[newlib-cygwin] Fix check for empty locale string in newlocale

[newlib-cygwin] Fix check for empty locale string in newlocale

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=34aded1f54da8e3035275bce3196cb607d3e386c

commit 34aded1f54da8e3035275bce3196cb607d3e386c
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Sat Oct 22 20:22:20 2016 +0200

    Fix check for empty locale string in newlocale
    
    The original test is broken.  It tests for a NULL locale which
    isn't just wrong, it simply can't occur at this point due to an
    earlier check for a NULL locale string.  Thus, the locale info
    for a category is never taken from the environment.
    
    Fixes Coverty CID 153467.
    
    Also, add comment.
    
    Also, add some parens for readability.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 newlib/libc/locale/newlocale.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/locale/newlocale.c b/newlib/libc/locale/newlocale.c
index bd4e385..c817625 100644
--- a/newlib/libc/locale/newlocale.c
+++ b/newlib/libc/locale/newlocale.c
@@ -101,7 +101,7 @@ _newlocale_r (struct _reent *p, int category_mask, const char *locale,
       category_mask |= LC_VALID_MASK;
     }
   /* Check for invalid mask values and valid locale ptr. */
-  if (category_mask & ~LC_VALID_MASK || !locale)
+  if ((category_mask & ~LC_VALID_MASK) || !locale)
     {
       p->_errno = EINVAL;
       return NULL;
@@ -119,7 +119,10 @@ _newlocale_r (struct _reent *p, int category_mask, const char *locale,
     {
       if (((1 << i) & category_mask) != 0)
 	{
-	  const char *cat = locale ?: __get_locale_env (p, i);
+	  /* If locale is "", fetch from environment.  Otherwise use locale
+	     name verbatim. */
+	  const char *cat = (locale[0] == '\0') ? __get_locale_env (p, i)
+						: locale;
 	  if (strlen (cat) > ENCODING_LEN)
 	    {
 	      p->_errno = EINVAL;