add RC_FUNC_GETGROUPS configure magic

4 files changed, 36 insertions, 5 deletions

diff --git a/acconfig.h b/acconfig.h
index 62e6542..c00f411 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -72,3 +72,6 @@
 
 /* Define if you have SA_INTERRUPT (and sigaction()). */
 #undef HAVE_SA_INTERRUPT
+
+/* Define if you have POSIX getgroups(). */
+#undef HAVE_POSIX_GETGROUPS
diff --git a/acinclude.m4 b/acinclude.m4
index c8913a0..60ec318 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1,3 +1,19 @@
+dnl This macro sets HAVE_POSIX_GETGROUPS if the
+dnl getgroups() function accepts a zero first argument.
+AC_DEFUN(RC_FUNC_GETGROUPS, [
+	AC_CACHE_CHECK(for POSIX getgroups, rc_cv_func_posix_getgroups, AC_TRY_RUN([
+#include <sys/types.h>
+#include <unistd.h>
+int main(void) {
+	return getgroups(0, (void *)0) == -1;
+}
+	], rc_cv_func_posix_getgroups=yes, rc_cv_func_posix_getgroups=no, rc_cv_func_posix_getgroups=yes))
+	case "$rc_cv_func_posix_getgroups" in
+	yes) AC_DEFINE(HAVE_POSIX_GETGROUPS) ;;
+	esac
+])
+
+
 dnl The AC_FUNC_SETPGRP macro doesn't
 dnl #include <unistd.h>, so it fails on OSF-1, where setpgrp
 dnl will happily accept arguments, but the protoype doesn't
@@ -7,7 +23,9 @@ AC_DEFUN(RC_FUNC_SETPGRP, [
 	AC_CACHE_CHECK(for setpgrp that takes no arguments, ac_cv_func_setpgrp_void, AC_TRY_RUN([
 #include <unistd.h>
 /* If setpgrp() takes no arguments, this may fail to compile, but
-if it compiles the call should succeed.  */
+if it compiles the call should succeed.  Note that the assignments
+to ac_cv_func_setpgrp_void are the other way round from what you
+would expect. */
 int main(void) {
 	return setpgrp(1,1) != -1;
 }
diff --git a/configure.ac b/configure.ac
index 2d48ed4..c0f2261 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,12 +1,12 @@
 AC_INIT(rc.h)
 
 dnl Automake stuff.
-AM_INIT_AUTOMAKE(rc, 1.5s19980724)
+AM_INIT_AUTOMAKE(rc, 1.5s19980727)
 AM_CONFIG_HEADER(config.h)
 
 AC_ARG_PROGRAM
 
-AC_DEFINE(RELDATE, "1998-07-24")
+AC_DEFINE(RELDATE, "1998-07-27")
 
 dnl If we're using gcc, specify `-Wall'.  I've also checked the code
 dnl with `-pedantic -W -Wall -Wpointer-arith -Wstrict-prototypes
@@ -36,7 +36,7 @@ AC_TYPE_UID_T
 AC_CHECK_TYPE(ssize_t, long)
 
 AC_CHECK_FUNCS(getgroups setpgrp setrlimit)
-
+RC_FUNC_GETGROUPS
 
 dnl sigsetjmp() isn't a real function in some places.
 AC_CACHE_CHECK(for sigsetjmp, rc_cv_sigsetjmp,
diff --git a/which.c b/which.c
index c4bbc29..3d23e3d 100644
--- a/which.c
+++ b/which.c
@@ -8,10 +8,12 @@
    and to strip out unneeded functionality.
 */
 
-#include "rc.h"
 #include <errno.h>
 #include <sys/stat.h>
 
+#include "rc.h"
+#include "getgroups.h"
+
 #define X_USR 0100
 #define X_GRP 0010
 #define X_OTH 0001
@@ -83,7 +85,15 @@ extern char *which(char *name, bool verbose) {
 		uid = geteuid();
 		gid = getegid();
 #if HAVE_GETGROUPS
+#if HAVE_POSIX_GETGROUPS
 		ngroups = getgroups(0, (GETGROUPS_T *)0);
+		if (ngroups < 0) {
+			uerror("getgroups");
+			rc_exit(1);
+		}
+#else
+			ngroups = NGROUPS;
+#endif
 		gidset = ealloc(ngroups * sizeof(GETGROUPS_T));
 		getgroups(ngroups, gidset);
 #endif