--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2021 Hengqi Chen
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+#include "gethostlatency.h"
+
+#define MAX_ENTRIES 10240
+
+const volatile pid_t targ_tgid = 0;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, MAX_ENTRIES);
+ __type(key, __u32);
+ __type(value, struct val_t);
+} start SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} events SEC(".maps");
+
+static __always_inline
+int probe_entry(struct pt_regs *ctx) {
+ if (!PT_REGS_PARM1(ctx))
+ return 0;
+
+ struct val_t val = {};
+ __u32 pid = bpf_get_current_pid_tgid() >> 32;
+
+ if (targ_tgid && targ_tgid != pid)
+ return 0;
+
+ if (bpf_get_current_comm(&val.comm, sizeof(val.comm)) == 0) {
+ bpf_probe_read_user(&val.host, sizeof(val.host),
+ (void *)PT_REGS_PARM1(ctx));
+ val.pid = pid;
+ val.time = bpf_ktime_get_ns();
+ bpf_map_update_elem(&start, &pid, &val, BPF_ANY);
+ }
+
+ return 0;
+}
+
+static __always_inline
+int probe_return(struct pt_regs *ctx) {
+ struct val_t *valp;
+ __u32 pid = bpf_get_current_pid_tgid() >> 32;
+ __u64 now = bpf_ktime_get_ns();
+
+ valp = bpf_map_lookup_elem(&start, &pid);
+ if (!valp)
+ return 0;
+
+ // update time from timestamp to delta
+ valp->time = now - valp->time;
+ bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, valp,
+ sizeof(*valp));
+ bpf_map_delete_elem(&start, &pid);
+ return 0;
+}
+
+SEC("kprobe/handle_entry")
+int handle_entry(struct pt_regs *ctx)
+{
+ return probe_entry(ctx);
+}
+
+SEC("kretprobe/handle_return")
+int handle_return(struct pt_regs *ctx)
+{
+ return probe_return(ctx);
+}
+
+char LICENSE[] SEC("license") = "GPL";
--- /dev/null
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+// Copyright (c) 2021 Hengqi Chen
+//
+// Based on gethostlatency(8) from BCC by Brendan Gregg.
+// 24-Mar-2021 Hengqi Chen Created this.
+#include <argp.h>
+#include <errno.h>
+#include <signal.h>
+#include <time.h>
+
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+#include "gethostlatency.h"
+#include "gethostlatency.skel.h"
+#include "trace_helpers.h"
+#include "uprobe_helpers.h"
+
+#define PERF_BUFFER_PAGES 16
+#define PERF_POLL_TIMEOUT_MS 100
+#define warn(...) fprintf(stderr, __VA_ARGS__)
+
+volatile sig_atomic_t canceled = 0;
+pid_t traced_pid = 0;
+
+const char *argp_program_version = "gethostlatency 0.1";
+const char *argp_program_bug_address =
+ "https://github.com/iovisor/bcc/tree/master/libbpf-tools";
+const char argp_program_doc[] =
+"Show latency for getaddrinfo/gethostbyname[2] calls.\n"
+"\n"
+"USAGE: gethostlatency [-h] [-p PID]\n"
+"\n"
+"EXAMPLES:\n"
+" gethostlatency # time getaddrinfo/gethostbyname[2] calls\n"
+" gethostlatency -p 1216 # only trace PID 1216\n";
+
+static const struct argp_option opts[] = {
+ {"pid", 'p', "PID", 0, "Process ID to trace"},
+ {NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help"},
+ {},
+};
+
+static error_t parse_arg(int key, char *arg, struct argp_state *state)
+{
+ long pid;
+
+ switch (key) {
+ case 'p':
+ errno = 0;
+ pid = strtol(arg, NULL, 10);
+ if (errno || pid <= 0) {
+ warn("Invalid PID: %s\n", arg);
+ argp_usage(state);
+ }
+ traced_pid = pid;
+ break;
+ case 'h':
+ argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
+ break;
+ default:
+ return ARGP_ERR_UNKNOWN;
+ }
+ return 0;
+}
+
+static void sig_int(int signo)
+{
+ canceled = 1;
+}
+
+static const char *strftime_now(char *s, size_t max, const char *format)
+{
+ struct tm *tm;
+ time_t t;
+
+ t = time(NULL);
+ tm = localtime(&t);
+ if (tm == NULL) {
+ warn("localtime: %s\n", strerror(errno));
+ return "<failed>";
+ }
+ if (strftime(s, max, format, tm) == 0) {
+ warn("strftime error\n");
+ return "<failed>";
+ }
+ return s;
+}
+
+void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
+{
+ const struct val_t *e = data;
+ char s[16] = {};
+ const char *now;
+
+ now = strftime_now(s, sizeof(s), "%H:%M:%S");
+ printf("%-11s %-10d %-20s %-10.2f %-16s\n",
+ now, e->pid, e->comm, (double)e->time/1000000, e->host);
+}
+
+void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt)
+{
+ warn("lost %llu events on CPU #%d\n", lost_cnt, cpu);
+}
+
+static int get_libc_path(char *path)
+{
+ FILE *f;
+ char buf[256] = {};
+ char *filename;
+ float version;
+
+ f = fopen("/proc/self/maps", "r");
+ if (!f) {
+ return -errno;
+ }
+
+ while (fscanf(f, "%*x-%*x %*s %*s %*s %*s %[^\n]\n", buf) != EOF) {
+ if (strchr(buf, '/') != buf) {
+ continue;
+ }
+ filename = strrchr(buf, '/') + 1;
+ if (sscanf(filename, "libc-%f.so", &version) == 1) {
+ memcpy(path, buf, strlen(buf));
+ fclose(f);
+ return 0;
+ }
+ }
+
+ fclose(f);
+ return -1;
+}
+
+static int attach_uprobes(struct gethostlatency_bpf *obj)
+{
+ int err;
+ char libc_path[PATH_MAX] = {};
+ off_t func_off;
+
+ err = get_libc_path(libc_path);
+ if (err) {
+ warn("could not find libc.so\n");
+ return -1;
+ }
+
+ func_off = get_elf_func_offset(libc_path, "getaddrinfo");
+ if (func_off < 0) {
+ warn("could not find getaddrinfo in %s\n", libc_path);
+ return -1;
+ }
+ obj->links.handle_entry =
+ bpf_program__attach_uprobe(obj->progs.handle_entry, false,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_entry);
+ if (err) {
+ warn("failed to attach getaddrinfo: %d\n", err);
+ return -1;
+ }
+ obj->links.handle_return =
+ bpf_program__attach_uprobe(obj->progs.handle_return, true,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_return);
+ if (err) {
+ warn("failed to attach getaddrinfo: %d\n", err);
+ return -1;
+ }
+
+ func_off = get_elf_func_offset(libc_path, "gethostbyname");
+ if (func_off < 0) {
+ warn("Could not find gethostbyname in %s\n", libc_path);
+ return -1;
+ }
+ obj->links.handle_entry =
+ bpf_program__attach_uprobe(obj->progs.handle_entry, false,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_entry);
+ if (err) {
+ warn("failed to attach gethostbyname: %d\n", err);
+ return -1;
+ }
+ obj->links.handle_return =
+ bpf_program__attach_uprobe(obj->progs.handle_return, true,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_return);
+ if (err) {
+ warn("failed to attach gethostbyname: %d\n", err);
+ return -1;
+ }
+
+ func_off = get_elf_func_offset(libc_path, "gethostbyname2");
+ if (func_off < 0) {
+ warn("Could not find gethostbyname2 in %s\n", libc_path);
+ return -1;
+ }
+ obj->links.handle_entry =
+ bpf_program__attach_uprobe(obj->progs.handle_entry, false,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_entry);
+ if (err) {
+ warn("failed to attach gethostbyname2: %d\n", err);
+ return -1;
+ }
+ obj->links.handle_return =
+ bpf_program__attach_uprobe(obj->progs.handle_return, true,
+ traced_pid ?: -1, libc_path, func_off);
+ err = libbpf_get_error(obj->links.handle_return);
+ if (err) {
+ warn("failed to attach gethostbyname2: %d\n", err);
+ return -1;
+ }
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ static const struct argp argp = {
+ .options = opts,
+ .parser = parse_arg,
+ .doc = argp_program_doc,
+ };
+ struct perf_buffer_opts pb_opts;
+ struct perf_buffer *pb = NULL;
+ struct gethostlatency_bpf *obj;
+ int err;
+
+ err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
+ if (err)
+ return err;
+
+ err = bump_memlock_rlimit();
+ if (err) {
+ warn("failed to increase rlimit: %d\n", err);
+ return 1;
+ }
+
+ obj = gethostlatency_bpf__open();
+ if (!obj) {
+ warn("failed to open BPF object\n");
+ return 1;
+ }
+
+ obj->rodata->targ_tgid = traced_pid;
+
+ err = gethostlatency_bpf__load(obj);
+ if (err) {
+ warn("failed to load BPF object: %d\n", err);
+ goto cleanup;
+ }
+
+ err = attach_uprobes(obj);
+ if (err) {
+ goto cleanup;
+ }
+
+ pb_opts.sample_cb = handle_event;
+ pb_opts.lost_cb = handle_lost_events;
+ pb = perf_buffer__new(bpf_map__fd(obj->maps.events), PERF_BUFFER_PAGES,
+ &pb_opts);
+ err = libbpf_get_error(pb);
+ if (err) {
+ warn("failed to open perf buffer: %d\n", err);
+ goto cleanup;
+ }
+
+ if (signal(SIGINT, sig_int) == SIG_ERR) {
+ warn("can't set signal handler: %s\n", strerror(-errno));
+ goto cleanup;
+ }
+
+ printf("%-11s %-10s %-20s %-10s %-16s\n",
+ "TIME", "PID", "COMM", "LATms", "HOST");
+
+ while (1) {
+ if ((err = perf_buffer__poll(pb, PERF_POLL_TIMEOUT_MS)) < 0)
+ break;
+ if (canceled)
+ goto cleanup;
+ }
+ warn("error polling perf buffer: %d\n", err);
+
+cleanup:
+ gethostlatency_bpf__destroy(obj);
+
+ return err != 0;
+}
projects / platform / upstream / bcc.git / commitdiff