--- /dev/null
+/*
+ * Example debug transport using a Linux/Unix TCP socket
+ *
+ * Provides a TCP server socket which a debug client can connect to.
+ * After that data is just passed through.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <poll.h>
+#include <errno.h>
+#include "duktape.h"
+
+#if !defined(DUK_DEBUG_PORT)
+#define DUK_DEBUG_PORT 9091
+#endif
+
+#if 0
+#define DEBUG_PRINTS
+#endif
+
+static int server_sock = -1;
+static int client_sock = -1;
+
+/*
+ * Transport init and finish
+ */
+
+void duk_trans_socket_init(void) {
+ struct sockaddr_in addr;
+ int on;
+
+ server_sock = socket(AF_INET, SOCK_STREAM, 0);
+ if (server_sock < 0) {
+ fprintf(stderr, "%s: failed to create server socket: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ }
+
+ on = 1;
+ if (setsockopt(server_sock, SOL_SOCKET, SO_REUSEADDR, (const char *) &on, sizeof(on)) < 0) {
+ fprintf(stderr, "%s: failed to set SO_REUSEADDR for server socket: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ }
+
+ memset((void *) &addr, 0, sizeof(addr));
+ addr.sin_family = AF_INET;
+ addr.sin_addr.s_addr = INADDR_ANY;
+ addr.sin_port = htons(DUK_DEBUG_PORT);
+
+ if (bind(server_sock, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+ fprintf(stderr, "%s: failed to bind server socket: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ }
+
+ listen(server_sock, 1 /*backlog*/);
+ return;
+
+ fail:
+ if (server_sock >= 0) {
+ (void) close(server_sock);
+ server_sock = -1;
+ }
+}
+
+void duk_trans_socket_finish(void) {
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+ if (server_sock >= 0) {
+ (void) close(server_sock);
+ server_sock = -1;
+ }
+}
+
+void duk_trans_socket_waitconn(void) {
+ struct sockaddr_in addr;
+ socklen_t sz;
+
+ if (server_sock < 0) {
+ fprintf(stderr, "%s: no server socket, skip waiting for connection\n",
+ __FILE__);
+ fflush(stderr);
+ return;
+ }
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+
+ fprintf(stderr, "Waiting for debug connection on port %d\n", (int) DUK_DEBUG_PORT);
+ fflush(stderr);
+
+ sz = (socklen_t) sizeof(addr);
+ client_sock = accept(server_sock, (struct sockaddr *) &addr, &sz);
+ if (client_sock < 0) {
+ fprintf(stderr, "%s: accept() failed, skip waiting for connection: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ }
+
+ fprintf(stderr, "Debug connection established\n");
+ fflush(stderr);
+
+ /* XXX: For now, close the listen socket because we won't accept new
+ * connections anyway. A better implementation would allow multiple
+ * debug attaches.
+ */
+
+ if (server_sock >= 0) {
+ (void) close(server_sock);
+ server_sock = -1;
+ }
+ return;
+
+ fail:
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+}
+
+/*
+ * Duktape callbacks
+ */
+
+/* Duktape debug transport callback: (possibly partial) read. */
+duk_size_t duk_trans_socket_read_cb(void *udata, char *buffer, duk_size_t length) {
+ ssize_t ret;
+
+ (void) udata; /* not needed by the example */
+
+#if defined(DEBUG_PRINTS)
+ fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
+ __func__, (void *) udata, (void *) buffer, (long) length);
+ fflush(stderr);
+#endif
+
+ if (client_sock < 0) {
+ return 0;
+ }
+
+ if (length == 0) {
+ /* This shouldn't happen. */
+ fprintf(stderr, "%s: read request length == 0, closing connection\n",
+ __FILE__);
+ fflush(stderr);
+ goto fail;
+ }
+
+ if (buffer == NULL) {
+ /* This shouldn't happen. */
+ fprintf(stderr, "%s: read request buffer == NULL, closing connection\n",
+ __FILE__);
+ fflush(stderr);
+ goto fail;
+ }
+
+ /* In a production quality implementation there would be a sanity
+ * timeout here to recover from "black hole" disconnects.
