diff options
Diffstat (limited to 'tools/lib/bpf/ringbuf.c')
| -rw-r--r-- | tools/lib/bpf/ringbuf.c | 507 |
1 files changed, 452 insertions, 55 deletions
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 4fc6c6cbb4eb..9702b70da444 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -16,14 +16,12 @@ #include <asm/barrier.h> #include <sys/mman.h> #include <sys/epoll.h> -#include <tools/libc_compat.h> +#include <time.h> #include "libbpf.h" #include "libbpf_internal.h" #include "bpf.h" - -/* make sure libbpf doesn't use kernel-only integer typedefs */ -#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 +#include "str_error.h" struct ring { ring_buffer_sample_fn sample_cb; @@ -37,13 +35,30 @@ struct ring { struct ring_buffer { struct epoll_event *events; - struct ring *rings; + struct ring **rings; size_t page_size; int epoll_fd; int ring_cnt; }; -static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r) +struct user_ring_buffer { + struct epoll_event event; + unsigned long *consumer_pos; + unsigned long *producer_pos; + void *data; + unsigned long mask; + size_t page_size; + int map_fd; + int epoll_fd; +}; + +/* 8-byte ring buffer header structure */ +struct ringbuf_hdr { + __u32 len; + __u32 pad; +}; + +static void ringbuf_free_ring(struct ring_buffer *rb, struct ring *r) { if (r->consumer_pos) { munmap(r->consumer_pos, rb->page_size); @@ -53,6 +68,8 @@ static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r) munmap(r->producer_pos, rb->page_size + 2 * (r->mask + 1)); r->producer_pos = NULL; } + + free(r); } /* Add extra RINGBUF maps to this ring buffer manager */ @@ -63,37 +80,40 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd, __u32 len = sizeof(info); struct epoll_event *e; struct ring *r; + __u64 mmap_sz; void *tmp; int err; memset(&info, 0, sizeof(info)); - err = bpf_obj_get_info_by_fd(map_fd, &info, &len); + err = bpf_map_get_info_by_fd(map_fd, &info, &len); if (err) { err = -errno; - pr_warn("ringbuf: failed to get map info for fd=%d: %d\n", - map_fd, err); - return err; + pr_warn("ringbuf: failed to get map info for fd=%d: %s\n", + map_fd, errstr(err)); + return libbpf_err(err); } if (info.type != BPF_MAP_TYPE_RINGBUF) { pr_warn("ringbuf: map fd=%d is not BPF_MAP_TYPE_RINGBUF\n", map_fd); - return -EINVAL; + return libbpf_err(-EINVAL); } - tmp = reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings)); + tmp = libbpf_reallocarray(rb->rings, rb->ring_cnt + 1, sizeof(*rb->rings)); if (!tmp) - return -ENOMEM; + return libbpf_err(-ENOMEM); rb->rings = tmp; - tmp = reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events)); + tmp = libbpf_reallocarray(rb->events, rb->ring_cnt + 1, sizeof(*rb->events)); if (!tmp) - return -ENOMEM; + return libbpf_err(-ENOMEM); rb->events = tmp; - r = &rb->rings[rb->ring_cnt]; - memset(r, 0, sizeof(*r)); + r = calloc(1, sizeof(*r)); + if (!r) + return libbpf_err(-ENOMEM); + rb->rings[rb->ring_cnt] = r; r->map_fd = map_fd; r->sample_cb = sample_cb; @@ -101,28 +121,31 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd, r->mask = info.max_entries - 1; /* Map writable consumer page */ - tmp = mmap(NULL, rb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, - map_fd, 0); + tmp = mmap(NULL, rb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0); if (tmp == MAP_FAILED) { err = -errno; - pr_warn("ringbuf: failed to mmap consumer page for map fd=%d: %d\n", - map_fd, err); - return err; + pr_warn("ringbuf: failed to mmap consumer page for map fd=%d: %s\n", + map_fd, errstr(err)); + goto err_out; } r->consumer_pos = tmp; /* Map read-only producer page and data pages. We map twice as big * data size to allow simple reading of samples that wrap around the * end of a ring buffer. See kernel implementation for details. - * */ - tmp = mmap(NULL, rb->page_size + 2 * info.max_entries, PROT_READ, - MAP_SHARED, map_fd, rb->page_size); + */ + mmap_sz = rb->page_size + 2 * (__u64)info.max_entries; + if (mmap_sz != (__u64)(size_t)mmap_sz) { + err = -E2BIG; + pr_warn("ringbuf: ring buffer size (%u) is too big\n", info.max_entries); + goto err_out; + } + tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ, MAP_SHARED, map_fd, rb->page_size); if (tmp == MAP_FAILED) { err = -errno; - ringbuf_unmap_ring(rb, r); - pr_warn("ringbuf: failed to mmap data pages for map fd=%d: %d\n", - map_fd, err); - return err; + pr_warn("ringbuf: failed to mmap data pages for map fd=%d: %s\n", + map_fd, errstr(err)); + goto err_out; } r->producer_pos = tmp; r->data = tmp + rb->page_size; @@ -134,14 +157,17 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd, e->data.fd = rb->ring_cnt; if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, e) < 0) { err = -errno; - ringbuf_unmap_ring(rb, r); - pr_warn("ringbuf: failed to epoll add map fd=%d: %d\n", - map_fd, err); - return err; + pr_warn("ringbuf: failed to epoll add map fd=%d: %s\n", + map_fd, errstr(err)); + goto err_out; } rb->ring_cnt++; return 0; + +err_out: + ringbuf_free_ring(rb, r); + return libbpf_err(err); } void ring_buffer__free(struct ring_buffer *rb) @@ -152,7 +178,7 @@ void ring_buffer__free(struct ring_buffer *rb) return; for (i = 0; i < rb->ring_cnt; ++i) - ringbuf_unmap_ring(rb, &rb->rings[i]); + ringbuf_free_ring(rb, rb->rings[i]); if (rb->epoll_fd >= 0) close(rb->epoll_fd); @@ -169,18 +195,18 @@ ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx, int err; if (!OPTS_VALID(opts, ring_buffer_opts)) - return NULL; + return errno = EINVAL, NULL; rb = calloc(1, sizeof(*rb)); if (!rb) - return NULL; + return errno = ENOMEM, NULL; rb->page_size = getpagesize(); rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); if (rb->epoll_fd < 0) { err = -errno; - pr_warn("ringbuf: failed to create epoll instance: %d\n", err); + pr_warn("ringbuf: failed to create epoll instance: %s\n", errstr(err)); goto err_out; } @@ -192,7 +218,7 @@ ring_buffer__new(int map_fd, ring_buffer_sample_fn sample_cb, void *ctx, err_out: ring_buffer__free(rb); - return NULL; + return errno = -err, NULL; } static inline int roundup_len(__u32 len) @@ -206,9 +232,11 @@ static inline int roundup_len(__u32 len) return (len + 7) / 8 * 8; } -static int ringbuf_process_ring(struct ring* r) +static int64_t ringbuf_process_ring(struct ring *r, size_t n) { - int *len_ptr, len, err, cnt = 0; + int *len_ptr, len, err; + /* 64-bit to avoid overflow in case of extreme application behavior */ + int64_t cnt = 0; unsigned long cons_pos, prod_pos; bool got_new_data; void *sample; @@ -231,7 +259,7 @@ static int ringbuf_process_ring(struct ring* r) if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) { sample = (void *)len_ptr + BPF_RINGBUF_HDR_SZ; err = r->sample_cb(r->ctx, sample, len); - if (err) { + if (err < 0) { /* update consumer pos and bail out */ smp_store_release(r->consumer_pos, cons_pos); @@ -241,48 +269,417 @@ static int ringbuf_process_ring(struct ring* r) } smp_store_release(r->consumer_pos, cons_pos); + + if (cnt >= n) + goto done; } } while (got_new_data); done: return cnt; } +/* Consume available ring buffer(s) data without event polling, up to n + * records. + * + * Returns number of