svn commit: r268087 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Tue Jul  1 09:21:32 2014
New Revision: 268087
URL: http://svnweb.freebsd.org/changeset/base/268087

Log:
  Don't call crcopysafe or uifind unnecessarily in execve.
  
  MFC after:    1 week

Modified:
  head/sys/kern/kern_exec.c

Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c   Tue Jul  1 08:36:56 2014        (r268086)
+++ head/sys/kern/kern_exec.c   Tue Jul  1 09:21:32 2014        (r268087)
@@ -336,7 +336,7 @@ do_execve(td, args, mac_p)
        struct proc *p = td->td_proc;
        struct nameidata nd;
        struct ucred *newcred = NULL, *oldcred;
-       struct uidinfo *euip;
+       struct uidinfo *euip = NULL;
        register_t *stack_base;
        int error, i;
        struct image_params image_params, *imgp;
@@ -601,8 +601,6 @@ interpret:
        /*
         * Malloc things before we need locks.
         */
-       newcred = crget();
-       euip = uifind(attr.va_uid);
        i = imgp->args->begin_envv - imgp->args->begin_argv;
        /* Cache arguments if they fit inside our allowance */
        if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
@@ -631,7 +629,7 @@ interpret:
        PROC_LOCK(p);
        if (oldsigacts)
                p->p_sigacts = newsigacts;
-       oldcred = crcopysafe(p, newcred);
+       oldcred = p->p_ucred;
        /* Stop profiling */
        stopprofclock(p);
 
@@ -721,6 +719,8 @@ interpret:
                vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
                if (error != 0)
                        goto done1;
+               newcred = crdup(oldcred);
+               euip = uifind(attr.va_uid);
                PROC_LOCK(p);
                /*
                 * Set the new credentials.
@@ -745,7 +745,6 @@ interpret:
                change_svuid(newcred, newcred->cr_uid);
                change_svgid(newcred, newcred->cr_gid);
                p->p_ucred = newcred;
-               newcred = NULL;
        } else {
                if (oldcred->cr_uid == oldcred->cr_ruid &&
                    oldcred->cr_gid == oldcred->cr_rgid)
@@ -764,10 +763,12 @@ interpret:
                 */
                if (oldcred->cr_svuid != oldcred->cr_uid ||
                    oldcred->cr_svgid != oldcred->cr_gid) {
+                       PROC_UNLOCK(p);
+                       newcred = crdup(oldcred);
+                       PROC_LOCK(p);
                        change_svuid(newcred, newcred->cr_uid);
                        change_svgid(newcred, newcred->cr_gid);
                        p->p_ucred = newcred;
-                       newcred = NULL;
                }
        }
 
@@ -844,11 +845,10 @@ done1:
        /*
         * Free any resources malloc'd earlier that we didn't use.
         */
-       uifree(euip);
-       if (newcred == NULL)
+       if (euip != NULL)
+               uifree(euip);
+       if (newcred != NULL)
                crfree(oldcred);
-       else
-               crfree(newcred);
        VOP_UNLOCK(imgp->vp, 0);
 
        /*
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