/*
* libringbuffer/shm.c
*
- * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * Dual LGPL v2.1/GPL v2 license.
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "shm.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
+#include <sys/types.h>
#include <sys/stat.h> /* For mode constants */
#include <fcntl.h> /* For O_* constants */
#include <assert.h>
#include <signal.h>
#include <dirent.h>
#include <lttng/align.h>
+#include <limits.h>
+#include <helper.h>
+
+/*
+ * Ensure we have the required amount of space available by writing 0
+ * into the entire buffer. Not doing so can trigger SIGBUS when going
+ * beyond the available shm space.
+ */
+static
+int zero_file(int fd, size_t len)
+{
+ ssize_t retlen;
+ size_t written = 0;
+ char *zeropage;
+ long pagelen;
+ int ret;
+
+ pagelen = sysconf(_SC_PAGESIZE);
+ if (pagelen < 0)
+ return (int) pagelen;
+ zeropage = calloc(pagelen, 1);
+ if (!zeropage)
+ return -ENOMEM;
+
+ while (len > written) {
+ do {
+ retlen = write(fd, zeropage,
+ min_t(size_t, pagelen, len - written));
+ } while (retlen == -1UL && errno == EINTR);
+ if (retlen < 0) {
+ ret = (int) retlen;
+ goto error;
+ }
+ written += retlen;
+ }
+ ret = 0;
+error:
+ free(zeropage);
+ return ret;
+}
struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
{
table = zmalloc(sizeof(struct shm_object_table) +
max_nb_obj * sizeof(table->objects[0]));
+ if (!table)
+ return NULL;
table->size = max_nb_obj;
return table;
}
-struct shm_object *shm_object_table_append(struct shm_object_table *table,
- size_t memory_map_size)
+static
+int create_posix_shm(void)
+{
+ char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX";
+ int shmfd, ret;
+
+ /*
+ * Allocate shm, and immediately unlink its shm oject, keeping
+ * only the file descriptor as a reference to the object. If it
+ * already exists (caused by short race window during which the
+ * global object exists in a concurrent shm_open), simply retry.
+ * We specifically do _not_ use the / at the beginning of the
+ * pathname so that some OS implementations can keep it local to
+ * the process (POSIX leaves this implementation-defined).
+ */
+ do {
+ /*
+ * Using mktemp filename with O_CREAT | O_EXCL open
+ * flags.
+ */
+ (void) mktemp(tmp_name);
+ if (tmp_name[0] == '\0') {
+ PERROR("mktemp");
+ goto error_shm_open;
+ }
+ shmfd = shm_open(tmp_name,
+ O_CREAT | O_EXCL | O_RDWR, 0700);
+ } while (shmfd < 0 && (errno == EEXIST || errno == EACCES));
+ if (shmfd < 0) {
+ PERROR("shm_open");
+ goto error_shm_open;
+ }
+ ret = shm_unlink(tmp_name);
+ if (ret < 0 && errno != ENOENT) {
+ PERROR("shm_unlink");
+ goto error_shm_release;
+ }
+ return shmfd;
+
+error_shm_release:
+ ret = close(shmfd);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
+error_shm_open:
+ return -1;
+}
+
+static
+int create_shared_file(const char *shm_path)
+{
+ return open(shm_path, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+}
+
+static
+struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table,
+ size_t memory_map_size,
+ const char *shm_path)
{
int shmfd, waitfd[2], ret, i, sigblocked = 0;
struct shm_object *obj;
char *memory_map;
- char tmp_name[NAME_MAX] = "ust-shm-tmp-XXXXXX";
sigset_t all_sigs, orig_sigs;
if (table->allocated_len >= table->size)
}
sigblocked = 1;
- /*
- * Allocate shm, and immediately unlink its shm oject, keeping
- * only the file descriptor as a reference to the object. If it
- * already exists (caused by short race window during which the
- * global object exists in a concurrent shm_open), simply retry.
- * We specifically do _not_ use the / at the beginning of the
- * pathname so that some OS implementations can keep it local to
- * the process (POSIX leaves this implementation-defined).
