X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.c;h=566ed467fe2f715bc60f56449b222964c8b51acd;hb=053e6e240f3fb5b2427fb28f8f09c652e2bdb39a;hp=10b3bcef110a979ce2169ccf10417e470e122ba9;hpb=8a208943e21700211beee3ea64180a5a534c7d2a;p=lttng-ust.git

diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c
index 10b3bcef..566ed467 100644
--- a/libringbuffer/shm.c
+++ b/libringbuffer/shm.c
@@ -19,7 +19,6 @@
  */
 
 #define _LGPL_SOURCE
-#include <config.h>
 #include "shm.h"
 #include <unistd.h>
 #include <fcntl.h>
@@ -34,12 +33,14 @@
 #include <lttng/align.h>
 #include <limits.h>
 #include <stdbool.h>
+#include <stdint.h>
 #ifdef HAVE_LIBNUMA
 #include <numa.h>
 #include <numaif.h>
 #endif
 #include <helper.h>
 #include <ust-fd.h>
+#include "mmap.h"
 
 /*
  * Ensure we have the required amount of space available by writing 0
@@ -127,19 +128,27 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
 	}
 	memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
 
-	/* create shm */
+	/*
+	 * Set POSIX shared memory object size
+	 *
+	 * First, use ftruncate() to set its size, some implementations won't
+	 * allow writes past the size set by ftruncate.
+	 * Then, use write() to fill it with zeros, this allows us to fully
+	 * allocate it and detect a shortage of shm space without dealing with
+	 * a SIGBUS.
+	 */
 
 	shmfd = stream_fd;
-	ret = zero_file(shmfd, memory_map_size);
-	if (ret) {
-		PERROR("zero_file");
-		goto error_zero_file;
-	}
 	ret = ftruncate(shmfd, memory_map_size);
 	if (ret) {
 		PERROR("ftruncate");
 		goto error_ftruncate;
 	}
+	ret = zero_file(shmfd, memory_map_size);
+	if (ret) {
+		PERROR("zero_file");
+		goto error_zero_file;
+	}
 	/*
 	 * Also ensure the file metadata is synced with the storage by using
 	 * fsync(2).
@@ -154,7 +163,7 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
 
 	/* memory_map: mmap */
 	memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
-			  MAP_SHARED, shmfd, 0);
+			  MAP_SHARED | LTTNG_MAP_POPULATE, shmfd, 0);
 	if (memory_map == MAP_FAILED) {
 		PERROR("mmap");
 		goto error_mmap;
@@ -327,11 +336,6 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
 	obj->shm_fd = shm_fd;
 	obj->shm_fd_ownership = 1;
 
-	ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC);
-	if (ret < 0) {
-		PERROR("fcntl");
-		goto error_fcntl;
-	}
 	/* The write end of the pipe needs to be non-blocking */
 	ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK);
 	if (ret < 0) {
@@ -341,7 +345,7 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
 
 	/* memory_map: mmap */
 	memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
-			  MAP_SHARED, shm_fd, 0);
+			  MAP_SHARED | LTTNG_MAP_POPULATE, shm_fd, 0);
 	if (memory_map == MAP_FAILED) {
 		PERROR("mmap");
 		goto error_mmap;
@@ -522,6 +526,6 @@ struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
 
 void align_shm(struct shm_object *obj, size_t align)
 {
-	size_t offset_len = offset_align(obj->allocated_len, align);
+	size_t offset_len = lttng_ust_offset_align(obj->allocated_len, align);
 	obj->allocated_len += offset_len;
 }