From 8baac760500980d4b83e8de2e90265bfaa19df13 Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Tue, 4 Jun 2019 05:57:47 -0400
Subject: support read() and write() bigger than one page

---
 pipe.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

(limited to 'pipe.c')

diff --git a/pipe.c b/pipe.c
index 1274a3a..31bf0cc 100644
--- a/pipe.c
+++ b/pipe.c
@@ -76,9 +76,11 @@ pipeclose(struct pipe *p, int writable)
 
 //PAGEBREAK: 40
 int
-pipewrite(struct pipe *p, char *addr, int n)
+pipewrite(struct pipe *p, uint64 addr, int n)
 {
   int i;
+  char ch;
+  struct proc *pr = myproc();
 
   acquire(&p->lock);
   for(i = 0; i < n; i++){
@@ -90,7 +92,9 @@ pipewrite(struct pipe *p, char *addr, int n)
       wakeup(&p->nread);
       sleep(&p->nwrite, &p->lock);  //DOC: pipewrite-sleep
     }
-    p->data[p->nwrite++ % PIPESIZE] = addr[i];
+    if(copyin(pr->pagetable, &ch, addr + i, 1) == -1)
+      break;
+    p->data[p->nwrite++ % PIPESIZE] = ch;
   }
   wakeup(&p->nread);  //DOC: pipewrite-wakeup1
   release(&p->lock);
@@ -98,9 +102,11 @@ pipewrite(struct pipe *p, char *addr, int n)
 }
 
 int
-piperead(struct pipe *p, char *addr, int n)
+piperead(struct pipe *p, uint64 addr, int n)
 {
   int i;
+  struct proc *pr = myproc();
+  char ch;
 
   acquire(&p->lock);
   while(p->nread == p->nwrite && p->writeopen){  //DOC: pipe-empty
@@ -113,7 +119,9 @@ piperead(struct pipe *p, char *addr, int n)
   for(i = 0; i < n; i++){  //DOC: piperead-copy
     if(p->nread == p->nwrite)
       break;
-    addr[i] = p->data[p->nread++ % PIPESIZE];
+    ch = p->data[p->nread++ % PIPESIZE];
+    if(copyout(pr->pagetable, addr + i, &ch, 1) == -1)
+      break;
   }
   wakeup(&p->nwrite);  //DOC: piperead-wakeup
   release(&p->lock);
-- 
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