[src/trunk]: src/sys/kern fcntl(2), flock(2): Unify error branches.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4f6689d93c99
branches:  trunk
changeset: 374424:4f6689d93c99
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sat Apr 22 14:23:50 2023 +0000

description:
fcntl(2), flock(2): Unify error branches.

Let's make this a bit less error-prone by having everything converge
in the same place instead of multiple returns in different contexts.

diffstat:

 sys/kern/sys_descrip.c |  33 +++++++++++++++++++--------------
 1 files changed, 19 insertions(+), 14 deletions(-)

diffs (99 lines):

diff -r df4aa4b41fd9 -r 4f6689d93c99 sys/kern/sys_descrip.c
--- a/sys/kern/sys_descrip.c    Sat Apr 22 14:23:32 2023 +0000
+++ b/sys/kern/sys_descrip.c    Sat Apr 22 14:23:50 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_descrip.c,v 1.44 2023/04/22 14:23:32 riastradh Exp $       */
+/*     $NetBSD: sys_descrip.c,v 1.45 2023/04/22 14:23:50 riastradh Exp $       */
 
 /*-
  * Copyright (c) 2008, 2020 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_descrip.c,v 1.44 2023/04/22 14:23:32 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_descrip.c,v 1.45 2023/04/22 14:23:50 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -234,13 +234,15 @@ fcntl_forfs(int fd, file_t *fp, int cmd,
 int
 do_fcntl_lock(int fd, int cmd, struct flock *fl)
 {
-       file_t *fp;
+       struct file *fp = NULL;
        proc_t *p;
        int (*fo_advlock)(struct file *, void *, int, struct flock *, int);
        int error, flg;
 
-       if ((fp = fd_getfile(fd)) == NULL)
-               return EBADF;
+       if ((fp = fd_getfile(fd)) == NULL) {
+               error = EBADF;
+               goto out;
+       }
        if ((fo_advlock = fp->f_ops->fo_advlock) == NULL) {
                error = EINVAL;
                goto out;
@@ -308,7 +310,8 @@ do_fcntl_lock(int fd, int cmd, struct fl
                break;
        }
 
-out:   fd_putfile(fd);
+out:   if (fp)
+               fd_putfile(fd);
        return error;
 }
 
@@ -605,15 +608,17 @@ sys_flock(struct lwp *l, const struct sy
                syscallarg(int) how;
        } */
        int fd, how, error;
-       file_t *fp;
+       struct file *fp = NULL;
        int (*fo_advlock)(struct file *, void *, int, struct flock *, int);
        struct flock lf;
 
        fd = SCARG(uap, fd);
        how = SCARG(uap, how);
 
-       if ((fp = fd_getfile(fd)) == NULL)
-               return EBADF;
+       if ((fp = fd_getfile(fd)) == NULL) {
+               error = EBADF;
+               goto out;
+       }
        if ((fo_advlock = fp->f_ops->fo_advlock) == NULL) {
                error = EOPNOTSUPP;
                goto out;
@@ -628,8 +633,7 @@ sys_flock(struct lwp *l, const struct sy
                lf.l_type = F_UNLCK;
                atomic_and_uint(&fp->f_flag, ~FHASLOCK);
                error = (*fo_advlock)(fp, fp, F_UNLCK, &lf, F_FLOCK);
-               fd_putfile(fd);
-               return error;
+               goto out;
        case LOCK_EX:
                lf.l_type = F_WRLCK;
                break;
@@ -637,8 +641,8 @@ sys_flock(struct lwp *l, const struct sy
                lf.l_type = F_RDLCK;
                break;
        default:
-               fd_putfile(fd);
-               return EINVAL;
+               error = EINVAL;
+               goto out;
        }
 
        atomic_or_uint(&fp->f_flag, FHASLOCK);
@@ -647,7 +651,8 @@ sys_flock(struct lwp *l, const struct sy
        } else {
                error = (*fo_advlock)(fp, fp, F_SETLK, &lf, F_FLOCK|F_WAIT);
        }
-out:   fd_putfile(fd);
+out:   if (fp)
+               fd_putfile(fd);
        return error;
 }