unlikely (zrc != Z_OK) || unlikely (z.avail_out != 0))
+	      free (zdata);
+	    else
+	      {
+		result->sectiondata[cnt] = zdata;
+		result->sectiondata_gzip_mask |= 1U << cnt;
+	      }
+	  }
+
+	break;
+      }
+#endif
 
   return result;
 }
@@ -159,6 +237,7 @@ valid_p (Dwarf *result)
   if (likely (result != NULL)
       && unlikely (result->sectiondata[IDX_debug_info] == NULL))
     {
+      __libdw_free_zdata (result);
       __libdw_seterrno (DWARF_E_NO_DWARF);
       free (result);
       result = NULL;
@@ -189,6 +268,7 @@ scngrp_read (Dwarf *result, Elf *elf, GElf_Ehdr *ehdr, Elf_Scn *scngrp)
   if (data == NULL)
     {
       /* We cannot read the section content.  Fail!  */
+      __libdw_free_zdata (result);
       free (result);
       return NULL;
     }
@@ -204,6 +284,7 @@ scngrp_read (Dwarf *result, Elf *elf, GElf_Ehdr *ehdr, Elf_Scn *scngrp)
 	{
 	  /* A section group refers to a non-existing section.  Should
 	     never happen.  */
+	  __libdw_free_zdata (result);
 	  __libdw_seterrno (DWARF_E_INVALID_ELF);
 	  free (result);
 	  return NULL;
diff --git a/libdw/dwarf_end.c b/libdw/dwarf_end.c
index ec10542e..1e733cae 100644
--- a/libdw/dwarf_end.c
+++ b/libdw/dwarf_end.c
@@ -1,5 +1,5 @@
 /* Release debugging handling context.
-   Copyright (C) 2002-2010 Red Hat, Inc.
+   Copyright (C) 2002-2011 Red Hat, Inc.
    This file is part of Red Hat elfutils.
    Written by Ulrich Drepper <[email protected]>, 2002.
 
@@ -54,6 +54,8 @@
 
 #include <search.h>
 #include <stdlib.h>
+#include <assert.h>
+#include <string.h>
 
 #include "libdwP.h"
 #include "cfi.h"
@@ -76,6 +78,24 @@ cu_free (void *arg)
 }
 
 
+#if USE_ZLIB
+void
+internal_function
+__libdw_free_zdata (Dwarf *dwarf)
+{
+  unsigned int gzip_mask = dwarf->sectiondata_gzip_mask;
+  while (gzip_mask != 0)
+    {
+      int i = ffs (gzip_mask);
+      assert (i > 0);
+      --i;
+      assert (i < IDX_last);
+      free (dwarf->sectiondata[i]);
+      gzip_mask &= ~(1U << i);
+    }
+}
+#endif
+
 int
 dwarf_end (dwarf)
      Dwarf *dwarf;
@@ -106,6 +126,8 @@ dwarf_end (dwarf)
       /* Free the pubnames helper structure.  */
       free (dwarf->pubnames_sets);
 
+      __libdw_free_zdata (dwarf);
+
       /* Free the ELF descriptor if necessary.  */
       if (dwarf->free_elf)
 	elf_end (dwarf->elf);
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index da6efc53..b84bf02c 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -1,5 +1,5 @@
 /* Internal definitions for libdwarf.
-   Copyright (C) 2002-2010 Red Hat, Inc.
+   Copyright (C) 2002-2011 Red Hat, Inc.
    This file is part of Red Hat elfutils.
    Written by Ulrich Drepper <[email protected]>, 2002.
 
