@@ -72,7 +72,7 @@ TEST_GEN_PROGS_EXTENDED = test_sock_addr test_skb_cgroup_id_user \
flow_dissector_load test_flow_dissector test_tcp_check_syncookie_user \
test_lirc_mode2_user
-TEST_CUSTOM_PROGS = urandom_read
+TEST_CUSTOM_PROGS = urandom_read fd2path_loadgen
include ../lib.mk
@@ -92,6 +92,9 @@ $(OUTPUT)/urandom_read: urandom_read.c
$(OUTPUT)/test_stub.o: test_stub.c
$(CC) -c $(CFLAGS) -o $@ $<
+$(OUTPUT)/fd2path_loadgen: fd2path_loadgen.c
+ $(CC) -o $@ $< -Wl,--build-id
+
BPFOBJ := $(OUTPUT)/libbpf.a
$(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED): $(OUTPUT)/test_stub.o $(BPFOBJ)
@@ -266,7 +269,8 @@ TRUNNER_TESTS_DIR := prog_tests
TRUNNER_BPF_PROGS_DIR := progs
TRUNNER_EXTRA_SOURCES := test_progs.c cgroup_helpers.c trace_helpers.c \
flow_dissector_load.h
-TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read \
+TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read \
+ $(OUTPUT)/fd2path_loadgen \
$(wildcard progs/btf_dump_test_case_*.c)
TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
TRUNNER_BPF_CFLAGS := -I. -I$(OUTPUT) $(BPF_CFLAGS) $(CLANG_CFLAGS)
new file mode 100644
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <alloca.h>
+#include <sys/stat.h>
+
+enum FS_TYPE {
+ PIPE_0,
+ PIPE_1,
+ SOCK,
+ PROC,
+ DEV,
+ LOCAL,
+ INDICATOR,
+ MAX_FDS
+};
+
+#ifndef MAX_LOOP_TIMES
+#define MAX_LOOP_TIMES 100
+#endif
+
+int main(int argc, char *argv[])
+{
+ int *fds = alloca(sizeof(int) * MAX_FDS);
+ int *pipefd = fds;
+ int *sockfd = fds + SOCK;
+ int *procfd = fds + PROC;
+ int *devfd = fds + DEV;
+ int *localfd = fds + LOCAL;
+ int *indicatorfd = fds + INDICATOR;
+ int times = MAX_LOOP_TIMES;
+
+ /* unmountable pseudo-filesystems */
+ if (pipe(pipefd) < 0)
+ return 1;
+
+ /* unmountable pseudo-filesystems */
+ *sockfd = socket(AF_INET, SOCK_STREAM, 0);
+ if (sockfd < 0)
+ return 1;
+
+ /* mountable pseudo-filesystems */
+ *procfd = open("/proc/self/comm", O_RDONLY);
+ if (procfd < 0)
+ return 1;
+
+ *devfd = open("/dev/urandom", O_RDONLY);
+ if (devfd < 0)
+ return 1;
+
+ *localfd = open("/tmp/fd2path_loadgen.txt", O_CREAT|O_RDONLY);
+ if (localfd < 0)
+ return 1;
+
+ *indicatorfd = open("/tmp/", O_PATH);
+
+ while (times--) {
+ struct stat fileStat;
+
+ for (int i = 0; i < MAX_FDS; i++) {
+ fstat(fds[i], &fileStat);
+ usleep(1);
+ }
+ }
+
+ for (int i = 0; i < MAX_FDS; i++)
+ close(fds[i]);
+
+ remove("/tmp/fd2path_loadgen.txt");
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <pthread.h>
+#include <test_progs.h>
+
+#ifndef MAX_PATH_LENGTH
+#define MAX_PATH_LENGTH 128
+#endif
+
+#ifndef TASK_COMM_LEN
+#define TASK_COMM_LEN 16
+#endif
+
+#ifndef MAX_STAT_EVENTS
+#define MAX_STAT_EVENTS 64ull
+#endif
+
+struct get_path_trace_t {
+ int pid;
+ unsigned long fd;
+ char comm[TASK_COMM_LEN];
+ char path[MAX_PATH_LENGTH];
+};
+
+static const char *loadgen = "./fd2path_loadgen";
+static int exp_cnt = MAX_STAT_EVENTS;
+
+void *thread_loadgen(void *arg)
+{
+ assert(system(loadgen) == 0);
+ return NULL;
+}
+
+static void get_path_print_output(void *ctx, int cpu, void *data, __u32 size)
+{
+ struct get_path_trace_t *e = data;
+ char pathname[MAX_PATH_LENGTH] = {'0'};
+ char buf[MAX_PATH_LENGTH] = {'0'};
+ int ret, duration = 0;
+
+ if (strncmp(e->comm, &loadgen[2], MAX_PATH_LENGTH))
+ return;
+ snprintf(pathname, MAX_PATH_LENGTH, "/proc/%d/fd/%lu", e->pid, e->fd);
+ readlink(pathname, buf, MAX_PATH_LENGTH);
+ exp_cnt--;
+ ret = strncmp(buf, e->path, MAX_PATH_LENGTH);
+ CHECK(ret != 0, "get_file_path", "failed to get path: %lu->%s\n",
+ e->fd, e->path);
