libbacktrace: pass -1 to error callback for unrecognized DWARF

	PR libbacktrace/98818
	* dwarf.c (dwarf_buf_error): Add errnum parameter.  Change all
	callers.
	* backtrace.h: Update backtrace_error_callback comment.

2 files changed, 43 insertions, 30 deletions

diff --git a/libbacktrace/backtrace.h b/libbacktrace/backtrace.h
index 2814763f417..caaa66d3686 100644
--- a/libbacktrace/backtrace.h
+++ b/libbacktrace/backtrace.h
@@ -71,13 +71,14 @@ struct backtrace_state;
    invalid after this function returns.
 
    As a special case, the ERRNUM argument will be passed as -1 if no
-   debug info can be found for the executable, but the function
-   requires debug info (e.g., backtrace_full, backtrace_pcinfo).  The
-   MSG in this case will be something along the lines of "no debug
-   info".  Similarly, ERRNUM will be passed as -1 if there is no
-   symbol table, but the function requires a symbol table (e.g.,
-   backtrace_syminfo).  This may be used as a signal that some other
-   approach should be tried.  */
+   debug info can be found for the executable, or if the debug info
+   exists but has an unsupported version, but the function requires
+   debug info (e.g., backtrace_full, backtrace_pcinfo).  The MSG in
+   this case will be something along the lines of "no debug info".
+   Similarly, ERRNUM will be passed as -1 if there is no symbol table,
+   but the function requires a symbol table (e.g., backtrace_syminfo).
+   This may be used as a signal that some other approach should be
+   tried.  */
 
 typedef void (*backtrace_error_callback) (void *data, const char *msg,
 					  int errnum);
diff --git a/libbacktrace/dwarf.c b/libbacktrace/dwarf.c
index 9097df6cc76..546b4b26a32 100644
--- a/libbacktrace/dwarf.c
+++ b/libbacktrace/dwarf.c
@@ -410,13 +410,13 @@ struct dwarf_data
 /* Report an error for a DWARF buffer.  */
 
 static void
-dwarf_buf_error (struct dwarf_buf *buf, const char *msg)
+dwarf_buf_error (struct dwarf_buf *buf, const char *msg, int errnum)
 {
   char b[200];
 
   snprintf (b, sizeof b, "%s in %s at %d",
 	    msg, buf->name, (int) (buf->buf - buf->start));
-  buf->error_callback (buf->data, b, 0);
+  buf->error_callback (buf->data, b, errnum);
 }
 
 /* Require at least COUNT bytes in BUF.  Return 1 if all is well, 0 on
@@ -430,7 +430,7 @@ require (struct dwarf_buf *buf, size_t count)
 
   if (!buf->reported_underflow)
     {
-      dwarf_buf_error (buf, "DWARF underflow");
+      dwarf_buf_error (buf, "DWARF underflow", 0);
       buf->reported_underflow = 1;
     }
 
@@ -592,7 +592,7 @@ read_address (struct dwarf_buf *buf, int addrsize)
     case 8:
       return read_uint64 (buf);
     default:
-      dwarf_buf_error (buf, "unrecognized address size");
+      dwarf_buf_error (buf, "unrecognized address size", 0);
       return 0;
     }
 }
@@ -643,7 +643,7 @@ read_uleb128 (struct dwarf_buf *buf)
 	ret |= ((uint64_t) (b & 0x7f)) << shift;
       else if (!overflow)
 	{
-	  dwarf_buf_error (buf, "LEB128 overflows uint64_t");
+	  dwarf_buf_error (buf, "LEB128 overflows uint64_t", 0);
 	  overflow = 1;
 	}
       shift += 7;
@@ -678,7 +678,7 @@ read_sleb128 (struct dwarf_buf *buf)
 	val |= ((uint64_t) (b & 0x7f)) << shift;
       else if (!overflow)
 	{
-	  dwarf_buf_error (buf, "signed LEB128 overflows uint64_t");
+	  dwarf_buf_error (buf, "signed LEB128 overflows uint64_t", 0);
 	  overflow = 1;
 	}
       shift += 7;
@@ -818,7 +818,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
 	offset = read_offset (buf, is_dwarf64);
 	if (offset >= dwarf_sections->size[DEBUG_STR])
 	  {
-	    dwarf_buf_error (buf, "DW_FORM_strp out of range");
+	    dwarf_buf_error (buf, "DW_FORM_strp out of range", 0);
 	    return 0;
 	  }
 	val->encoding = ATTR_VAL_STRING;
@@ -833,7 +833,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
 	offset = read_offset (buf, is_dwarf64);
 	if (offset >= dwarf_sections->size[DEBUG_LINE_STR])
 	  {
-	    dwarf_buf_error (buf, "DW_FORM_line_strp out of range");
+	    dwarf_buf_error (buf, "DW_FORM_line_strp out of range", 0);
 	    return 0;
 	  }
 	val->encoding = ATTR_VAL_STRING;
@@ -880,7 +880,8 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
 	if (form == DW_FORM_implicit_const)
 	  {
 	    dwarf_buf_error (buf,
-			     "DW_FORM_indirect to DW_FORM_implicit_const");
+			     "DW_FORM_indirect to DW_FORM_implicit_const",
+			     0);
 	    return 0;
 	  }
 	return read_attribute ((enum dwarf_form) form, 0, buf, is_dwarf64,
@@ -1013,7 +1014,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
 	  }
 	if (offset >= altlink->dwarf_sections.size[DEBUG_STR])
 	  {
-	    dwarf_buf_error (buf, "DW_FORM_strp_sup out of range");
+	    dwarf_buf_error (buf, "DW_FORM_strp_sup out of range", 0);
 	    return 0;
 	  }
 	val->encoding = ATTR_VAL_STRING;
@@ -1022,7 +1023,7 @@ read_attribute (enum dwarf_form form, uint64_t implicit_val,
 	return 1;
       }
     default:
-      dwarf_buf_error (buf, "unrecognized DWARF form");
+      dwarf_buf_error (buf, "unrecognized DWARF form", -1);
       return 0;
     }
 }
@@ -1071,7 +1072,9 @@ resolve_string (const struct dwarf_sections *dwarf_sections, int is_dwarf64,
 	offset = read_offset (&offset_buf, is_dwarf64);
 	if (offset >= dwarf_sections->size[DEBUG_STR])
 	  {
-	    dwarf_buf_error (&offset_buf, "DW_FORM_strx offset out of range");
+	    dwarf_buf_error (&offset_buf,
+			     "DW_FORM_strx offset out of range",
+			     0);
 	    return 0;
 	  }
 	*string = (const char *) dwarf_sections->data[DEBUG_STR] + offset;
@@ -1879,7 +1882,7 @@ add_ranges_from_rnglists (
 	  break;
 
