kconsumerd: fix strict aliasing
[lttng-tools.git] / liblttngkconsumerd / lttngkconsumerd.c
index 69ef9a0e8b65173e9d6544bea875e6a9b6e9753c..1893e0ae66a2f110150b7e6aa219d32771c0b0c6 100644 (file)
@@ -18,6 +18,7 @@
  */
 
 #define _GNU_SOURCE
+#include <assert.h>
 #include <fcntl.h>
 #include <poll.h>
 #include <pthread.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>
-#include <urcu/list.h>
 
+#include <lttng-kernel-ctl.h>
+#include <lttng-sessiond-comm.h>
 #include <lttng/lttng-kconsumerd.h>
-
-#include "kernelctl.h"
-#include "lttngerr.h"
-#include "lttng-sessiond-comm.h"
+#include <lttngerr.h>
 
 static struct lttng_kconsumerd_global_data {
        /*
@@ -125,22 +124,21 @@ static void kconsumerd_del_fd(struct lttng_kconsumerd_fd *lcf)
 }
 
 /*
- * Add a fd to the global list protected by a mutex.
+ * Create a struct lttcomm_kconsumerd_msg from the
+ * information received on the receiving socket
  */
-static int kconsumerd_add_fd(struct lttcomm_kconsumerd_msg *buf,
+struct lttng_kconsumerd_fd *kconsumerd_allocate_fd(
+               struct lttcomm_kconsumerd_msg *buf,
                int consumerd_fd)
 {
        struct lttng_kconsumerd_fd *tmp_fd;
-       int ret = 0;
 
-       pthread_mutex_lock(&kconsumerd_data.lock);
-       /* Check if already exist */
-       ret = kconsumerd_find_session_fd(buf->fd);
-       if (ret == 1) {
+       tmp_fd = malloc(sizeof(struct lttng_kconsumerd_fd));
+       if (tmp_fd == NULL) {
+               perror("malloc struct lttng_kconsumerd_fd");
                goto end;
        }
 
-       tmp_fd = malloc(sizeof(struct lttng_kconsumerd_fd));
        tmp_fd->sessiond_fd = buf->fd;
        tmp_fd->consumerd_fd = consumerd_fd;
        tmp_fd->state = buf->state;
@@ -152,42 +150,31 @@ static int kconsumerd_add_fd(struct lttcomm_kconsumerd_msg *buf,
        tmp_fd->output = buf->output;
        strncpy(tmp_fd->path_name, buf->path_name, PATH_MAX);
        tmp_fd->path_name[PATH_MAX - 1] = '\0';
+       DBG("Allocated %s (sessiond_fd %d, consumerd_fd %d, out_fd %d)",
+                       tmp_fd->path_name, tmp_fd->sessiond_fd,
+                       tmp_fd->consumerd_fd, tmp_fd->out_fd);
 
-       /* Opening the tracefile in write mode */
-       if (tmp_fd->path_name != NULL) {
-               ret = open(tmp_fd->path_name,
-                               O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU|S_IRWXG|S_IRWXO);
-               if (ret < 0) {
-                       ERR("Opening %s", tmp_fd->path_name);
-                       perror("open");
-                       goto end;
-               }
-               tmp_fd->out_fd = ret;
-               DBG("Adding %s (%d, %d, %d)", tmp_fd->path_name,
-                               tmp_fd->sessiond_fd, tmp_fd->consumerd_fd, tmp_fd->out_fd);
-       }
+end:
+       return tmp_fd;
+}
 
-       if (tmp_fd->output == LTTNG_EVENT_MMAP) {
-               /* get the len of the mmap region */
-               ret = kernctl_get_mmap_len(tmp_fd->consumerd_fd, &tmp_fd->mmap_len);
-               if (ret != 0) {
-                       ret = errno;
-                       perror("kernctl_get_mmap_len");
-                       goto end;
-               }
+/*
+ * Add a fd to the global list protected by a mutex.
+ */
+static int kconsumerd_add_fd(struct lttng_kconsumerd_fd *tmp_fd)
+{
+       int ret;
 
-               tmp_fd->mmap_base = mmap(NULL, tmp_fd->mmap_len,
-                               PROT_READ, MAP_PRIVATE, tmp_fd->consumerd_fd, 0);
-               if (tmp_fd->mmap_base == MAP_FAILED) {
-                       perror("Error mmaping");
-                       ret = -1;
-                       goto end;
-               }
+       pthread_mutex_lock(&kconsumerd_data.lock);
+       /* Check if already exist */
+       ret = kconsumerd_find_session_fd(tmp_fd->sessiond_fd);
+       if (ret == 1) {
+               goto end;
        }
-
        cds_list_add(&tmp_fd->list, &kconsumerd_data.fd_list.head);
        kconsumerd_data.fds_count++;
        kconsumerd_data.need_update = 1;
+
 end:
        pthread_mutex_unlock(&kconsumerd_data.lock);
        return ret;
@@ -258,11 +245,16 @@ static int kconsumerd_consumerd_recv_fd(
                enum lttng_kconsumerd_command cmd_type)
 {
        struct iovec iov[1];
-       int ret = 0, i, tmp2;
+       int ret = 0, i, j, tmp2;
        struct cmsghdr *cmsg;
        int nb_fd;
        char recv_fd[CMSG_SPACE(sizeof(int))];
        struct lttcomm_kconsumerd_msg lkm;
+       struct lttng_kconsumerd_fd *new_fd;
+       union {
+               unsigned char vc[4];
+               int vi;
+       } tmp;
 
