Added argument parser and set all logs to STDERR

event_loop.c

@@ -23,7 +23,7 @@ static struct epoll_event _evs[MAX_EPOLL_EVENTS];
 bool loop_init(loop_cb_t callback) {
     _efd = epoll_create1(0);
     if (_efd == -1) {
-        printf("[!] epoll_create1 failed: %d\n", errno);
+        fprintf(stderr, "[!] epoll_create1 failed: %d\n", errno);
         return false;
     }
     _cb = callback;
@@ -36,7 +36,7 @@ void loop_deinit() {
 
 bool loop_ctl(int op, int fd, struct epoll_event *event) {
     if (epoll_ctl(_efd, op, fd, event) == -1) {
-        printf("[!] epoll_ctl failed: %d\n", errno);
+        fprintf(stderr, "[!] epoll_ctl failed: %d\n", errno);
         return false;
     }
     return true;
@@ -50,7 +50,7 @@ bool loop_wait() {
         -1
     );
     if (result < 0) {
-        printf("[!] epoll_wait failed: %d\n", errno);
+        fprintf(stderr, "[!] epoll_wait failed: %d\n", errno);
         return false;
     }
     if (!result) {

main.c

@@ -1,6 +1,8 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
 
 #include <errno.h>
 #include <signal.h>
@@ -9,6 +11,7 @@
 
 #include "event_loop.h"
 #include "server.h"
+#include "utils.h"
 
 /*
  * Data
@@ -20,6 +23,54 @@ static int _server_fd = -1;
 /*
  * Private API
  */
+// Parse command line arguments and check if mandatory ones are present.
+// Parameters:
+//  - argc
+//  - argv
+// Returns:
+//  - true on success
+//  - false on failure
+bool parse_cli_args(int argc, char** argv) {
+    if (argc < 2) {
+        return false;
+    }
+    int key_length, value_length;
+    int i = 1;
+    char first_sym;
+    while (i < argc) {
+        key_length = strlen(argv[i] + 1);
+        first_sym = argv[i][0];
+        if (key_length != 1 || (first_sym != '+' && first_sym != '-')) {
+            fprintf(stderr, "[!] Argument '%s' is discarded\n", argv[i]);
+            return false;
+        }
+        // flag
+        if (first_sym == '+') {
+            cli_arg_set(argv[i] + 1, argv[i] + 1);
+            i++;
+            continue;
+        }
+        // argument
+        if (i + 1 >= argc) {
+            fprintf(stderr, "[!] Argument '%s' misses a value\n", argv[i]);
+            return false;
+        }
+        value_length = strlen(argv[i + 1]);
+        if (value_length < 1) {
+            fprintf(stderr, "[!] Argument '%s' has empty value\n", argv[i]);
+            return false;
+        }
+        cli_arg_set(argv[i] + 1, argv[i + 1]);
+        i += 2;
+    }
+    bool required_args_present = true;
+    required_args_present &= cli_arg_get("M") ? true : false;
+    required_args_present &= cli_arg_get("A") ? true : false;
+    required_args_present &= cli_arg_get("P") ? true : false;
+    required_args_present &= cli_arg_get("E") ? true : false;
+    return required_args_present;
+}
+
 // Initialize signals.
 // Returns:
 //  - true on success
@@ -32,7 +83,7 @@ static bool signals_init() {
     sigaddset(&mask, SIGINT);
     sigaddset(&mask, SIGQUIT);
     if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) {
-        printf("[!] sigprocmask failed: %d\n", errno);
+        fprintf(stderr, "[!] sigprocmask failed: %d\n", errno);
         return false;
     }
     _sig_fd = signalfd(
@@ -41,7 +92,7 @@ static bool signals_init() {
         SFD_NONBLOCK
     );
     if (_sig_fd == -1) {
-        printf("[!] signalfd failed: %d\n", errno);
+        fprintf(stderr, "[!] signalfd failed: %d\n", errno);
         return false;
     }
     struct epoll_event ev;
@@ -54,7 +105,7 @@ static bool signals_init() {
     );
     if (!loop_res) {
         close(_sig_fd);
-        printf("[!] loop_ctl failed\n");
+        fprintf(stderr, "[!] loop_ctl failed\n");
         return false;
     }
     return true;
@@ -69,7 +120,7 @@ static void signals_deinit() {
 // Returns:
 //  - true on success
 static bool server_init() {
-    _server_fd = server_open("0.0.0.0", 20070);
+    _server_fd = server_open(cli_arg_get("A"), atoi(cli_arg_get("P")));
     if (_server_fd == -1) {
         return false;
     }
@@ -83,7 +134,7 @@ static bool server_init() {
     );
     if (!loop_res) {
         server_close();
-        printf("[!] loop_ctl failed\n");
+        fprintf(stderr, "[!] loop_ctl failed\n");
         return false;
     }
     return true;
@@ -106,16 +157,20 @@ static void on_fd_event(int fd, uint32_t events) {
     // Server event
     else if (fd == _server_fd) {
         if (!server_event(_server_fd)) {
-            printf("[!] server_event failed\n");
+            fprintf(stderr, "[!] server_event failed\n");
             _to_work = false;
         }
     }
     else {
-        printf("[!] Event has happened on an unknown file descriptor\n");
+        fprintf(stderr, "[!] Event has happened on an unknown file descriptor\n");
     }
 }
 
