add support for a configuration file

Signed-off-by: Liam Beguin <liambeguin@gmail.com>

src/conffile.c

@@ -0,0 +1,212 @@
+// vim: set expandtab tabstop=4 softtabstop=4 shiftwidth=4:
+/*
+ * tio - a simple TTY terminal I/O application
+ *
+ * Copyright (c) 2020-2022  Liam Beguin
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#define _GNU_SOURCE
+#include "config.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <getopt.h>
+#include <termios.h>
+#include <limits.h>
+#include <unistd.h>
+#include <regex.h>
+#include <ini.h>
+#include "conffile.h"
+#include "misc.h"
+#include "options.h"
+#include "error.h"
+#include "print.h"
+
+static struct conf_data *d;
+
+static int get_match(const char *input, const char *pattern, char **match)
+{
+    int ret;
+    int len = 0;
+    regex_t re;
+    regmatch_t m[2];
+    char err[128];
+
+    /* compile a regex with the pattern */
+    ret = regcomp(&re, pattern, REG_EXTENDED);
+    if (ret) {
+        regerror(ret, &re, err, sizeof(err));
+        printf("reg error: %s\n", err);
+        return ret;
+    }
+
+    /* try to match on input */
+    ret = regexec(&re, input, 2, m, 0);
+    if (!ret)
+        len = m[1].rm_eo - m[1].rm_so;
+
+    regfree(&re);
+
+    if (len)
+        asprintf(match, "%s", &input[m[1].rm_so]);
+
+    return len;
+}
+
+/**
+ * data_handler() - walk config file to load parameters matching user input
+ *
+ * INIH handler used to get all parameters from a given section
+ */
+static int data_handler(void *user, const char *section, const char *name,
+                        const char *value)
+{
+    _unused(user);
+
+    if (strcmp(section, d->section_name))
+        return 0;
+
+    if (!strcmp(name, "tty")) {
+        asprintf(&d->tty, value, d->match);
+        option.tty_device = d->tty;
+    } else if (!strcmp(name, "baudrate")) {
+        option.baudrate = string_to_long((char *)value);
+    } else if (!strcmp(name, "databits")) {
+        option.databits = atoi(value);
+    } else if (!strcmp(name, "flow")) {
+        asprintf(&d->flow, "%s", value);
+        option.flow = d->flow;
+    } else if (!strcmp(name, "stopbits")) {
+        option.stopbits = atoi(value);
+    } else if (!strcmp(name, "parity")) {
+        asprintf(&d->parity, "%s", value);
+        option.parity = d->parity;
+    } else if (!strcmp(name, "output-delay")) {
+        option.output_delay = atoi(value);
+    } else if (!strcmp(name, "no-autoconnect")) {
+        option.no_autoconnect = atoi(value);
+    } else if (!strcmp(name, "log")) {
+        option.log = atoi(value);
+    } else if (!strcmp(name, "local-echo")) {
+        option.local_echo = atoi(value);
+    } else if (!strcmp(name, "timestamp")) {
+        option.timestamp = atoi(value);
+    } else if (!strcmp(name, "log-filename")) {
+        asprintf(&d->log_filename, "%s", value);
+        option.log_filename = d->log_filename;
+    } else if (!strcmp(name, "map")) {
+        asprintf(&d->map, "%s", value);
+        option.map = d->map;
+    }
+
+    return 0;
+}
+
+/**
+ * section_search_handler() - walk config file to find section matching user input
+ *
+ * INIH handler used to resolve the section matching the user's input.
+ * This will look for the pattern element of each section and try to match it
+ * with the user input.
+ */
+static int section_search_handler(void *user, const char *section, const char
+                                  *varname, const char *varval)
+{
+    _unused(user);
+
+    if (strcmp(varname, "pattern"))
+        return 0;
+
+    if (!strcmp(varval, d->user)) {
+        /* pattern matches as plain text */
+        asprintf(&d->section_name, "%s", section);
+    } else if (get_match(d->user, varval, &d->match) > 0) {
+        /* pattern matches as regex */
+        asprintf(&d->section_name, "%s", section);
+    }
+
+    return 0;
+}
+
+int resolve_conf_file(void)
+{
+    asprintf(&d->path, "%s/tio/tiorc", getenv("XDG_CONFIG_HOME"));
+    if (!access(d->path, F_OK))
+        return 0;
+
+    asprintf(&d->path, "%s/.config/tio/tiorc", getenv("HOME"));
+    if (!access(d->path, F_OK))
+        return 0;
+
+    asprintf(&d->path, "%s/.tiorc", getenv("HOME"));
+    if (!access(d->path, F_OK))
+        return 0;
+
+    return -EINVAL;
+}
+
+void conf_parse_file(const int argc, char *argv[])
+{
+    int ret;
+    int i;
+
+    d = malloc(sizeof(struct conf_data));
+    memset(d, 0, sizeof(struct conf_data));
+
+    resolve_conf_file();
+
+    for (i = 1; i < argc; i++) {
+        if (argv[i][0] != '-') {
+            d->user = argv[i];
+            break;
+        }
+    }
+
+    if (!d->user)
+            return;
+
+    ret = ini_parse(d->path, section_search_handler, NULL);
+    if (!d->section_name) {
+        debug_printf("unable to match user input to configuration section (%d)\n", ret);
+        return;
+    }
+
+    ret = ini_parse(d->path, data_handler, NULL);
+    if (ret < 0) {
+        fprintf(stderr, "Error: unable to parse configuration file (%d)\n", ret);
+        exit(EXIT_FAILURE);
+    }
+}
+
+void conf_exit(void)
+{
+    free(d->tty);
+    free(d->flow);
+    free(d->parity);
+    free(d->log_filename);
+    free(d->map);
+
+    free(d->match);
+    free(d->section_name);
+    free(d->path);
+
+    free(d);
+}

