gcc -fanalyzer

[marco . bodrato]

Ciao,

gcc complains about missing call to 'va_end' in scanf/doscan.c and 
printf/doprnt.c .

man stdarg on my Debian reads: "Each  invocation of va_copy() must be matched 
by a corresponding invocation of va_end() in the same function."
So that probably gcc is right. I assume we never noticed, because probably 
va_end is a noop,
But, we may want to correct it anyway.

Correcting scanf/doscan.c is quite easy, I'd suggest:

~/src/gmp$ hg diff scanf/doscan.c
diff -r 8225bdfc499f scanf/doscan.c
--- a/scanf/doscan.c    Tue Sep 05 18:32:26 2023 +0200
+++ b/scanf/doscan.c    Sat Sep 16 18:40:28 2023 +0200
@@ -761,6 +761,7 @@
     }
 
  done:
+  va_end (ap);
   (*__gmp_free_func) (alloc_fmt, alloc_fmt_size);
   return fields;
}
~/src/gmp$

On the printf/doprnt.c side, I'm not sure.
There is a "va_copy (ap" at the beginning, so we can va_end before returning.
Each loop starts with a "va_copy (this_ap" and can end with a corresponding 
va_end.
But last_ap is va_copy-ed again and again; should we insert a va_end before 
each new copy?

I attach a possible patch for printf/doprnt.c .

Ĝis,
m

diff -r 8225bdfc499f printf/doprnt.c
--- a/printf/doprnt.c	Tue Sep 05 18:32:26 2023 +0200
+++ b/printf/doprnt.c	Sat Sep 16 18:59:51 2023 +0200
@@ -340,6 +340,7 @@
 		ret = __gmp_doprnt_integer (funs, data, &param, gmp_str);
 		 __GMP_FREE_FUNC_TYPE (gmp_str, strlen(gmp_str)+1, char);
 		DOPRNT_ACCUMULATE (ret);
+		va_end (last_ap);
 		va_copy (last_ap, ap);
 		last_fmt = fmt;
 	      }
@@ -372,6 +373,7 @@
 	      DOPRNT_ACCUMULATE (__gmp_doprnt_mpf (funs, data, &param,
 						   GMP_DECIMAL_POINT,
 						   va_arg (ap, mpf_srcptr)));
+	      va_end (last_ap);
 	      va_copy (last_ap, ap);
 	      last_fmt = fmt;
 	      break;
@@ -494,6 +496,7 @@
 	      case 'Z':  mpz_set_si ((mpz_ptr) p, (long) retval); break;
 	      }
 	    }
+	    va_end (last_ap);
 	    va_copy (last_ap, ap);
 	    last_fmt = fmt;
 	    goto next;
@@ -604,7 +607,7 @@
 
     next:
       /* Stop parsing the current "%" format, look for a new one. */
-      ;
+      va_end (this_ap);
     }
 
   TRACE (printf ("remainder: \"%s\"\n", last_fmt));
@@ -616,6 +619,8 @@
       goto error;
 
  done:
+  va_end (last_ap);
+  va_end (ap);
   __GMP_FREE_FUNC_TYPE (alloc_fmt, alloc_fmt_size, char);
   return retval;
 

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