Fix: close socket on protocol error, sendmsg MSG_NOSIGNAL
[lttng-ust.git] / liblttng-ust / lttng-ust-comm.c
index 3a3e1d2827c82ea48ef6a79c1b89293ffbfce5b9..fbdee7d3af8ea0d8d122ab3e4b3bb8a251ccc9a0 100644 (file)
@@ -52,6 +52,7 @@
 #include "compat.h"
 #include "../libringbuffer/tlsfixup.h"
 #include "lttng-ust-baddr.h"
+#include "getenv.h"
 
 /*
  * Has lttng ust comm constructor been called ?
@@ -110,8 +111,15 @@ static int lttng_ust_comm_should_quit;
 int ust_lock(void)
 {
        sigset_t sig_all_blocked, orig_mask;
-       int ret;
+       int ret, oldstate;
 
+       ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+       if (ret) {
+               ERR("pthread_setcancelstate: %s", strerror(ret));
+       }
+       if (oldstate != PTHREAD_CANCEL_ENABLE) {
+               ERR("pthread_setcancelstate: unexpected oldstate");
+       }
        sigfillset(&sig_all_blocked);
        ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
        if (ret) {
@@ -139,8 +147,15 @@ int ust_lock(void)
 void ust_lock_nocheck(void)
 {
        sigset_t sig_all_blocked, orig_mask;
-       int ret;
+       int ret, oldstate;
 
+       ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
+       if (ret) {
+               ERR("pthread_setcancelstate: %s", strerror(ret));
+       }
+       if (oldstate != PTHREAD_CANCEL_ENABLE) {
+               ERR("pthread_setcancelstate: unexpected oldstate");
+       }
        sigfillset(&sig_all_blocked);
        ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
        if (ret) {
@@ -160,7 +175,7 @@ void ust_lock_nocheck(void)
 void ust_unlock(void)
 {
        sigset_t sig_all_blocked, orig_mask;
-       int ret;
+       int ret, oldstate;
 
        sigfillset(&sig_all_blocked);
        ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
@@ -173,6 +188,13 @@ void ust_unlock(void)
        if (ret) {
                ERR("pthread_sigmask: %s", strerror(ret));
        }
+       ret = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
+       if (ret) {
+               ERR("pthread_setcancelstate: %s", strerror(ret));
+       }
+       if (oldstate != PTHREAD_CANCEL_DISABLE) {
+               ERR("pthread_setcancelstate: unexpected oldstate");
+       }
 }
 
 /*
@@ -313,11 +335,11 @@ const char *get_lttng_home_dir(void)
 {
        const char *val;
 
-       val = (const char *) getenv("LTTNG_HOME");
+       val = (const char *) lttng_secure_getenv("LTTNG_HOME");
        if (val != NULL) {
                return val;
        }
-       return (const char *) getenv("HOME");
+       return (const char *) lttng_secure_getenv("HOME");
 }
 
 /*
@@ -335,6 +357,16 @@ void lttng_fixup_ust_mutex_nest_tls(void)
        asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest)));
 }
 
+/*
+ * Fixup urcu bp TLS.
+ */
+static
+void lttng_fixup_urcu_bp_tls(void)
+{
+       rcu_read_lock();
+       rcu_read_unlock();
+}
+
 int lttng_get_notify_socket(void *owner)
 {
        struct sock_info *info = owner;
@@ -389,7 +421,7 @@ int setup_local_apps(void)
 
 /*
  * Get notify_sock timeout, in ms.
- * -1: don't wait. 0: wait forever. >0: timeout, in ms.
+ * -1: wait forever. 0: don't wait. >0: timeout, in ms.
  */
 static
 long get_timeout(void)
@@ -412,7 +444,7 @@ long get_notify_sock_timeout(void)
 }
 
 /*
- * Return values: -1: don't wait. 0: wait forever. 1: timeout wait.
+ * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
  */
 static
 int get_constructor_timeout(struct timespec *constructor_timeout)
@@ -435,7 +467,8 @@ int get_constructor_timeout(struct timespec *constructor_timeout)
         */
        ret = clock_gettime(CLOCK_REALTIME, constructor_timeout);
        if (ret) {
-               return -1;
+               /* Don't wait. */
+               return 0;
        }
        constructor_timeout->tv_sec += constructor_delay_ms / 1000UL;
        constructor_timeout->tv_nsec +=
@@ -444,6 +477,7 @@ int get_constructor_timeout(struct timespec *constructor_timeout)
                constructor_timeout->tv_sec++;
                constructor_timeout->tv_nsec -= 1000000000UL;
        }
+       /* Timeout wait (constructor_delay_ms). */
        return 1;
 }
 
