On Wed, Sep 28, 2016 at 11:28 AM, Jim Meyering <j...@meyering.net> wrote:
> FYI: grep (due to its use of the new getprogname module) would fail to
> configure on OpenBSD 5.1. I'll soon push this to gnulib and then
> update grep's gnulib submodule to latest to pull it in.
Glad I tested on Fedora 25-to-be. The above caused
program_invocation_short_name to always be the empty string. I fixed
it by declaring __progname only in the narrow/later case in which it
is required:
From af62896a5bd7c63b9569813a0eff11b6b4ab665d Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyer...@fb.com>
Date: Wed, 28 Sep 2016 20:57:24 -0700
Subject: [PATCH] getprogname: avoid __progname vs
program_invocation_short_name pitfall
I.e., don't let the OpenBSD 5.1 fix induce failure when using newer
glibc. Would have caused failure with Fedora 25's glibc-2.24-3, but
not with Fedora 24's glibc-2.23.1-10.
* lib/getprogname.c (__progname): Move this declaration down...
(getprogname): ... into the #elif block where used, and make it
explicitly "extern".
---
ChangeLog | 8 ++++++++
lib/getprogname.c | 11 +++++------
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 121c0c3..21a55e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2016-09-28 Jim Meyering <meyer...@fb.com>
+ getprogname: avoid __progname vs program_invocation_short_name pitfall
+ I.e., don't let the OpenBSD 5.1 fix induce failure when using newer
+ glibc. Would have caused failure with Fedora 25's glibc-2.24-3, but
+ not with Fedora 24's glibc-2.23.1-10.
+ * lib/getprogname.c (__progname): Move this declaration down...
+ (getprogname): ... into the #elif block where used, and make it
+ explicitly "extern".
+
getprogname: port to OpenBSD 5.1
* lib/getprogname.c (__progname) [HAVE_DECL___PROGNAME]: Declare.
(getprogname) [HAVE_DECL___PROGNAME]: Return __progname or "?".
diff --git a/lib/getprogname.c b/lib/getprogname.c
index 1e2ba20..7de2317 100644
--- a/lib/getprogname.c
+++ b/lib/getprogname.c
@@ -32,10 +32,6 @@
#ifndef HAVE_GETPROGNAME
-# ifdef HAVE_DECL___PROGNAME
-char *__progname;
-# endif
-
char const *
getprogname (void)
{
@@ -52,8 +48,11 @@ getprogname (void)
const char *p = __argv && __argv[0] ? __argv[0] : "?";
return last_component (p);
# elif HAVE_DECL___PROGNAME
- /* This variable exists at least on OpenBSD 5.1 and glibc-2.23,
- and appears always to be the basename component of argv[0]. */
+ /* Be careful to declare this only when we absolutely need it
+ (OpenBSD 5.1), rather than when it's available. Otherwise,
+ its mere declaration makes program_invocation_short_name
+ malfunction (have zero length) with Fedora 25's glibc. */
+ extern char *__progname;
const char *p = __progname;
return p && p[0] ? p : "?";
# elif _AIX
--
2.7.4
