reentr.c: Handle getspnam()

This has never worked to increase the buffer size if necessary.
Apparently the default has always been big enough.  But this commit
fixes it to retry if too small.

I don't think there is a way to write tests for this.  getspnam is
called only as a small part of pp_gpwent, and is not part of the API,
and is called only when run as root.

I did test it on my box, with gdb, starting with a buffer size of 1, and
single stepping and observing that it works as I expected.

1 files changed, 38 insertions, 3 deletions

diff --git a/reentr.c b/reentr.c
index ede96a9d18..10c2d88655 100644
--- a/reentr.c
+++ b/reentr.c
@@ -381,6 +381,16 @@ Perl_reentrant_retry(const char *f, ...)
 #endif
 
     if (key == 0) {
+
+#ifdef HAS_GETSPNAM_R
+
+	/* This is a #define as has no corresponding keyword */
+        if (strEQ(f, "getspnam")) {
+            key = KEY_getspnam;
+        }
+
+#endif
+
     }
     else if (key < 0) {
         key = -key;
@@ -510,9 +520,9 @@ Perl_reentrant_retry(const char *f, ...)
 #  endif
 #  ifdef USE_PWENT_BUFFER
 
-    case KEY_getpwnam:
-    case KEY_getpwuid:
-    case KEY_getpwent:
+    case  KEY_getpwnam:
+    case  KEY_getpwuid:
+    case  KEY_getpwent:
 	{
 
 #    ifdef PERL_REENTRANT_MAXSIZE
@@ -551,6 +561,31 @@ Perl_reentrant_retry(const char *f, ...)
 	break;
 
 #  endif
+#  ifdef USE_SPENT_BUFFER
+
+    case KEY_getspnam:
+	{
+            char * name;
+
+#    ifdef PERL_REENTRANT_MAXSIZE
+	    if (PL_reentrant_buffer->_spent_size <=
+		PERL_REENTRANT_MAXSIZE / 2)
+
+#    endif
+            RenewDouble(PL_reentrant_buffer->_spent_buffer,
+                    &PL_reentrant_buffer->_spent_size, char);
+            switch (key) {
+	        case KEY_getspnam:
+		    name = va_arg(ap, char *);
+		    retptr = getspnam(name); break;
+	        default:
+		    SETERRNO(ERANGE, LIB_INVARG);
+		    break;
+            }
+	}
+	break;
+
+#  endif
 #  ifdef USE_PROTOENT_BUFFER
 
     case KEY_getprotobyname: