agetty: stop using MAXHOSTNAMELEN

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 55 insertions, 23 deletions

diff --git a/term-utils/agetty.c b/term-utils/agetty.c
index 4e2313592..9bb0fd753 100644
--- a/term-utils/agetty.c
+++ b/term-utils/agetty.c
@@ -1220,6 +1220,41 @@ static void auto_baud(struct termios *tp)
 	tcsetattr(STDIN_FILENO, TCSANOW, tp);
 }
 
+static char *xgethostname(void)
+{
+	char *name;
+	size_t sz = get_hostname_max() + 1;
+
+	name = malloc(sizeof(char) * sz);
+	if (!name)
+		log_err(_("failed to allocate memory: %m"));
+
+	if (gethostname(name, sz) != 0)
+		return NULL;
+
+	name[sz - 1] = '\0';
+	return name;
+}
+
+static char *xgetdomainname(void)
+{
+#ifdef HAVE_GETDOMAINNAME
+	char *name;
+	size_t sz = get_hostname_max() + 1;
+
+	name = malloc(sizeof(char) * sz);
+	if (!name)
+		log_err(_("failed to allocate memory: %m"));
+
+	if (getdomainname(name, sz) != 0)
+		return NULL;
+
+	name[sz - 1] = '\0';
+	return name;
+#endif
+	return NULL;
+}
+
 /* Show login prompt, optionally preceded by /etc/issue contents. */
 static void do_prompt(struct options *op, struct termios *tp)
 {
@@ -1293,12 +1328,12 @@ static void do_prompt(struct options *op, struct termios *tp)
 	}
 #endif /* KDGKBLED */
 	if ((op->flags & F_NOHOSTNAME) == 0) {
-		char hn[MAXHOSTNAMELEN + 1];
-		if (gethostname(hn, sizeof(hn)) == 0) {
+		char *hn = xgethostname();
+
+		if (hn) {
 			struct hostent *ht;
 			char *dot = strchr(hn, '.');
 
-			hn[MAXHOSTNAMELEN] = '\0';
 			if ((op->flags & F_LONGHNAME) == 0) {
 				if (dot)
 					*dot = '\0';
@@ -1308,6 +1343,7 @@ static void do_prompt(struct options *op, struct termios *tp)
 			else
 				write_all(STDOUT_FILENO, hn, strlen(hn));
 			write_all(STDOUT_FILENO, " ", 1);
+			free(hn);
 		}
 	}
 	if (op->autolog == (char*)0) {
@@ -1732,7 +1768,7 @@ static void output_iface_ip(struct ifaddrs *addrs, const char *iface, sa_family_
 
 static void output_ip(sa_family_t family)
 {
-	char host[MAXHOSTNAMELEN + 1];
+	char *host;
 	struct addrinfo hints, *info = NULL;
 
 	memset(&hints, 0, sizeof(hints));
@@ -1740,9 +1776,8 @@ static void output_ip(sa_family_t family)
 	if (family == AF_INET6)
 		hints.ai_flags = AI_V4MAPPED;
 
-	if (gethostname(host, sizeof(host)) == 0
-	    && getaddrinfo(host, NULL, &hints, &info) == 0
-	    && info) {
+	host = xgethostname();
+	if (host && getaddrinfo(host, NULL, &hints, &info) == 0 && info) {
 
 		void *addr = NULL;
 		char buff[INET6_ADDRSTRLEN + 1];
@@ -1760,6 +1795,7 @@ static void output_ip(sa_family_t family)
 
 		freeaddrinfo(info);
 	}
+	free(host);
 }
 
 /*
@@ -1814,36 +1850,32 @@ static void output_special_char(unsigned char c, struct options *op,
 		break;
 	case 'o':
 	{
-		char domainname[MAXHOSTNAMELEN+1];
-#ifdef HAVE_GETDOMAINNAME
-		if (getdomainname(domainname, sizeof(domainname)))
-#endif
-		strcpy(domainname, "unknown_domain");
-		domainname[sizeof(domainname)-1] = '\0';
-		printf("%s", domainname);
+		char *dom = xgetdomainname();
+
+		fputs(dom ? dom : "unknown_domain", stdout);
+		free(dom);
 		break;
 	}
 	case 'O':
 	{
-		char *dom = "unknown_domain";
-		char host[MAXHOSTNAMELEN+1];
+		char *dom = NULL;
+		char *host = xgethostname();
 		struct addrinfo hints, *info = NULL;
 
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_flags = AI_CANONNAME;
 
-		if (gethostname(host, sizeof(host)) ||
-		    getaddrinfo(host, NULL, &hints, &info) ||
-		    info == NULL)
-			fputs(dom, stdout);
-		else {
+		if (host && getaddrinfo(host, NULL, &hints, &info) == 0 && info) {
 			char *canon;
+
 			if (info->ai_canonname &&
 			    (canon = strchr(info->ai_canonname, '.')))
 				dom = canon + 1;
-			fputs(dom, stdout);
-			freeaddrinfo(info);
 		}
+		fputs(dom ? dom : "unknown_domain", stdout);
+		if (info)
+			freeaddrinfo(info);
+		free(host);
 		break;
 	}
 	case 'd':