Added argument parsing with libparg, along with usefull running modes

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "external/uthash"]
 	path = external/uthash
 	url = https://github.com/troydhanson/uthash
+[submodule "external/parg"]
+	path = external/parg
+	url = https://github.com/jibsen/parg

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.0)
-project(bastion LANGUAGES C VERSION 0.1.2)
+project(bastion LANGUAGES C VERSION 0.1.3)
 
 set(CMAKE_VERBOSE_MAKEFILE FALSE)
 if(EXISTS "${CMAKE_SOURCE_DIR}/.git")
@@ -26,6 +26,8 @@ if(SESSION_RECORDING)
     add_definitions(-DSESSION_RECORDING)
 endif()
 
+execute_process(COMMAND git rev-parse HEAD RESULT_VARIABLE GIT_HASH_RESULT OUTPUT_VARIABLE GIT_HASH_FULL)
+string(STRIP ${GIT_HASH_FULL} GIT_HASH)
 configure_file("common/config.h.in" "common/config.h")
 include_directories("${CMAKE_CURRENT_BINARY_DIR}")
 include_directories("${CMAKE_CURRENT_SOURCE_DIR}")

bastion/CMakeLists.txt

@@ -1,3 +1,4 @@
+include_directories("${PROJECT_SOURCE_DIR}/external/parg/")
 include_directories("${PROJECT_SOURCE_DIR}/external/termrec/libtty")
 
 file(GLOB_RECURSE SOURCES *.c)
@@ -7,7 +8,8 @@ target_link_libraries(bastion common)
 if (SESSION_RECORDING)
     target_link_libraries(bastion libtty)
 endif()
-target_link_libraries(bastion bz2 config curl lzma ssh z)
+target_link_libraries(bastion libparg)
+target_link_libraries(bastion bz2 config curl lzma pthread ssh z)
 
 install(TARGETS bastion DESTINATION bin)
 

bastion/main.c

@@ -1,5 +1,6 @@
 #include <libssh/callbacks.h>
 #include <libssh/server.h>
+#include <parg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/wait.h>
@@ -8,6 +9,16 @@
 #include "session.h"
 #include "state.h"
 
+static void usage(char **argv)
+{
+    printf("Usage: %s [-h] [-v] [-t] [-f] [-c STRING]\n", argv[0]);
+    printf("  -h : show this help message and exit\n");
+    printf("  -v : show version and exit\n");
+    printf("  -t : test configuration file and exit\n");
+    printf("  -f : stay in foreground (don't fork)\n");
+    printf("  -c : specify a path to a configuration file to use instead of the default %s\n", CONFIG_PATH);
+}
+
 /* SIGCHLD handler for cleaning up dead children. */
 static void sigchld_handler(int signo) {
     (void) signo;
@@ -30,17 +41,8 @@ __attribute__((noreturn)) static void sigint_handler(int signo)
     exit(0);
 }
 
-int main()
+int main(int argc, char **argv)
 {
-    // Set up SIGCHLD handler
-    struct sigaction sa;
-    sa.sa_handler = sigchld_handler;
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
-    if (sigaction(SIGCHLD, &sa, NULL) != 0) {
-        fprintf(stderr, "Failed to register SIGCHLD handler\n");
-        return 1;
-    }
     // Set up SIGINT handler
     struct sigaction sa2;
     sa2.sa_handler = sigint_handler;
@@ -48,21 +50,86 @@ int main()
     sa2.sa_flags = 0;
     if (sigaction(SIGINT, &sa2, NULL) != 0) {
         fprintf(stderr, "Failed to register SIGINT handler\n");
-        return 2;
+        return 1;
+    }
+
+    // Argument parsing
+    struct parg_state ps;
+    int c;
+    char test_only = 0, dont_fork = 0;
+    const char *config_file = CONFIG_PATH;
+    parg_init(&ps);
+    //while ((int c = parg_getopt(&ps, argc, argv, "hs:v")) != -1) {
+    while ((c = parg_getopt(&ps, argc, argv, "hvtfc:")) != -1) {
+        switch (c) {
+          case 1:
+            printf("invalid non option '%s'\n", ps.optarg);
+            return 2;
+          case 'h':
+            usage(argv);
+            return 0;
+          case 'v':
+            printf("%s %s - %s\n", argv[0], VERSION, GIT_HASH);
+            return 0;
+          case 't':
+            test_only = 1;
+            break;
+          case 'f':
+            dont_fork = 1;
+            break;
+          case 'c':
+            config_file = ps.optarg;
+            break;
+          case '?':
+            if (ps.optopt == 'c') {
+                printf("option -c requires the path to a configuration in argument.\n");
+            }
+            else {
+                printf("unknown option -%c\n", ps.optopt);
+            }
+            usage(argv);
+            return 3;
+          default:
+            printf("error: unhandled option -%c\n", c);
+            return 4;
+            break;
+        }
+    }
+
+    if (test_only) {
+        if (config_load(config_file) != 0) {
+            fprintf(stderr, "Failed to load configuration file %s.\n", CONFIG_PATH);
+            config_clean();
+            return 5;
+        }
+        config_clean();
+        return 0;
+    }
+
+    struct sigaction sa;
+    if (!dont_fork) {
+        // Set up SIGCHLD handler
+        sa.sa_handler = sigchld_handler;
+        sigemptyset(&sa.sa_mask);
+        sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
+        if (sigaction(SIGCHLD, &sa, NULL) != 0) {
+            fprintf(stderr, "Failed to register SIGCHLD handler\n");
+            return 6;
+        }
     }
 
