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 READ_PATH_FMT   \
  22                 "/sys/kernel/debug/tracing/per_cpu/cpu%d/trace_pipe_raw"
  23 #define WRITE_PATH_FMT          "/dev/virtio-ports/trace-path-cpu%d"
  24 #define CTL_PATH                "/dev/virtio-ports/agent-ctl-path"
  25
  26 pthread_mutex_t mutex_notify = PTHREAD_MUTEX_INITIALIZER;
  27 pthread_cond_t cond_wakeup = PTHREAD_COND_INITIALIZER;
  28
  29 static int get_total_cpus(void)
  30 {
  31         int nr_cpus = (int)sysconf(_SC_NPROCESSORS_CONF);
  32
  33         if (nr_cpus <= 0) {
  34                 pr_err("Could not read cpus\n");
  35                 goto error;
  36         } else if (nr_cpus > MAX_CPUS) {
  37                 pr_err("Exceed max cpus(%d)\n", (int)MAX_CPUS);
  38                 goto error;
  39         }
  40
  41         return nr_cpus;
  42
  43 error:
  44         exit(EXIT_FAILURE);
  45 }
  46
  47 static void *agent_info_new(void)
  48 {
  49         struct agent_info *s;
  50         int i;
  51
  52         s = zalloc(sizeof(struct agent_info));
  53         if (s == NULL) {
  54                 pr_err("agent_info zalloc error\n");
  55                 exit(EXIT_FAILURE);
  56         }
  57
  58         s->pipe_size = PIPE_INIT;
  59         s->use_stdout = false;
  60         s->cpus = get_total_cpus();
  61         s->ctl_fd = -1;
  62
  63         /* read/write threads init */
  64         for (i = 0; i < s->cpus; i++)
  65                 s->rw_ti[i] = rw_thread_info_new();
  66
  67         return s;
  68 }
  69
  70 static unsigned long parse_size(const char *arg)
  71 {
  72         unsigned long value, round;
  73         char *ptr;
  74
  75         value = strtoul(arg, &ptr, 10);
  76         switch (*ptr) {
  77         case 'K': case 'k':
  78                 value <<= 10;
  79                 break;
  80         case 'M': case 'm':
  81                 value <<= 20;
  82                 break;
  83         default:
  84                 break;
  85         }
  86
  87         if (value > PIPE_MAX_SIZE) {
  88                 pr_err("Pipe size must be less than 1MB\n");
  89                 goto error;
  90         } else if (value < PIPE_MIN_SIZE) {
  91                 pr_err("Pipe size must be over 64KB\n");
  92                 goto error;
  93         }
  94
  95         /* Align buffer size with page unit */
  96         round = value & (PAGE_SIZE - 1);
  97         value = value - round;
  98
  99         return value;
 100 error:
 101         return 0;
 102 }
 103
 104 static void usage(char const *prg)
 105 {
 106         pr_err("usage: %s [-h] [-o] [-s <size of pipe>]\n", prg);
 107 }
 108
 109 static const char *make_path(int cpu_num, bool this_is_write_path)
 110 {
 111         int ret;
 112         char *buf;
 113
 114         buf = zalloc(PATH_MAX);
 115         if (buf == NULL) {
 116                 pr_err("Could not allocate buffer\n");
 117                 goto error;
 118         }
 119
 120         if (this_is_write_path)
 121                 /* write(output) path */
 122                 ret = snprintf(buf, PATH_MAX, WRITE_PATH_FMT, cpu_num);
 123         else
 124                 /* read(input) path */
 125                 ret = snprintf(buf, PATH_MAX, READ_PATH_FMT, cpu_num);
 126
 127         if (ret <= 0) {
 128                 pr_err("Failed to generate %s path(CPU#%d):%d\n",
 129                         this_is_write_path ? "read" : "write", cpu_num, ret);
 130                 goto error;
 131         }
 132
 133         return buf;
 134
 135 error:
 136         free(buf);
 137         return NULL;
 138 }
 139
 140 static const char *make_input_path(int cpu_num)
 141 {
 142         return make_path(cpu_num, false);
 143 }
 144
 145 static const char *make_output_path(int cpu_num)
 146 {
 147         return make_path(cpu_num, true);
