believe it or not, this was working

the macro expansion of "char *cp;" turned into
char *(curproc[cpu()]);  which declares a dynamically
sized array of char* called curproc.

so then &cp == &(curproc[cpu()]) was actually a
stack variable as "expected".  it was one past the
end of the array, but the implicit alloca allocated
more than was necessary.

do not tell me that making cp a #define was a bad idea.
there are worse problems to fix.  more on that later.

1 files changed, 6 insertions, 6 deletions

diff --git a/sysfile.c b/sysfile.c
index 279847b..a23b48a 100644
--- a/sysfile.c
+++ b/sysfile.c
@@ -49,11 +49,11 @@ sys_read(void)
 {
   struct file *f;
   int n;
-  char *cp;
+  char *p;
 
-  if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &cp, n) < 0)
+  if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0)
     return -1;
-  return fileread(f, cp, n);
+  return fileread(f, p, n);
 }
 
 int
@@ -61,11 +61,11 @@ sys_write(void)
 {
   struct file *f;
   int n;
-  char *cp;
+  char *p;
 
-  if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &cp, n) < 0)
+  if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0)
     return -1;
-  return filewrite(f, cp, n);
+  return filewrite(f, p, n);
 }
 
 int