        /* the number of fds we are about to receive */
        nb_fd = size / sizeof(struct lttcomm_kconsumerd_msg);
@@ -310,17 +302,37 @@ static int kconsumerd_consumerd_recv_fd(
                if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
                        switch (cmd_type) {
                                case ADD_STREAM:
-                                       DBG("kconsumerd_add_fd %s (%d)", lkm.path_name,
-                                                       ((int *) CMSG_DATA(cmsg))[0]);
-
-                                       ret = kconsumerd_add_fd(&lkm, ((int *) CMSG_DATA(cmsg))[0]);
-                                       if (ret < 0) {
+                                       for (j = 0; j < sizeof(int); j++)
+                                               tmp.vc[j] = CMSG_DATA(cmsg)[j];
+                                       DBG("kconsumerd_add_fd %s (%d)", lkm.path_name, tmp.vi);
+                                       new_fd = kconsumerd_allocate_fd(&lkm, tmp.vi);
+                                       if (new_fd == NULL) {
                                                lttng_kconsumerd_send_error(ctx, KCONSUMERD_OUTFD_ERROR);
                                                goto end;
                                        }
+
+                                       if (ctx->on_recv_fd != NULL) {
+                                               ret = ctx->on_recv_fd(new_fd);
+                                               if (ret == 0) {
+                                                       kconsumerd_add_fd(new_fd);
+                                               } else if (ret < 0) {
+                                                       goto end;
+                                               }
+                                       } else {
+                                               kconsumerd_add_fd(new_fd);
+                                       }
                                        break;
                                case UPDATE_STREAM:
-                                       kconsumerd_change_fd_state(lkm.fd, lkm.state);
+                                       if (ctx->on_update_fd != NULL) {
+                                               ret = ctx->on_update_fd(lkm.fd, lkm.state);
+                                               if (ret == 0) {
+                                                       kconsumerd_change_fd_state(lkm.fd, lkm.state);
+                                               } else if (ret < 0) {
+                                                       goto end;
+                                               }
+                                       } else {
+                                               kconsumerd_change_fd_state(lkm.fd, lkm.state);
+                                       }
                                        break;
                                default:
                                        break;
@@ -754,42 +766,64 @@ end:
  * Returns a pointer to the new context or NULL on error.
  */
 struct lttng_kconsumerd_local_data *lttng_kconsumerd_create(
-               int (*buffer_ready)(struct lttng_kconsumerd_fd *kconsumerd_fd))
+               int (*buffer_ready)(struct lttng_kconsumerd_fd *kconsumerd_fd),
+               int (*recv_fd)(struct lttng_kconsumerd_fd *kconsumerd_fd),
+               int (*update_fd)(int sessiond_fd, uint32_t state))
 {
-       int ret;
+       int ret, i;
        struct lttng_kconsumerd_local_data *ctx;
 
        ctx = malloc(sizeof(struct lttng_kconsumerd_local_data));
        if (ctx == NULL) {
                perror("allocating context");
-               goto end;
+               goto error;
        }
 
+       ctx->kconsumerd_error_socket = -1;
+       /* assign the callbacks */
        ctx->on_buffer_ready = buffer_ready;
+       ctx->on_recv_fd = recv_fd;
+       ctx->on_update_fd = update_fd;
 
        ret = pipe(ctx->kconsumerd_poll_pipe);
        if (ret < 0) {
                perror("Error creating poll pipe");
-               ctx = NULL;
-               goto end;
+               goto error_poll_pipe;
        }
 
        ret = pipe(ctx->kconsumerd_should_quit);
        if (ret < 0) {
                perror("Error creating recv pipe");
-               ctx = NULL;
-               goto end;
+               goto error_quit_pipe;
        }
 
        ret = pipe(ctx->kconsumerd_thread_pipe);
        if (ret < 0) {
                perror("Error creating thread pipe");
-               ctx = NULL;
-               goto end;
+               goto error_thread_pipe;
        }
 
-end:
        return ctx;
+
+
+error_thread_pipe:
+       for (i = 0; i < 2; i++) {
+               int err;
+
+               err = close(ctx->kconsumerd_should_quit[i]);
+               assert(!err);
+       }
+error_quit_pipe:
+       for (i = 0; i < 2; i++) {
+               int err;
+
+               err = close(ctx->kconsumerd_poll_pipe[i]);
+               assert(!err);
+       }
+error_poll_pipe:
+       free(ctx);
+error:
+       return NULL;
 }
 
 /*
@@ -840,6 +874,7 @@ void *lttng_kconsumerd_thread_receive_fds(void *data)
 
        DBG("Sending ready command to ltt-sessiond");
        ret = lttng_kconsumerd_send_error(ctx, KCONSUMERD_COMMAND_SOCK_READY);
+       /* return < 0 on error, but == 0 is not fatal */
        if (ret < 0) {
                ERR("Error sending ready command to ltt-sessiond");
                goto end;
@@ -968,6 +1003,7 @@ void lttng_kconsumerd_should_exit(struct lttng_kconsumerd_local_data *ctx)
 
 /*
  * Send return code to the session daemon.
+ * If the socket is not defined, we return 0, it is not a fatal error
  */
 int lttng_kconsumerd_send_error(
                struct lttng_kconsumerd_local_data *ctx, int cmd)
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