diff options
Diffstat (limited to 'tools/testing/selftests/bpf/trace_helpers.c')
| -rw-r--r-- | tools/testing/selftests/bpf/trace_helpers.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c new file mode 100644 index 000000000..82922f13d --- /dev/null +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -0,0 +1,214 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> +#include <errno.h> +#include <poll.h> +#include <unistd.h> +#include <linux/perf_event.h> +#include <sys/mman.h> +#include "trace_helpers.h" + +#define MAX_SYMS 300000 +static struct ksym syms[MAX_SYMS]; +static int sym_cnt; + +static int ksym_cmp(const void *p1, const void *p2) +{ + return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; +} + +int load_kallsyms(void) +{ + FILE *f = fopen("/proc/kallsyms", "r"); + char func[256], buf[256]; + char symbol; + void *addr; + int i = 0; + + if (!f) + return -ENOENT; + + while (!feof(f)) { + if (!fgets(buf, sizeof(buf), f)) + break; + if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) + break; + if (!addr) + continue; + syms[i].addr = (long) addr; + syms[i].name = strdup(func); + i++; + } + fclose(f); + sym_cnt = i; + qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); + return 0; +} + +struct ksym *ksym_search(long key) +{ + int start = 0, end = sym_cnt; + int result; + + /* kallsyms not loaded. return NULL */ + if (sym_cnt <= 0) + return NULL; + + while (start < end) { + size_t mid = start + (end - start) / 2; + + result = key - syms[mid].addr; + if (result < 0) + end = mid; + else if (result > 0) + start = mid + 1; + else + return &syms[mid]; + } + + if (start >= 1 && syms[start - 1].addr < key && + key < syms[start].addr) + /* valid ksym */ + return &syms[start - 1]; + + /* out of range. return _stext */ + return &syms[0]; +} + +long ksym_get_addr(const char *name) +{ + int i; + + for (i = 0; i < sym_cnt; i++) { + if (strcmp(syms[i].name, name) == 0) + return syms[i].addr; + } + + return 0; +} + +static int page_size; +static int page_cnt = 8; +static struct perf_event_mmap_page *header; + +int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header) +{ + void *base; + int mmap_size; + + page_size = getpagesize(); + mmap_size = page_size * (page_cnt + 1); + + base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (base == MAP_FAILED) { + printf("mmap err\n"); + return -1; + } + + *header = base; + return 0; +} + +int perf_event_mmap(int fd) +{ + return perf_event_mmap_header(fd, &header); +} + +static int perf_event_poll(int fd) +{ + struct pollfd pfd = { .fd = fd, .events = POLLIN }; + + return poll(&pfd, 1, 1000); +} + +struct perf_event_sample { + struct perf_event_header header; + __u32 size; + char data[]; +}; + +static enum bpf_perf_event_ret bpf_perf_event_print(void *event, void *priv) +{ + struct perf_event_sample *e = event; + perf_event_print_fn fn = priv; + int ret; + + if (e->header.type == PERF_RECORD_SAMPLE) { + ret = fn(e->data, e->size); + if (ret != LIBBPF_PERF_EVENT_CONT) + return ret; + } else if (e->header.type == PERF_RECORD_LOST) { + struct { + struct perf_event_header header; + __u64 id; + __u64 lost; + } *lost = (void *) e; + printf("lost %lld events\n", lost->lost); + } else { + printf("unknown event type=%d size=%d\n", + e->header.type, e->header.size); + } + + return LIBBPF_PERF_EVENT_CONT; +} + +int perf_event_poller(int fd, perf_event_print_fn output_fn) +{ + enum bpf_perf_event_ret ret; + void *buf = NULL; + size_t len = 0; + + for (;;) { + perf_event_poll(fd); + ret = bpf_perf_event_read_simple(header, page_cnt * page_size, + page_size, &buf, &len, + bpf_perf_event_print, + output_fn); + if (ret != LIBBPF_PERF_EVENT_CONT) + break; + } + free(buf); + + return ret; +} + +int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers, + int num_fds, perf_event_print_fn output_fn) +{ + enum bpf_perf_event_ret ret; + struct pollfd *pfds; + void *buf = NULL; + size_t len = 0; + int i; + + pfds = calloc(num_fds, sizeof(*pfds)); + if (!pfds) + return LIBBPF_PERF_EVENT_ERROR; + + for (i = 0; i < num_fds; i++) { + pfds[i].fd = fds[i]; + pfds[i].events = POLLIN; + } + + for (;;) { + poll(pfds, num_fds, 1000); + for (i = 0; i < num_fds; i++) { + if (!pfds[i].revents) + continue; + + ret = bpf_perf_event_read_simple(headers[i], + page_cnt * page_size, + page_size, &buf, &len, + bpf_perf_event_print, + output_fn); + if (ret != LIBBPF_PERF_EVENT_CONT) + break; + } + } + free(buf); + free(pfds); + + return ret; +} |