fileincref -> filedup (consistent with idup)

1ccff18b · rsc · 7895178d · 1ccff18b · 1ccff18b · 1ccff18b
--- a/defs.h
+++ b/defs.h
@@ -28,7 +28,7 @@ int             exec(char*, char**);
 // file.c
 struct file*    filealloc(void);
 void            fileclose(struct file*);
-void            fileincref(struct file*);
+struct file*    filedup(struct file*);
 void            fileinit(void);
 int             fileread(struct file*, char*, int n);
 int             filestat(struct file*, struct stat*);

--- a/file.c
+++ b/file.c
@@ -41,14 +41,15 @@ filealloc(void)
 }

 // Increment ref count for file f.
-void
-fileincref(struct file *f)
+struct file*
+filedup(struct file *f)
 {
  acquire(&file_table_lock);
  if(f->ref < 1 || f->type == FD_CLOSED)
-    panic("fileincref");
+    panic("filedup");
  f->ref++;
  release(&file_table_lock);
+  return f;
 }

 // Read from file f.  Addr is kernel address.

--- a/proc.c
+++ b/proc.c
@@ -129,10 +129,9 @@ copyproc(struct proc *p)
    }
    memmove(np->mem, p->mem, np->sz);

-    for(i = 0; i < NOFILE; i++){
-      if((np->ofile[i] = p->ofile[i]) != 0)
-        fileincref(np->ofile[i]);
-    }
+    for(i = 0; i < NOFILE; i++)
+      if(p->ofile[i])
+        np->ofile[i] = filedup(p->ofile[i]);
    np->cwd = idup(p->cwd);
  }


--- a/sysfile.c
+++ b/sysfile.c
@@ -83,7 +83,7 @@ sys_dup(void)
    return -1;
  if((fd=fdalloc(f)) < 0)
    return -1;
-  fileincref(f);
+  filedup(f);
  return fd;
 }