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 | |
27 | pthread_mutex_t mutex_notify = PTHREAD_MUTEX_INITIALIZER; |
28 | pthread_cond_t cond_wakeup = PTHREAD_COND_INITIALIZER; |
29 | |
30 | static 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 | |
44 | error: |
45 | exit(EXIT_FAILURE); |
46 | } |
47 | |
48 | static 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 | |
71 | static 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; |
101 | error: |
102 | return 0; |
103 | } |
104 | |
105 | static void usage(char const *prg) |
106 | { |
107 | pr_err("usage: %s [-h] [-o] [-s <size of pipe>]\n" , prg); |
108 | } |
109 | |
110 | static 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 | |
139 | error: |
140 | free(buf); |
141 | return NULL; |
142 | } |
143 | |
144 | static const char *make_input_path(int cpu_num) |
145 | { |
146 | return make_path(cpu_num, false); |
147 | } |
148 | |
149 | static const char *make_output_path(int cpu_num) |
150 | { |
151 | return make_path(cpu_num, true); |
152 | } |
153 | |
154 | static 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_num: 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_num: 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(ctl_path: (const char *)CTL_PATH); |
182 | |
183 | return NULL; |
184 | |
185 | error: |
186 | exit(EXIT_FAILURE); |
187 | } |
188 | |
189 | static 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(arg: optarg); |
203 | if (size == 0) |
204 | goto error; |
205 | s->pipe_size = size; |
206 | break; |
207 | case 'h': |
208 | default: |
209 | usage(prg: argv[0]); |
210 | goto error; |
211 | } |
212 | } |
213 | |
214 | agent_info_init(s); |
215 | |
216 | return NULL; |
217 | |
218 | error: |
219 | exit(EXIT_FAILURE); |
220 | } |
221 | |
222 | static 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(ctl_fd: 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 | |
245 | static 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 | |
260 | int 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 | |