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 
28 pthread_mutex_t mutex_notify = PTHREAD_MUTEX_INITIALIZER;
29 pthread_cond_t cond_wakeup = PTHREAD_COND_INITIALIZER;
30 
31 static 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 
45 error:
46 	exit(EXIT_FAILURE);
47 }
48 
49 static 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 
72 static 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;
102 error:
103 	return 0;
104 }
105 
106 static void usage(char const *prg)
107 {
108 	pr_err("usage: %s [-h] [-o] [-s <size of pipe>]\n", prg);
109 }
110 
111 static 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 
137 error:
138 	free(buf);
139 	return NULL;
140 }
141 
142 static const char *make_input_path(int cpu_num)
143 {
144 	return make_path(cpu_num, false);
145 }
146 
147 static const char *make_output_path(int cpu_num)
148 {
149 	return make_path(cpu_num, true);
150 }
151 
152 static 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 
183 error:
184 	exit(EXIT_FAILURE);
185 }
186 
187 static 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 
216 error:
217 	exit(EXIT_FAILURE);
218 }
219 
220 static 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 
243 static 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 
258 int 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