Fix miscellaneous issues (torvalds#397)

* lkl: Fix a crash issue when no configuration file is specified

When no env variables nor json files are configured, it sometimes
crashes due to uninitialized value of lkl_config->ifnum.  This patch
fixes this issue by simply zero-ing the values.

Fixes: 842d02f ("lkl: Support json configuration and multiple
interfaces")

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

* lkl: fix typos on getsockopt/setsockopt

This typo was there since the first version.

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

* lkl: let debug print disabled if 0 is specified.

Reported at https://goo.gl/WpdLjg

Signed-off-by: Hajime Tazaki <thehajime@gmail.com>

Documentation/lkl.txt

@@ -216,7 +216,7 @@ The following are the list of keys to describe a JSON file.
   value type: string
 
   Setting it causes some debug information (both from the kernel and the
-  LKL library) to be enabled.
+  LKL library) to be enabled.  If zero' is specified it is disabled.
   It is also used as a bit mask to turn on specific debugging facilities.
   E.g., setting it to "0x100" will cause the LKL kernel to pause after
   the hijack'ed app exits. This allows one to debug or collect info from

tools/lkl/lib/config.c

@@ -322,35 +322,11 @@ int load_config_env(struct lkl_config *cfg)
 
 int init_config(struct lkl_config *cfg)
 {
-	int i;
-
 	if (!cfg)
 		return -1;
-	for (i = 0; i < LKL_IF_MAX; i++) {
-		cfg->iftap[i] = NULL;
-		cfg->iftype[i] = NULL;
-		cfg->ifparams[i] = NULL;
-		cfg->ifmtu_str[i] = NULL;
-		cfg->ifip[i] = NULL;
-		cfg->ifipv6[i] = NULL;
-		cfg->ifgateway[i] = NULL;
-		cfg->ifgateway6[i] = NULL;
-		cfg->ifmac_str[i] = NULL;
-		cfg->ifnetmask_len[i] = NULL;
-		cfg->ifnetmask6_len[i] = NULL;
-		cfg->ifoffload_str[i] = NULL;
-		cfg->ifneigh_entries[i] = NULL;
-		cfg->ifqdisc_entries[i] = NULL;
-	}
-	cfg->gateway = NULL;
-	cfg->gateway6 = NULL;
-	cfg->debug = NULL;
-	cfg->mount = NULL;
-	cfg->single_cpu = NULL;
-	cfg->sysctls = NULL;
-	cfg->boot_cmdline = NULL;
-	cfg->dump = NULL;
-	cfg->delay_main = NULL;
+
+	memset(cfg, 0, sizeof(struct lkl_config));
+
 	return 0;
 }
 

tools/lkl/lib/hijack/hijack.c

@@ -179,7 +179,7 @@ int getsockopt(int fd, int level, int optname, void *optval, socklen_t *optlen)
 {
 	CHECK_HOST_CALL(getsockopt);
 	if (!is_lklfd(fd))
-		return host_setsockopt(fd, level, optname, optval, optlen);
+		return host_getsockopt(fd, level, optname, optval, optlen);
 	return lkl_call(__lkl__NR_getsockopt, 5, fd, lkl_solevel_xlate(level),
 			lkl_soname_xlate(optname), optval, (int*)optlen);
 }

tools/lkl/lib/hijack/init.c

@@ -418,13 +418,15 @@ hijack_init(void)
 		return;
 	for (i = 0; i < LKL_IF_MAX; i++)
 		nd_id[i] = -1;
-	if (!cfg->debug) {
-		lkl_host_ops.print = NULL;
-	} else {
+
+	if (cfg->debug) {
 		lkl_register_dbg_handler();
 		lkl_debug = strtol(cfg->debug, NULL, 0);
 	}
 
+	if (!cfg->debug || (lkl_debug == 0))
+		lkl_host_ops.print = NULL;
+
 	if (lkl_debug & 0x200) {
 		char c;