[PATCH] argp: argp.doc prints incorrectly when it starts with "\v" [BZ #19038]

[Girish Joshi]

Hello,
Following is the patch with ChangeLog entry and a test case.
Please let me know if any changes are needed in it.

diff --git a/ChangeLog b/ChangeLog
index fbe5cd8648..7b11db3127 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-04  Girish Joshi  <girish946@gmail.com>
+
+    [BZ #19038]
+    * argp/argp-help.c: Added validation for printing pre and post doc.
+    * argp/tst-argp-help.c: Added testcase for docstring help/usage.
+
 2019-07-04  Andreas Schwab  <schwab@suse.de>

     [BZ #24484]
diff --git a/argp/Makefile b/argp/Makefile
index d5c2d77658..073ea3049e 100644
--- a/argp/Makefile
+++ b/argp/Makefile
@@ -27,7 +27,7 @@ routines    = $(addprefix argp-, ba fmtstream
fs-xinl help parse pv \
                      pvh xinl eexst)

 tests        = argp-test tst-argp1 bug-argp1 tst-argp2 bug-argp2 \
-          tst-ldbl-argp
+          tst-ldbl-argp tst-argp-help

 CFLAGS-argp-help.c += $(uses-callbacks) -fexceptions
 CFLAGS-argp-parse.c += $(uses-callbacks)
@@ -35,5 +35,6 @@ CFLAGS-argp-fmtstream.c += -fexceptions

 bug-argp1-ARGS = -- --help
 bug-argp2-ARGS = -- -d 111 --dstaddr 222 -p 333 --peer 444
+tst-argp-help-ARGS = -- --help

 include ../Rules
diff --git a/argp/argp-help.c b/argp/argp-help.c
index 3b1727c4aa..ee4d247824 100644
--- a/argp/argp-help.c
+++ b/argp/argp-help.c
@@ -1465,10 +1465,11 @@ argp_doc (const struct argp *argp, const
struct argp_state *state,
   size_t inp_text_limit = 0;
   const char *doc = dgettext (argp->argp_domain, argp->doc);
   const struct argp_child *child = argp->children;
+  char *vt = 0;

   if (doc)
     {
-      char *vt = strchr (doc, '\v');
+      vt = strchr (doc, '\v');
       inp_text = post ? (vt ? vt + 1 : 0) : doc;
       inp_text_limit = (!post && vt) ? (vt - doc) : 0;
     }
@@ -1498,8 +1499,11 @@ argp_doc (const struct argp *argp, const struct
argp_state *state,

       if (text == inp_text && inp_text_limit)
     __argp_fmtstream_write (stream, inp_text, inp_text_limit);
-      else
-    __argp_fmtstream_puts (stream, text);
+      else{
+        if((!vt && !child) || (text == inp_text && !first_only)){
+          __argp_fmtstream_puts (stream, text);
+    }
+      }

       if (__argp_fmtstream_point (stream) > __argp_fmtstream_lmargin (stream))
     __argp_fmtstream_putc (stream, '\n');
diff --git a/argp/tst-argp-help.c b/argp/tst-argp-help.c
new file mode 100644
index 0000000000..7abb97f8df
--- /dev/null
+++ b/argp/tst-argp-help.c
@@ -0,0 +1,39 @@
+/* Copyright (C) 2002-2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   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/>.  */
+
+#include <argp.h>
+
+static int
+do_test (void)
+{
+
+  int argc = 2;
+  char *argv[3] = { (char *) "tst-argp-help", (char *) "--help", NULL };
+  int remaining;
+
+  static char doc[] = "\vthis is post_doc";
+  static struct argp argp = {NULL, NULL, NULL, doc};
+
+  /* Parse and process arguments.  */
+  argp_parse(&argp, argc, argv, 0, &remaining, NULL);
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

Thanks.