git: 9front

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ref: ed88bbce6290246ed6a93ba4a7fdb137a6e466ba
parent: 6f2948d1141bead4cd4c525d751819c5e01a8611
author: cinap_lenrek <cinap_lenrek@gmx.de>
date: Sun May 26 21:12:21 EDT 2013 

devfs/devsd: fix waserror() and unused variable compiler problem

the compiler optimizes setting unused variables out, which is
problematic if they are used in waserror() handler which the
compiler isnt aware of. rearrange the code to avoid this problem.


--- a/sys/src/9/port/devfs.c
+++ b/sys/src/9/port/devfs.c
@@ -748,29 +748,33 @@
 	} else
 		mustrd = 1;
 
-	/* read it */
-	cc = nil;
-	c = nil;
-	if (waserror()){
-		if (cc != nil)
-			cclose(cc);
-		if (c)
-			free(c);
-		if (!mustrd)
+	if(waserror()){
+		if(!mustrd)
 			return;
 		nexterror();
 	}
+
+	/* read it */
 	cc = namec(s, Aopen, OREAD, 0);
+	if(waserror()){
+		cclose(cc);
+		nexterror();
+	}
 	devtab[cc->type]->read(cc, confstr, sizeof confstr, 0);
+	poperror();
 	cclose(cc);
-	cc = nil;
 
 	/* validate, copy and erase config; mconfig will repopulate confstr */
 	if (strncmp(confstr, cfgstr, sizeof cfgstr - 1) != 0)
 		error("bad #k config, first line must be: 'fsdev:\\n'");
+
+	c = nil;
 	kstrdup(&c, confstr + sizeof cfgstr - 1);
+	if(waserror()){
+		free(c);
+		nexterror();
+	}
 	memset(confstr, 0, sizeof confstr);
-
 	/* process config copy one line at a time */
 	for (p = c; p != nil && *p != '\0'; p = e){
 		e = strchr(p, '\n');
@@ -780,8 +784,10 @@
 			e++;
 		mconfig(p, e - p);
 	}
-	USED(cc);		/* until now, can be used in waserror clause */
 	poperror();
+	free(c);
+
+	poperror();	/* mustrd */
 }
 
 static int
--- a/sys/src/9/port/devsd.c
+++ b/sys/src/9/port/devsd.c
@@ -1558,10 +1558,10 @@
 
 	d = nil;
 	if(waserror()){
-		free(d);
 		qunlock(&unit->ctl);
 		if(sdev != nil)
 			decref(&sdev->r);
+		free(d);
 		nexterror();
 	}
 
@@ -1600,13 +1600,11 @@
 		error(Eperm);
 	if(d[0].mode != ~0UL)
 		perm->perm = (perm->perm & ~0777) | (d[0].mode & 0777);
-
-	free(d);
-	d = nil; USED(d);
+	poperror();
 	qunlock(&unit->ctl);
 	if(sdev != nil)
 		decref(&sdev->r);
-	poperror();
+	free(d);
 	return n;
 }
 
-- 
⑨