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