Makefile, conf, passt: Drop passt4netns references, explicit argc check

Nobody currently calls this as passt4netns, that was the name I used
before 'pasta', drop any reference before it's too late.

While at it, explicitly check that argc is bigger than or equal to
one, just as a defensive measure: argv[0] being NULL is not an issue
anyway.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Makefile

@@ -62,7 +62,7 @@ endif
 
 prefix ?= /usr/local
 
-all: passt pasta passt4netns qrap
+all: passt pasta qrap
 
 avx2: CFLAGS += -Ofast -mavx2 -ftree-vectorize -funroll-loops
 avx2: clean all
@@ -81,16 +81,13 @@ pasta: passt
 	ln -s passt pasta
 	ln -s passt.1 pasta.1
 
-passt4netns: passt
-	ln -s passt passt4netns
-
 qrap: qrap.c passt.h
 	$(CC) $(CFLAGS) \
 		qrap.c -o qrap
 
 .PHONY: clean
 clean:
-	-${RM} passt *.o seccomp.h qrap pasta pasta.1 passt4netns \
+	-${RM} passt *.o seccomp.h qrap pasta pasta.1 \
 		passt.tar passt.tar.gz *.deb *.rpm
 
 install: passt pasta qrap

conf.c

@@ -532,7 +532,7 @@ static void conf_ip(struct ctx *c)
  */
 static void usage(const char *name)
 {
-	if (strstr(name, "pasta") || strstr(name, "passt4netns")) {
+	if (strstr(name, "pasta")) {
 		info("Usage: %s [OPTION]... [PID|PATH|NAME]", name);
 		info("");
 		info("Without PID|PATH|NAME, run the default shell in a new");
@@ -550,7 +550,7 @@ static void usage(const char *name)
 	info(   "    default: log to system logger only if started from a TTY");
 	info(   "  -h, --help		Display this help message and exit");
 
-	if (strstr(name, "pasta") || strstr(name, "passt4netns")) {
+	if (strstr(name, "pasta")) {
 		info(   "  -I, --ns-ifname NAME	namespace interface name");
 		info(   "    default: same interface name as external one");
 	} else {
@@ -562,7 +562,7 @@ static void usage(const char *name)
 	info(   "  -p, --pcap [FILE]	Log tap-facing traffic to pcap file");
 	info(   "    if FILE is not given, log to:");
 
-	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+	if (strstr(name, "pasta"))
 		info("      /tmp/pasta_ISO8601-TIMESTAMP_PID.pcap");
 	else
 		info("      /tmp/passt_ISO8601-TIMESTAMP_PID.pcap");
@@ -586,14 +586,14 @@ static void usage(const char *name)
 	info(   "  -D, --dns ADDR	Pass IPv4 or IPv6 address as DNS");
 	info(   "    can be specified multiple times");
 	info(   "    a single, empty option disables DNS information");
-	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+	if (strstr(name, "pasta"))
 		info(   "    default: don't send any addresses");
 	else
 		info(   "    default: use addresses from /etc/resolv.conf");
 
 	info(   "  -S, --search LIST	Space-separated list, search domains");
 	info(   "    a single, empty option disables the DNS search list");
-	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+	if (strstr(name, "pasta"))
 		info(   "    default: don't send any search list");
 	else
 		info(   "    default: use search list from /etc/resolv.conf");
@@ -609,7 +609,7 @@ static void usage(const char *name)
 	info(   "  -4, --ipv4-only	Enable IPv4 operation only");
 	info(   "  -6, --ipv6-only	Enable IPv6 operation only");
 
-	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+	if (strstr(name, "pasta"))
 		goto pasta_opts;
 
 	info(   "  -t, --tcp-ports SPEC	TCP port forwarding to guest");

passt.c

@@ -322,16 +322,21 @@ int main(int argc, char **argv)
 	sigaction(SIGTERM, &sa, NULL);
 	sigaction(SIGQUIT, &sa, NULL);
 
-	if (strstr(argv[0], "pasta") || strstr(argv[0], "passt4netns")) {
+	if (argc < 1)
+		exit(EXIT_FAILURE);
+
+	if (strstr(argv[0], "pasta")) {
 		sa.sa_handler = pasta_child_handler;
 		sigaction(SIGCHLD, &sa, NULL);
 		signal(SIGPIPE, SIG_IGN);
 
 		c.mode = MODE_PASTA;
 		log_name = "pasta";
-	} else {
+	} else if (strstr(argv[0], "passt")) {
 		c.mode = MODE_PASST;
 		log_name = "passt";
+	} else {
+		exit(EXIT_FAILURE);
 	}
 
 	if (madvise(pkt_buf, TAP_BUF_BYTES, MADV_HUGEPAGE))