 148 }
 149
 150 static void *agent_info_init(struct agent_info *s)
 151 {
 152         int cpu;
 153         const char *in_path = NULL;
 154         const char *out_path = NULL;
 155
 156         /* init read/write threads */
 157         for (cpu = 0; cpu < s->cpus; cpu++) {
 158                 /* set read(input) path per read/write thread */
 159                 in_path = make_input_path(cpu);
 160                 if (in_path == NULL)
 161                         goto error;
 162
 163                 /* set write(output) path per read/write thread*/
 164                 if (!s->use_stdout) {
 165                         out_path = make_output_path(cpu);
 166                         if (out_path == NULL)
 167                                 goto error;
 168                 } else
 169                         /* stdout mode */
 170                         pr_debug("stdout mode\n");
 171
 172                 rw_thread_init(cpu, in_path, out_path, s->use_stdout,
 173                                                 s->pipe_size, s->rw_ti[cpu]);
 174         }
 175
 176         /* init controller of read/write threads */
 177         s->ctl_fd = rw_ctl_init((const char *)CTL_PATH);
 178
 179         return NULL;
 180
 181 error:
 182         exit(EXIT_FAILURE);
 183 }
 184
 185 static void *parse_args(int argc, char *argv[], struct agent_info *s)
 186 {
 187         int cmd;
 188         unsigned long size;
 189
 190         while ((cmd = getopt(argc, argv, "hos:")) != -1) {
 191                 switch (cmd) {
 192                 /* stdout mode */
 193                 case 'o':
 194                         s->use_stdout = true;
 195                         break;
 196                 /* size of pipe */
 197                 case 's':
 198                         size = parse_size(optarg);
 199                         if (size == 0)
 200                                 goto error;
 201                         s->pipe_size = size;
 202                         break;
 203                 case 'h':
 204                 default:
 205                         usage(argv[0]);
 206                         goto error;
 207                 }
 208         }
 209
 210         agent_info_init(s);
 211
 212         return NULL;
 213
 214 error:
 215         exit(EXIT_FAILURE);
 216 }
 217
 218 static void agent_main_loop(struct agent_info *s)
 219 {
 220         int cpu;
 221         pthread_t rw_thread_per_cpu[MAX_CPUS];
 222
 223         /* Start all read/write threads */
 224         for (cpu = 0; cpu < s->cpus; cpu++)
 225                 rw_thread_per_cpu[cpu] = rw_thread_run(s->rw_ti[cpu]);
 226
 227         rw_ctl_loop(s->ctl_fd);
 228
 229         /* Finish all read/write threads */
 230         for (cpu = 0; cpu < s->cpus; cpu++) {
 231                 int ret;
 232
 233                 ret = pthread_join(rw_thread_per_cpu[cpu], NULL);
 234                 if (ret != 0) {
 235                         pr_err("pthread_join() error:%d (cpu %d)\n", ret, cpu);
 236                         exit(EXIT_FAILURE);
 237                 }
 238         }
 239 }
 240
 241 static void agent_info_free(struct agent_info *s)
 242 {
 243         int i;
 244
 245         close(s->ctl_fd);
 246         for (i = 0; i < s->cpus; i++) {
 247                 close(s->rw_ti[i]->in_fd);
 248                 close(s->rw_ti[i]->out_fd);
 249                 close(s->rw_ti[i]->read_pipe);
 250                 close(s->rw_ti[i]->write_pipe);
 251                 free(s->rw_ti[i]);
 252         }
 253         free(s);
 254 }
 255
 256 int main(int argc, char *argv[])
 257 {
 258         struct agent_info *s = NULL;
 259
 260         s = agent_info_new();
 261         parse_args(argc, argv, s);
 262
 263         agent_main_loop(s);
 264
 265         agent_info_free(s);
 266
 267         return 0;
 268 }