@@ -150,6 +150,11 @@ struct Dwarf
   /* The section data.  */
   Elf_Data *sectiondata[IDX_last];
 
+#if USE_ZLIB
+  /* The 1 << N bit is set if sectiondata[N] is malloc'd decompressed data.  */
+  unsigned int sectiondata_gzip_mask:IDX_last;
+#endif
+
   /* True if the file has a byte order different from the host.  */
   bool other_byte_order;
 
@@ -385,6 +390,12 @@ extern void *__libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
 /* Default OOM handler.  */
 extern void __libdw_oom (void) __attribute ((noreturn, visibility ("hidden")));
 
+#if USE_ZLIB
+extern void __libdw_free_zdata (Dwarf *dwarf) internal_function;
+#else
+# define __libdw_free_zdata(dwarf)	((void) (dwarf))
+#endif
+
 /* Allocate the internal data for a unit not seen before.  */
 extern struct Dwarf_CU *__libdw_intern_next_unit (Dwarf *dbg, bool debug_types)
      __nonnull_attribute__ (1) internal_function;
diff --git a/src/ChangeLog b/src/ChangeLog
index c8b897a9..a7c2513d 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,19 @@
 2011-02-23  Roland McGrath  <[email protected]>
 
+	* readelf.c (section_name): New function.
+	(print_debug_abbrev_section): Use it instead of constant.
+	(print_debug_aranges_section): Likewise.
+	(print_debug_ranges_section): Likewise.
+	(print_debug_units): Likewise.
+	(print_debug_line_section): Likewise.
+	(print_debug_loc_section): Likewise.
+	(print_debug_macinfo_section): Likewise.
+	(print_debug_pubnames_section): Likewise.
+	(print_debug_str_section): Likewise.
+	(print_debug) [USE_ZLIB]: Match .zdebug_* sections too.
+	(print_debug_abbrev_section): Use decoded d_size, not sh_size.
+	(print_debug_str_section): Likewise.
+
 	* readelf.c (dwarf_attr_string): Grok DW_AT_GNU_odr_signature.
 
 2011-02-11  Roland McGrath  <[email protected]>
diff --git a/src/readelf.c b/src/readelf.c
index 0e50a692..78ee2b77 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -1154,6 +1154,13 @@ print_phdr (Ebl *ebl, GElf_Ehdr *ehdr)
 }
 
 
+static const char *
+section_name (Ebl *ebl, GElf_Ehdr *ehdr, GElf_Shdr *shdr)
+{
+  return elf_strptr (ebl->elf, ehdr->e_shstrndx, shdr->sh_name) ?: "???";
+}
+
+
 static void
 handle_scngrp (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
 {
@@ -4406,16 +4413,16 @@ skip_listptr_hole (struct listptr_table *table, size_t *idxp,
 
 static void
 print_debug_abbrev_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
-			    Ebl *ebl __attribute__ ((unused)),
-			    GElf_Ehdr *ehdr __attribute__ ((unused)),
+			    Ebl *ebl, GElf_Ehdr *ehdr,
 			    Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
   printf (gettext ("\nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"
 		   " [ Code]\n"),
-	  elf_ndxscn (scn), ".debug_abbrev", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
 
   Dwarf_Off offset = 0;
-  while (offset < shdr->sh_size)
+  while (offset < dbg->sectiondata[IDX_debug_abbrev]->d_size)
     {
       printf (gettext ("\nAbbreviation section at offset %" PRIu64 ":\n"),
 	      offset);
@@ -4477,8 +4484,7 @@ print_debug_abbrev_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
    takes care of it.  */
 static void
 print_debug_aranges_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
-			     Ebl *ebl __attribute__ ((unused)),
-			     GElf_Ehdr *ehdr, Elf_Scn *scn,
+			     Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
 			     GElf_Shdr *shdr, Dwarf *dbg)
 {
   Dwarf_Aranges *aranges;
@@ -4495,7 +4501,8 @@ print_debug_aranges_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
 		    "\
 \nDWARF section [%2zu] '%s' at offset %#" PRIx64 " contains %zu entries:\n",
 		    cnt),
-	  elf_ndxscn (scn), ".debug_aranges", (uint64_t) shdr->sh_offset, cnt);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset, cnt);
 
