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 } 269