reterVision · September 1, 2025 00:25 · Jan 7, 2014 · Jan 7, 2014
diff --git a/epoll_sample.c b/epoll_sample.c
@@ -1 +1,249 @@
-test
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/epoll.h>
+#include <errno.h>
+
+#define MAXEVENTS 64
+
+static int make_socket_non_blocking(int sfd)
+{
+    int flags, s;
+
+    flags = fcntl(sfd, F_GETFL, 0);
+    if(flags == -1)
+    {
+        perror("fcntl");
+        return -1;
+    }
+
+    flags |= O_NONBLOCK;
+    s = fcntl(sfd, F_SETFL, flags);
+    if(s == -1)
+    {
+        perror("fcntl");
+        return -1;
+    }
+
+    return 0;
+}
+
+static int create_and_bind(char *port)
+{
+    struct addrinfo hints;
+    struct addrinfo *result, *rp;
+    int s, sfd;
+
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = AI_PASSIVE;
+
+    s = getaddrinfo(NULL, port, &hints, &result);
+    if(s != 0)
+    {
+        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(s));
+        return -1;
+    }
+
+    for(rp=result;rp!=NULL;rp=rp->ai_next)
+    {
+        sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if(sfd == -1)
+        {
+            continue;
+        }
+
+        s = bind(sfd, rp->ai_addr, rp->ai_addrlen);
+        if(s == 0)
+        {
+            break;
+        }
+
+        close(sfd);
+    }
+
+    if(rp == NULL)
+    {
+        fprintf(stderr, "Could not bind\n");
+        return -1;
+    }
+
+    freeaddrinfo(result);
+    return sfd;
+}
+
+int main(int argc, char *argv[])
+{
+    int sfd, s;
+    int efd;
+    struct epoll_event event;
+    struct epoll_event *events;
+
+    if(argc != 2)
+    {
+        fprintf(stderr, "Usage: %s [port]\n", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+
+    sfd = create_and_bind(argv[1]);
+    if(sfd == -1)
+        abort();
+
+    s = make_socket_non_blocking(sfd);
+    if(s == -1)
+        abort();
+
+    s = listen(sfd, SOMAXCONN);
+    if(s == -1)
+    {
+        perror("listen");
+        abort();
+    }
+
+    efd = epoll_create1(0);
+    if(efd == -1)
+    {
+        perror("epoll_create");
+        abort();
+    }
+
+    event.data.fd = sfd;
+    event.events = EPOLLIN | EPOLLET;
+    s = epoll_ctl(efd, EPOLL_CTL_ADD, sfd, &event);
+    if(s == -1)
+    {
+        perror("epoll_ctl");
+        abort();
+    }
+
+    /* Buffer where events are returned */
+    events = calloc(MAXEVENTS, sizeof(event));
+
+    /* event loop */
+    while(1)
+    {
+        int n, i;
+
+        fprintf(stdout, "Blocking and waiting for epoll event...\n");
+        n = epoll_wait(efd, events, MAXEVENTS, -1);
+        fprintf(stdout, "Received epoll event\n");
+        for(i=0; i<n; i++)
+        {
+            if((events[i].events & EPOLLERR) ||
+               (events[i].events & EPOLLHUP) ||
+               (!(events[i].events & EPOLLIN)))
+            {
+                fprintf(stderr, "epoll error\n");
+                close(events[i].data.fd);
+                continue;
+            }
+            else if(sfd == events[i].data.fd)
+            {
+                while(1)
+                {
+                    struct sockaddr in_addr;
+                    socklen_t in_len;
+                    int infd;
+                    char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
+
+                    in_len = sizeof(in_addr);
+                    infd = accept(sfd, &in_addr, &in_len);
+                    if(infd == -1)
+                    {
+                        if((errno == EAGAIN) ||
+                           (errno == EWOULDBLOCK))
+                        {
+                            break;
+                        }
+                        else
+                        {
+                            perror("accept");
+                            break;
+                        }
+                    }
+                    s = getnameinfo(&in_addr, in_len,
+                                    hbuf, sizeof(hbuf),
+                                    sbuf, sizeof(sbuf),
+                                    NI_NUMERICHOST | NI_NUMERICSERV);
+                    if(s == 0)
+                    {
+                        printf("Accepted connection on descriptor %d"
+                              "(host=%s, port=%s)\n", infd, hbuf, sbuf);
+                    }
+
+                    s = make_socket_non_blocking(infd);
+                    if(s == -1)
+                        abort();
+
+                    event.data.fd = infd;
+                    event.events = EPOLLIN | EPOLLET;
+                    s = epoll_ctl(efd, EPOLL_CTL_ADD, infd, &event);
+                    if(s == -1)
+                    {
+                        perror("epoll_ctl");
+                        abort();
+                    }
+                }
+                continue;
+            }
+            else
+            {
+                int done = 0;
+
+                while(1)
+                {
+                    ssize_t count;
+                    char buf[512];
+
+                    count = read(events[i].data.fd, buf, sizeof(buf));
+                    if(count == -1)
+                    {
+                        if(errno != EAGAIN)
+                        {
+                            perror("read");
+                            done =1;
+                        }
+                        break;
+                    }
+                    else if(count == 0)
+                    {
+                        done = 1;
+                        break;
+                    }
+
+                    buf[count] = '\n';
+                    s = write(1, buf, count+1);
+                    if(s == -1)
+                    {
+                        perror("write");
+                        abort();
+                    }
+
+                    s = write(events[i].data.fd, buf, count+1);
+                    if(s == -1)
+                    {
+                        perror("socket write");
+                        abort();
+                    }
+                }
+                if(done)
+                {
+                    printf("Closed connection on descriptor %d\n",
+                           events[i].data.fd);
+                    close(events[i].data.fd);
+                }
+            }
+        }
+    }
+
+    free(events);
+    close(sfd);
+
+    return EXIT_SUCCESS;
+}
diff --git a/epoll_sample.c b/epoll_sample.c
@@ -0,0 +1 @@
+test