   /* Compute floor(log16(cnt)).  */
   size_t tmp = cnt;
@@ -4533,8 +4540,8 @@ print_debug_aranges_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
 /* Print content of DWARF .debug_ranges section.  */
 static void
 print_debug_ranges_section (Dwfl_Module *dwflmod,
-			    Ebl *ebl __attribute__ ((unused)),
-			    GElf_Ehdr *ehdr, Elf_Scn *scn, GElf_Shdr *shdr,
+			    Ebl *ebl, GElf_Ehdr *ehdr,
+			    Elf_Scn *scn, GElf_Shdr *shdr,
 			    Dwarf *dbg)
 {
   Elf_Data *data = elf_rawdata (scn, NULL);
@@ -4548,7 +4555,8 @@ print_debug_ranges_section (Dwfl_Module *dwflmod,
 
   printf (gettext ("\
 \nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
-	  elf_ndxscn (scn), ".debug_ranges", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
 
   sort_listptr (&known_rangelistptr, "rangelistptr");
   size_t listptr_idx = 0;
@@ -5644,14 +5652,12 @@ attr_callback (Dwarf_Attribute *attrp, void *arg)
 
 static void
 print_debug_units (Dwfl_Module *dwflmod,
-		   Ebl *ebl __attribute__ ((unused)),
-		   GElf_Ehdr *ehdr __attribute__ ((unused)),
-		   Elf_Scn *scn,
-		   GElf_Shdr *shdr, Dwarf *dbg,
-		   bool debug_types)
+		   Ebl *ebl, GElf_Ehdr *ehdr,
+		   Elf_Scn *scn, GElf_Shdr *shdr,
+		   Dwarf *dbg, bool debug_types)
 {
   const bool silent = !(print_debug_sections & section_info);
-  const char *secname = debug_types ? ".debug_types" : ".debug_info";
+  const char *secname = section_name (ebl, ehdr, shdr);
 
   if (!silent)
     printf (gettext ("\
@@ -5814,13 +5820,13 @@ print_debug_types_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
 
 
 static void
-print_debug_line_section (Dwfl_Module *dwflmod, Ebl *ebl,
-			  GElf_Ehdr *ehdr __attribute__ ((unused)),
+print_debug_line_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
 			  Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
   printf (gettext ("\
 \nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
-	  elf_ndxscn (scn), ".debug_line", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
 
   if (shdr->sh_size == 0)
     return;
@@ -5853,7 +5859,7 @@ print_debug_line_section (Dwfl_Module *dwflmod, Ebl *ebl,
 	    {
 	    invalid_data:
 	      error (0, 0, gettext ("invalid data in section [%zu] '%s'"),
-		     elf_ndxscn (scn), ".debug_line");
+		     elf_ndxscn (scn), section_name (ebl, ehdr, shdr));
 	      return;
 	    }
 	  unit_length = read_8ubyte_unaligned_inc (dbg, linep);
@@ -5921,7 +5927,7 @@ print_debug_line_section (Dwfl_Module *dwflmod, Ebl *ebl,
 	  error (0, 0,
 		 gettext ("invalid data at offset %tu in section [%zu] '%s'"),
 		 linep - (const unsigned char *) data->d_buf,
-		 elf_ndxscn (scn), ".debug_line");
+		 elf_ndxscn (scn), section_name (ebl, ehdr, shdr));
 	  linep = lineendp;
 	  continue;
 	}
@@ -6304,7 +6310,7 @@ advance address by fixed value %u to %s\n"),
 
 static void
 print_debug_loc_section (Dwfl_Module *dwflmod,
-			 Ebl *ebl __attribute__ ((unused)), GElf_Ehdr *ehdr,
+			 Ebl *ebl, GElf_Ehdr *ehdr,
 			 Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
   Elf_Data *data = elf_rawdata (scn, NULL);
@@ -6318,7 +6324,8 @@ print_debug_loc_section (Dwfl_Module *dwflmod,
 
