diff options
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/syscall_tp_kern.c | 62 | ||||
| -rw-r--r-- | samples/bpf/syscall_tp_user.c | 71 |
3 files changed, 137 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 770d46cdf9f4..f1010fe759fe 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -39,6 +39,7 @@ hostprogs-y += per_socket_stats_example hostprogs-y += load_sock_ops hostprogs-y += xdp_redirect hostprogs-y += xdp_redirect_map +hostprogs-y += syscall_tp # Libbpf dependencies LIBBPF := ../../tools/lib/bpf/bpf.o @@ -82,6 +83,7 @@ test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o +syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -125,6 +127,7 @@ always += tcp_iw_kern.o always += tcp_clamp_kern.o always += xdp_redirect_kern.o always += xdp_redirect_map_kern.o +always += syscall_tp_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(srctree)/tools/lib/ @@ -163,6 +166,7 @@ HOSTLOADLIBES_xdp_tx_iptunnel += -lelf HOSTLOADLIBES_test_map_in_map += -lelf HOSTLOADLIBES_xdp_redirect += -lelf HOSTLOADLIBES_xdp_redirect_map += -lelf +HOSTLOADLIBES_syscall_tp += -lelf # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: # make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang diff --git a/samples/bpf/syscall_tp_kern.c b/samples/bpf/syscall_tp_kern.c new file mode 100644 index 000000000000..9149c524d279 --- /dev/null +++ b/samples/bpf/syscall_tp_kern.c @@ -0,0 +1,62 @@ +/* Copyright (c) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <uapi/linux/bpf.h> +#include "bpf_helpers.h" + +struct syscalls_enter_open_args { + unsigned long long unused; + long syscall_nr; + long filename_ptr; + long flags; + long mode; +}; + +struct syscalls_exit_open_args { + unsigned long long unused; + long syscall_nr; + long ret; +}; + +struct bpf_map_def SEC("maps") enter_open_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u32), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") exit_open_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(u32), + .max_entries = 1, +}; + +static __always_inline void count(void *map) +{ + u32 key = 0; + u32 *value, init_val = 1; + + value = bpf_map_lookup_elem(map, &key); + if (value) + *value += 1; + else + bpf_map_update_elem(map, &key, &init_val, BPF_NOEXIST); +} + +SEC("tracepoint/syscalls/sys_enter_open") +int trace_enter_open(struct syscalls_enter_open_args *ctx) +{ + count((void *)&enter_open_map); + return 0; +} + +SEC("tracepoint/syscalls/sys_exit_open") +int trace_enter_exit(struct syscalls_exit_open_args *ctx) +{ + count((void *)&exit_open_map); + return 0; +} diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c new file mode 100644 index 000000000000..a3cb91ebf4e7 --- /dev/null +++ b/samples/bpf/syscall_tp_user.c @@ -0,0 +1,71 @@ +/* Copyright (c) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <stdio.h> +#include <unistd.h> +#include <fcntl.h> +#include <stdlib.h> +#include <signal.h> +#include <linux/bpf.h> +#include <string.h> +#include <linux/perf_event.h> +#include <errno.h> +#include <assert.h> +#include <stdbool.h> +#include <sys/resource.h> +#include "libbpf.h" +#include "bpf_load.h" + +/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*. + * This requires kernel CONFIG_FTRACE_SYSCALLS to be set. + */ + +static void verify_map(int map_id) +{ + __u32 key = 0; + __u32 val; + + if (bpf_map_lookup_elem(map_id, &key, &val) != 0) { + fprintf(stderr, "map_lookup failed: %s\n", strerror(errno)); + return; + } + if (val == 0) + fprintf(stderr, "failed: map #%d returns value 0\n", map_id); +} + +int main(int argc, char **argv) +{ + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + char filename[256]; + int fd; + + setrlimit(RLIMIT_MEMLOCK, &r); + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + fprintf(stderr, "%s", bpf_log_buf); + return 1; + } + + /* current load_bpf_file has perf_event_open default pid = -1 + * and cpu = 0, which permits attached bpf execution on + * all cpus for all pid's. bpf program execution ignores + * cpu affinity. + */ + /* trigger some "open" operations */ + fd = open(filename, O_RDONLY); + if (fd < 0) { + fprintf(stderr, "open failed: %s\n", strerror(errno)); + return 1; + } + close(fd); + + /* verify the map */ + verify_map(map_fd[0]); + verify_map(map_fd[1]); + + return 0; +} |