* [PATCH] strerror_r-posix: port even better to Android
@ 2021-09-09 2:26 Paul Eggert
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From: Paul Eggert @ 2021-09-09 2:26 UTC (permalink / raw)
To: bug-gnulib, landfillbaby69; +Cc: Paul Eggert
* lib/strerror_r.c: Use STRERROR_R_CHAR_P to decide whether the
system strerror_r returns char *, and HAVE_DECL_STRERROR_R to
decide whether it either does that or returns an integer. In the
former case, use the system strerror_r even on platforms like
Android API level 23 that don’t have __xpg_strerror_r; also
check for strerror_r failure just in case.
* m4/error.m4 (gl_PREREQ_ERROR):
* m4/strerror_r.m4 (gl_PREREQ_STRERROR_R):
Use system extensions on Android, to avoid mishandling strerror_r
on API level 23 and later.
* modules/error, modules/strerror_r-posix (configure.ac):
Surround gl_PREREQ_ERROR with AS_IF instead of plain if, so that
AC_REQUIREs are propagated out.
---
ChangeLog | 15 +++++++++++++++
lib/strerror_r.c | 35 +++++++++++++++++------------------
m4/error.m4 | 6 +++++-
m4/strerror_r.m4 | 3 ++-
modules/error | 4 ++--
modules/strerror_r-posix | 4 ++--
6 files changed, 43 insertions(+), 24 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 1db7e333b..7c56ed2a2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
2021-09-08 Paul Eggert <eggert@cs.ucla.edu>
+ strerror_r-posix: port even better to Android
+ * lib/strerror_r.c: Use STRERROR_R_CHAR_P to decide whether the
+ system strerror_r returns char *, and HAVE_DECL_STRERROR_R to
+ decide whether it either does that or returns an integer. In the
+ former case, use the system strerror_r even on platforms like
+ Android API level 23 that don’t have __xpg_strerror_r; also
+ check for strerror_r failure just in case.
+ * m4/error.m4 (gl_PREREQ_ERROR):
+ * m4/strerror_r.m4 (gl_PREREQ_STRERROR_R):
+ Use system extensions on Android, to avoid mishandling strerror_r
+ on API level 23 and later.
+ * modules/error, modules/strerror_r-posix (configure.ac):
+ Surround gl_PREREQ_ERROR with AS_IF instead of plain if, so that
+ AC_REQUIREs are propagated out.
+
strerror_r-posix: port better to Android
* m4/strerror_r.m4 (gl_FUNC_STRERROR_R): Move requirement of
gl_USE_SYSTEM_EXTENSIONS from here ...
diff --git a/lib/strerror_r.c b/lib/strerror_r.c
index f0244520b..90043c223 100644
--- a/lib/strerror_r.c
+++ b/lib/strerror_r.c
@@ -34,33 +34,26 @@
#include "strerror-override.h"
-#if (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__) && HAVE___XPG_STRERROR_R /* glibc >= 2.3.4, cygwin >= 1.7.9 */
+#if STRERROR_R_CHAR_P
-# define USE_XPG_STRERROR_R 1
-extern
-#ifdef __cplusplus
-"C"
-#endif
-int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
+# if HAVE___XPG_STRERROR_R
+_GL_EXTERN_C int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
+# endif
-#elif HAVE_DECL_STRERROR_R && !(__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__)
+#elif HAVE_DECL_STRERROR_R
-/* The system's strerror_r function is OK, except that its third argument
+/* The system's strerror_r function's API is OK, except that its third argument
is 'int', not 'size_t', or its return type is wrong. */
# include <limits.h>
-# define USE_SYSTEM_STRERROR_R 1
-
-#else /* (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__ ? !HAVE___XPG_STRERROR_R : !HAVE_DECL_STRERROR_R) */
+#else
/* Use the system's strerror(). Exclude glibc and cygwin because the
system strerror_r has the wrong return type, and cygwin 1.7.9
strerror_r clobbers strerror. */