   printf (gettext ("\
 \nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
-	  elf_ndxscn (scn), ".debug_loc", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
 
   sort_listptr (&known_loclistptr, "loclistptr");
   size_t listptr_idx = 0;
@@ -6427,13 +6434,13 @@ mac_compare (const void *p1, const void *p2)
 
 static void
 print_debug_macinfo_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
-			     Ebl *ebl __attribute__ ((unused)),
-			     GElf_Ehdr *ehdr __attribute__ ((unused)),
+			     Ebl *ebl, GElf_Ehdr *ehdr,
 			     Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
   printf (gettext ("\
 \nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
-	  elf_ndxscn (scn), ".debug_macinfo", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
   putc_unlocked ('\n', stdout);
 
   /* There is no function in libdw to iterate over the raw content of
@@ -6599,12 +6606,12 @@ print_pubnames (Dwarf *dbg __attribute__ ((unused)), Dwarf_Global *global,
 /* Print the known exported symbols in the DWARF section '.debug_pubnames'.  */
 static void
 print_debug_pubnames_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
-			      Ebl *ebl __attribute__ ((unused)),
-			      GElf_Ehdr *ehdr __attribute__ ((unused)),
+			      Ebl *ebl, GElf_Ehdr *ehdr,
 			      Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
   printf (gettext ("\nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"),
-	  elf_ndxscn (scn), ".debug_pubnames", (uint64_t) shdr->sh_offset);
+	  elf_ndxscn (scn), section_name (ebl, ehdr, shdr),
+	  (uint64_t) shdr->sh_offset);
 
   int n = 0;
   (void) dwarf_getpubnames (dbg, print_pubnames, &n, 0);
@@ -6613,12 +6620,13 @@ print_debug_pubnames_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
 /* Print the content of the DWARF string section '.debug_str'.  */
 static void
 print_debug_str_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
-			 Ebl *ebl __attribute__ ((unused)),
-			 GElf_Ehdr *ehdr __attribute__ ((unused)),
+			 Ebl *ebl, GElf_Ehdr *ehdr,
 			 Elf_Scn *scn, GElf_Shdr *shdr, Dwarf *dbg)
 {
+  const size_t sh_size = dbg->sectiondata[IDX_debug_str]->d_size;
+
   /* Compute floor(log16(shdr->sh_size)).  */
-  GElf_Addr tmp = shdr->sh_size;
+  GElf_Addr tmp = sh_size;
   int digits = 1;
   while (tmp >= 16)
     {
@@ -6630,12 +6638,12 @@ print_debug_str_section (Dwfl_Module *dwflmod __attribute__ ((unused)),
   printf (gettext ("\nDWARF section [%2zu] '%s' at offset %#" PRIx64 ":\n"
 		   " %*s  String\n"),
 	  elf_ndxscn (scn),
-	  ".debug_str", (uint64_t) shdr->sh_offset,
+	  section_name (ebl, ehdr, shdr), (uint64_t) shdr->sh_offset,
 	  /* TRANS: the debugstr| prefix makes the string unique.  */
 	  digits + 2, sgettext ("debugstr|Offset"));
 
   Dwarf_Off offset = 0;
-  while (offset < shdr->sh_size)
+  while (offset < sh_size)
     {
       size_t len;
       const char *str = dwarf_getstring (dbg, offset, &len);
@@ -6981,7 +6989,13 @@ print_debug (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr)
 	  int n;
 
 	  for (n = 0; n < ndebug_sections; ++n)
-	    if (strcmp (name, debug_sections[n].name) == 0)
+	    if (strcmp (name, debug_sections[n].name) == 0
+#if USE_ZLIB
+		|| (name[0] == '.' && name[1] == 'z'
+		    && debug_sections[n].name[1] == 'd'
+		    && strcmp (&name[2], &debug_sections[n].name[1]) == 0)
+#endif
+		)
 	      {
 		if ((print_debug_sections | implicit_debug_sections)
 		    & debug_sections[n].bitmask)