lib/vfscore: Cleanup sys_symlink

This commit cleans up sys_symlink() according to the current coding
conventions and uses separate jump labels for exits depending on
if the vnode lock needs to be released or not.

Signed-off-by: Marc Rittinghaus <marc.rittinghaus@unikraft.io>
Reviewed-by: Sergiu Moga <sergiu.moga@protonmail.com>
Approved-by: Razvan Deaconescu <razvand@unikraft.io>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Closes: #866

diff --git a/lib/vfscore/syscalls.c b/lib/vfscore/syscalls.c
index 12946cc30a18efe2aefaa3fafa466481fe2e5667..6e2d3574a70b66a78389d4657cce03c27f5a0980 100644 (file)
--- a/lib/vfscore/syscalls.c
+++ b/lib/vfscore/syscalls.c
@@ -881,55 +881,48 @@ sys_rename(char *src, char *dest)
 int
 sys_symlink(const char *oldpath, const char *newpath)
 {
-       struct task     *t = main_task;
-       int             error;
-       char            np[PATH_MAX];
-       struct dentry   *newdp;
-       struct dentry   *newdirdp;
-       char            *name;
-
-       if (oldpath == NULL || newpath == NULL) {
-               return (EFAULT);
-       }
+       struct dentry *newdirdp = NULL;
+       struct dentry *newdp = NULL;
+       char np[PATH_MAX];
+       char *name;
+       int error;
 
        DPRINTF(VFSDB_SYSCALL, ("sys_link: oldpath=%s newpath=%s\n",
                                oldpath, newpath));
 
-       newdp           = NULL;
-       newdirdp        = NULL;
-
-       error = task_conv(t, newpath, VWRITE, np);
-       if (error != 0) {
-               return (error);
-       }
+       error = task_conv(main_task, newpath, VWRITE, np);
+       if (unlikely(error))
+               goto out;
 
-       /* parent directory for new path must exist */
-       if ((error = lookup(np, &newdirdp, &name)) != 0)
+       /* parent directory for newpath must exist */
+       error = lookup(np, &newdirdp, &name);
+       if (unlikely(error))
                goto out;
 
        vn_lock(newdirdp->d_vnode);
 
        /* newpath should not already exist */
-       if (namei_last_nofollow(np, newdirdp, &newdp) == 0) {
+       if (unlikely(namei_last_nofollow(np, newdirdp, &newdp) == 0)) {
                drele(newdp);
                error = EEXIST;
-               goto out;
+               goto out_unlock;
        }
 
+       UK_ASSERT(!newdp);
+
        /* check for write access at newpath */
-       if ((error = vn_access(newdirdp->d_vnode, VWRITE)) != 0) {
-               goto out;
-       }
+       error = vn_access(newdirdp->d_vnode, VWRITE);
+       if (unlikely(error))
+               goto out_unlock;
 
        error = VOP_SYMLINK(newdirdp->d_vnode, name, oldpath);
 
-out:
-       if (newdirdp != NULL) {
-               vn_unlock(newdirdp->d_vnode);
-               drele(newdirdp);
-       }
+out_unlock:
+       vn_unlock(newdirdp->d_vnode);
+       drele(newdirdp);
 
-       return (error);
+out:
+       return error;
 }
 
 int