libdw: Add locking to dwarf_getsrcfiles, dwarf_getsrclines, dwarf_macro_getsrcfiles

	* libdw/dwarf_begin_elf.c (dwarf_begin_elf): Init macro_lock.
	* libdw/dwarf_end.c (cu_free): Free src_lock.
	(dwarf_end): Free macro_lock.
	* libdw/dwarf_getsrcfiles.c (dwarf_getsrcfiles): Use src_lock.
	* libdw/dwarf_getsrclines.c (dwarf_getsrclines): Ditto.
	* libdw/dwarf_macro_getsrclines.c (dwarf_macro_getsrclines): Use
	macro_lock.
	* libdw/libdwP.h (struct Dwarf): Define macro_lock.
	(struct Dwarf_CU): Define src_lock.
	* libdw/libdw_findcu.c (__libdw_intern_next_unit): Init src_lock.

Signed-off-by: Aaron Merey <[email protected]>

7 files changed, 47 insertions, 13 deletions

diff --git a/libdw/dwarf_begin_elf.c b/libdw/dwarf_begin_elf.c
index 8a3a939b..58a309e9 100644
--- a/libdw/dwarf_begin_elf.c
+++ b/libdw/dwarf_begin_elf.c
@@ -580,6 +580,7 @@ dwarf_begin_elf (Elf *elf, Dwarf_Cmd cmd, Elf_Scn *scngrp)
       return NULL;
     }
   mutex_init (result->dwarf_lock);
+  mutex_init (result->macro_lock);
   eu_search_tree_init (&result->cu_tree);
   eu_search_tree_init (&result->tu_tree);
   eu_search_tree_init (&result->split_tree);
diff --git a/libdw/dwarf_end.c b/libdw/dwarf_end.c
index 92389c07..c12815e1 100644
--- a/libdw/dwarf_end.c
+++ b/libdw/dwarf_end.c
@@ -70,6 +70,7 @@ cu_free (void *arg)
       Dwarf_Abbrev_Hash_free (&p->abbrev_hash);
       rwlock_fini (p->abbrev_lock);
       rwlock_fini (p->split_lock);
+      mutex_fini (p->src_lock);
 
       /* Free split dwarf one way (from skeleton to split).  */
       if (p->unit_type == DW_UT_skeleton
@@ -130,6 +131,7 @@ dwarf_end (Dwarf *dwarf)
         free (dwarf->mem_tails);
       pthread_rwlock_destroy (&dwarf->mem_rwl);
       mutex_fini (dwarf->dwarf_lock);
+      mutex_fini (dwarf->macro_lock);
 
       /* Free the pubnames helper structure.  */
       free (dwarf->pubnames_sets);
diff --git a/libdw/dwarf_getsrcfiles.c b/libdw/dwarf_getsrcfiles.c
index 24e4b7d2..9becd1d5 100644
--- a/libdw/dwarf_getsrcfiles.c
+++ b/libdw/dwarf_getsrcfiles.c
@@ -47,9 +47,10 @@ dwarf_getsrcfiles (Dwarf_Die *cudie, Dwarf_Files **files, size_t *nfiles)
     }
 
   int res = -1;
+  struct Dwarf_CU *const cu = cudie->cu;
+  mutex_lock (cudie->cu->src_lock);
 
   /* Get the information if it is not already known.  */
-  struct Dwarf_CU *const cu = cudie->cu;
   if (cu->files == NULL)
     {
       /* For split units there might be a simple file table (without lines).
@@ -96,7 +97,10 @@ dwarf_getsrcfiles (Dwarf_Die *cudie, Dwarf_Files **files, size_t *nfiles)
 	  Dwarf_Off debug_line_offset;
 	  if (__libdw_formptr (stmt_list, IDX_debug_line, DWARF_E_NO_DEBUG_LINE,
 			       NULL, &debug_line_offset) == NULL)
-	    return -1;
+	    {
+	      mutex_unlock (cudie->cu->src_lock);
+	      return -1;
+	    }
 
 	  res = __libdw_getsrcfiles (cu->dbg, debug_line_offset,
 				     __libdw_getcompdir (cudie),
@@ -115,8 +119,7 @@ dwarf_getsrcfiles (Dwarf_Die *cudie, Dwarf_Files **files, size_t *nfiles)
 	*nfiles = cu->files->nfiles;
     }
 
-  // XXX Eventually: unlocking here.
-
+  mutex_unlock (cudie->cu->src_lock);
   return res;
 }
 INTDEF (dwarf_getsrcfiles)
diff --git a/libdw/dwarf_getsrclines.c b/libdw/dwarf_getsrclines.c
index da78db67..be10cdee 100644
--- a/libdw/dwarf_getsrclines.c
+++ b/libdw/dwarf_getsrclines.c
@@ -1442,8 +1442,10 @@ dwarf_getsrclines (Dwarf_Die *cudie, Dwarf_Lines **lines, size_t *nlines)
       return -1;
     }
 
