samples/bpf: add a samples/bpf test for BPF_TASK_FD_QUERY (ecb96f7f) · Commits · 戴 / test

samples/bpf/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@ hostprogs-y += cpustat
		hostprogs-y += xdp_adjust_tail
		hostprogs-y += xdpsock
		hostprogs-y += xdp_fwd
		hostprogs-y += task_fd_query

		# Libbpf dependencies
		LIBBPF = $(TOOLS_PATH)/lib/bpf/libbpf.a
		@@ -105,6 +106,7 @@ cpustat-objs := bpf_load.o cpustat_user.o
		xdp_adjust_tail-objs := xdp_adjust_tail_user.o
		xdpsock-objs := bpf_load.o xdpsock_user.o
		xdp_fwd-objs := bpf_load.o xdp_fwd_user.o
		task_fd_query-objs := bpf_load.o task_fd_query_user.o $(TRACE_HELPERS)

		# Tell kbuild to always build the programs
		always := $(hostprogs-y)
		@@ -160,6 +162,7 @@ always += cpustat_kern.o
		always += xdp_adjust_tail_kern.o
		always += xdpsock_kern.o
		always += xdp_fwd_kern.o
		always += task_fd_query_kern.o

		HOSTCFLAGS += -I$(objtree)/usr/include
		HOSTCFLAGS += -I$(srctree)/tools/lib/
		@@ -175,6 +178,7 @@ HOSTCFLAGS_offwaketime_user.o += -I$(srctree)/tools/lib/bpf/
		HOSTCFLAGS_spintest_user.o += -I$(srctree)/tools/lib/bpf/
		HOSTCFLAGS_trace_event_user.o += -I$(srctree)/tools/lib/bpf/
		HOSTCFLAGS_sampleip_user.o += -I$(srctree)/tools/lib/bpf/
		HOSTCFLAGS_task_fd_query_user.o += -I$(srctree)/tools/lib/bpf/

		HOST_LOADLIBES += $(LIBBPF) -lelf
		HOSTLOADLIBES_tracex4 += -lrt

samples/bpf/task_fd_query_kern.c

0 → 100644

+19 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		#include <linux/version.h>
		#include <linux/ptrace.h>
		#include <uapi/linux/bpf.h>
		#include "bpf_helpers.h"

		SEC("kprobe/blk_start_request")
		int bpf_prog1(struct pt_regs *ctx)
		{
		return 0;
		}

		SEC("kretprobe/blk_account_io_completion")
		int bpf_prog2(struct pt_regs *ctx)
		{
		return 0;
		}
		char _license[] SEC("license") = "GPL";
		u32 _version SEC("version") = LINUX_VERSION_CODE;

samples/bpf/task_fd_query_user.c

0 → 100644

+382 −0

Original line number	Diff line number	Diff line
		// 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;
		}

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