     // Initializing ssh context
     if (ssh_init() != 0) {
         fprintf(stderr, "Failed to initialize libssh global cryptographic data structures.\n");
-        return 3;
+        return 7;
     };
 
     // Initializing configuration context
-    if (config_load() != 0) {
+    if (config_load(config_file) != 0) {
         fprintf(stderr, "Failed to load configuration file %s.\n", CONFIG_PATH);
         config_clean();
         ssh_finalize();
-        return 4;
+        return 8;
     }
 
     // Initializing ssh_bind
@@ -71,7 +138,7 @@ int main()
         fprintf(stderr, "Error initializing ssh_bind\n");
         config_clean();
         ssh_finalize();
-        return 5;
+        return 9;
     }
     int listen_port = config_get_port();
     ssh_bind_options_set(sshbind, SSH_BIND_OPTIONS_BINDPORT, &listen_port);
@@ -84,7 +151,7 @@ int main()
         ssh_bind_free(sshbind);
         config_clean();
         ssh_finalize();
-        return 6;
+        return 10;
     }
 
     while (1) {
@@ -100,11 +167,18 @@ int main()
 
         // Blocks until there is a new incoming connection
         if (ssh_bind_accept(sshbind,session) == SSH_OK){
-            switch(fork()) {
+            int res = 0;
+            if (!dont_fork) {
+                res = fork();
+            }
+
+            switch(res) {
               case 0:
-                /* Remove the SIGCHLD handler inherited from parent. */
+                if (!dont_fork) {
-                sa.sa_handler = SIG_DFL;
+                    /* Remove the SIGCHLD handler inherited from parent. */
-                sigaction(SIGCHLD, &sa, NULL);
+                    sa.sa_handler = SIG_DFL;
+                    sigaction(SIGCHLD, &sa, NULL);
+                }
                 /* Remove socket binding, which allows us to restart the parent process, without terminating existing sessions. */
                 ssh_bind_free(sshbind);
                 sshbind = NULL;
@@ -134,7 +208,7 @@ int main()
             ssh_bind_free(sshbind);
             config_clean();
             ssh_finalize();
-            return 7;
+            return 10;
         }
         /* Since the session has been passed to a child fork, do some cleaning up at the parent process. */
         ssh_disconnect(session);

common/config.c

@@ -7,12 +7,12 @@
 config_t * config = NULL;
 
 char // returns 0 if ok, greater than 0 otherwise
-config_load(void)
+config_load(const char *config_file)
 {
     config = malloc(sizeof(config_t));
     config_init(config);
     config_set_tab_width(config, 4);
-    if (config_read_file(config, CONFIG_PATH) != CONFIG_TRUE) {
+    if (config_read_file(config, config_file) != CONFIG_TRUE) {
         switch(config_error_type(config)) {
           case CONFIG_ERR_NONE:
             fprintf(stderr, "Configuration read error with none type reported... This shouldn't happen!\n");

common/config.h.in

@@ -3,6 +3,8 @@
 
 #define CONFIG_DIR "@CMAKE_INSTALL_PREFIX@/etc/bastion/"
 #define CONFIG_PATH CONFIG_DIR "bastion.conf"
+#define VERSION "@PROJECT_VERSION@"
+#define GIT_HASH "@GIT_HASH@"
 
 #define MAX_HOSTNAME_LENGTH 64
 
@@ -17,7 +19,7 @@
 #define SESSION_RECORDING_DIRECTORY_MODE S_IRUSR | S_IWUSR | S_IXUSR
 #endif
 
-char config_load(void);
+char config_load(const char *config_file);
 int config_get_port(void);
 const char * config_get_key_dsa(void);
 const char * config_get_key_rsa(void);

external/CMakeLists.txt

@@ -34,3 +34,6 @@ if (SESSION_RECORDING)
     target_link_libraries(termplay bz2 curl lzma pthread z)
     install(TARGETS termplay DESTINATION bin)
 endif()
+
+# Build parg library for argument parsing
+add_library(libparg parg/parg.c parg/parg.h)

external/parg

@@ -0,0 +1 @@
+Subproject commit 97f3a075109ebace4f660fb341c6b99b2a4b092a