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, 22 insertions, 0 deletions

diff --git a/reentr.h b/reentr.h
index 9e65001dcb..25f21ad1a6 100644
--- a/reentr.h
+++ b/reentr.h
@@ -357,6 +357,22 @@
 #    undef  USE_PWENT_BUFFER
 #  endif
 
+/* The getspent getspnam using buffer? */
+
+#  if defined(HAS_GETSPNAM_R) && (GETSPNAM_R_PROTO == REENTRANT_PROTO_I_CSBWR || GETSPNAM_R_PROTO == REENTRANT_PROTO_S_CSBI)
+#    define GETSPNAM_R_HAS_BUFFER
+#  else
+#    undef  GETSPNAM_R_HAS_BUFFER
+#  endif
+
+/* Any of the getspent getspnam using buffer? */
+
+#  if (defined(GETSPENT_R_HAS_BUFFER) || defined(GETSPNAM_R_HAS_BUFFER))
+#    define USE_SPENT_BUFFER
+#  else
+#    undef  USE_SPENT_BUFFER
+#  endif
+
 /* The gethostent gethostbyaddr gethostbyname using ptr? */
 
 #  if defined(HAS_GETHOSTENT_R) && (GETHOSTENT_R_PROTO == REENTRANT_PROTO_I_SBWRE)
@@ -1495,6 +1511,12 @@ typedef struct {
 
 
 
+
+/* Special case this; if others came along, could automate it */
+#  ifdef HAS_GETSPNAM_R
+#    define KEY_getspnam -1
+#  endif
+
 #endif /* USE_REENTRANT_API */
 
 #endif