tools/virtio/virtio-trace/trace-agent.c

   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 }