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- Avoid dropping the proc lock around a simple permissions check and just

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hold hold it across the check to avoid extra lock operations in the
  common case.
- Copy in the new args to a temporary pargs structure before we drop the
  reference to the old one.  Thus, if the copyin() fails, the process
  arguments are unchanged rather than being deleted.  Also, p_args is no
  longer NULL during the sysctl operation.
This commit is contained in:
jhb 2003-03-12 16:14:55 +00:00
parent 00b21712df
commit 7510e91aa2
1 changed files with 17 additions and 19 deletions
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36
sys/kern/kern_proc.c
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@ -1025,7 +1025,7 @@ sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
int *name = (int*) arg1;
u_int namelen = arg2;
struct proc *p;
struct pargs *pa;
struct pargs *pa, *newpa;
int error = 0;
if (namelen != 1)
@ -1039,12 +1039,12 @@ sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
PROC_UNLOCK(p);
return (0);
}
PROC_UNLOCK(p);
if (req->newptr && curproc != p)
if (req->newptr && curproc != p) {
PROC_UNLOCK(p);
return (EPERM);
}
PROC_LOCK(p);
pa = p->p_args;
pargs_hold(pa);
PROC_UNLOCK(p);
@ -1055,24 +1055,22 @@ sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
if (req->newptr == NULL)
return (error);
PROC_LOCK(p);
pa = p->p_args;
p->p_args = NULL;
PROC_UNLOCK(p);
pargs_drop(pa);
if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit)
return (error);
pa = pargs_alloc(req->newlen);
error = SYSCTL_IN(req, pa->ar_args, req->newlen);
if (!error) {
PROC_LOCK(p);
p->p_args = pa;
PROC_UNLOCK(p);
} else
pargs_free(pa);
return (error);
newpa = pargs_alloc(req->newlen);
error = SYSCTL_IN(req, newpa->ar_args, req->newlen);
if (error) {
pargs_free(newpa);
return (error);
}
PROC_LOCK(p);
pa = p->p_args;
p->p_args = newpa;
PROC_UNLOCK(p);
pargs_drop(pa);
return (0);
}
SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD, 0, "Process table");