Commits

Anonymous committed 9d59eb0

Make fetchint and fetchstr use proc instead of taking a struct proc

Previously, these were inconsistent: they used their struct proc
argument for bounds checking, but always copied the argument from the
current address space (and hence the current process). Drop the
struct proc argument and always use the current proc.

Suggested by Carmi Merimovich.

Comments (0)

Files changed (3)

 int             argint(int, int*);
 int             argptr(int, char**, int);
 int             argstr(int, char**);
-int             fetchint(struct proc*, uint, int*);
-int             fetchstr(struct proc*, uint, char**);
+int             fetchint(uint, int*);
+int             fetchstr(uint, char**);
 void            syscall(void);
 
 // timer.c
 // library system call function. The saved user %esp points
 // to a saved program counter, and then the first argument.
 
-// Fetch the int at addr from process p.
+// Fetch the int at addr from the current process.
 int
-fetchint(struct proc *p, uint addr, int *ip)
+fetchint(uint addr, int *ip)
 {
-  if(addr >= p->sz || addr+4 > p->sz)
+  if(addr >= proc->sz || addr+4 > proc->sz)
     return -1;
   *ip = *(int*)(addr);
   return 0;
 }
 
-// Fetch the nul-terminated string at addr from process p.
+// Fetch the nul-terminated string at addr from the current process.
 // Doesn't actually copy the string - just sets *pp to point at it.
 // Returns length of string, not including nul.
 int
-fetchstr(struct proc *p, uint addr, char **pp)
+fetchstr(uint addr, char **pp)
 {
   char *s, *ep;
 
-  if(addr >= p->sz)
+  if(addr >= proc->sz)
     return -1;
   *pp = (char*)addr;
-  ep = (char*)p->sz;
+  ep = (char*)proc->sz;
   for(s = *pp; s < ep; s++)
     if(*s == 0)
       return s - *pp;
 int
 argint(int n, int *ip)
 {
-  return fetchint(proc, proc->tf->esp + 4 + 4*n, ip);
+  return fetchint(proc->tf->esp + 4 + 4*n, ip);
 }
 
 // Fetch the nth word-sized system call argument as a pointer
   int addr;
   if(argint(n, &addr) < 0)
     return -1;
-  return fetchstr(proc, addr, pp);
+  return fetchstr(addr, pp);
 }
 
 extern int sys_chdir(void);
   for(i=0;; i++){
     if(i >= NELEM(argv))
       return -1;
-    if(fetchint(proc, uargv+4*i, (int*)&uarg) < 0)
+    if(fetchint(uargv+4*i, (int*)&uarg) < 0)
       return -1;
     if(uarg == 0){
       argv[i] = 0;
       break;
     }
-    if(fetchstr(proc, uarg, &argv[i]) < 0)
+    if(fetchstr(uarg, &argv[i]) < 0)
       return -1;
   }
   return exec(path, argv);