 int main(int argc, char **argv) {
+    if (!parse_cli_args(argc, argv)) {
+        print_usage_text();
+        return 1;
+    }
     if (!loop_init(on_fd_event)) {
         return 1;
     }
@@ -131,10 +186,10 @@ int main(int argc, char **argv) {
 
     while (_to_work) {
         if (!loop_wait()) {
-            printf("[!] loop_wait returns false, stopping...\n");
+            fprintf(stderr, "[!] loop_wait returns false, stopping...\n");
             break;
         }
-        printf("--- loop ---\n");
+        fprintf(stderr, "--- loop ---\n");
     }
     
     server_close();

server.c

@@ -34,7 +34,7 @@ bool _accept() {
 int server_open(const char* host, int port) {
     struct hostent *he = gethostbyname(host);
     if (!he) {
-        printf("[!] gethostbyname failed: %d (h_errno)\n", h_errno);
+        fprintf(stderr, "[!] gethostbyname failed: %d (h_errno)\n", h_errno);
         return -1;
     }
     _fd = socket(
@@ -43,13 +43,13 @@ int server_open(const char* host, int port) {
         IPPROTO_TCP
     );
     if (_fd == -1) {
-        printf("[!] socket failed: %d\n", errno);
+        fprintf(stderr, "[!] socket failed: %d\n", errno);
         return -1;
     }
     const int opt = 1;
     if (setsockopt(_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
         close(_fd);
-        printf("[!] setsockopt failed: %d\n", errno);
+        fprintf(stderr, "[!] setsockopt failed: %d\n", errno);
         return -1;
     }
     struct sockaddr_in addr;
@@ -58,12 +58,12 @@ int server_open(const char* host, int port) {
     memcpy(&addr.sin_addr, he->h_addr, he->h_length);
     if (bind(_fd, (const void *)&addr, sizeof(addr)) == -1) {
         close(_fd);
-        printf("[!] bind failed: %d\n", errno);
+        fprintf(stderr, "[!] bind failed: %d\n", errno);
         return -1;
     }
     if (listen(_fd, LISTEN_BACKLOG) == -1) {
         close(_fd);
-        printf("[!] listen failed: %d\n", errno);
+        fprintf(stderr, "[!] listen failed: %d\n", errno);
         return -1;
     }
     return _fd;

utils.c

@@ -0,0 +1,75 @@
+#include "utils.h"
+
+#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
+
+/*
+ * Macros
+ */
+#define MAX_CLI_ARGS    (20)
+
+/*
+ * Type definitions
+ */
+typedef struct {
+    const char *key;
+    char *value;
+} cli_arg_t;
+
+/*
+ * Data
+ */
+static cli_arg_t _cli_args[MAX_CLI_ARGS];
+
+/*
+ * Public API
+ */
+void print_usage_text() {
+    printf("ipoim -M <mode> -A <address> -P <port> -C <carrier> ...\n");
+    printf(" --- MANDATORY ARGUMENTS ---\n");
+    printf("    -M <mode>           - operation mode ('provider' or 'last-mile')\n");
+    printf("    -A <address>        - IPv4 to listen on/connect to\n");
+    printf("    -P <port>           - port to listen on/connect to\n");
+    printf("    -E <carrier>        - extension to use, one of:\n");
+    printf("        * pipe          - use STDIN and STDOUT\n");
+    printf(" --- OPTIONAL ARGUMENTS ---\n");
+    printf("    +V                  - be verbose\n");
+}
+
+bool cli_arg_set(const char *key, char *value) {
+    int index_to_use = -1;
+    for (int i = 0; i < MAX_CLI_ARGS; ++i) {
+        // empty entry
+        if (_cli_args[i].key == NULL) {
+            // update index only if no place is found yet
+            if (index_to_use == -1)
+                index_to_use = i;
+        }
+        // entry with the same name
+        else if (!strcmp(_cli_args[i].key, key)) {
+            index_to_use = i;
+            break;
+        }
+    }
+    // no space for the argument
+    if (index_to_use == -1) {
+        return false;
+    }
+    _cli_args[index_to_use].key = key;
+    _cli_args[index_to_use].value = value;
+    return true;
+}
+
+const char *cli_arg_get(const char *key) {
+    for (int i = 0; i < MAX_CLI_ARGS; ++i) {
+        if (_cli_args[i].key == NULL) {
+            continue;
+        }
+        if (strcmp(_cli_args[i].key, key)) {
+            continue;
+        }
+        return _cli_args[i].value;
+    }
+    return NULL;
+}

utils.h

@@ -1,6 +1,29 @@
 #ifndef __UTILS_H
 #define __UTILS_H
 
+#include <stdbool.h>
 
+// Print usage text.
+void print_usage_text();
+
+// Set CLI argument.
+// Parameters:
+//  - key       - argument key (without leading dash)
+//  - value     - argument value as string
+// Returns:
+//  - true on success
+//  - false on failure
+// Remarks:
+//  - neither key nor value are copied, they are saved as pointers
+//  - use this function only with data from argv
+bool cli_arg_set(const char *key, char *value);
+
+// Get CLI argument.
+// Parameters:
+//  - key       - argument key (without leading dash)
+// Returns:
+//  - pointer to the value (not owned by you)
+//  - NULL on failure
+const char *cli_arg_get(const char *key);
 
 #endif