1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 // Copyright (c) 2020 Wenbo Zhang
3 //
4 // Based on filelife(8) from BCC by Brendan Gregg & Allan McAleavy.
5 // 20-Mar-2020 Wenbo Zhang Created this.
6 #include <argp.h>
7 #include <signal.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include <string.h>
11 #include <unistd.h>
12 #include <time.h>
13 #include <bpf/libbpf.h>
14 #include <bpf/bpf.h>
15 #include "filelife.h"
16 #include "filelife.skel.h"
17 #include "trace_helpers.h"
18
19 #define PERF_BUFFER_PAGES 16
20 #define PERF_POLL_TIMEOUT_MS 100
21
22 static volatile sig_atomic_t exiting = 0;
23
24 static struct env {
25 pid_t pid;
26 bool verbose;
27 } env = { };
28
29 const char *argp_program_version = "filelife 0.1";
30 const char *argp_program_bug_address =
31 "https://github.com/iovisor/bcc/tree/master/libbpf-tools";
32 const char argp_program_doc[] =
33 "Trace the lifespan of short-lived files.\n"
34 "\n"
35 "USAGE: filelife [--help] [-p PID]\n"
36 "\n"
37 "EXAMPLES:\n"
38 " filelife # trace all events\n"
39 " filelife -p 123 # trace pid 123\n";
40
41 static const struct argp_option opts[] = {
42 { "pid", 'p', "PID", 0, "Process PID to trace" },
43 { "verbose", 'v', NULL, 0, "Verbose debug output" },
44 { NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help" },
45 {},
46 };
47
parse_arg(int key,char * arg,struct argp_state * state)48 static error_t parse_arg(int key, char *arg, struct argp_state *state)
49 {
50 int pid;
51
52 switch (key) {
53 case 'h':
54 argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
55 break;
56 case 'v':
57 env.verbose = true;
58 break;
59 case 'p':
60 errno = 0;
61 pid = strtol(arg, NULL, 10);
62 if (errno || pid <= 0) {
63 fprintf(stderr, "invalid PID: %s\n", arg);
64 argp_usage(state);
65 }
66 env.pid = pid;
67 break;
68 default:
69 return ARGP_ERR_UNKNOWN;
70 }
71 return 0;
72 }
73
libbpf_print_fn(enum libbpf_print_level level,const char * format,va_list args)74 static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
75 {
76 if (level == LIBBPF_DEBUG && !env.verbose)
77 return 0;
78 return vfprintf(stderr, format, args);
79 }
80
sig_int(int signo)81 static void sig_int(int signo)
82 {
83 exiting = 1;
84 }
85
handle_event(void * ctx,int cpu,void * data,__u32 data_sz)86 void handle_event(void *ctx, int cpu, void *data, __u32 data_sz)
87 {
88 const struct event *e = data;
89 struct tm *tm;
90 char ts[32];
91 time_t t;
92
93 time(&t);
94 tm = localtime(&t);
95 strftime(ts, sizeof(ts), "%H:%M:%S", tm);
96 printf("%-8s %-6d %-16s %-7.2f %s\n",
97 ts, e->tgid, e->task, (double)e->delta_ns / 1000000000,
98 e->file);
99 }
100
handle_lost_events(void * ctx,int cpu,__u64 lost_cnt)101 void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt)
102 {
103 fprintf(stderr, "lost %llu events on CPU #%d\n", lost_cnt, cpu);
104 }
105
main(int argc,char ** argv)106 int main(int argc, char **argv)
107 {
108 static const struct argp argp = {
109 .options = opts,
110 .parser = parse_arg,
111 .doc = argp_program_doc,
112 };
113 struct perf_buffer *pb = NULL;
114 struct filelife_bpf *obj;
115 int err;
116
117 err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
118 if (err)
119 return err;
120
121 libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
122 libbpf_set_print(libbpf_print_fn);
123
124 obj = filelife_bpf__open();
125 if (!obj) {
126 fprintf(stderr, "failed to open BPF object\n");
127 return 1;
128 }
129
130 /* initialize global data (filtering options) */
131 obj->rodata->targ_tgid = env.pid;
132
133 err = filelife_bpf__load(obj);
134 if (err) {
135 fprintf(stderr, "failed to load BPF object: %d\n", err);
136 goto cleanup;
137 }
138
139 err = filelife_bpf__attach(obj);
140 if (err) {
141 fprintf(stderr, "failed to attach BPF programs\n");
142 goto cleanup;
143 }
144
145 printf("Tracing the lifespan of short-lived files ... Hit Ctrl-C to end.\n");
146 printf("%-8s %-6s %-16s %-7s %s\n", "TIME", "PID", "COMM", "AGE(s)", "FILE");
147
148 pb = perf_buffer__new(bpf_map__fd(obj->maps.events), PERF_BUFFER_PAGES,
149 handle_event, handle_lost_events, NULL, NULL);
150 if (!pb) {
151 err = -errno;
152 fprintf(stderr, "failed to open perf buffer: %d\n", err);
153 goto cleanup;
154 }
155
156 if (signal(SIGINT, sig_int) == SIG_ERR) {
157 fprintf(stderr, "can't set signal handler: %s\n", strerror(errno));
158 err = 1;
159 goto cleanup;
160 }
161
162 while (!exiting) {
163 err = perf_buffer__poll(pb, PERF_POLL_TIMEOUT_MS);
164 if (err < 0 && err != -EINTR) {
165 fprintf(stderr, "error polling perf buffer: %s\n", strerror(-err));
166 goto cleanup;
167 }
168 /* reset err to return 0 if exiting */
169 err = 0;
170 }
171
172 cleanup:
173 perf_buffer__free(pb);
174 filelife_bpf__destroy(obj);
175
176 return err != 0;
177 }
178