X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.c;h=3dbb9f4928a6d81b43c01fc1dbd4dbd3620ebf0c;hb=c0c0989ab70574e09b2f7e8b48c2da6af664a849;hp=85b1e4b7e6ce9b1c4ef1fc61e04a17dfb554c85a;hpb=74d81a6cca2cd4a7718bba9368f382f9f2fbba84;p=lttng-ust.git diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c index 85b1e4b7..3dbb9f49 100644 --- a/libringbuffer/shm.c +++ b/libringbuffer/shm.c @@ -1,27 +1,15 @@ /* - * libringbuffer/shm.c + * SPDX-License-Identifier: LGPL-2.1-only * * Copyright (C) 2005-2012 Mathieu Desnoyers - * - * 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 */ +#define _LGPL_SOURCE #include "shm.h" #include #include #include +#include #include /* For mode constants */ #include /* For O_* constants */ #include @@ -29,9 +17,16 @@ #include #include #include -#include #include +#include +#include +#ifdef HAVE_LIBNUMA +#include +#include +#endif #include +#include +#include "mmap.h" /* * Ensure we have the required amount of space available by writing 0 @@ -77,20 +72,23 @@ 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; } static struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, - size_t memory_map_size) + size_t memory_map_size, + int stream_fd) { - int shmfd, waitfd[2], ret, i, sigblocked = 0; + int shmfd, waitfd[2], ret, i; struct shm_object *obj; char *memory_map; - char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX"; - sigset_t all_sigs, orig_sigs; + if (stream_fd < 0) + return NULL; if (table->allocated_len >= table->size) return NULL; obj = &table->objects[table->allocated_len]; @@ -116,73 +114,44 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, } 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. + * 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. */ - 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; + shmfd = stream_fd; + 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; } - ret = ftruncate(shmfd, memory_map_size); - if (ret) { - PERROR("ftruncate"); - goto error_ftruncate; + + /* + * Also ensure the file metadata is synced with the storage by using + * fsync(2). Some platforms don't allow fsync on POSIX shm fds, ignore + * EINVAL accordingly. + */ + ret = fsync(shmfd); + if (ret && errno != EINVAL) { + PERROR("fsync"); + goto error_fsync; } + obj->shm_fd_ownership = 0; obj->shm_fd = shmfd; /* 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; @@ -196,23 +165,9 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, return obj; error_mmap: +error_fsync: error_ftruncate: -error_shm_release: error_zero_file: -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]); @@ -231,6 +186,7 @@ struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, { struct shm_object *obj; void *memory_map; + int waitfd[2], i, ret; if (table->allocated_len >= table->size) return NULL; @@ -240,9 +196,30 @@ struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, if (!memory_map) goto alloc_error; - obj->wait_fd[0] = -1; - obj->wait_fd[1] = -1; + /* 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->shm_fd_ownership = 0; obj->type = SHM_OBJECT_MEM; obj->memory_map = memory_map; @@ -252,23 +229,77 @@ struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, 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; } +/* + * libnuma prints errors on the console even for numa_available(). + * Work-around this limitation by using get_mempolicy() directly to + * check whether the kernel supports mempolicy. + */ +#ifdef HAVE_LIBNUMA +static bool lttng_is_numa_available(void) +{ + int ret; + + ret = get_mempolicy(NULL, NULL, 0, NULL, 0); + if (ret && errno == ENOSYS) { + return false; + } + return numa_available() > 0; +} +#endif + struct shm_object *shm_object_table_alloc(struct shm_object_table *table, size_t memory_map_size, - enum shm_object_type type) + enum shm_object_type type, + int stream_fd, + int cpu) { + struct shm_object *shm_object; +#ifdef HAVE_LIBNUMA + int oldnode = 0, node; + bool numa_avail; + + numa_avail = lttng_is_numa_available(); + if (numa_avail) { + oldnode = numa_preferred(); + if (cpu >= 0) { + node = numa_node_of_cpu(cpu); + if (node >= 0) + numa_set_preferred(node); + } + if (cpu < 0 || node < 0) + numa_set_localalloc(); + } +#endif /* HAVE_LIBNUMA */ switch (type) { case SHM_OBJECT_SHM: - return _shm_object_table_alloc_shm(table, memory_map_size); + shm_object = _shm_object_table_alloc_shm(table, memory_map_size, + stream_fd); + break; case SHM_OBJECT_MEM: - return _shm_object_table_alloc_mem(table, memory_map_size); + shm_object = _shm_object_table_alloc_mem(table, memory_map_size); + break; default: assert(0); } - return NULL; +#ifdef HAVE_LIBNUMA + if (numa_avail) + numa_set_preferred(oldnode); +#endif /* HAVE_LIBNUMA */ + return shm_object; } struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, @@ -291,12 +322,8 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, obj->wait_fd[0] = -1; /* read end is unset */ obj->wait_fd[1] = wakeup_fd; 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) { @@ -306,7 +333,7 @@ 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; @@ -328,17 +355,31 @@ error_mmap: * 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) + 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; - obj->wait_fd[1] = -1; + obj->wait_fd[0] = -1; /* read end is unset */ + obj->wait_fd[1] = wakeup_fd; obj->shm_fd = -1; + obj->shm_fd_ownership = 0; + + 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; @@ -347,10 +388,13 @@ struct shm_object *shm_object_table_append_mem(struct shm_object_table *table, obj->index = table->allocated_len++; return obj; + +error_fcntl: + return NULL; } static -void shmp_object_destroy(struct shm_object *obj) +void shmp_object_destroy(struct shm_object *obj, int consumer) { switch (obj->type) { case SHM_OBJECT_SHM: @@ -362,36 +406,89 @@ void shmp_object_destroy(struct shm_object *obj) PERROR("umnmap"); assert(0); } - ret = close(obj->shm_fd); - if (ret) { - PERROR("close"); - assert(0); + + if (obj->shm_fd_ownership) { + /* Delete FDs only if called from app (not consumer). */ + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->shm_fd); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->shm_fd); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + 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); + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->wait_fd[i]); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + 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; + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->wait_fd[i]); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + ret = close(obj->wait_fd[i]); + if (ret) { + PERROR("close"); + assert(0); + } + } + } free(obj->memory_map); break; + } default: assert(0); } } -void shm_object_table_destroy(struct shm_object_table *table) +void shm_object_table_destroy(struct shm_object_table *table, int consumer) { int i; for (i = 0; i < table->allocated_len; i++) - shmp_object_destroy(&table->objects[i]); + shmp_object_destroy(&table->objects[i], consumer); free(table); } @@ -417,6 +514,6 @@ 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; }