i broke sbrk, fix it

3b95801a · rtm · 2b19190c · 3b95801a · 3b95801a · 3b95801a
--- a/defs.h
+++ b/defs.h
@@ -16,7 +16,7 @@ struct jmpbuf;
 void setupsegs(struct proc *);
 struct proc * copyproc(struct proc*);
 struct spinlock;
-int growproc(int);
+uint growproc(int);
 void sleep(void *, struct spinlock *);
 void wakeup(void *);
 void scheduler(void);

--- a/proc.c
+++ b/proc.c
@@ -138,7 +138,7 @@ copyproc(struct proc* p)
  return np;
 }
-int
+uint
 growproc(int n)
 {
  struct proc *cp = curproc[cpu()];
@@ -146,14 +146,14 @@ growproc(int n)
  newmem = kalloc(cp->sz + n);
  if(newmem == 0)
-    return -1;
+    return 0xffffffff;
  memmove(newmem, cp->mem, cp->sz);
  memset(newmem + cp->sz, 0, n);
  oldmem = cp->mem;
  cp->mem = newmem;
  kfree(oldmem, cp->sz);
  cp->sz += n;
-  return 0;
+  return cp->sz - n;
 }
 // Per-CPU process scheduler. 

--- a/syscall.c
+++ b/syscall.c
@@ -473,15 +473,16 @@ sys_getpid(void)
 int
 sys_sbrk(void)
 {
+  unsigned addr;
  int n;
  struct proc *cp = curproc[cpu()];
  if(fetcharg(0, &n) < 0)
    return -1;
-  if(growproc(n) != 0)
+  if((addr = growproc(n)) == 0xffffffff)
    return -1;
  setupsegs(cp);  
-  return 0;
+  return addr;
 }
 int

--- a/trap.c
+++ b/trap.c
@@ -37,7 +37,6 @@ trap(struct trapframe *tf)
  if(v == T_SYSCALL){
    struct proc *cp = curproc[cpu()];
-    int num = cp->tf->eax;
    if(cp->killed)
      proc_exit();
    cp->tf = tf;

--- a/usertests.c
+++ b/usertests.c
@@ -124,6 +124,7 @@ mem(void)
  m1 = 0;
  while ((m2 = malloc(1024)) != 0) {
+    printf(1, "malloc %x\n", m2);
    *(char **) m2 = m1;
    m1 = m2;
  }
@@ -138,6 +139,8 @@ mem(void)
    exit();
  }
  free(m1);
+  printf(1, "mem ok\n");
 }
 int
@@ -145,10 +148,10 @@ main(int argc, char *argv[])
 {
  puts("usertests starting\n");
-  // pipe1();
-  // preempt();
-  // exitwait();
  mem();
+  pipe1();
+  preempt();
+  exitwait();
  puts("usertests finished\n");
  exit();