@@ -518,8 +552,8 @@ void handle_pending_statedump(struct sock_info *sock_info)
        int ctor_passed = sock_info->constructor_sem_posted;
 
        if (ctor_passed && sock_info->statedump_pending) {
-               pthread_mutex_lock(&ust_fork_mutex);
                sock_info->statedump_pending = 0;
+               pthread_mutex_lock(&ust_fork_mutex);
                lttng_handle_pending_statedump(sock_info);
                pthread_mutex_unlock(&ust_fork_mutex);
        }
@@ -539,13 +573,13 @@ int handle_message(struct sock_info *sock_info,
 
        if (ust_lock()) {
                ret = -LTTNG_UST_ERR_EXITING;
-               goto end;
+               goto error;
        }
 
        ops = objd_ops(lum->handle);
        if (!ops) {
                ret = -ENOENT;
-               goto end;
+               goto error;
        }
 
        switch (lum->cmd) {
@@ -606,12 +640,12 @@ int handle_message(struct sock_info *sock_info,
                                }
                                ret = len;
                                free(bytecode);
-                               goto end;
+                               goto error;
                        } else {
                                DBG("incorrect filter data message size: %zd", len);
                                ret = -EINVAL;
                                free(bytecode);
-                               goto end;
+                               goto error;
                        }
                }
                bytecode->bc.len = lum->u.filter.data_size;
@@ -671,12 +705,12 @@ int handle_message(struct sock_info *sock_info,
                                }
                                ret = len;
                                free(node);
-                               goto end;
+                               goto error;
                        } else {
                                DBG("Incorrect exclusion data message size: %zd", len);
                                ret = -EINVAL;
                                free(node);
-                               goto end;
+                               goto error;
                        }
                }
                if (ops->cmd) {
@@ -717,11 +751,11 @@ int handle_message(struct sock_info *sock_info,
                                        goto error;
                                }
                                ret = len;
-                               goto end;
+                               goto error;
                        } else {
                                DBG("incorrect channel data message size: %zd", len);
                                ret = -EINVAL;
-                               goto end;
+                               goto error;
                        }
                }
                args.channel.chan_data = chan_data;
@@ -742,7 +776,7 @@ int handle_message(struct sock_info *sock_info,
                        &args.stream.shm_fd,
                        &args.stream.wakeup_fd);
                if (ret) {
-                       goto end;
+                       goto error;
                }
                if (ops->cmd)
                        ret = ops->cmd(lum->handle, lum->cmd,
@@ -762,7 +796,6 @@ int handle_message(struct sock_info *sock_info,
                break;
        }
 
-end:
        lur.handle = lum->handle;
        lur.cmd = lum->cmd;
        lur.ret_val = ret;
@@ -1104,8 +1137,6 @@ error:
 static
 void wait_for_sessiond(struct sock_info *sock_info)
 {
-       int ret;
-
        if (ust_lock()) {
                goto quit;
        }
@@ -1121,23 +1152,32 @@ void wait_for_sessiond(struct sock_info *sock_info)
 
        DBG("Waiting for %s apps sessiond", sock_info->name);
        /* Wait for futex wakeup */
-       if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) {
-               ret = futex_async((int32_t *) sock_info->wait_shm_mmap,
-                       FUTEX_WAIT, 0, NULL, NULL, 0);
-               if (ret < 0) {
-                       if (errno == EFAULT) {
-                               wait_poll_fallback = 1;
-                               DBG(
+       if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
+               goto end_wait;
+
+       while (futex_async((int32_t *) sock_info->wait_shm_mmap,
+                       FUTEX_WAIT, 0, NULL, NULL, 0)) {
+               switch (errno) {
+               case EWOULDBLOCK:
+                       /* Value already changed. */
+                       goto end_wait;
+               case EINTR:
+                       /* Retry if interrupted by signal. */
+                       break;  /* Get out of switch. */
+               case EFAULT:
+                       wait_poll_fallback = 1;
+                       DBG(
 "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
 "do not support FUTEX_WAKE on read-only memory mappings correctly. "
 "Please upgrade your kernel "
 "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
 "mainline). LTTng-UST will use polling mode fallback.");
-                               if (ust_debug())
-                                       PERROR("futex");
-                       }
+                       if (ust_debug())
+                               PERROR("futex");
+                       goto end_wait;
                }
        }
+end_wait:
        return;
 
 quit:
@@ -1356,7 +1396,13 @@ restart:
                        print_cmd(lum.cmd, lum.handle);
                        ret = handle_message(sock_info, sock, &lum);
                        if (ret) {
-                               ERR("Error handling message for %s socket", sock_info->name);
+                               ERR("Error handling message for %s socket",
+                                       sock_info->name);
+                               /*
+                                * Close socket if protocol error is
+                                * detected.
+                                */
+                               goto end;
                        }
                        continue;
                default:
@@ -1419,6 +1465,7 @@ void __attribute__((constructor)) lttng_ust_init(void)
         * to be the dynamic linker mutex) and ust_lock, taken within
         * the ust lock.
         */
+       lttng_fixup_urcu_bp_tls();
        lttng_fixup_ringbuffer_tls();
        lttng_fixup_vtid_tls();
        lttng_fixup_nest_count_tls();
@@ -1535,9 +1582,7 @@ static
 void lttng_ust_cleanup(int exiting)
 {
        cleanup_sock_info(&global_apps, exiting);
-       if (local_apps.allowed) {
-               cleanup_sock_info(&local_apps, exiting);
-       }
+       cleanup_sock_info(&local_apps, exiting);
        /*
         * The teardown in this function all affect data structures
         * accessed under the UST lock by the listener thread. This
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