rotctl.c: Add options to save/read command history

As commands from a previous session may not be desired, make reading the
history file at rotctl start and writing to it at rotctl close optional
by use of the -i/--read_history or -I/--save-history options.
Compilation is conditional on having Readline and Readline History
support detected at build system configuration time.

History is stored in '$HOME/.rotctl_history' by default.  An alternate
path may be specified by setting the ROTCTL_HIST_DIR environment
variable:

$ ROTCTL_HIST_DIR=~/.rotctl rotctl -iI

will temporarily set the history directory to /home/USER/.rotctl and
create .rotctl_history if it does not exist.  If the file cannot be read
or written a warning message will be given on stderr.

tests/rotctl.c

@@ -33,6 +33,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <ctype.h>
+#include <errno.h>
 #include <getopt.h>
 
 #ifdef HAVE_LIBREADLINE
@@ -48,6 +49,8 @@ extern char *readline ();
 #endif                              /* HAVE_LIBREADLINE */
 
 #ifdef HAVE_READLINE_HISTORY
+#  include <sys/stat.h>
+#  define HST_SHRT_OPTS "iI"
 #  if defined(HAVE_READLINE_HISTORY_H)
 #    include <readline/history.h>
 #  elif defined(HAVE_HISTORY_H)
@@ -57,7 +60,9 @@ extern void add_history ();
 extern int write_history ();
 extern int read_history ();
 #  endif                            /* defined(HAVE_READLINE_HISTORY_H) */
-                                    /* no history */
+#else
+/* no history */
+#define HST_SHRT_OPTS ""
 #endif                              /* HAVE_READLINE_HISTORY */
 
 
@@ -88,6 +93,10 @@ static struct option long_options[] =
 	{"set-conf", 1, 0, 'C'},
 	{"show-conf",0, 0, 'L'},
 	{"dump-caps",0, 0, 'u'},
+#ifdef HAVE_READLINE_HISTORY
+	{"read-history", 0, 0, 'i'},
+	{"save-history", 0, 0, 'I'},
+#endif
 	{"verbose",  0, 0, 'v'},
 	{"help",     0, 0, 'h'},
 	{"version",  0, 0, 'V'},
@@ -120,6 +129,14 @@ int main (int argc, char *argv[])
 	int verbose = 0;
 	int show_conf = 0;
 	int dump_caps_opt = 0;
+#ifdef HAVE_READLINE_HISTORY
+	int rd_hist = 0;
+	int sv_hist = 0;
+	const char *hist_dir = NULL;
+	const char hist_file[] = "/.rotctl_history";
+	char *hist_path = NULL;
+	struct stat hist_dir_stat;
+#endif
 	const char *rot_file=NULL;
 	int serial_rate = 0;
 	char conf_parms[MAXCONFLEN] = "";
@@ -128,7 +145,7 @@ int main (int argc, char *argv[])
 		int c;
 		int option_index = 0;
 
-		c = getopt_long (argc, argv, SHORT_OPTIONS,
+		c = getopt_long (argc, argv, SHORT_OPTIONS HST_SHRT_OPTS,
 			long_options, &option_index);
 		if (c == -1)
 			break;
@@ -180,6 +197,14 @@ int main (int argc, char *argv[])
 				else
 					send_cmd_term = optarg[0];
 				break;
+#ifdef HAVE_READLINE_HISTORY
+			case 'i':
+				rd_hist++;
+				break;
+			case 'I':
+				sv_hist++;
+				break;
+#endif
 			case 'v':
 				verbose++;
 				break;
@@ -268,9 +293,28 @@ int main (int argc, char *argv[])
 
 #ifdef HAVE_LIBREADLINE
 	if (interactive && prompt && have_rl) {
-		rl_readline_name = "rigctl";
+		rl_readline_name = "rotctl";
 #ifdef HAVE_READLINE_HISTORY
 		using_history();	/* Initialize Readline History */
+
+		if (rd_hist || sv_hist) {
+			if (!(hist_dir = getenv("ROTCTL_HIST_DIR")))
+				hist_dir = getenv("HOME");
+
+			if (((stat(hist_dir, &hist_dir_stat) == -1) && (errno == ENOENT))
+				|| !(S_ISDIR(hist_dir_stat.st_mode))) {
+				fprintf(stderr, "Warning: %s is not a directory!\n", hist_dir);
+			}
+
+			hist_path = (char *)calloc((sizeof(char) * (strlen(hist_dir) + strlen(hist_file) + 1)), sizeof(char));
+
+			strncpy(hist_path, hist_dir, strlen(hist_dir));
+			strncat(hist_path, hist_file, strlen(hist_file));
+		}
+
+		if (rd_hist && hist_path)
+			if (read_history(hist_path) == ENOENT)
+				fprintf(stderr, "Warning: Could not read history from %s\n", hist_path);
 #endif
 	}
 #endif	/* HAVE_LIBREADLINE */
@@ -282,6 +326,20 @@ int main (int argc, char *argv[])
 	}
 	while (retcode == 0 || retcode == 2);
 
+#ifdef HAVE_LIBREADLINE
+	if (interactive && prompt && have_rl) {
+#ifdef HAVE_READLINE_HISTORY
+		if (sv_hist && hist_path)
+			if (write_history(hist_path) == ENOENT)
+				fprintf(stderr, "\nWarning: Could not write history to %s\n", hist_path);
+
+		if ((rd_hist || sv_hist) && hist_path) {
+			free(hist_path);
+			hist_path = (char *)NULL;
+		}
+	}
+#endif
+#endif
 	rot_close(my_rot); /* close port */
 	rot_cleanup(my_rot); /* if you care about memory */
 
@@ -303,6 +361,10 @@ void usage()
 		"  -L, --show-conf            list all config parameters\n"
 		"  -l, --list                 list all model numbers and exit\n"
 		"  -u, --dump-caps            dump capabilities and exit\n"
+#ifdef HAVE_READLINE_HISTORY
+		"  -i, --read-history         read prior interactive session history\n"
+		"  -I, --save-history         save current interactive session history\n"
+#endif
 		"  -v, --verbose              set verbose mode, cumulative\n"
 		"  -h, --help                 display this help and exit\n"
 		"  -V, --version              output version information and exit\n\n"