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