1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Guest agent for virtio-trace
4 *
5 * Copyright (C) 2012 Hitachi, Ltd.
6 * Created by Yoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com>
7 *            Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
8 */
9
10#define _GNU_SOURCE
11#include <limits.h>
12#include <stdio.h>
13#include <stdlib.h>
14#include <unistd.h>
15#include "trace-agent.h"
16
17#define PAGE_SIZE		(sysconf(_SC_PAGE_SIZE))
18#define PIPE_DEF_BUFS		16
19#define PIPE_MIN_SIZE		(PAGE_SIZE*PIPE_DEF_BUFS)
20#define PIPE_MAX_SIZE		(1024*1024)
21#define TRACEFS 		"/sys/kernel/tracing"
22#define DEBUGFS 		"/sys/kernel/debug/tracing"
23#define READ_PATH_FMT		"%s/per_cpu/cpu%d/trace_pipe_raw"
24#define WRITE_PATH_FMT		"/dev/virtio-ports/trace-path-cpu%d"
25#define CTL_PATH		"/dev/virtio-ports/agent-ctl-path"
26
27pthread_mutex_t mutex_notify = PTHREAD_MUTEX_INITIALIZER;
28pthread_cond_t cond_wakeup = PTHREAD_COND_INITIALIZER;
29
30static int get_total_cpus(void)
31{
32	int nr_cpus = (int)sysconf(_SC_NPROCESSORS_CONF);
33
34	if (nr_cpus <= 0) {
35		pr_err("Could not read cpus\n");
36		goto error;
37	} else if (nr_cpus > MAX_CPUS) {
38		pr_err("Exceed max cpus(%d)\n", (int)MAX_CPUS);
39		goto error;
40	}
41
42	return nr_cpus;
43
44error:
45	exit(EXIT_FAILURE);
46}
47
48static void *agent_info_new(void)
49{
50	struct agent_info *s;
51	int i;
52
53	s = zalloc(sizeof(struct agent_info));
54	if (s == NULL) {
55		pr_err("agent_info zalloc error\n");
56		exit(EXIT_FAILURE);
57	}
58
59	s->pipe_size = PIPE_INIT;
60	s->use_stdout = false;
61	s->cpus = get_total_cpus();
62	s->ctl_fd = -1;
63
64	/* read/write threads init */
65	for (i = 0; i < s->cpus; i++)
66		s->rw_ti[i] = rw_thread_info_new();
67
68	return s;
69}
70
71static unsigned long parse_size(const char *arg)
72{
73	unsigned long value, round;
74	char *ptr;
75
76	value = strtoul(arg, &ptr, 10);
77	switch (*ptr) {
78	case 'K': case 'k':
79		value <<= 10;
80		break;
81	case 'M': case 'm':
82		value <<= 20;
83		break;
84	default:
85		break;
86	}
87
88	if (value > PIPE_MAX_SIZE) {
89		pr_err("Pipe size must be less than 1MB\n");
90		goto error;
91	} else if (value < PIPE_MIN_SIZE) {
92		pr_err("Pipe size must be over 64KB\n");
93		goto error;
94	}
95
96	/* Align buffer size with page unit */
97	round = value & (PAGE_SIZE - 1);
98	value = value - round;
99
100	return value;
101error:
102	return 0;
103}
104
105static void usage(char const *prg)
106{
107	pr_err("usage: %s [-h] [-o] [-s <size of pipe>]\n", prg);
108}
109
110static const char *make_path(int cpu_num, bool this_is_write_path)
111{
112	int ret;
113	char *buf;
114
115	buf = zalloc(PATH_MAX);
116	if (buf == NULL) {
117		pr_err("Could not allocate buffer\n");
118		goto error;
119	}
120
121	if (this_is_write_path)
122		/* write(output) path */
123		ret = snprintf(buf, PATH_MAX, WRITE_PATH_FMT, cpu_num);
124	else {
125		/* read(input) path */
126		ret = snprintf(buf, PATH_MAX, READ_PATH_FMT, TRACEFS, cpu_num);
127		if (ret > 0 && access(buf, F_OK) != 0)
128			ret = snprintf(buf, PATH_MAX, READ_PATH_FMT, DEBUGFS, cpu_num);
