273 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Guest agent for virtio-trace4 *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_SOURCE11#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 1619#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 27pthread_mutex_t mutex_notify = PTHREAD_MUTEX_INITIALIZER;28pthread_cond_t cond_wakeup = PTHREAD_COND_INITIALIZER;29 30static 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 44error:45 exit(EXIT_FAILURE);46}47 48static 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 71static 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;101error:102 return 0;103}104 105static void usage(char const *prg)106{107 pr_err("usage: %s [-h] [-o] [-s <size of pipe>]\n", prg);108}109 110static 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 139error:140 free(buf);141 return NULL;142}143 144static const char *make_input_path(int cpu_num)145{146 return make_path(cpu_num, false);147}148 149static const char *make_output_path(int cpu_num)150{151 return make_path(cpu_num, true);152}153 154static 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 } else173 /* 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 185error:186 exit(EXIT_FAILURE);187}188 189static 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 218error:219 exit(EXIT_FAILURE);220}221 222static 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 245static 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 260int 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