Get the maximum TCP timeout in sessiond

[lttng-tools.git] / src / common / sessiond-comm / inet.c

diff --git a/src/common/sessiond-comm/inet.c b/src/common/sessiond-comm/inet.c
index eb0c4fde3f6972de1d846020f10aa58a0deaad35..b5a016e6f54fd46e3eb297b02c94c192cefe995a 100644 (file)
--- a/src/common/sessiond-comm/inet.c
+++ b/src/common/sessiond-comm/inet.c
@@ -50,6 +50,8 @@ static const struct lttcomm_proto_ops inet_ops = {
        .sendmsg = lttcomm_sendmsg_inet_sock,
 };
 
+unsigned long lttcomm_inet_tcp_timeout;
+
 /*
  * Creates an PF_INET socket.
  */
@@ -448,3 +450,68 @@ int lttcomm_close_inet_sock(struct lttcomm_sock *sock)
 
        return ret;
 }
+
+/*
+ * Return value read from /proc or else 0 if value is not found.
+ */
+static unsigned long read_proc_value(const char *path)
+{
+       int ret, fd;
+       long r_val;
+       unsigned long val = 0;
+       char buf[64];
+
+       fd = open(path, O_RDONLY);
+       if (fd < 0) {
+               goto error;
+       }
+
+       ret = read(fd, buf, sizeof(buf));
+       if (ret < 0) {
+               PERROR("read proc failed");
+               goto error_close;
+       }
+
+       errno = 0;
+       r_val = strtol(buf, NULL, 10);
+       if (errno != 0 || r_val < -1L) {
+               val = 0;
+               goto error_close;
+       } else {
+               if (r_val > 0) {
+                       val = r_val;
+               }
+       }
+
+error_close:
+       ret = close(fd);
+       if (ret) {
+               PERROR("close /proc value");
+       }
+error:
+       return val;
+}
+
+LTTNG_HIDDEN
+void lttcomm_inet_init(void)
+{
+       unsigned long syn_retries, fin_timeout, syn_timeout;
+
+       /* Assign default value and see if we can change it. */
+       lttcomm_inet_tcp_timeout = DEFAULT_INET_TCP_TIMEOUT;
+
+       syn_retries = read_proc_value(LTTCOMM_INET_PROC_SYN_RETRIES_PATH);
+       fin_timeout = read_proc_value(LTTCOMM_INET_PROC_FIN_TIMEOUT_PATH);
+
+       syn_timeout = syn_retries * LTTCOMM_INET_SYN_TIMEOUT_FACTOR;
+
+       /*
+        * Get the maximum between the two possible timeout value and use that to
+        * get the maximum with the default timeout.
+        */
+       lttcomm_inet_tcp_timeout = max_t(unsigned long,
+                       max_t(unsigned long, syn_timeout, fin_timeout),
+                       lttcomm_inet_tcp_timeout);
+
+       DBG("TCP inet operation timeout set to %lu sec", lttcomm_inet_tcp_timeout);
+}