src/conffile.h

@@ -0,0 +1,42 @@
+/*
+ * tio - a simple TTY terminal I/O application
+ *
+ * Copyright (c) 2020       Liam Beguin
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef CONFFILE_H
+#define CONFFILE_H
+
+struct conf_data {
+	const char *user;
+
+	char *path;
+	char *section_name;
+	char *match;
+
+	char *tty;
+	char *flow;
+	char *parity;
+	char *log_filename;
+	char *map;
+};
+
+void conf_parse_file(const int argc, char *argv[]);
+void conf_exit(void);
+
+#endif /* CONFFILE_H */

src/main.c

@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include "options.h"
+#include "conffile.h"
 #include "tty.h"
 #include "log.h"
 #include "error.h"
@@ -36,6 +37,10 @@ int main(int argc, char *argv[])
     /* Add error exit handler */
     atexit(&error_exit);
 
+    /* Parse configuration file */
+    conf_parse_file(argc, argv);
+    atexit(&conf_exit);
+
     /* Parse options */
     parse_options(argc, argv);
 

src/meson.build

@@ -13,6 +13,14 @@ tio_sources = [
   'print.c'
 ]
 
+# dependencies
+if get_option('conffile')
+    inih = meson.get_compiler('c').find_library('inih')
+    tio_sources += 'conffile.c'
+else
+    inih = dependency()
+endif
+
 tio_c_args = []
 
 if enable_setspeed2
@@ -28,6 +36,7 @@ endif
 executable('tio',
   tio_sources,
   c_args: tio_c_args,
+  dependencies: inih,
   install: true )
 
 subdir('bash-completion')

src/options.c

@@ -269,7 +269,9 @@ void parse_options(int argc, char *argv[])
     }
 
     /* Assume first non-option is the tty device name */
-    if (optind < argc)
+    if (strcmp(option.tty_device, ""))
+	    optind++;
+    else if (optind < argc)
         option.tty_device = argv[optind++];
 
     if (strlen(option.tty_device) == 0)