X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.c;h=c4c651e4b925543e373e9b016398636be4c03293;hb=c7667bfebfa1d054ad8d54fd98ada3c86184e327;hp=85b1e4b7e6ce9b1c4ef1fc61e04a17dfb554c85a;hpb=74d81a6cca2cd4a7718bba9368f382f9f2fbba84;p=lttng-ust.git diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c index 85b1e4b7..c4c651e4 100644 --- a/libringbuffer/shm.c +++ b/libringbuffer/shm.c @@ -18,10 +18,12 @@ * 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 +31,9 @@ #include #include #include -#include #include #include +#include /* * Ensure we have the required amount of space available by writing 0 @@ -77,20 +79,23 @@ 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]; @@ -116,58 +121,9 @@ 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. - */ - 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; - } + /* create shm */ + + shmfd = stream_fd; ret = zero_file(shmfd, memory_map_size); if (ret) { PERROR("zero_file"); @@ -178,6 +134,7 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, PERROR("ftruncate"); goto error_ftruncate; } + obj->shm_fd_ownership = 0; obj->shm_fd = shmfd; /* memory_map: mmap */ @@ -197,22 +154,7 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, error_mmap: 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 +173,7 @@ 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 +183,30 @@ 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; @@ -252,17 +216,29 @@ 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; } 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) { switch (type) { case SHM_OBJECT_SHM: - return _shm_object_table_alloc_shm(table, memory_map_size); + return _shm_object_table_alloc_shm(table, memory_map_size, + stream_fd); case SHM_OBJECT_MEM: return _shm_object_table_alloc_mem(table, memory_map_size); default: @@ -291,6 +267,7 @@ 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) { @@ -328,17 +305,31 @@ 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 +338,13 @@ 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 +356,89 @@ 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); }