# undef strerror
-# define USE_SYSTEM_STRERROR 1
-
# if defined __NetBSD__ || defined __hpux || (defined _WIN32 && !defined __CYGWIN__) || defined __sgi || (defined __sun && !defined _LP64) || defined __CYGWIN__
/* No locking needed. */
@@ -166,22 +159,28 @@ strerror_r (int errnum, char *buf, size_t buflen)
int ret;
int saved_errno = errno;
-#if USE_XPG_STRERROR_R
+#if STRERROR_R_CHAR_P
{
+ ret = 0;
+
+# if HAVE___XPG_STRERROR_R
ret = __xpg_strerror_r (errnum, buf, buflen);
if (ret < 0)
ret = errno;
+# endif
+
if (!*buf)
{
/* glibc 2.13 would not touch buf on err, so we have to fall
back to GNU strerror_r which always returns a thread-safe
untruncated string to (partially) copy into our buf. */
- safe_copy (buf, buflen, strerror_r (errnum, buf, buflen));
+ char *errstring = strerror_r (errnum, buf, buflen);
+ ret = errstring ? safe_copy (buf, buflen, errstring) : errno;
}
}
-#elif USE_SYSTEM_STRERROR_R
+#elif HAVE_DECL_STRERROR_R
if (buflen > INT_MAX)
buflen = INT_MAX;
@@ -245,7 +244,7 @@ strerror_r (int errnum, char *buf, size_t buflen)
}
# endif
-#else /* USE_SYSTEM_STRERROR */
+#else /* strerror_r is not declared. */
/* Try to do what strerror (errnum) does, but without clobbering the
buffer used by strerror(). */
diff --git a/m4/error.m4 b/m4/error.m4
index 77f67f78b..8e3cf95d9 100644
--- a/m4/error.m4
+++ b/m4/error.m4
@@ -1,4 +1,4 @@
-#serial 14
+#serial 15
# Copyright (C) 1996-1998, 2001-2004, 2009-2021 Free Software Foundation, Inc.
#
@@ -22,6 +22,10 @@ AC_DEFUN([gl_ERROR],
# Prerequisites of lib/error.c.
AC_DEFUN([gl_PREREQ_ERROR],
[
+ dnl Use system extensions on Android, so that AC_FUNC_STRERROR_R
+ dnl discovers the GNU API for strerror_r on Android API level 23 and later.
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
AC_REQUIRE([AC_FUNC_STRERROR_R])
:
])
diff --git a/m4/strerror_r.m4 b/m4/strerror_r.m4
index 29b309221..bc40ec294 100644
--- a/m4/strerror_r.m4
+++ b/m4/strerror_r.m4
@@ -1,4 +1,4 @@
-# strerror_r.m4 serial 22
+# strerror_r.m4 serial 23
dnl Copyright (C) 2002, 2007-2021 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -37,6 +37,7 @@ AC_DEFUN([gl_FUNC_STRERROR_R],
# Prerequisites of lib/strerror_r.c.
AC_DEFUN([gl_PREREQ_STRERROR_R], [
+ AC_REQUIRE([AC_FUNC_STRERROR_R])
dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
AC_CHECK_FUNCS_ONCE([catgets])
diff --git a/modules/error b/modules/error
index 2945c4845..08370da77 100644
--- a/modules/error
+++ b/modules/error
@@ -15,10 +15,10 @@ msvc-nothrow [test $ac_cv_lib_error_at_line = no]
configure.ac:
gl_ERROR
-if test $ac_cv_lib_error_at_line = no; then
+AS_IF([test "$ac_cv_lib_error_at_line" = no], [
AC_LIBOBJ([error])
gl_PREREQ_ERROR
-fi
+])
m4_ifdef([AM_XGETTEXT_OPTION],
[AM_][XGETTEXT_OPTION([--flag=error:3:c-format])
AM_][XGETTEXT_OPTION([--flag=error_at_line:5:c-format])])
diff --git a/modules/strerror_r-posix b/modules/strerror_r-posix
index f91bc0e7c..25f049365 100644
--- a/modules/strerror_r-posix
+++ b/modules/strerror_r-posix
@@ -14,10 +14,10 @@ strerror-override [test $HAVE_DECL_STRERROR_R = 0 || test $REPLACE_STRERROR_R =
configure.ac:
gl_FUNC_STRERROR_R
-if test $HAVE_DECL_STRERROR_R = 0 || test $REPLACE_STRERROR_R = 1; then
+AS_IF([test $HAVE_DECL_STRERROR_R = 0 || test $REPLACE_STRERROR_R = 1], [
AC_LIBOBJ([strerror_r])
gl_PREREQ_STRERROR_R
-fi
+])
gl_STRING_MODULE_INDICATOR([strerror_r])
dnl For the modules argp, error.
gl_MODULE_INDICATOR([strerror_r-posix])
--
2.30.2
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