diff options
Diffstat (limited to 'samples/bpf/task_fd_query_user.c')
| -rw-r--r-- | samples/bpf/task_fd_query_user.c | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/samples/bpf/task_fd_query_user.c b/samples/bpf/task_fd_query_user.c new file mode 100644 index 000000000000..8381d792f138 --- /dev/null +++ b/samples/bpf/task_fd_query_user.c @@ -0,0 +1,382 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> +#include <stdbool.h> +#include <string.h> +#include <stdint.h> +#include <fcntl.h> +#include <linux/bpf.h> +#include <sys/ioctl.h> +#include <sys/resource.h> +#include <sys/types.h> +#include <sys/stat.h> + +#include "libbpf.h" +#include "bpf_load.h" +#include "bpf_util.h" +#include "perf-sys.h" +#include "trace_helpers.h" + +#define CHECK_PERROR_RET(condition) ({ \ + int __ret = !!(condition); \ + if (__ret) { \ + printf("FAIL: %s:\n", __func__); \ + perror(" "); \ + return -1; \ + } \ +}) + +#define CHECK_AND_RET(condition) ({ \ + int __ret = !!(condition); \ + if (__ret) \ + return -1; \ +}) + +static __u64 ptr_to_u64(void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + +#define PMU_TYPE_FILE "/sys/bus/event_source/devices/%s/type" +static int bpf_find_probe_type(const char *event_type) +{ + char buf[256]; + int fd, ret; + + ret = snprintf(buf, sizeof(buf), PMU_TYPE_FILE, event_type); + CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf)); + + fd = open(buf, O_RDONLY); + CHECK_PERROR_RET(fd < 0); + + ret = read(fd, buf, sizeof(buf)); + close(fd); + CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf)); + + errno = 0; + ret = (int)strtol(buf, NULL, 10); + CHECK_PERROR_RET(errno); + return ret; +} + +#define PMU_RETPROBE_FILE "/sys/bus/event_source/devices/%s/format/retprobe" +static int bpf_get_retprobe_bit(const char *event_type) +{ + char buf[256]; + int fd, ret; + + ret = snprintf(buf, sizeof(buf), PMU_RETPROBE_FILE, event_type); + CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf)); + + fd = open(buf, O_RDONLY); + CHECK_PERROR_RET(fd < 0); + + ret = read(fd, buf, sizeof(buf)); + close(fd); + CHECK_PERROR_RET(ret < 0 || ret >= sizeof(buf)); + CHECK_PERROR_RET(strlen(buf) < strlen("config:")); + + errno = 0; + ret = (int)strtol(buf + strlen("config:"), NULL, 10); + CHECK_PERROR_RET(errno); + return ret; +} + +static int test_debug_fs_kprobe(int prog_fd_idx, const char *fn_name, + __u32 expected_fd_type) +{ + __u64 probe_offset, probe_addr; + __u32 len, prog_id, fd_type; + char buf[256]; + int err; + + len = sizeof(buf); + err = bpf_task_fd_query(getpid(), event_fd[prog_fd_idx], 0, buf, &len, + &prog_id, &fd_type, &probe_offset, + &probe_addr); + if (err < 0) { + printf("FAIL: %s, for event_fd idx %d, fn_name %s\n", + __func__, prog_fd_idx, fn_name); + perror(" :"); + return -1; + } + if (strcmp(buf, fn_name) != 0 || + fd_type != expected_fd_type || + probe_offset != 0x0 || probe_addr != 0x0) { + printf("FAIL: bpf_trace_event_query(event_fd[%d]):\n", + prog_fd_idx); + printf("buf: %s, fd_type: %u, probe_offset: 0x%llx," + " probe_addr: 0x%llx\n", + buf, fd_type, probe_offset, probe_addr); + return -1; + } + return 0; +} + +static int test_nondebug_fs_kuprobe_common(const char *event_type, + const char *name, __u64 offset, __u64 addr, bool is_return, + char *buf, __u32 *buf_len, __u32 *prog_id, __u32 *fd_type, + __u64 *probe_offset, __u64 *probe_addr) +{ + int is_return_bit = bpf_get_retprobe_bit(event_type); + int type = bpf_find_probe_type(event_type); + struct perf_event_attr attr = {}; + int fd; + + if (type < 0 || is_return_bit < 0) { + printf("FAIL: %s incorrect type (%d) or is_return_bit (%d)\n", + __func__, type, is_return_bit); + return -1; + } + + attr.sample_period = 1; + attr.wakeup_events = 1; + if (is_return) + attr.config |= 1 << is_return_bit; + + if (name) { + attr.config1 = ptr_to_u64((void *)name); + attr.config2 = offset; + } else { + attr.config1 = 0; + attr.config2 = addr; + } + attr.size = sizeof(attr); + attr.type = type; + + fd = sys_perf_event_open(&attr, -1, 0, -1, 0); + CHECK_PERROR_RET(fd < 0); + + CHECK_PERROR_RET(ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) < 0); + CHECK_PERROR_RET(ioctl(fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) < 0); + CHECK_PERROR_RET(bpf_task_fd_query(getpid(), fd, 0, buf, buf_len, + prog_id, fd_type, probe_offset, probe_addr) < 0); + + return 0; +} + +static int test_nondebug_fs_probe(const char *event_type, const char *name, + __u64 offset, __u64 addr, bool is_return, + __u32 expected_fd_type, + __u32 expected_ret_fd_type, + char *buf, __u32 buf_len) +{ + __u64 probe_offset, probe_addr; + __u32 prog_id, fd_type; + int err; + + err = test_nondebug_fs_kuprobe_common(event_type, name, + offset, addr, is_return, + buf, &buf_len, &prog_id, + &fd_type, &probe_offset, + &probe_addr); + if (err < 0) { + printf("FAIL: %s, " + "for name %s, offset 0x%llx, addr 0x%llx, is_return %d\n", + __func__, name ? name : "", offset, addr, is_return); + perror(" :"); + return -1; + } + if ((is_return && fd_type != expected_ret_fd_type) || + (!is_return && fd_type != expected_fd_type)) { + printf("FAIL: %s, incorrect fd_type %u\n", + __func__, fd_type); + return -1; + } + if (name) { + if (strcmp(name, buf) != 0) { + printf("FAIL: %s, incorrect buf %s\n", __func__, buf); + return -1; + } + if (probe_offset != offset) { + printf("FAIL: %s, incorrect probe_offset 0x%llx\n", + __func__, probe_offset); + return -1; + } + } else { + if (buf_len != 0) { + printf("FAIL: %s, incorrect buf %p\n", + __func__, buf); + return -1; + } + + if (probe_addr != addr) { + printf("FAIL: %s, incorrect probe_addr 0x%llx\n", + __func__, probe_addr); + return -1; + } + } + return 0; +} + +static int test_debug_fs_uprobe(char *binary_path, long offset, bool is_return) +{ + const char *event_type = "uprobe"; + struct perf_event_attr attr = {}; + char buf[256], event_alias[256]; + __u64 probe_offset, probe_addr; + __u32 len, prog_id, fd_type; + int err, res, kfd, efd; + ssize_t bytes; + + snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/%s_events", + event_type); + kfd = open(buf, O_WRONLY | O_APPEND, 0); + CHECK_PERROR_RET(kfd < 0); + + res = snprintf(event_alias, sizeof(event_alias), "test_%d", getpid()); + CHECK_PERROR_RET(res < 0 || res >= sizeof(event_alias)); + + res = snprintf(buf, sizeof(buf), "%c:%ss/%s %s:0x%lx", + is_return ? 'r' : 'p', event_type, event_alias, + binary_path, offset); + CHECK_PERROR_RET(res < 0 || res >= sizeof(buf)); + CHECK_PERROR_RET(write(kfd, buf, strlen(buf)) < 0); + + close(kfd); + kfd = -1; + + snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id", + event_type, event_alias); + efd = open(buf, O_RDONLY, 0); + CHECK_PERROR_RET(efd < 0); + + bytes = read(efd, buf, sizeof(buf)); + CHECK_PERROR_RET(bytes <= 0 || bytes >= sizeof(buf)); + close(efd); + buf[bytes] = '\0'; + + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_period = 1; + attr.wakeup_events = 1; + kfd = sys_perf_event_open(&attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); + CHECK_PERROR_RET(kfd < 0); + CHECK_PERROR_RET(ioctl(kfd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) < 0); + CHECK_PERROR_RET(ioctl(kfd, PERF_EVENT_IOC_ENABLE, 0) < 0); + + len = sizeof(buf); + err = bpf_task_fd_query(getpid(), kfd, 0, buf, &len, + &prog_id, &fd_type, &probe_offset, + &probe_addr); + if (err < 0) { + printf("FAIL: %s, binary_path %s\n", __func__, binary_path); + perror(" :"); + return -1; + } + if ((is_return && fd_type != BPF_FD_TYPE_URETPROBE) || + (!is_return && fd_type != BPF_FD_TYPE_UPROBE)) { + printf("FAIL: %s, incorrect fd_type %u\n", __func__, + fd_type); + return -1; + } + if (strcmp(binary_path, buf) != 0) { + printf("FAIL: %s, incorrect buf %s\n", __func__, buf); + return -1; + } + if (probe_offset != offset) { + printf("FAIL: %s, incorrect probe_offset 0x%llx\n", __func__, + probe_offset); + return -1; + } + + close(kfd); + return 0; +} + +int main(int argc, char **argv) +{ + struct rlimit r = {1024*1024, RLIM_INFINITY}; + extern char __executable_start; + char filename[256], buf[256]; + __u64 uprobe_file_offset; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + if (setrlimit(RLIMIT_MEMLOCK, &r)) { + perror("setrlimit(RLIMIT_MEMLOCK)"); + return 1; + } + + if (load_kallsyms()) { + printf("failed to process /proc/kallsyms\n"); + return 1; + } + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + /* test two functions in the corresponding *_kern.c file */ + CHECK_AND_RET(test_debug_fs_kprobe(0, "blk_start_request", + BPF_FD_TYPE_KPROBE)); + CHECK_AND_RET(test_debug_fs_kprobe(1, "blk_account_io_completion", + BPF_FD_TYPE_KRETPROBE)); + + /* test nondebug fs kprobe */ + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0, + false, BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + buf, sizeof(buf))); +#ifdef __x86_64__ + /* set a kprobe on "bpf_check + 0x5", which is x64 specific */ + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x5, 0x0, + false, BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + buf, sizeof(buf))); +#endif + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", "bpf_check", 0x0, 0x0, + true, BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + buf, sizeof(buf))); + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, + ksym_get_addr("bpf_check"), false, + BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + buf, sizeof(buf))); + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, + ksym_get_addr("bpf_check"), false, + BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + NULL, 0)); + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, + ksym_get_addr("bpf_check"), true, + BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + buf, sizeof(buf))); + CHECK_AND_RET(test_nondebug_fs_probe("kprobe", NULL, 0x0, + ksym_get_addr("bpf_check"), true, + BPF_FD_TYPE_KPROBE, + BPF_FD_TYPE_KRETPROBE, + 0, 0)); + + /* test nondebug fs uprobe */ + /* the calculation of uprobe file offset is based on gcc 7.3.1 on x64 + * and the default linker script, which defines __executable_start as + * the start of the .text section. The calculation could be different + * on different systems with different compilers. The right way is + * to parse the ELF file. We took a shortcut here. + */ + uprobe_file_offset = (__u64)main - (__u64)&__executable_start; + CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0], + uprobe_file_offset, 0x0, false, + BPF_FD_TYPE_UPROBE, + BPF_FD_TYPE_URETPROBE, + buf, sizeof(buf))); + CHECK_AND_RET(test_nondebug_fs_probe("uprobe", (char *)argv[0], + uprobe_file_offset, 0x0, true, + BPF_FD_TYPE_UPROBE, + BPF_FD_TYPE_URETPROBE, + buf, sizeof(buf))); + + /* test debug fs uprobe */ + CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset, + false)); + CHECK_AND_RET(test_debug_fs_uprobe((char *)argv[0], uprobe_file_offset, + true)); + + return 0; +} |