-  /* Get the information if it is not already known.  */
   struct Dwarf_CU *const cu = cudie->cu;
+  mutex_lock (cu->src_lock);
+
+  /* Get the information if it is not already known.  */
   if (cu->lines == NULL)
     {
       /* For split units always pick the lines from the skeleton.  */
@@ -1464,10 +1466,13 @@ dwarf_getsrclines (Dwarf_Die *cudie, Dwarf_Lines **lines, size_t *nlines)
 		  *lines = cu->lines;
 		  *nlines = cu->lines->nlines;
 		}
+
+	      mutex_unlock (cu->src_lock);
 	      return res;
 	    }
 
 	  __libdw_seterrno (DWARF_E_NO_DEBUG_LINE);
+	  mutex_unlock (cu->src_lock);
 	  return -1;
 	}
 
@@ -1485,21 +1490,29 @@ dwarf_getsrclines (Dwarf_Die *cudie, Dwarf_Lines **lines, size_t *nlines)
       Dwarf_Off debug_line_offset;
       if (__libdw_formptr (stmt_list, IDX_debug_line, DWARF_E_NO_DEBUG_LINE,
 			   NULL, &debug_line_offset) == NULL)
-	return -1;
+	{
+	  mutex_unlock (cu->src_lock);
+	  return -1;
+	}
 
       if (__libdw_getsrclines (cu->dbg, debug_line_offset,
 			       __libdw_getcompdir (cudie),
 			       cu->address_size, &cu->lines, &cu->files) < 0)
-	return -1;
+	{
+	  mutex_unlock (cu->src_lock);
+	  return -1;
+	}
     }
   else if (cu->lines == (void *) -1l)
-    return -1;
+    {
+      mutex_unlock (cu->src_lock);
+      return -1;
+    }
 
   *lines = cu->lines;
   *nlines = cu->lines->nlines;
 
-  // XXX Eventually: unlocking here.
-
+  mutex_unlock (cu->src_lock);
   return 0;
 }
 INTDEF(dwarf_getsrclines)
diff --git a/libdw/dwarf_macro_getsrcfiles.c b/libdw/dwarf_macro_getsrcfiles.c
index 5e02935d..6ccbeadb 100644
--- a/libdw/dwarf_macro_getsrcfiles.c
+++ b/libdw/dwarf_macro_getsrcfiles.c
@@ -41,6 +41,8 @@ dwarf_macro_getsrcfiles (Dwarf *dbg, Dwarf_Macro *macro,
 
   /* macro is declared NN */
   Dwarf_Macro_Op_Table *const table = macro->table;
+
+  mutex_lock (table->dbg->macro_lock);
   if (table->files == NULL)
     {
       Dwarf_Off line_offset = table->line_offset;
@@ -48,6 +50,7 @@ dwarf_macro_getsrcfiles (Dwarf *dbg, Dwarf_Macro *macro,
 	{
 	  *files = NULL;
 	  *nfiles = 0;
+	  mutex_unlock (table->dbg->macro_lock);
 	  return 0;
 	}
 
@@ -80,9 +83,14 @@ dwarf_macro_getsrcfiles (Dwarf *dbg, Dwarf_Macro *macro,
     }
 
   if (table->files == (void *) -1)
-    return -1;
+    {
+      mutex_unlock (table->dbg->macro_lock);
+      return -1;
+    }
 
   *files = table->files;
   *nfiles = table->files->nfiles;
+
+  mutex_unlock (table->dbg->macro_lock);
   return 0;
 }
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index a9d4c0a7..3216f2a1 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -265,11 +265,13 @@ struct Dwarf
   pthread_rwlock_t mem_rwl;
 
   /* Recursive mutex intended for setting/getting alt_dwarf, next_tu_offset,
-     and next_cu_offset.  Covers dwarf_getsrclines, dwarf_getsrcfiles and
-     dwarf_macro_getsrcfiles.  Should also be held when calling
+     and next_cu_offset.  Should be held when calling
      __libdw_intern_next_unit.  */
   mutex_define(, dwarf_lock);
 
+  /* Synchronize access to dwarf_macro_getsrcfiles.  */
+  mutex_define(, macro_lock);
+
   /* Internal memory handling.  This is basically a simplified thread-local
      reimplementation of obstacks.  Unfortunately the standard obstack
      implementation is not usable in libraries.  */
@@ -461,6 +463,10 @@ struct Dwarf_CU
      Covers __libdw_find_split_unit.  */
   rwlock_define(, split_lock);
 
+  /* Synchronize access to the lines and files members.
+     Covers dwarf_getsrclines and dwarf_getsrcfiles.  */
+  mutex_define(, src_lock);
+
   /* Memory boundaries of this CU.  */
   void *startp;
   void *endp;
diff --git a/libdw/libdw_findcu.c b/libdw/libdw_findcu.c
index 613f61c8..f0243643 100644
--- a/libdw/libdw_findcu.c
+++ b/libdw/libdw_findcu.c
@@ -179,6 +179,7 @@ __libdw_intern_next_unit (Dwarf *dbg, bool debug_types)
   eu_search_tree_init (&newp->locs_tree);
   rwlock_init (newp->abbrev_lock);
   rwlock_init (newp->split_lock);
+  mutex_init (newp->src_lock);
 
   /* v4 debug type units have version == 4 and unit_type == DW_UT_type.  */
   if (debug_types)