records consumed across all registered ring buffers (or + * n, whichever is less), or negative number if any of the callbacks return + * error. + */ +int ring_buffer__consume_n(struct ring_buffer *rb, size_t n) +{ + int64_t err, res = 0; + int i; + + for (i = 0; i < rb->ring_cnt; i++) { + struct ring *ring = rb->rings[i]; + + err = ringbuf_process_ring(ring, n); + if (err < 0) + return libbpf_err(err); + res += err; + n -= err; + + if (n == 0) + break; + } + return res > INT_MAX ? INT_MAX : res; +} + /* Consume available ring buffer(s) data without event polling. - * Returns number of records consumed across all registered ring buffers, or - * negative number if any of the callbacks return error. + * Returns number of records consumed across all registered ring buffers (or + * INT_MAX, whichever is less), or negative number if any of the callbacks + * return error. */ int ring_buffer__consume(struct ring_buffer *rb) { - int i, err, res = 0; + int64_t err, res = 0; + int i; for (i = 0; i < rb->ring_cnt; i++) { - struct ring *ring = &rb->rings[i]; + struct ring *ring = rb->rings[i]; - err = ringbuf_process_ring(ring); + err = ringbuf_process_ring(ring, INT_MAX); if (err < 0) - return err; + return libbpf_err(err); res += err; + if (res > INT_MAX) { + res = INT_MAX; + break; + } } return res; } /* Poll for available data and consume records, if any are available. - * Returns number of records consumed, or negative number, if any of the - * registered callbacks returned error. + * Returns number of records consumed (or INT_MAX, whichever is less), or + * negative number, if any of the registered callbacks returned error. */ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms) { - int i, cnt, err, res = 0; + int i, cnt; + int64_t err, res = 0; cnt = epoll_wait(rb->epoll_fd, rb->events, rb->ring_cnt, timeout_ms); + if (cnt < 0) + return libbpf_err(-errno); + for (i = 0; i < cnt; i++) { __u32 ring_id = rb->events[i].data.fd; - struct ring *ring = &rb->rings[ring_id]; + struct ring *ring = rb->rings[ring_id]; - err = ringbuf_process_ring(ring); + err = ringbuf_process_ring(ring, INT_MAX); if (err < 0) - return err; - res += cnt; + return libbpf_err(err); + res += err; + } + if (res > INT_MAX) + res = INT_MAX; + return res; +} + +/* Get an fd that can be used to sleep until data is available in the ring(s) */ +int ring_buffer__epoll_fd(const struct ring_buffer *rb) +{ + return rb->epoll_fd; +} + +struct ring *ring_buffer__ring(struct ring_buffer *rb, unsigned int idx) +{ + if (idx >= rb->ring_cnt) + return errno = ERANGE, NULL; + + return rb->rings[idx]; +} + +unsigned long ring__consumer_pos(const struct ring *r) +{ + /* Synchronizes with smp_store_release() in ringbuf_process_ring(). */ + return smp_load_acquire(r->consumer_pos); +} + +unsigned long ring__producer_pos(const struct ring *r) +{ + /* Synchronizes with smp_store_release() in __bpf_ringbuf_reserve() in + * the kernel. + */ + return smp_load_acquire(r->producer_pos); +} + +size_t ring__avail_data_size(const struct ring *r) +{ + unsigned long cons_pos, prod_pos; + + cons_pos = ring__consumer_pos(r); + prod_pos = ring__producer_pos(r); + return prod_pos - cons_pos; +} + +size_t ring__size(const struct ring *r) +{ + return r->mask + 1; +} + +int ring__map_fd(const struct ring *r) +{ + return r->map_fd; +} + +int ring__consume_n(struct ring *r, size_t n) +{ + int64_t res; + + res = ringbuf_process_ring(r, n); + if (res < 0) + return libbpf_err(res); + + return res > INT_MAX ? INT_MAX : res; +} + +int ring__consume(struct ring *r) +{ + return ring__consume_n(r, INT_MAX); +} + +static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb) +{ + if (rb->consumer_pos) { + munmap(rb->consumer_pos, rb->page_size); + rb->consumer_pos = NULL; + } + if (rb->producer_pos) { + munmap(rb->producer_pos, rb->page_size + 2 * (rb->mask + 1)); + rb->producer_pos = NULL; + } +} + +void user_ring_buffer__free(struct user_ring_buffer *rb) +{ + if (!rb) + return; + + user_ringbuf_unmap_ring(rb); + + if (rb->epoll_fd >= 0) + close(rb->epoll_fd); + + free(rb); +} + +static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd) +{ + struct bpf_map_info info; + __u32 len = sizeof(info); + __u64 mmap_sz; + void *tmp; + struct epoll_event *rb_epoll; + int err; + + memset(&info, 0, sizeof(info)); + + err = bpf_map_get_info_by_fd(map_fd, &info, &len); + if (err) { + err = -errno; + pr_warn("user ringbuf: failed to get map info for fd=%d: %s\n", + map_fd, errstr(err)); + return err; + } + + if (info.type != BPF_MAP_TYPE_USER_RINGBUF) { + pr_warn("user ringbuf: map fd=%d is not BPF_MAP_TYPE_USER_RINGBUF\n", map_fd); + return -EINVAL; + } + + rb->map_fd = map_fd; + rb->mask = info.max_entries - 1; + + /* Map read-only consumer page */ + tmp = mmap(NULL, rb->page_size, PROT_READ, MAP_SHARED, map_fd, 0); + if (tmp == MAP_FAILED) { + err = -errno; + pr_warn("user ringbuf: failed to mmap consumer page for map fd=%d: %s\n", + map_fd, errstr(err)); + return err; + } + rb->consumer_pos = tmp; + + /* Map read-write the producer page and data pages. We map the data + * region as twice the total size of the ring buffer to allow the + * simple reading and writing of samples that wrap around the end of + * the buffer. See the kernel implementation for details. + */ + mmap_sz = rb->page_size + 2 * (__u64)info.max_entries; + if (mmap_sz != (__u64)(size_t)mmap_sz) { + pr_warn("user ringbuf: ring buf size (%u) is too big\n", info.max_entries); + return -E2BIG; + } + tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED, + map_fd, rb->page_size); + if (tmp == MAP_FAILED) { + err = -errno; + pr_warn("user ringbuf: failed to mmap data pages for map fd=%d: %s\n", + map_fd, errstr(err)); + return err; + } + + rb->producer_pos = tmp; + rb->data = tmp + rb->page_size; + + rb_epoll = &rb->event; + rb_epoll->events = EPOLLOUT; + if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, rb_epoll) < 0) { + err = -errno; + pr_warn("user ringbuf: failed to epoll add map fd=%d: %s\n", map_fd, errstr(err)); + return err; + } + + return 0; +} + +struct user_ring_buffer * +user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts) +{ + struct user_ring_buffer *rb; + int err; + + if (!OPTS_VALID(opts, user_ring_buffer_opts)) + return errno = EINVAL, NULL; + + rb = calloc(1, sizeof(*rb)); + if (!rb) + return errno = ENOMEM, NULL; + + rb->page_size = getpagesize(); + + rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (rb->epoll_fd < 0) { + err = -errno; + pr_warn("user ringbuf: failed to create epoll instance: %s\n", errstr(err)); + goto err_out; } - return cnt < 0 ? -errno : res; + + err = user_ringbuf_map(rb, map_fd); + if (err) + goto err_out; + + return rb; + +err_out: + user_ring_buffer__free(rb); + return errno = -err, NULL; +} + +static void user_ringbuf_commit(struct user_ring_buffer *rb, void *sample, bool discard) +{ + __u32 new_len; + struct ringbuf_hdr *hdr; + uintptr_t hdr_offset; + + hdr_offset = rb->mask + 1 + (sample - rb->data) - BPF_RINGBUF_HDR_SZ; + hdr = rb->data + (hdr_offset & rb->mask); + + new_len = hdr->len & ~BPF_RINGBUF_BUSY_BIT; + if (discard) + new_len |= BPF_RINGBUF_DISCARD_BIT; + + /* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + __atomic_exchange_n(&hdr->len, new_len, __ATOMIC_ACQ_REL); +} + +void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample) +{ + user_ringbuf_commit(rb, sample, true); +} + +void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample) +{ + user_ringbuf_commit(rb, sample, false); +} + +void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size) +{ + __u32 avail_size, total_size, max_size; + /* 64-bit to avoid overflow in case of extreme application behavior */ + __u64 cons_pos, prod_pos; + struct ringbuf_hdr *hdr; + + /* The top two bits are used as special flags */ + if (size & (BPF_RINGBUF_BUSY_BIT | BPF_RINGBUF_DISCARD_BIT)) + return errno = E2BIG, NULL; + + /* Synchronizes with smp_store_release() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + cons_pos = smp_load_acquire(rb->consumer_pos); + /* Synchronizes with smp_store_release() in user_ringbuf_commit() */ + prod_pos = smp_load_acquire(rb->producer_pos); + + max_size = rb->mask + 1; + avail_size = max_size - (prod_pos - cons_pos); + /* Round up total size to a multiple of 8. */ + total_size = (size + BPF_RINGBUF_HDR_SZ + 7) / 8 * 8; + + if (total_size > max_size) + return errno = E2BIG, NULL; + + if (avail_size < total_size) + return errno = ENOSPC, NULL; + + hdr = rb->data + (prod_pos & rb->mask); + hdr->len = size | BPF_RINGBUF_BUSY_BIT; + hdr->pad = 0; + + /* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + smp_store_release(rb->producer_pos, prod_pos + total_size); + + return (void *)rb->data + ((prod_pos + BPF_RINGBUF_HDR_SZ) & rb->mask); +} + +static __u64 ns_elapsed_timespec(const struct timespec *start, const struct timespec *end) +{ + __u64 start_ns, end_ns, ns_per_s = 1000000000; + + start_ns = (__u64)start->tv_sec * ns_per_s + start->tv_nsec; + end_ns = (__u64)end->tv_sec * ns_per_s + end->tv_nsec; + + return end_ns - start_ns; +} + +void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms) +{ + void *sample; + int err, ms_remaining = timeout_ms; + struct timespec start; + + if (timeout_ms < 0 && timeout_ms != -1) + return errno = EINVAL, NULL; + + if (timeout_ms != -1) { + err = clock_gettime(CLOCK_MONOTONIC, &start); + if (err) + return NULL; + } + + do { + int cnt, ms_elapsed; + struct timespec curr; + __u64 ns_per_ms = 1000000; + + sample = user_ring_buffer__reserve(rb, size); + if (sample) + return sample; + else if (errno != ENOSPC) + return NULL; + + /* The kernel guarantees at least one event notification + * delivery whenever at least one sample is drained from the + * ring buffer in an invocation to bpf_ringbuf_drain(). Other + * additional events may be delivered at any time, but only one + * event is guaranteed per bpf_ringbuf_drain() invocation, + * provided that a sample is drained, and the BPF program did + * not pass BPF_RB_NO_WAKEUP to bpf_ringbuf_drain(). If + * BPF_RB_FORCE_WAKEUP is passed to bpf_ringbuf_drain(), a + * wakeup event will be delivered even if no samples are + * drained. + */ + cnt = epoll_wait(rb->epoll_fd, &rb->event, 1, ms_remaining); + if (cnt < 0) + return NULL; + + if (timeout_ms == -1) + continue; + + err = clock_gettime(CLOCK_MONOTONIC, &curr); + if (err) + return NULL; + + ms_elapsed = ns_elapsed_timespec(&start, &curr) / ns_per_ms; + ms_remaining = timeout_ms - ms_elapsed; + } while (ms_remaining > 0); + + /* Try one more time to reserve a sample after the specified timeout has elapsed. */ + return user_ring_buffer__reserve(rb, size); } |