X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-epoll.c;h=5d6153b64d075b5da4dc9881680be992e6018b6f;hp=e1672c4c3178afbbce32acddebf2b30cea66fe09;hb=11a2fd460f033afa2d5f41a70eb1fd3a84fcf89d;hpb=9ddba5259d1cb5f9f5ef03ea1e3276082c7e6b80 diff --git a/src/common/compat/compat-epoll.c b/src/common/compat/compat-epoll.c index e1672c4c3..5d6153b64 100644 --- a/src/common/compat/compat-epoll.c +++ b/src/common/compat/compat-epoll.c @@ -16,6 +16,8 @@ */ #define _GNU_SOURCE +#define _LGPL_SOURCE +#include #include #include #include @@ -26,11 +28,44 @@ #include #include +#include +#include #include "poll.h" unsigned int poll_max_size; +/* + * Resize the epoll events structure of the new size. + * + * Return 0 on success or else -1 with the current events pointer untouched. + */ +static int resize_poll_event(struct lttng_poll_event *events, + uint32_t new_size) +{ + struct epoll_event *ptr; + + assert(events); + + ptr = realloc(events->events, new_size * sizeof(*ptr)); + if (ptr == NULL) { + PERROR("realloc epoll add"); + goto error; + } + if (new_size > events->alloc_size) { + /* Zero newly allocated memory */ + memset(ptr + events->alloc_size, 0, + (new_size - events->alloc_size) * sizeof(*ptr)); + } + events->events = ptr; + events->alloc_size = new_size; + + return 0; + +error: + return -1; +} + /* * Create epoll set and allocate returned events structure. */ @@ -42,12 +77,17 @@ int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) goto error; } + if (!poll_max_size) { + ERR("poll_max_size not initialized yet"); + goto error; + } + /* Don't bust the limit here */ - if (size > poll_max_size && poll_max_size != 0) { + if (size > poll_max_size) { size = poll_max_size; } - ret = epoll_create1(flags); + ret = compat_glibc_epoll_create(size, flags); if (ret < 0) { /* At this point, every error is fatal */ PERROR("epoll_create1"); @@ -63,7 +103,7 @@ int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) goto error_close; } - events->events_size = size; + events->alloc_size = events->init_size = size; events->nb_fd = 0; return 0; @@ -82,14 +122,19 @@ error: */ int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) { - int ret, new_size; - struct epoll_event ev, *ptr; + int ret; + struct epoll_event ev; if (events == NULL || events->events == NULL || fd < 0) { ERR("Bad compat epoll add arguments"); goto error; } + /* + * Zero struct epoll_event to ensure all representations of its + * union are zeroed. + */ + memset(&ev, 0, sizeof(ev)); ev.events = req_events; ev.data.fd = fd; @@ -112,17 +157,6 @@ int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_event events->nb_fd++; - if (events->nb_fd >= events->events_size) { - new_size = 2 * events->events_size; - ptr = realloc(events->events, new_size * sizeof(struct epoll_event)); - if (ptr == NULL) { - PERROR("realloc epoll add"); - goto error; - } - events->events = ptr; - events->events_size = new_size; - } - end: return 0; @@ -137,7 +171,7 @@ int compat_epoll_del(struct lttng_poll_event *events, int fd) { int ret; - if (events == NULL || fd < 0) { + if (events == NULL || fd < 0 || events->nb_fd == 0) { goto error; } @@ -153,8 +187,6 @@ int compat_epoll_del(struct lttng_poll_event *events, int fd) PERROR("epoll_ctl DEL fatal"); goto error; } - PERROR("epoll_ctl del"); - goto error; } events->nb_fd--; @@ -172,12 +204,33 @@ error: int compat_epoll_wait(struct lttng_poll_event *events, int timeout) { int ret; + uint32_t new_size; - if (events == NULL || events->events == NULL || - events->events_size < events->nb_fd) { + if (events == NULL || events->events == NULL) { ERR("Wrong arguments in compat_epoll_wait"); goto error; } + assert(events->nb_fd >= 0); + + if (events->nb_fd == 0) { + errno = EINVAL; + return -1; + } + + /* + * Resize if needed before waiting. We could either expand the array or + * shrink it down. It's important to note that after this step, we are + * ensured that the events argument of the epoll_wait call will be large + * enough to hold every possible returned events. + */ + new_size = 1U << utils_get_count_order_u32(events->nb_fd); + if (new_size != events->alloc_size && new_size >= events->init_size) { + ret = resize_poll_event(events, new_size); + if (ret < 0) { + /* ENOMEM problem at this point. */ + goto error; + } + } do { ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout); @@ -201,35 +254,39 @@ error: /* * Setup poll set maximum size. */ -void compat_epoll_set_max_size(void) +int compat_epoll_set_max_size(void) { - int ret, fd; + int ret, fd, retval = 0; + ssize_t size_ret; char buf[64]; - poll_max_size = DEFAULT_POLL_SIZE; - fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY); if (fd < 0) { - return; + retval = -1; + goto end; } - ret = read(fd, buf, sizeof(buf)); - if (ret < 0) { + size_ret = lttng_read(fd, buf, sizeof(buf)); + /* + * Allow reading a file smaller than buf, but keep space for + * final \0. + */ + if (size_ret < 0 || size_ret >= sizeof(buf)) { PERROR("read set max size"); - goto error; + retval = -1; + goto end_read; } - + buf[size_ret] = '\0'; poll_max_size = atoi(buf); - if (poll_max_size <= 0) { - /* Extra precaution */ - poll_max_size = DEFAULT_POLL_SIZE; - } - - DBG("epoll set max size is %d", poll_max_size); - -error: +end_read: ret = close(fd); if (ret) { PERROR("close"); } +end: + if (!poll_max_size) { + poll_max_size = DEFAULT_POLL_SIZE; + } + DBG("epoll set max size is %d", poll_max_size); + return retval; }