Use strerror_r() where available, since strerror() isn't always

thread-safe.  Example systems where strerror() isn't thread-safe:
Linux+glibc, AIX


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@62503 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -1,5 +1,9 @@
 Changes with APR b1  
 
+  *) Use strerror_r() where available, since strerror() isn't always
+     thread-safe.  Example systems where strerror() isn't thread-safe:
+     Linux+glibc, AIX  [Jeff Trawick]
+
   *) Fix some file cleanup problems in apr_proc_create() which could
      result in the pipes for stdin/stdout/stderr being closed
      immediately.  [Jeff Trawick]

acconfig.h

@@ -26,6 +26,7 @@
 #undef READDIR_IS_THREAD_SAFE
 #undef GETHOSTBYNAME_IS_THREAD_SAFE
 #undef GETHOSTBYADDR_IS_THREAD_SAFE
+#undef STRERROR_R_RC_INT
 
 #undef NEED_RLIM_T
 #undef USEBCOPY

build/apr_common.m4

@@ -420,7 +420,41 @@ fi
 rm -f conftest*
 ])dnl
 
-
+dnl
+dnl APR_CHECK_STRERROR_R_RC
+dnl
+dnl  Decide which style of retcode is used by this system's 
+dnl  strerror_r().  It either returns int (0 for success, -1
+dnl  for failure), or it returns a pointer to the error 
+dnl  string.
+dnl
+dnl
+AC_DEFUN(APR_CHECK_STRERROR_R_RC,[
+AC_MSG_CHECKING(for type of return code from strerror_r)
+AC_TRY_RUN([
+#include <errno.h>
+#include <stdio.h>
+main()
+{
+  char buf[1024];
+  if (strerror_r(ERANGE, buf, sizeof buf) < 1) {
+    exit(0);
+  }
+  else {
+    exit(1);
+  }
+}], [
+    ac_cv_strerror_r_rc_int=yes ], [
+    ac_cv_strerror_r_rc_int=no ], [
+    ac_cv_strerror_r_rc_int=no ] )
+if test "x$ac_cv_strerror_r_rc_int" = xyes; then
+  AC_DEFINE(STRERROR_R_RC_INT)
+  msg="int"
+else
+  msg="pointer"
+fi
+AC_MSG_RESULT([$msg])
+] )
 dnl
 dnl APR_CHECK_ICONV_INBUF
 dnl

configure.in

@@ -588,6 +588,10 @@ APR_CHECK_INET_NETWORK
 AC_SUBST(apr_inaddr_none)
 AC_CHECK_FUNC(_getch)
 AC_CHECK_FUNCS(gmtime_r localtime_r)
+AC_CHECK_FUNCS(strerror_r, [ strerror_r="1" ], [ strerror_r="0" ])
+if test "$strerror_r" = "1"; then
+  APR_CHECK_STRERROR_R_RC
+fi
 AC_CHECK_FUNCS(iconv, [ iconv="1" ], [ iconv="0" ])
 if test "$iconv" = "1"; then
   APR_CHECK_ICONV_INBUF

misc/unix/errorcodes.c

@@ -357,11 +357,51 @@ static char *apr_os_strerror(char* buf, apr_size_t bufsize, int err)
 }
 #endif
 
+#if defined(HAVE_STRERROR_R) && defined(STRERROR_R_RC_INT)
+/* AIX and Tru64 style */
+static char *native_strerror(apr_status_t statcode, char *buf,
+                             apr_size_t bufsize)
+{
+    if (strerror_r(statcode, buf, bufsize) < 0) {
+        return stuffbuffer(buf, bufsize, 
+                           "APR does not understand this error code");
+    }
+    else {
+        return buf;
+    }
+}
+#elif defined(HAVE_STRERROR_R)
+/* glibc style */
+static char *native_strerror(apr_status_t statcode, char *buf,
+                             apr_size_t bufsize)
+{
+    const char *msg;
+
+    buf[0] = '\0';
+    msg = strerror_r(statcode, buf, bufsize);
+    if (buf[0] == '\0') { /* libc didn't use our buffer */
+        return stuffbuffer(buf, bufsize, msg);
+    }
+    else {
+        return buf;
+    }
+}
+#else
+/* plain old strerror(); 
+ * thread-safe on some platforms (e.g., Solaris, OS/390)
+ */
+static char *native_strerror(apr_status_t statcode, char *buf,
+                             apr_size_t bufsize)
+{
+    return stuffbuffer(buf, bufsize, strerror(statcode));
+}
+#endif
+
 APR_DECLARE(char *) apr_strerror(apr_status_t statcode, char *buf,
                                  apr_size_t bufsize)
 {
     if (statcode < APR_OS_START_ERROR) {
-        return stuffbuffer(buf, bufsize, strerror(statcode));
+        return native_strerror(statcode, buf, bufsize);
     }
     else if (statcode < APR_OS_START_USEERR) {
         return stuffbuffer(buf, bufsize, apr_error_string(statcode));