make sure the mmap based io_sendfile actually works (and terminates)

io/io_sendfile.c

@@ -60,13 +60,12 @@ int64 io_sendfile(int64 out,int64 in,uint64 off,uint64 bytes) {
 	if (off>=e->mapofs && off<e->mapofs+e->maplen)
 	  goto mapok;	/* ok; mmapped the right chunk*/
 	munmap(e->mmapped,e->maplen);
-	e->mmapped=0;
       }
       e->mapofs=off&0xffffffffffff0000ull;
-      if (e->mapofs+0xffff>off+bytes)
+      if (e->mapofs+0x10000>off+bytes)
 	e->maplen=off+bytes-e->mapofs;
       else
-	e->maplen=0xffff;
+	e->maplen=0x10000;
       if ((e->mmapped=mmap(0,e->maplen,PROT_READ,MAP_SHARED,in,e->mapofs))==MAP_FAILED) {
 	e->mmapped=0;
 	goto readwrite;

t.c

@@ -23,12 +23,19 @@
      __asm__ __volatile__ ("rdtsc" : "=a" (low) : : "edx")
 
 int main(int argc,char* argv[]) {
+  char buf[100];
+  int i;
+  printf("%d\n",i=fmt_pad(buf,"fnord",5,7,10));
+  buf[i]=0;
+  puts(buf);
+#if 0
   char ip[16];
   char buf[32];
   printf("%d (expect 2)\n",scan_ip6("::",ip));
   printf("%d (expect 3)\n",scan_ip6("::1",ip));
   printf("%d (expect 16)\n",scan_ip6("fec0:0:0:ffff::1/0",ip));
   printf("%.*s\n",fmt_ip6(buf,ip),buf);
+#endif
 #if 0
   static stralloc s,t;
   stralloc_copys(&s,"fnord");