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