qa: fix a few issues detected by coverity

sys/src/kern/386/uartpci.c

@@ -25,7 +25,7 @@ uartpci(int ctlrno, Pcidev* p, int barno, int n, int freq, char* name)
 		return nil;
 	}
 
-	head = uart = malloc(sizeof(Uart)*n);
+	head = uart = mallocz(sizeof(Uart)*n, 1);
 
 	for(i = 0; i < n; i++){
 		ctlr = i8250alloc(io, p->intl, p->tbdf);

sys/src/kern/boot/boot.h

@@ -62,7 +62,7 @@ extern void	savelogs(void);
 /* libc equivalent */
 extern int	cache(int);
 extern char*	checkkey(Method*, char*, char*);
-extern void	fatal(char*);
+extern void	fatal(char*) __attribute__ ((noreturn));
 extern void	getpasswd(char*, int);
 extern void	key(int, Method*);
 extern int	outin(char*, char*, int);

sys/src/kern/boot/bootip.c

@@ -39,6 +39,8 @@ configip(int bargc, char **bargv, int needfs)
 	memmove(arg, bargv, bargc * sizeof(char*));
 	arg[bargc] = 0;
 
+	buf[0] = 0; /* no default for outin */
+
 print("ipconfig...");
 	argc = bargc;
 	argv = arg;

sys/src/kern/port/devself.c

@@ -282,20 +282,21 @@ write_working_dir(Proc* p, void *va, long n, int64_t off)
 }
 
 static long
-selfread(Chan *c, void *va, long n, int64_t off)
+selfread(Chan *c, void *va, long n, int64_t offset)
 {
-	int64_t offset;
 	ProcSegment *sg;
 	int i, j;
 	char statbuf[NSEG*STATSIZE];
+	
+	if(offset < 0)
+		error("invalid offset");
 
-	offset = off;
 	switch(QID(c->qid)){
 	case Qdir:
 		return devdirread(c, va, n, selfdir, nelem(selfdir), selfgen);
 	case Qsegments:
-		rlock(&up->seglock);
 		j = 0;
+		rlock(&up->seglock);
 		for(i = 0; i < NSEG; i++) {
 			sg = up->seg[i];
 			if(sg == 0)
@@ -317,7 +318,7 @@ selfread(Chan *c, void *va, long n, int64_t off)
 		memmove(va, &statbuf[offset], n);
 		return n;
 	case Qwdir:
-		return read_working_dir(up, va, n, off);
+		return read_working_dir(up, va, n, offset);
 
 	case Qpid:
 		return readnum(offset, va, n, up->pid, NUMSIZE);

sys/src/kern/port/portfns.h

@@ -65,7 +65,7 @@ void		closeegrp(Egrp*);
 void		closefgrp(Fgrp*);
 void		closepgrp(Pgrp*);
 void		closergrp(Rgrp*);
-void		cmderror(Cmdbuf*, char*);
+void		cmderror(Cmdbuf*, char*) __attribute__ ((noreturn));
 int		cmount(Chan**, Chan*, int, char*);
 #define	commonerror()	(up->errstr)
 #define	commonuser()	(up->user)
@@ -125,8 +125,8 @@ int		eqchanddq(Chan*, int, uint32_t, Qid, int);
 int		eqqid(Qid, Qid);
 void		error(char*) __attribute__ ((noreturn));
 void		errorl(char*, long) __attribute__ ((noreturn));
-void		errorf(char*, ...);
-void		exhausted(char*);
+void		errorf(char*, ...) __attribute__ ((noreturn));
+void		exhausted(char*) __attribute__ ((noreturn));
 void		exit(int) __attribute__ ((noreturn));
 uint64_t		fastticks(uint64_t*);
 uint64_t		fastticks2us(uint64_t);

sys/src/lib/control/control.c

@@ -243,8 +243,11 @@ controlsetthread(void *v)
 			prevbut=mouse.buttons;
 			break;
 		case ACtl:
-			_ctlcontrol(cs, str);
-			free(str);
+			if(str != nil){
+				_ctlcontrol(cs, str);
+				free(str);
+				str = nil;
+			}
 			break;
 		case AExit:
 			threadexits(nil);