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

   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);
 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);
 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((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(optarg);
 203                         if (size == 0)
 204                                 goto error;
 205                         s->pipe_size = size;
 206                         break;
 207                 case 'h':
 208                 default:
 209                         usage(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(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 }