 	default:
-	  dwarf_buf_error (&rnglists_buf, "unrecognized DW_RLE value");
+	  dwarf_buf_error (&rnglists_buf, "unrecognized DW_RLE value", -1);
 	  return 0;
 	}
     }
@@ -2146,7 +2149,7 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
       version = read_uint16 (&unit_buf);
       if (version < 2 || version > 5)
 	{
-	  dwarf_buf_error (&unit_buf, "unrecognized DWARF version");
+	  dwarf_buf_error (&unit_buf, "unrecognized DWARF version", -1);
 	  goto fail;
 	}
 
@@ -2425,7 +2428,8 @@ read_v2_paths (struct backtrace_state *state, struct unit *u,
 	    {
 	      dwarf_buf_error (hdr_buf,
 			       ("invalid directory index in "
-				"line number program header"));
+				"line number program header"),
+			       0);
 	      return 0;
 	    }
 	  dir_len = strlen (dir);
@@ -2494,7 +2498,8 @@ read_lnct (struct backtrace_state *state, struct dwarf_data *ddata,
 		{
 		  dwarf_buf_error (hdr_buf,
 				   ("invalid directory index in "
-				    "line number program header"));
+				    "line number program header"),
+				   0);
 		  return 0;
 		}
 	      dir = hdr->dirs[val.u.uint];
@@ -2509,7 +2514,8 @@ read_lnct (struct backtrace_state *state, struct dwarf_data *ddata,
   if (path == NULL)
     {
       dwarf_buf_error (hdr_buf,
-		       "missing file name in line number program header");
+		       "missing file name in line number program header",
+		       0);
       return 0;
     }
 
@@ -2636,7 +2642,7 @@ read_line_header (struct backtrace_state *state, struct dwarf_data *ddata,
   hdr->version = read_uint16 (line_buf);
   if (hdr->version < 2 || hdr->version > 5)
     {
-      dwarf_buf_error (line_buf, "unsupported line number version");
+      dwarf_buf_error (line_buf, "unsupported line number version", -1);
       return 0;
     }
 
@@ -2650,7 +2656,8 @@ read_line_header (struct backtrace_state *state, struct dwarf_data *ddata,
       if (read_byte (line_buf) != 0)
 	{
 	  dwarf_buf_error (line_buf,
-			   "non-zero segment_selector_size not supported");
+			   "non-zero segment_selector_size not supported",
+			   -1);
 	  return 0;
 	}
     }
@@ -2791,7 +2798,8 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
 		      {
 			dwarf_buf_error (line_buf,
 					 ("invalid directory index "
-					  "in line number program"));
+					  "in line number program"),
+					 0);
 			return 0;
 		      }
 		    dir_len = strlen (dir);
@@ -2857,7 +2865,8 @@ read_line_program (struct backtrace_state *state, struct dwarf_data *ddata,
 		      {
 			dwarf_buf_error (line_buf,
 					 ("invalid file number in "
-					  "line number program"));
+					  "line number program"),
+					 0);
 			return 0;
 		      }
 		    filename = hdr->filenames[fileno];
@@ -3092,7 +3101,9 @@ read_referenced_name (struct dwarf_data *ddata, struct unit *u,
   code = read_uleb128 (&unit_buf);
   if (code == 0)
     {
-      dwarf_buf_error (&unit_buf, "invalid abstract origin or specification");
+      dwarf_buf_error (&unit_buf,
+		       "invalid abstract origin or specification",
+		       0);
       return NULL;
     }
 
@@ -3295,7 +3306,8 @@ read_function_entry (struct backtrace_state *state, struct dwarf_data *ddata,
 			    {
 			      dwarf_buf_error (unit_buf,
 					       ("invalid file number in "
-						"DW_AT_call_file attribute"));
+						"DW_AT_call_file attribute"),
+					       0);
 			      return 0;
 			    }
 			  function->caller_filename =