+ */
+
+ ret = read(client_sock, (void *) buffer, (size_t) length);
+ if (ret < 0) {
+ fprintf(stderr, "%s: debug read failed, closing connection: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ } else if (ret == 0) {
+ fprintf(stderr, "%s: debug read failed, ret == 0 (EOF), closing connection\n",
+ __FILE__);
+ fflush(stderr);
+ goto fail;
+ } else if (ret > (ssize_t) length) {
+ fprintf(stderr, "%s: debug read failed, ret too large (%ld > %ld), closing connection\n",
+ __FILE__, (long) ret, (long) length);
+ fflush(stderr);
+ goto fail;
+ }
+
+ return (duk_size_t) ret;
+
+ fail:
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+ return 0;
+}
+
+/* Duktape debug transport callback: (possibly partial) write. */
+duk_size_t duk_trans_socket_write_cb(void *udata, const char *buffer, duk_size_t length) {
+ ssize_t ret;
+
+ (void) udata; /* not needed by the example */
+
+#if defined(DEBUG_PRINTS)
+ fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
+ __func__, (void *) udata, (const void *) buffer, (long) length);
+ fflush(stderr);
+#endif
+
+ if (client_sock < 0) {
+ return 0;
+ }
+
+ if (length == 0) {
+ /* This shouldn't happen. */
+ fprintf(stderr, "%s: write request length == 0, closing connection\n",
+ __FILE__);
+ fflush(stderr);
+ goto fail;
+ }
+
+ if (buffer == NULL) {
+ /* This shouldn't happen. */
+ fprintf(stderr, "%s: write request buffer == NULL, closing connection\n",
+ __FILE__);
+ fflush(stderr);
+ goto fail;
+ }
+
+ /* In a production quality implementation there would be a sanity
+ * timeout here to recover from "black hole" disconnects.
+ */
+
+ ret = write(client_sock, (const void *) buffer, (size_t) length);
+ if (ret <= 0 || ret > (ssize_t) length) {
+ fprintf(stderr, "%s: debug write failed, closing connection: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail;
+ }
+
+ return (duk_size_t) ret;
+
+ fail:
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+ return 0;
+}
+
+duk_size_t duk_trans_socket_peek_cb(void *udata) {
+ struct pollfd fds[1];
+ int poll_rc;
+
+ (void) udata; /* not needed by the example */
+
+#if defined(DEBUG_PRINTS)
+ fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
+ fflush(stderr);
+#endif
+
+ if (client_sock < 0) {
+ return 0;
+ }
+
+ fds[0].fd = client_sock;
+ fds[0].events = POLLIN;
+ fds[0].revents = 0;
+
+ poll_rc = poll(fds, 1, 0);
+ if (poll_rc < 0) {
+ fprintf(stderr, "%s: poll returned < 0, closing connection: %s\n",
+ __FILE__, strerror(errno));
+ fflush(stderr);
+ goto fail; /* also returns 0, which is correct */
+ } else if (poll_rc > 1) {
+ fprintf(stderr, "%s: poll returned > 1, treating like 1\n",
+ __FILE__);
+ fflush(stderr);
+ return 1; /* should never happen */
+ } else if (poll_rc == 0) {
+ return 0; /* nothing to read */
+ } else {
+ return 1; /* something to read */
+ }
+
+ fail:
+ if (client_sock >= 0) {
+ (void) close(client_sock);
+ client_sock = -1;
+ }
+ return 0;
+}
+
+void duk_trans_socket_read_flush_cb(void *udata) {
+ (void) udata; /* not needed by the example */
+
+#if defined(DEBUG_PRINTS)
+ fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
+ fflush(stderr);
+#endif
+
+ /* Read flush: Duktape may not be making any more read calls at this
+ * time. If the transport maintains a receive window, it can use a
+ * read flush as a signal to update the window status to the remote
+ * peer. A read flush is guaranteed to occur before Duktape stops
+ * reading for a while; it may occur in other situations as well so
+ * it's not a 100% reliable indication.
+ */
+
+ /* This TCP transport requires no read flush handling so ignore.
+ * You can also pass a NULL to duk_debugger_attach() and not
+ * implement this callback at all.
+ */
+}
+
+void duk_trans_socket_write_flush_cb(void *udata) {
+ (void) udata; /* not needed by the example */
+
+#if defined(DEBUG_PRINTS)
+ fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
+ fflush(stderr);
+#endif
+
+ /* Write flush. If the transport combines multiple writes
+ * before actually sending, a write flush is an indication
+ * to write out any pending bytes: Duktape may not be doing
+ * any more writes on this occasion.
+ */
+
+ /* This TCP transport requires no write flush handling so ignore.
+ * You can also pass a NULL to duk_debugger_attach() and not
+ * implement this callback at all.
+ */
+ return;
+}
projects / ceph.git / blobdiff