Add kern_setgroups() and kern_getgroups() and use them to implement

ibcs2_[gs]etgroups() rather than using the stackgap.  This also makes
ibcs2_[gs]etgroups() MPSAFE.  Also, it cleans up one bit of weirdness in
the old setgroups() where it allocated an entire credential just so it had
a place to copy the group list into.  Now setgroups just allocates a
NGROUPS_MAX array on the stack that it copies into and then passes to
kern_setgroups().

2 files changed, 27 insertions, 44 deletions

diff --git a/sys/i386/ibcs2/ibcs2_misc.c b/sys/i386/ibcs2/ibcs2_misc.c
index c4efc02..c875075 100644
--- a/sys/i386/ibcs2/ibcs2_misc.c
+++ b/sys/i386/ibcs2/ibcs2_misc.c
@@ -651,35 +651,25 @@ ibcs2_getgroups(td, uap)
 	struct thread *td;
 	struct ibcs2_getgroups_args *uap;
 {
-	int error, i;
-	ibcs2_gid_t *iset = NULL;
-	struct getgroups_args sa;
-	gid_t *gp;
-	caddr_t sg = stackgap_init();
+	ibcs2_gid_t iset[NGROUPS_MAX];
+	gid_t gp[NGROUPS_MAX];
+	u_int i, ngrp;
+	int error;
 
 	if (uap->gidsetsize < 0)
 		return (EINVAL);
-	if (uap->gidsetsize > NGROUPS_MAX)
-		uap->gidsetsize = NGROUPS_MAX;
-	sa.gidsetsize = uap->gidsetsize;
-	if (uap->gidsetsize) {
-		sa.gidset = stackgap_alloc(&sg, NGROUPS_MAX *
-						    sizeof(gid_t *));
-		iset = stackgap_alloc(&sg, uap->gidsetsize *
-				      sizeof(ibcs2_gid_t));
+	ngrp = MIN(uap->gidsetsize, NGROUPS_MAX);
+	error = kern_getgroups(td, &ngrp, gp);
+	if (error)
+		return (error);
+	if (uap->gidsetsize > 0) {
+		for (i = 0; i < ngrp; i++)
+			iset[i] = (ibcs2_gid_t)gp[i];
+		error = copyout(iset, uap->gidset, ngrp * sizeof(ibcs2_gid_t));
 	}
-	if ((error = getgroups(td, &sa)) != 0)
-		return error;
-	if (uap->gidsetsize == 0)
-		return 0;
-
-	for (i = 0, gp = sa.gidset; i < td->td_retval[0]; i++)
-		iset[i] = (ibcs2_gid_t)*gp++;
-	if (td->td_retval[0] && (error = copyout((caddr_t)iset,
-					  (caddr_t)uap->gidset,
-					  sizeof(ibcs2_gid_t) * td->td_retval[0])))
-		return error;
-        return 0;
+	if (error == 0)
+		td->td_retval[0] = ngrp;
+	return (error);
 }
 
 int
@@ -687,28 +677,21 @@ ibcs2_setgroups(td, uap)
 	struct thread *td;
 	struct ibcs2_setgroups_args *uap;
 {
+	ibcs2_gid_t iset[NGROUPS_MAX];
+	gid_t gp[NGROUPS_MAX];
 	int error, i;
-	ibcs2_gid_t *iset;
-	struct setgroups_args sa;
-	gid_t *gp;
-	caddr_t sg = stackgap_init();
 
 	if (uap->gidsetsize < 0 || uap->gidsetsize > NGROUPS_MAX)
 		return (EINVAL);
-	sa.gidsetsize = uap->gidsetsize;
-	sa.gidset = stackgap_alloc(&sg, sa.gidsetsize *
-					    sizeof(gid_t *));
-	iset = stackgap_alloc(&sg, sa.gidsetsize *
-			      sizeof(ibcs2_gid_t *));
-	if (sa.gidsetsize) {
-		if ((error = copyin((caddr_t)uap->gidset, (caddr_t)iset, 
-				   sizeof(ibcs2_gid_t *) *
-				   uap->gidsetsize)) != 0)
-			return error;
+	if (uap->gidsetsize && uap->gidset) {
+		error = copyin(uap->gidset, iset, sizeof(ibcs2_gid_t) *
+		    uap->gidsetsize);
+		if (error)
+			return (error);
+		for (i = 0; i < uap->gidsetsize; i++)
+			gp[i] = (gid_t)iset[i];
 	}
-	for (i = 0, gp = sa.gidset; i < sa.gidsetsize; i++)
-		*gp++ = (gid_t)iset[i];
-	return setgroups(td, &sa);
+	return (kern_setgroups(td, uap->gidsetsize, gp));
 }
 
 int
diff --git a/sys/i386/ibcs2/syscalls.xenix b/sys/i386/ibcs2/syscalls.xenix
index ae8be83..8b9b84a 100644
--- a/sys/i386/ibcs2/syscalls.xenix
+++ b/sys/i386/ibcs2/syscalls.xenix
@@ -56,9 +56,9 @@
 				    ibcs2_sigset_t *oset); }
 41	AUE_NULL	MSTD	{ int ibcs2_sigpending(ibcs2_sigset_t *mask); }
 42	AUE_NULL	MSTD	{ int ibcs2_sigsuspend(ibcs2_sigset_t *mask); }
-43	AUE_GETGROUPS	STD	{ int ibcs2_getgroups(int gidsetsize, \
+43	AUE_GETGROUPS	MSTD	{ int ibcs2_getgroups(int gidsetsize, \
 				    ibcs2_gid_t *gidset); }
-44	AUE_SETGROUPS	STD	{ int ibcs2_setgroups(int gidsetsize, \
+44	AUE_SETGROUPS	MSTD	{ int ibcs2_setgroups(int gidsetsize, \
 				    ibcs2_gid_t *gidset); }
 45	AUE_NULL	MSTD	{ int ibcs2_sysconf(int name); }
 46	AUE_PATHCONF	MSTD	{ int ibcs2_pathconf(char *path, int name); }