Fix handling of sessiond respawn after a SIGKILL
[lttng-tools.git] / liblttsessiondcomm / liblttsessiondcomm.c
index a5b3818c42b4e8d80facf287b149c54fc07fbd99..e7e4204339d61dc0b1daa97cdadd3b1c6fd8033c 100644 (file)
@@ -3,8 +3,8 @@
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
+ * as published by the Free Software Foundation; only version 2
+ * of the License.
  * 
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -26,6 +26,7 @@
 #include <sys/types.h>
 #include <sys/un.h>
 #include <unistd.h>
+#include <assert.h>
 
 #include "liblttsessiondcomm.h"
 
@@ -36,10 +37,12 @@ static const char *lttcomm_readable_code[] = {
        [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
-       [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESS) ] = "No session found",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_FAIL) ] = "Create trace failed",
@@ -48,6 +51,25 @@ static const char *lttcomm_readable_code[] = {
        [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
        [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_COMMAND_SOCK_READY) ] = "Kconsumerd command socket ready",
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_SUCCESS_RECV_FD) ] = "Kconsumerd success on receiving fds",
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_ERROR_RECV_FD) ] = "Kconsumerd error on receiving fds",
@@ -57,7 +79,11 @@ static const char *lttcomm_readable_code[] = {
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_SUCCESS) ] = "Kconsumerd exiting normally",
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_EXIT_FAILURE) ] = "Kconsumerd exiting on error",
        [ LTTCOMM_ERR_INDEX(KCONSUMERD_OUTFD_ERROR) ] = "Kconsumerd error opening the tracefile",
-       [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "No event found",
+       [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EBADF) ] = "Kconsumerd splice EBADF",
+       [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_EINVAL) ] = "Kconsumerd splice EINVAL",
+       [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ENOMEM) ] = "Kconsumerd splice ENOMEM",
+       [ LTTCOMM_ERR_INDEX(KCONSUMERD_SPLICE_ESPIPE) ] = "Kconsumerd splice ESPIPE",
+       [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 };
 
 /*
@@ -160,6 +186,8 @@ int lttcomm_create_unix_sock(const char *pathname)
        sun.sun_family = AF_UNIX;
        strncpy(sun.sun_path, pathname, strlen(pathname));
 
+       /* Unlink the old file if present */
+       (void) unlink(pathname);
        ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
        if (ret < 0) {
                perror("bind");
@@ -198,12 +226,10 @@ int lttcomm_listen_unix_sock(int sock)
  */
 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 {
-       struct msghdr msg;
+       struct msghdr msg = { 0 };
        struct iovec iov[1];
        ssize_t ret = -1;
 
-       memset(&msg, 0, sizeof(msg));
-
        iov[0].iov_base = buf;
        iov[0].iov_len = len;
        msg.msg_iov = iov;
@@ -225,12 +251,10 @@ ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
  */
 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 {
-       struct msghdr msg;
+       struct msghdr msg = { 0 };
        struct iovec iov[1];
        ssize_t ret = -1;
 
-       memset(&msg, 0, sizeof(msg));
-
        iov[0].iov_base = buf;
        iov[0].iov_len = len;
        msg.msg_iov = iov;
@@ -261,3 +285,47 @@ int lttcomm_close_unix_sock(int sock)
 
        return ret;
 }
+
+/*
+ *  lttcomm_send_fds_unix_sock
+ *
+ *  Send multiple fds on a unix socket.
+ */
+ssize_t lttcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
+{
+       struct msghdr msg = { 0 };
+       struct cmsghdr *cmptr;
+       struct iovec iov[1];
+       ssize_t ret = -1;
+       unsigned int sizeof_fds = nb_fd * sizeof(int);
+       char tmp[CMSG_SPACE(sizeof_fds)];
+
+       /*
+        * Note: the consumerd receiver only supports receiving one FD per
+        * message.
+        */
+       assert(nb_fd == 1);
+
+       msg.msg_control = (caddr_t)tmp;
+       msg.msg_controllen = CMSG_LEN(sizeof_fds);
+
+       cmptr = CMSG_FIRSTHDR(&msg);
+       cmptr->cmsg_level = SOL_SOCKET;
+       cmptr->cmsg_type = SCM_RIGHTS;
+       cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
+       memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
+       /* Sum of the length of all control messages in the buffer: */
+       msg.msg_controllen = cmptr->cmsg_len;
+
+       iov[0].iov_base = buf;
+       iov[0].iov_len = len;
+       msg.msg_iov = iov;
+       msg.msg_iovlen = 1;
+
+       ret = sendmsg(sock, &msg, 0);
+       if (ret < 0) {
+               perror("sendmsg");
+       }
+
+       return ret;
+}
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