129	}
130
131	if (ret <= 0) {
132		pr_err("Failed to generate %s path(CPU#%d):%d\n",
133			this_is_write_path ? "read" : "write", cpu_num, ret);
134		goto error;
135	}
136
137	return buf;
138
139error:
140	free(buf);
141	return NULL;
142}
143
144static const char *make_input_path(int cpu_num)
145{
146	return make_path(cpu_num, false);
147}
148
149static const char *make_output_path(int cpu_num)
150{
151	return make_path(cpu_num, true);
152}
153
154static void *agent_info_init(struct agent_info *s)
155{
156	int cpu;
157	const char *in_path = NULL;
158	const char *out_path = NULL;
159
160	/* init read/write threads */
161	for (cpu = 0; cpu < s->cpus; cpu++) {
162		/* set read(input) path per read/write thread */
163		in_path = make_input_path(cpu);
164		if (in_path == NULL)
165			goto error;
166
167		/* set write(output) path per read/write thread*/
168		if (!s->use_stdout) {
169			out_path = make_output_path(cpu);
170			if (out_path == NULL)
171				goto error;
172		} else
173			/* stdout mode */
174			pr_debug("stdout mode\n");
175
176		rw_thread_init(cpu, in_path, out_path, s->use_stdout,
177						s->pipe_size, s->rw_ti[cpu]);
178	}
179
180	/* init controller of read/write threads */
181	s->ctl_fd = rw_ctl_init((const char *)CTL_PATH);
182
183	return NULL;
184
185error:
186	exit(EXIT_FAILURE);
187}
188
189static void *parse_args(int argc, char *argv[], struct agent_info *s)
190{
191	int cmd;
192	unsigned long size;
193
194	while ((cmd = getopt(argc, argv, "hos:")) != -1) {
195		switch (cmd) {
196		/* stdout mode */
197		case 'o':
198			s->use_stdout = true;
199			break;
200		/* size of pipe */
201		case 's':
202			size = parse_size(optarg);
203			if (size == 0)
204				goto error;
205			s->pipe_size = size;
206			break;
207		case 'h':
208		default:
209			usage(argv[0]);
210			goto error;
211		}
212	}
213
214	agent_info_init(s);
215
216	return NULL;
217
218error:
219	exit(EXIT_FAILURE);
220}
221
222static void agent_main_loop(struct agent_info *s)
223{
224	int cpu;
225	pthread_t rw_thread_per_cpu[MAX_CPUS];
226
227	/* Start all read/write threads */
228	for (cpu = 0; cpu < s->cpus; cpu++)
229		rw_thread_per_cpu[cpu] = rw_thread_run(s->rw_ti[cpu]);
230
231	rw_ctl_loop(s->ctl_fd);
232
233	/* Finish all read/write threads */
234	for (cpu = 0; cpu < s->cpus; cpu++) {
235		int ret;
236
237		ret = pthread_join(rw_thread_per_cpu[cpu], NULL);
238		if (ret != 0) {
239			pr_err("pthread_join() error:%d (cpu %d)\n", ret, cpu);
240			exit(EXIT_FAILURE);
241		}
242	}
243}
244
245static void agent_info_free(struct agent_info *s)
246{
247	int i;
248
249	close(s->ctl_fd);
250	for (i = 0; i < s->cpus; i++) {
251		close(s->rw_ti[i]->in_fd);
252		close(s->rw_ti[i]->out_fd);
253		close(s->rw_ti[i]->read_pipe);
254		close(s->rw_ti[i]->write_pipe);
255		free(s->rw_ti[i]);
256	}
257	free(s);
258}
259
260int main(int argc, char *argv[])
261{
262	struct agent_info *s = NULL;
263
264	s = agent_info_new();
265	parse_args(argc, argv, s);
266
267	agent_main_loop(s);
268
269	agent_info_free(s);
270
271	return 0;
272}
273