login: Support /etc/issue through login-loop

apps/login-loop.c

@@ -1,18 +1,199 @@
-/* vim: tabstop=4 shiftwidth=4 noexpandtab
+/**
+ * @brief Repeatedly invoke `login` in a loop.
+ *
+ * This is more closely related to the 'getty' command in Linux
+ * than our actual 'getty' command as it is also where we process
+ * and display /etc/issue.
+ *
+ * @copyright
  * This file is part of ToaruOS and is released under the terms
  * of the NCSA / University of Illinois License - see LICENSE.md
- * Copyright (C) 2018 K. Lange
- *
- * login-loop - Continuously call `login`
- *
- * Used by the VGA terminal to provide interactive login sessions.
+ * Copyright (C) 2018-2021 K. Lange
  */
 #include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
 #include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
 #include <sys/wait.h>
+#include <sys/utsname.h>
+#include <sys/time.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+
+struct colorNames {
+	const char * name;
+	const char * output;
+} ColorNames[] = {
+	{"black", "\033[30m"},
+	{"blue", "\033[34m"},
+	{"bold", "\033[1m"},
+	{"brown", "\033[33m"},
+	{"cyan", "\033[36"},
+	{"darkgray", "\033[90m"},
+	{"gray", "\033[37m"},
+	{"green", "\033[32m"},
+	{"lightblue", "\033[94m"},
+	{"lightcyan", "\033[96m"},
+	{"lightgray", "\033[97m"},
+	{"lightgreen", "\033[92m"},
+	{"lightmagenta", "\033[95m"},
+	{"lightred", "\033[91m"},
+	{"magenta", "\033[35m"},
+	{"red", "\033[31m"},
+	{"reset", "\033[0m"},
+	{"reverse", "\033[7m"},
+	{"yellow", "\033[93m"},
+	{NULL, NULL},
+};
+
+char * get_arg(FILE * f) {
+	static char buf[32];
+	int n = fgetc(f);
+	if (n == '{') {
+		int count = 0;
+		do {
+			int x = fgetc(f);
+			if (x == '}') break;
+			if (x < 0) break;
+			buf[count++] = x;
+			buf[count] = '\0';
+		} while (count < 31);
+		if (count) return buf;
+	}
+	return NULL;
+}
+
+char * get_ipv4_address(char * arg) {
+	if (arg) {
+		char if_path[1024];
+		snprintf(if_path, 300, "/dev/net/%s", arg);
+		int netdev = open(if_path, O_RDWR);
+		if (netdev >= 0) {
+			uint32_t ip_addr = 0;
+			if (!ioctl(netdev, SIOCGIFADDR, &ip_addr)) {
+				return inet_ntoa((struct in_addr){ntohl(ip_addr)});
+			}
+		}
+	} else {
+		/* Read /dev/net for interfaces */
+		DIR * d = opendir("/dev/net");
+		if (d) {
+			struct dirent * ent;
+			while ((ent = readdir(d))) {
+				if (ent->d_name[0] == '.') continue;
+				closedir(d);
+				return get_ipv4_address(ent->d_name);
+			}
+			closedir(d);
+		}
+	}
+
+	return "127.0.0.1";
+}
+
+void print_issue(void) {
+	printf("\033[H\033[2J");
+	fflush(stdout);
+
+	FILE * f = fopen("/etc/issue","r");
+	if (!f) return;
+
+	/* Parse and display /etc/issue with support
+	 * for some escape sequences that fill in
+	 * dynamic information... */
+
+	struct utsname u;
+	uname(&u);
+
+	struct tm * timeinfo;
+	struct timeval now;
+	gettimeofday(&now, NULL);
+	timeinfo = localtime((time_t *)&now.tv_sec);
+
+	static char buf[1024];
+
+	while (!feof(f)) {
+		int c = fgetc(f);
+
+		if (c < 0) break; /* Probably EOF */
+
+		if (c == '\\') {
+			int next = fgetc(f);
+			switch (next) {
+				case '\n':
+					/* A linefeed we should quietly skip. */
+					continue;
+				case '\\':
+					/* A literal backslash */
+					printf("\\");
+					continue;
+
+				/* Various things from uname */
+				case 'n':
+					printf("%s", u.nodename);
+					continue;
+				case 's':
+					printf("%s", u.sysname);
+					continue;
+				case 'r':
+					printf("%s", u.release);
+					continue;
+				case 'm':
+					printf("%s", u.machine);
+					continue;
+				case 'v':
+					printf("%s", u.version);
+					continue;
+
+				/* Various other useful things */
+				case '4':
+					printf("%s", get_ipv4_address(get_arg(f)));
+					continue;
+				case 'l':
+					printf("%s", ttyname(STDIN_FILENO));
+					continue;
+				case 't':
+					strftime(buf,1024,"%T %Z",timeinfo);
+					printf("%s", buf);
+					continue;
+				case 'd':
+					strftime(buf,1024,"%a %b %d %Y",timeinfo);
+					printf("%s", buf);
+					continue;
+
+				/* Formatting stuff listed in Linux's getty(8) manpage */
+				case 'e': {
+					char * arg = get_arg(f);
+					if (arg) {
+						for (struct colorNames * cn = ColorNames; cn->name; cn++) {
+							if (!strcmp(arg,cn->name)) {
+								printf("%s", cn->output);
+								break;
+							}
+						}
+					} else {
+						printf("\033");
+					}
+					continue;
+				}
+			}
+		} else {
+			printf("%c", c);
+		}
+	}
+
+
+	fclose(f);
+}
 
 int main(int argc, char * argv[]) {
 	while (1) {
+		print_issue();
 		pid_t f = fork();
 		if (!f) {
 			char * args[] = {

apps/login.c

@@ -69,10 +69,6 @@ int main(int argc, char ** argv) {
 		}
 	}
 
-	printf("\n");
-	system("uname -a");
-	printf("\n");
-
 	signal(SIGINT, sig_pass);
 	signal(SIGWINCH, sig_pass);
 	signal(SIGSEGV, sig_segv);

base/etc/issue

@@ -0,0 +1,10 @@
+\e{bold}\t\e{reset} on \e{bold}\d\e{reset}
+\e{yellow}\l\e{reset} on \e{lightblue}\n\e{reset} - \e{bold}\s \r\e{reset}
+
+ This live CD has two available user accounts: \e{bold}local\e{reset} is listed in /etc/sudoers
+ and \e{bold} guest\e{reset} is not. For both accounts, the password is the same as the account
+ name. The \e{bold}root\e{reset} account can also be accessed directly with the password \e{bold}toor\e{reset}.
+ You may also type \e{bold}restart\e{reset} at the login prompt to reboot. Please note that
+ VGA text mode and serial terminal access provides only a limited subset of the
+ available functionality of ToaruOS.
+