- Tweak kern_msgctl() to return a copy of the requested message queue id

  structure in the struct pointed to by the 3rd argument for IPC_STAT and
  get rid of the 4th argument.  The old way returned a pointer into the
  kernel array that the calling function would then access afterwards
  without holding the appropriate locks and doing non-lock-safe things like
  copyout() with the data anyways.  This change removes that unsafeness and
  resulting race conditions as well as simplifying the interface.
- Implement kern_foo wrappers for stat(), lstat(), fstat(), statfs(),
  fstatfs(), and fhstatfs().  Use these wrappers to cut out a lot of
  code duplication for freebsd4 and netbsd compatability system calls.
- Add a new lookup function kern_alternate_path() that looks up a filename
  under an alternate prefix and determines which filename should be used.
  This is basically a more general version of linux_emul_convpath() that
  can be shared by all the ABIs thus allowing for further reduction of
  code duplication.

1 files changed, 17 insertions, 19 deletions

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 987ccda..81fead1 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1030,20 +1030,15 @@ struct ofstat_args {
 int
 ofstat(struct thread *td, struct ofstat_args *uap)
 {
-	struct file *fp;
-	struct stat ub;
 	struct ostat oub;
+	struct stat ub;
 	int error;
 
-	if ((error = fget(td, uap->fd, &fp)) != 0)
-		goto done2;
-	error = fo_stat(fp, &ub, td->td_ucred, td);
+	error = kern_fstat(td, uap->fd, &ub);
 	if (error == 0) {
 		cvtstat(&ub, &oub);
 		error = copyout(&oub, uap->sb, sizeof(oub));
 	}
-	fdrop(fp, td);
-done2:
 	return (error);
 }
 #endif /* COMPAT_43 */
@@ -1064,17 +1059,25 @@ struct fstat_args {
 int
 fstat(struct thread *td, struct fstat_args *uap)
 {
-	struct file *fp;
 	struct stat ub;
 	int error;
 
-	if ((error = fget(td, uap->fd, &fp)) != 0)
-		goto done2;
-	error = fo_stat(fp, &ub, td->td_ucred, td);
+	error = kern_fstat(td, uap->fd, &ub);
 	if (error == 0)
 		error = copyout(&ub, uap->sb, sizeof(ub));
+	return (error);
+}
+
+int
+kern_fstat(struct thread *td, int fd, struct stat *sbp)
+{
+	struct file *fp;
+	int error;
+
+	if ((error = fget(td, fd, &fp)) != 0)
+		return (error);
+	error = fo_stat(fp, sbp, td->td_ucred, td);
 	fdrop(fp, td);
-done2:
 	return (error);
 }
 
@@ -1094,20 +1097,15 @@ struct nfstat_args {
 int
 nfstat(struct thread *td, struct nfstat_args *uap)
 {
-	struct file *fp;
-	struct stat ub;
 	struct nstat nub;
+	struct stat ub;
 	int error;
 
-	if ((error = fget(td, uap->fd, &fp)) != 0)
-		goto done2;
-	error = fo_stat(fp, &ub, td->td_ucred, td);
+	error = kern_fstat(td, uap->fd, &ub);
 	if (error == 0) {
 		cvtnstat(&ub, &nub);
 		error = copyout(&nub, uap->sb, sizeof(nub));
 	}
-	fdrop(fp, td);
-done2:
 	return (error);
 }