Initial commit

- basic main.c implementation
- event_loop implementation

.gitignore

@@ -0,0 +1,3 @@
+*.swp
+*.swo
+build/

build.sh

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+#!/usr/bin/bash
+
+# check if build directory exists
+if [ -d build ]; then
+    echo "[I] build/ directory exists, deleting..."
+    rm -rf build
+fi
+# create build/ directory
+mkdir build
+
+# build
+echo "[I] Building ipoim..."
+gcc *.c $(curl-config --cflags) $(curl-config --libs) -I. -o build/ipoim

event_loop.c

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+#include "event_loop.h"
+
+#include <stdio.h>
+
+#include <errno.h>
+#include <sys/epoll.h>
+
+/*
+ * Macros
+ */
+#define MAX_EPOLL_EVENTS        (20)
+
+/*
+ * Data
+ */
+static int _efd = -1;
+static loop_cb_t _cb = NULL;
+static struct epoll_event _evs[MAX_EPOLL_EVENTS];
+
+/*
+ * Public API
+ */
+bool loop_init(loop_cb_t callback) {
+    _efd = epoll_create1(0);
+    if (_efd == -1) {
+        printf("[!] epoll_create1 failed: %d\n", errno);
+        return false;
+    }
+    _cb = callback;
+    return true;
+}
+
+void loop_deinit() {
+    close(_efd);
+}
+
+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);
+        return false;
+    }
+    return true;
+}
+
+bool loop_wait() {
+    int result = epoll_wait(
+        _efd,
+        _evs,
+        MAX_EPOLL_EVENTS,
+        -1
+    );
+    if (result < 0) {
+        printf("[!] epoll_wait failed: %d\n", errno);
+        return false;
+    }
+    if (!result) {
+        return true;
+    }
+    for (int i = 0; i < result; ++i) {
+        _cb(_evs[i].data.fd, _evs[i].events);
+    }
+    return true;
+}

event_loop.h

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+#ifndef __EVENT_LOOP_H
+#define __EVENT_LOOP_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <sys/epoll.h>
+#include <unistd.h>
+
+/*
+ * Type definitions
+ */
+typedef void (*loop_cb_t)(int fd, uint32_t events);
+
+/*
+ * Public API
+ */
+// Initialize the event loop.
+// Parameters:
+//  - callback  - callback to use in loop_wait
+// Returns:
+//  - true on success
+//  - false on failure
+// Remarks:
+//  - must be called before event loop is used
+bool loop_init(loop_cb_t callback);
+
+// Finalize the event loop.
+//  - must be called on app termination
+void loop_deinit();
+
+// Set callback for file descriptor event.
+// Remarks:
+//  - this callback gets called in loop_wait
+void loop_set_callback(loop_cb_t callback);
+
+// Call epoll_ctl.
+// Parameters:
+//  - op        - op
+//  - fd        - fd
+//  - event     - event
+// Returns:
+//  - true on success
+//  - false on failure
+// Remarks:
+//  - just calls epoll_ctl
+bool loop_ctl(int op, int fd, struct epoll_event *event);
+
+// Call epoll_wait and process the events.
+// Returns:
+//  - true on success
+//  - false on failure
+// Remarks:
+//  - you should terminate the app if this function
+//    fails
+bool loop_wait();
+
+
+#endif

main.c

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+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/epoll.h>
+#include <sys/signalfd.h>
+
+#include "event_loop.h"
+
+/*
+ * Data
+ */
+static bool _to_work = true;
+static int _sig_fd = -1;
+
+/*
+ * Private API
+ */
+// Initialize signals.
+// Returns:
+//  - true on success
+// Remarks:
+//  - loop_init() must be called before this one
+static bool signals_init() {
+    sigset_t mask;
+    sigemptyset(&mask);
+    sigaddset(&mask, SIGTERM);
+    sigaddset(&mask, SIGINT);
+    sigaddset(&mask, SIGQUIT);
+    if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) {
+        printf("[!] sigprocmask failed: %d\n", errno);
+        return false;
+    }
+    _sig_fd = signalfd(
+        -1,
+        &mask,
+        SFD_NONBLOCK
+    );
+    if (_sig_fd == -1) {
+        printf("[!] signalfd failed: %d\n", errno);
+        return false;
+    }
+    struct epoll_event ev;
+    ev.data.fd = _sig_fd;
+    ev.events = EPOLLIN;
+    bool loop_res = loop_ctl(
+        EPOLL_CTL_ADD,
+        _sig_fd,
+        &ev
+    );
+    if (!loop_res) {
+        close(_sig_fd);
+        printf("[!] loop_ctl failed\n");
+        return false;
+    }
+    return true;
+}
+
+static void signals_deinit() {
+    close(_sig_fd);
+}
+
+/*
+ * Callbacks and main
+ */
+// This callback is called by loop_wait when event happens.
+static void on_fd_event(int fd, uint32_t events) {
+    // Termination
+    if (fd == _sig_fd) {
+        _to_work = false;
+    }
+    else {
+        printf("[!] Event has happened on an unknown file descriptor\n");
+    }
+}
+
+int main(int argc, char **argv) {
+    if (!loop_init(on_fd_event)) {
+        return 1;
+    }
+    if (!signals_init()) {
+        loop_deinit();
+        return 1;
+    }
+
+    while (_to_work) {
+        if (!loop_wait()) {
+            printf("[!] loop_wait returns false, stopping...\n");
+            break;
+        }
+        printf("--- loop ---\n");
+    }
+    
+    signals_deinit();
+    loop_deinit();
+    return 0;
+}

utils.h

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+#ifndef __UTILS_H
+#define __UTILS_H
+
+
+
+#endif