+++ /dev/null
-/*
- * libringbuffer/shm.c
- *
- * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Dual LGPL v2.1/GPL v2 license.
- */
-
-#include "shm.h"
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h> /* For mode constants */
-#include <fcntl.h> /* For O_* constants */
-#include <assert.h>
-#include <stdio.h>
-#include <signal.h>
-#include <dirent.h>
-#include <lttng/align.h>
-#include <helper.h>
-
-struct shm_object_table *shm_object_table_create(size_t max_nb_obj)
-{
- struct shm_object_table *table;
-
- table = zmalloc(sizeof(struct shm_object_table) +
- max_nb_obj * sizeof(table->objects[0]));
- table->size = max_nb_obj;
- return table;
-}
-
-struct shm_object *shm_object_table_append(struct shm_object_table *table,
- size_t memory_map_size)
-{
- 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)
- return NULL;
- obj = &table->objects[table->allocated_len];
-
- /* 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));
-
- /* shm_fd: create shm */
-
- /*
- * Theoretically, we could leak a shm if the application crashes
- * between open and unlink. Disable signals on this thread for
- * increased safety against this scenario.
- */
- sigfillset(&all_sigs);
- ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs);
- if (ret == -1) {
- PERROR("pthread_sigmask");
- goto error_pthread_sigmask;
- }
- 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;
- }
- sigblocked = 0;
- ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
- if (ret == -1) {
- PERROR("pthread_sigmask");
- goto error_sigmask_release;
- }
- ret = ftruncate(shmfd, memory_map_size);
- if (ret) {
- PERROR("ftruncate");
- goto error_ftruncate;
- }
- obj->shm_fd = shmfd;
-
- /* memory_map: mmap */
- memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
- MAP_SHARED, shmfd, 0);
- if (memory_map == MAP_FAILED) {
- PERROR("mmap");
- goto error_mmap;
- }
- obj->memory_map = memory_map;
- obj->memory_map_size = memory_map_size;
- obj->allocated_len = 0;
- obj->index = table->allocated_len++;
-
- return obj;
-
-error_mmap:
-error_ftruncate:
-error_shm_release:
-error_sigmask_release:
- ret = close(shmfd);
- if (ret) {
- PERROR("close");
- assert(0);
- }
-error_shm_open:
- if (sigblocked) {
- ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL);
- if (ret == -1) {
- PERROR("pthread_sigmask");
- }
- }
-error_pthread_sigmask:
-error_fcntl:
- for (i = 0; i < 2; i++) {
- ret = close(waitfd[i]);
- if (ret) {
- PERROR("close");
- assert(0);
- }
- }
-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)
-{
- struct shm_object *obj;
- char *memory_map;
-
- if (table->allocated_len >= table->size)
- 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. */
- obj->shm_fd = shm_fd;
-
- /* memory_map: mmap */
- memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE,
- MAP_SHARED, shm_fd, 0);
- if (memory_map == MAP_FAILED) {
- PERROR("mmap");
- goto error_mmap;
- }
- obj->memory_map = memory_map;
- obj->memory_map_size = memory_map_size;
- obj->allocated_len = memory_map_size;
- obj->index = table->allocated_len++;
-
- return obj;
-
-error_mmap:
- return NULL;
-}
-
-static
-void shmp_object_destroy(struct shm_object *obj)
-{
- int ret, i;
-
- if (!obj->is_shadow) {
- 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]);
- if (ret) {
- PERROR("close");
- assert(0);
- }
- }
-}
-
-void shm_object_table_destroy(struct shm_object_table *table)
-{
- int i;
-
- for (i = 0; i < table->allocated_len; i++)
- shmp_object_destroy(&table->objects[i]);
- free(table);
-}
-
-/*
- * zalloc_shm - allocate memory within a shm object.
- *
- * Shared memory is already zeroed by shmget.
- * *NOT* multithread-safe (should be protected by mutex).
- * Returns a -1, -1 tuple on error.
- */
-struct shm_ref zalloc_shm(struct shm_object *obj, size_t len)
-{
- struct shm_ref ref;
- struct shm_ref shm_ref_error = { -1, -1 };
-
- if (obj->memory_map_size - obj->allocated_len < len)
- return shm_ref_error;
- ref.index = obj->index;
- ref.offset = obj->allocated_len;
- obj->allocated_len += len;
- return ref;
-}
-
-void align_shm(struct shm_object *obj, size_t align)
-{
- size_t offset_len = offset_align(obj->allocated_len, align);
- obj->allocated_len += offset_len;
-}
projects / lttng-ust.git / blobdiff