+}
+
+void test_get_file_path(void)
+{
+ const char *prog_name = "raw_tracepoint/sys_enter:newfstat";
+ const char *file = "./test_get_file_path.o";
+ int err, nr_cpus, duration = 0;
+ struct perf_buffer_opts pb_opts = {};
+ struct perf_buffer *pb = NULL;
+ struct bpf_map *perf_buf_map;
+ cpu_set_t cpu_set, cpu_seen;
+ struct bpf_link *link = NULL;
+ struct timespec tv = {0, 10};
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ pthread_t t = 0;
+
+ obj = bpf_object__open_file(file, NULL);
+ if (CHECK(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
+ return;
+
+ err = bpf_object__load(obj);
+ if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
+ goto out_close;
+
+ prog = bpf_object__find_program_by_title(obj, prog_name);
+ if (CHECK(!prog, "find_prog", "prog '%s' not found\n", prog_name))
+ goto out_close;
+
+ link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
+ if (CHECK(IS_ERR(link), "attach_tp", "err %ld\n", PTR_ERR(link)))
+ goto out_close;
+
+ nr_cpus = libbpf_num_possible_cpus();
+ if (CHECK(nr_cpus < 0, "nr_cpus", "err %d\n", nr_cpus))
+ goto out_close;
+
+ CPU_ZERO(&cpu_seen);
+ for (int i = 0; i < nr_cpus; i++) {
+ CPU_ZERO(&cpu_set);
+ CPU_SET(i, &cpu_set);
+
+ err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set),
+ &cpu_set);
+ if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
+ i, err))
+ goto out_detach;
+
+ usleep(1);
+ }
+
+ perf_buf_map = bpf_object__find_map_by_name(obj, "perfmap");
+ if (CHECK(!perf_buf_map, "bpf_find_map", "not found\n"))
+ goto out_close;
+
+ pb_opts.sample_cb = get_path_print_output;
+ pb_opts.ctx = &cpu_seen;
+ pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
+ if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
+ goto out_detach;
+
+ pthread_create(&t, NULL, thread_loadgen, NULL);
+
+ /* trigger some fstat syscall action */
+ for (int i = 0; i < MAX_STAT_EVENTS; i++)
+ nanosleep(&tv, NULL);
+
+ while (exp_cnt > 0) {
+ err = perf_buffer__poll(pb, 100);
+ if (err < 0 && CHECK(err < 0, "pb__poll", "err %d\n", err))
+ goto out_free_pb;
+ }
+
+out_free_pb:
+ perf_buffer__free(pb);
+out_detach:
+ bpf_link__destroy(link);
+out_close:
+ bpf_object__close(obj);
+
+ pthread_join(t, NULL);
+}
new file mode 100644
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <linux/ptrace.h>
+#include <stdbool.h>
+#include <string.h>
+#include "bpf_helpers.h"
+
+#ifndef MAX_PATH_LENGTH
+#define MAX_PATH_LENGTH 128
+#endif
+
+#ifndef TASK_COMM_LEN
+#define TASK_COMM_LEN 16
+#endif
+
+struct path_trace_t {
+ int pid;
+ unsigned long fd;
+ char comm[TASK_COMM_LEN];
+ char path[MAX_PATH_LENGTH];
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(max_entries, 128);
+ __uint(key_size, sizeof(int));
+ __uint(value_size, sizeof(__u32));
+} perfmap SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, struct path_trace_t);
+} pathdata_map SEC(".maps");
+
+SEC("raw_tracepoint/sys_enter:newfstat")
+int bpf_prog(struct bpf_raw_tracepoint_args *ctx)
+{
+ struct path_trace_t *data;
+ struct pt_regs *regs;
+ __u32 key = 0;
+
+ data = bpf_map_lookup_elem(&pathdata_map, &key);
+ if (!data)
+ return 0;
+ data->pid = bpf_get_current_pid_tgid() >> 32;
+ regs = (struct pt_regs *)ctx->args[0];
+ bpf_probe_read(&data->fd, sizeof(data->fd), ®s->rdi);
+ bpf_get_current_comm(&data->comm, TASK_COMM_LEN);
+ if (bpf_get_file_path(data->path, MAX_PATH_LENGTH, data->fd) < 0)
+ return 0;
+ bpf_perf_event_output(ctx, &perfmap, BPF_F_CURRENT_CPU,
+ data, sizeof(*data));
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";