Fix BZ #18872 -- memory leak in printf_positional.

stdio-common/Makefile

@@ -57,17 +57,23 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
 	 bug19 bug19a tst-popen2 scanf13 scanf14 scanf15 bug20 bug21 bug22 \
 	 scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \
 	 bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3 \
-	 bug25 tst-printf-round bug23-2 bug23-3 bug23-4 bug26 tst-fmemopen3
+	 bug25 tst-printf-round bug23-2 bug23-3 bug23-4 bug26 tst-fmemopen3 \
+	 tst-printf-bz18872
 
 test-srcs = tst-unbputc tst-printf
 
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)tst-unbputc.out $(objpfx)tst-printf.out \
+		 $(objpfx)tst-printf-bz18872-mem.out \
 		 $(objpfx)tst-setvbuf1-cmp.out
+generated += tst-printf-bz18872.c tst-printf-bz18872.mtrace \
+	     tst-printf-bz18872-mem.out
 endif
 
 include ../Rules
 
+tst-printf-bz18872-ENV = MALLOC_TRACE=$(objpfx)tst-printf-bz18872.mtrace
+
 ifeq ($(run-built-tests),yes)
 $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc
 	$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
@@ -76,6 +82,15 @@ $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc
 $(objpfx)tst-printf.out: tst-printf.sh $(objpfx)tst-printf
 	$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
 	$(evaluate-test)
+
+# We generate this source because it requires a printf invocation with
+# 10K arguments.
+$(objpfx)tst-printf-bz18872.c: tst-printf-bz18872.sh
+	rm -f $@ && $(BASH) $^ > $@.new && mv $@.new $@
+
+$(objpfx)tst-printf-bz18872-mem.out: $(objpfx)tst-printf-bz18872.out
+	$(common-objpfx)malloc/mtrace $(objpfx)tst-printf-bz18872.mtrace > $@; \
+	$(evaluate-test)
 endif
 
 CFLAGS-vfprintf.c = -Wno-uninitialized

stdio-common/tst-printf-bz18872.sh

@@ -0,0 +1,70 @@
+#!/bin/bash
+# Copyright (C) 2015 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+# To test BZ #18872, we need a printf() with 10K arguments.
+# Such a printf could be generated with non-trivial macro
+# application, but it's simpler to generate the test source
+# via this script.
+
+n_args=10000
+
+cat <<'EOF'
+#include <stdio.h>
+#include <mcheck.h>
+
+/*
+  Compile do_test without optimization: GCC 4.9/5.0/6.0 takes a long time
+  to build this source. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67396  */
+#pragma GCC push_options
+#pragma GCC optimize ("-O0")
+
+int do_test (void)
+{
+    mtrace ();
+    printf (
+EOF
+
+for ((j = 0; j < $n_args / 10; j++)); do
+  for ((k = 0; k < 10; k++)); do
+    printf '"%%%d$s" ' $((10 * $j + $k + 1))
+  done
+  printf "\n"
+done
+
+printf '"%%%d$s",\n' $(($n_args + 1))
+
+for ((j = 0; j < $n_args / 10; j++)); do
+  for ((k = 0; k < 10; k++)); do
+    printf '"a", '
+  done
+  printf "  /* %4d */\n" $((10 * $j + $k))
+done
+
+printf '"\\n");'
+
+
+cat <<'EOF'
+
+  return 0;
+}
+#pragma GCC pop_options
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
+
+EOF

stdio-common/vfprintf.c

@@ -2091,6 +2091,10 @@ printf_positional (_IO_FILE *s, const CHAR_T *format, int readonly_format,
 		 - specs[nspecs_done].end_of_fmt);
     }
  all_done:
+  if (__glibc_unlikely (specs_malloced))
+    free (specs);
+  if (__glibc_unlikely (args_malloced != NULL))
+    free (args_malloced);
   if (__glibc_unlikely (workstart != NULL))
     free (workstart);
   return done;