- */
- do {
- /*
- * Using mktemp filename with O_CREAT | O_EXCL open
- * flags.
- */
- mktemp(tmp_name);
- if (tmp_name[0] == '\0') {
- PERROR("mktemp");
- goto error_shm_open;
- }
- shmfd = shm_open(tmp_name,
- O_CREAT | O_EXCL | O_RDWR, 0700);
- } while (shmfd < 0 && (errno == EEXIST || errno == EACCES));
- if (shmfd < 0) {
- PERROR("shm_open");
- goto error_shm_open;
- }
- ret = shm_unlink(tmp_name);
- if (ret < 0 && errno != ENOENT) {
- PERROR("shm_unlink");
- goto error_shm_release;
+
+ if (!shm_path) {
+ obj->shm_path[0] = '\0';
+ shmfd = create_posix_shm();
+ } else {
+ strncpy(obj->shm_path, shm_path,
+ sizeof(obj->shm_path));
+ obj->shm_path[sizeof(obj->shm_path) - 1] = '\0';
+
+ /* Path should already exist, but could fail. */
+ shmfd = create_shared_file(shm_path);
}
+ if (shmfd < 0)
+ goto error_shm_open;
+
sigblocked = 0;
ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
if (ret == -1) {
PERROR("pthread_sigmask");
goto error_sigmask_release;
}
+ 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");
PERROR("mmap");
goto error_mmap;
}
+ obj->type = SHM_OBJECT_SHM;
obj->memory_map = memory_map;
obj->memory_map_size = memory_map_size;
obj->allocated_len = 0;
error_mmap:
error_ftruncate:
-error_shm_release:
+error_zero_file:
error_sigmask_release:
ret = close(shmfd);
if (ret) {
PERROR("close");
assert(0);
}
+ if (shm_path) {
+ ret = unlink(shm_path);
+ if (ret) {
+ PERROR("ret");
+ }
+ }
error_shm_open:
if (sigblocked) {
ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
}
error_pipe:
return NULL;
-
}
-struct shm_object *shm_object_table_append_shadow(struct shm_object_table *table,
- int shm_fd, int wait_fd, size_t memory_map_size)
+static
+struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table,
+ size_t memory_map_size)
+{
+ struct shm_object *obj;
+ void *memory_map;
+ int waitfd[2], i, ret;
+
+ if (table->allocated_len >= table->size)
+ return NULL;
+ obj = &table->objects[table->allocated_len];
+
+ memory_map = zmalloc(memory_map_size);
+ if (!memory_map)
+ goto alloc_error;
+
+ /* wait_fd: create pipe */
+ ret = pipe(waitfd);
+ if (ret < 0) {
+ PERROR("pipe");
+ goto error_pipe;
+ }
+ for (i = 0; i < 2; i++) {
+ ret = fcntl(waitfd[i], 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(waitfd[1], F_SETFL, O_NONBLOCK);
+ if (ret < 0) {
+ PERROR("fcntl");
+ goto error_fcntl;
+ }
+ memcpy(obj->wait_fd, waitfd, sizeof(waitfd));
+
+ /* no shm_fd */
+ obj->shm_fd = -1;
+
+ obj->type = SHM_OBJECT_MEM;
+ obj->memory_map = memory_map;
+ obj->memory_map_size = memory_map_size;
+ obj->allocated_len = 0;
+ obj->index = table->allocated_len++;
+
+ return obj;
+
+error_fcntl:
+ for (i = 0; i < 2; i++) {
+ ret = close(waitfd[i]);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
+ }
+error_pipe:
+ free(memory_map);
+alloc_error:
+ return NULL;
+}
+
+struct shm_object *shm_object_table_alloc(struct shm_object_table *table,
+ size_t memory_map_size,
+ enum shm_object_type type,
+ const char *shm_path)
+{
+ switch (type) {
+ case SHM_OBJECT_SHM:
+ return _shm_object_table_alloc_shm(table, memory_map_size,
+ shm_path);
+ case SHM_OBJECT_MEM:
+ return _shm_object_table_alloc_mem(table, memory_map_size);
+ default:
+ assert(0);
+ }
+ return NULL;
+}
+
+struct shm_object *shm_object_table_append_shm(struct shm_object_table *table,
+ int shm_fd, int wakeup_fd, uint32_t stream_nr,
+ size_t memory_map_size)
{
struct shm_object *obj;
char *memory_map;
+ int ret;
if (table->allocated_len >= table->size)
return NULL;
+ /* streams _must_ be received in sequential order, else fail. */
+ if (stream_nr + 1 != table->allocated_len)
+ return NULL;
+
obj = &table->objects[table->allocated_len];
- /* wait_fd: set read end of the pipe. */
- obj->wait_fd[0] = wait_fd;
- obj->wait_fd[1] = -1; /* write end is unset. */
+ /* wait_fd: set write end of the pipe. */
+ obj->wait_fd[0] = -1; /* read end is unset */
+ obj->wait_fd[1] = wakeup_fd;
obj->shm_fd = shm_fd;
+ 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) {
+ PERROR("fcntl");
+ goto error_fcntl;
+ }
+
/* memory_map: mmap */
memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
MAP_SHARED, shm_fd, 0);
PERROR("mmap");
goto error_mmap;
}
+ obj->type = SHM_OBJECT_SHM;
obj->memory_map = memory_map;
obj->memory_map_size = memory_map_size;
obj->allocated_len = memory_map_size;
return obj;
+error_fcntl:
error_mmap:
return NULL;
}
+/*
+ * Passing ownership of mem to object.
+ */
+struct shm_object *shm_object_table_append_mem(struct shm_object_table *table,
+ void *mem, size_t memory_map_size, int wakeup_fd)
+{
+ struct shm_object *obj;
+ int ret;
+
+ if (table->allocated_len >= table->size)
+ return NULL;
+ obj = &table->objects[table->allocated_len];
+
+ obj->wait_fd[0] = -1; /* read end is unset */
+ obj->wait_fd[1] = wakeup_fd;
+ obj->shm_fd = -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) {
+ PERROR("fcntl");
+ goto error_fcntl;
+ }
+
+ obj->type = SHM_OBJECT_MEM;
+ obj->memory_map = mem;
+ obj->memory_map_size = memory_map_size;
+ obj->allocated_len = memory_map_size;
+ obj->index = table->allocated_len++;
+
+ return obj;
+
+error_fcntl:
+ return NULL;
+}
+
static
void shmp_object_destroy(struct shm_object *obj)
{
- int ret, i;
-
- ret = munmap(obj->memory_map, obj->memory_map_size);
- if (ret) {
- PERROR("umnmap");
- assert(0);
- }
- ret = close(obj->shm_fd);
- if (ret) {
- PERROR("close");
- assert(0);
- }
- for (i = 0; i < 2; i++) {
- if (obj->wait_fd[i] < 0)
- continue;
- ret = close(obj->wait_fd[i]);
+ switch (obj->type) {
+ case SHM_OBJECT_SHM:
+ {
+ int ret, i;
+
+ ret = munmap(obj->memory_map, obj->memory_map_size);
+ if (ret) {
+ PERROR("umnmap");
+ assert(0);
+ }
+ ret = close(obj->shm_fd);
if (ret) {
PERROR("close");
assert(0);
}
+ if (obj->shm_path[0]) {
+ ret = unlink(obj->shm_path);
+ if (ret) {
+ PERROR("ret");
+ }
+ }
+ for (i = 0; i < 2; i++) {
+ if (obj->wait_fd[i] < 0)
+ continue;
+ ret = close(obj->wait_fd[i]);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
+ }
+ break;
+ }
+ case SHM_OBJECT_MEM:
+ {
+ int ret, i;
+
+ for (i = 0; i < 2; i++) {
+ if (obj->wait_fd[i] < 0)
+ continue;
+ ret = close(obj->wait_fd[i]);
+ if (ret) {
+ PERROR("close");
+ assert(0);
+ }
+ }
+ free(obj->memory_map);
+ break;
+ }
+ default:
+ assert(0);
}
}
projects / lttng-ust.git / blobdiff