Introduced ssh_timeout_elapsed functions

Functions to mesure elapsed time before and after a serie of
calls. Introduces a dependancy to clock_gettime() and librt,
hope this doesn't break anything. Porting to gettimeofday() should
not be too hard.
(cherry picked from commit 59f7647cd9)

src/client.c

@@ -685,12 +685,16 @@ int ssh_connect(ssh_session session) {
   ssh_log(session,SSH_LOG_PROTOCOL,"Socket connecting, now waiting for the callbacks to work");
 pending:
 	session->pending_call_state=SSH_PENDING_CALL_CONNECT;
-  if(ssh_is_blocking(session)) {
-    int timeout = session->timeout * 1000 + session->timeout_usec;
-	if (timeout <= 0)
-	  timeout = -1;
-    ssh_handle_packets_termination(session,timeout,ssh_connect_termination,session);
-  }
+	if(ssh_is_blocking(session)) {
+	  int timeout = session->timeout * 1000 + session->timeout_usec;
+	  if (timeout <= 0)
+	    timeout = -1;
+	  ssh_handle_packets_termination(session,timeout,ssh_connect_termination,session);
+	  if(!ssh_connect_termination(session)){
+	    ssh_set_error(session,SSH_FATAL,"Timeout connecting to %s",session->host);
+	    session->session_state = SSH_SESSION_STATE_ERROR;
+	  }
+	}
   else
     ssh_handle_packets_termination(session,0,ssh_connect_termination, session);
   ssh_log(session,SSH_LOG_PACKET,"ssh_connect: Actual state : %d",session->session_state);

src/misc.c

@@ -41,6 +41,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <ctype.h>
+#include <time.h>
 
 #ifdef _WIN32
 
@@ -855,6 +856,91 @@ int ssh_analyze_banner(ssh_session session, int server, int *ssh1, int *ssh2) {
   return 0;
 }
 
+/* try the Monotonic clock if possible for perfs reasons */
+#ifdef _POSIX_MONOTONIC_CLOCK
+#define CLOCK CLOCK_MONOTONIC
+#else
+#define CLOCK CLOCK_REALTIME
+#endif
+
+/**
+ * @internal
+ * @brief initializes a timestamp to the current time
+ * @param[out] ts pointer to an allocated ssh_timestamp structure
+ */
+void ssh_timestamp_init(struct ssh_timestamp *ts){
+  struct timespec tp;
+  clock_gettime(CLOCK, &tp);
+  ts->seconds = tp.tv_sec;
+  ts->useconds = tp.tv_nsec / 1000;
+}
+
+/**
+ * @internal
+ * @brief gets the time difference between two timestamps in ms
+ * @param[in] old older value
+ * @param[in] new newer value
+ * @returns difference in milliseconds
+ */
+
+static int ssh_timestamp_difference(struct ssh_timestamp *old,
+    struct ssh_timestamp *new){
+  long seconds, usecs, msecs;
+  seconds = new->seconds - old->seconds;
+  usecs = new->useconds - old->useconds;
+  if (usecs < 0){
+    seconds--;
+    usecs += 1000000;
+  }
+  msecs = seconds * 1000 + usecs/1000;
+  return msecs;
+}
+
+/**
+ * @internal
+ * @brief Checks if a timeout is elapsed, in function of a previous
+ * timestamp and an assigned timeout
+ * @param[in] ts pointer to an existing timestamp
+ * @param[in] timeout timeout in milliseconds. Negative values mean infinite
+ *                   timeout
+ * @returns 1 if timeout is elapsed
+ *          0 otherwise
+ */
+int ssh_timeout_elapsed(struct ssh_timestamp *ts, int timeout) {
+  struct ssh_timestamp now;
+  if(timeout < 0)
+    return 0; // -1 means infinite timeout
+  if(timeout == 0)
+    return 1; // 0 means no timeout
+  ssh_timestamp_init(&now);
+
+  if(ssh_timestamp_difference(ts,&now) >= timeout)
+    return 1;
+  else
+    return 0;
+}
+
+/**
+ * @brief updates a timeout value so it reflects the remaining time
+ * @param[in] ts pointer to an existing timestamp
+ * @param[in] timeout timeout in milliseconds. Negative values mean infinite
+ *             timeout
+ * @returns   remaining time in milliseconds, 0 if elapsed, -1 if never.
+ */
+int ssh_timeout_update(struct ssh_timestamp *ts, int timeout){
+  struct ssh_timestamp now;
+  int ms, ret;
+  if(timeout == 0)
+    return 0;
+  if(timeout==-1)
+    return -1;
+  ssh_timestamp_init(&now);
+  ms = ssh_timestamp_difference(ts,&now);
+  if(ms < 0)
+    ms = 0;
+  ret = timeout - ms;
+  return ret >= 0 ? ret: 0;
+}
 /** @} */
 
 /* vim: set ts=4 sw=4 et cindent: */

src/poll.c

@@ -585,6 +585,7 @@ void ssh_poll_ctx_remove(ssh_poll_ctx ctx, ssh_poll_handle p) {
  *                      the poll() function.
  * @returns SSH_OK      No error.
  *          SSH_ERROR   Error happened during the poll.
+ *          SSH_AGAIN   Timeout occured
  */
 
 int ssh_poll_ctx_dopoll(ssh_poll_ctx ctx, int timeout) {
@@ -598,8 +599,10 @@ int ssh_poll_ctx_dopoll(ssh_poll_ctx ctx, int timeout) {
     return 0;
 
   rc = ssh_poll(ctx->pollfds, ctx->polls_used, timeout);
-  if(rc <= 0)
+  if(rc < 0)
     return SSH_ERROR;
+  if (rc == 0)
+    return SSH_AGAIN;
   used = ctx->polls_used;
   for (i = 0; i < used && rc > 0; ) {
     if (!ctx->pollfds[i].revents) {

src/session.c

@@ -304,18 +304,27 @@ int ssh_is_blocking(ssh_session session){
  *                    will block, in milliseconds. Specifying a negative value
  *                    means an infinite timeout. This parameter is passed to
  *                    the poll() function.
- * @returns           SSH_OK on success, SSH_ERROR otherwise.
+ * @returns           SSH_OK on success, SSH_AGAIN if timeout occurred,
+ *                    SSH_ERROR otherwise.
  */
 
 int ssh_blocking_flush(ssh_session session, int timeout){
 	ssh_socket s;
+	struct ssh_timestamp ts;
+	int rc;
 	if(session==NULL)
 		return SSH_ERROR;
 
 	enter_function();
 	s=session->socket;
+	ssh_timestamp_init(&ts);
 	while (ssh_socket_buffered_write_bytes(s) > 0 && session->alive) {
-		ssh_handle_packets(session, timeout);
+		rc=ssh_handle_packets(session, timeout);
+		if(ssh_timeout_elapsed(&ts,timeout)){
+		  rc=SSH_AGAIN;
+		  break;
+		}
+		timeout = ssh_timeout_update(&ts, timeout);
 	}
 
 	leave_function();
@@ -415,6 +424,7 @@ void ssh_set_fd_except(ssh_session session) {
 int ssh_handle_packets(ssh_session session, int timeout) {
 	ssh_poll_handle spoll_in,spoll_out;
 	ssh_poll_ctx ctx;
+	int rc;
   if(session==NULL || session->socket==NULL)
   	return SSH_ERROR;
   enter_function();
@@ -429,7 +439,8 @@ int ssh_handle_packets(ssh_session session, int timeout) {
   	if(spoll_in != spoll_out)
   	  ssh_poll_ctx_add(ctx,spoll_out);
   }
-  if( ssh_poll_ctx_dopoll(ctx,timeout) )
+  rc = ssh_poll_ctx_dopoll(ctx,timeout);
+  if(rc == SSH_ERROR)
     session->session_state = SSH_SESSION_STATE_ERROR;
   leave_function();
   if (session->session_state != SSH_SESSION_STATE_ERROR)
@@ -460,17 +471,19 @@ int ssh_handle_packets(ssh_session session, int timeout) {
 int ssh_handle_packets_termination(ssh_session session, int timeout,
     ssh_termination_function fct, void *user){
   int ret = SSH_ERROR;
+  struct ssh_timestamp ts;
+  ssh_timestamp_init(&ts);
+
   while(!fct(user)){
     ret = ssh_handle_packets(session, timeout);
     if(ret == SSH_ERROR)
       return SSH_ERROR;
-    if(timeout == 0){
-      if(fct(user))
-        return SSH_OK;
-      else
-        return SSH_AGAIN;
+    if(fct(user)) {
+      return SSH_OK;
+    } else if (ssh_timeout_elapsed(&ts, timeout)) {
+      return SSH_AGAIN;
     }
-    /* TODO: verify that total timeout has not expired and then return SSH_AGAIN */
+    timeout = ssh_timeout_update(&ts,timeout);
   }
   return ret;
 }