| 1 | /* lttd |
| 2 | * |
| 3 | * Linux Trace Toolkit Daemon |
| 4 | * |
| 5 | * This is a simple daemon that reads a few relayfs channels and save them in a |
| 6 | * trace. |
| 7 | * |
| 8 | * |
| 9 | * Copyright 2005 - |
| 10 | * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> |
| 11 | */ |
| 12 | |
| 13 | #include <stdio.h> |
| 14 | #include <errno.h> |
| 15 | #include <sys/types.h> |
| 16 | #include <sys/stat.h> |
| 17 | #include <unistd.h> |
| 18 | #include <stdlib.h> |
| 19 | #include <dirent.h> |
| 20 | #include <string.h> |
| 21 | #include <fcntl.h> |
| 22 | #include <sys/poll.h> |
| 23 | |
| 24 | enum { |
| 25 | GET_SUBBUF, |
| 26 | PUT_SUBBUF, |
| 27 | GET_N_BUBBUFS, |
| 28 | GET_SUBBUF_SIZE |
| 29 | }; |
| 30 | |
| 31 | struct fd_pair { |
| 32 | int channel; |
| 33 | int trace; |
| 34 | }; |
| 35 | |
| 36 | struct channel_trace_fd { |
| 37 | struct fd_pair *pair; |
| 38 | int num_pairs; |
| 39 | }; |
| 40 | |
| 41 | static char *trace_name = NULL; |
| 42 | static char *channel_name = NULL; |
| 43 | static int daemon_mode = 0; |
| 44 | static int append_mode = 0; |
| 45 | |
| 46 | /* Args : |
| 47 | * |
| 48 | * -t directory Directory name of the trace to write to. Will be created. |
| 49 | * -c directory Root directory of the relayfs trace channels. |
| 50 | * -d Run in background (daemon). |
| 51 | * -a Trace append mode. |
| 52 | */ |
| 53 | void show_arguments(void) |
| 54 | { |
| 55 | printf("Please use the following arguments :\n"); |
| 56 | printf("\n"); |
| 57 | printf("-t directory Directory name of the trace to write to.\n" |
| 58 | " It will be created.\n"); |
| 59 | printf("-c directory Root directory of the relayfs trace channels.\n"); |
| 60 | printf("-d Run in background (daemon).\n"); |
| 61 | printf("-a Append to an possibly existing trace.\n"); |
| 62 | printf("\n"); |
| 63 | } |
| 64 | |
| 65 | |
| 66 | /* parse_arguments |
| 67 | * |
| 68 | * Parses the command line arguments. |
| 69 | * |
| 70 | * Returns 1 if the arguments were correct, but doesn't ask for program |
| 71 | * continuation. Returns -1 if the arguments are incorrect, or 0 if OK. |
| 72 | */ |
| 73 | int parse_arguments(int argc, char **argv) |
| 74 | { |
| 75 | int ret = 0; |
| 76 | int argn = 1; |
| 77 | |
| 78 | if(argc == 2) { |
| 79 | if(strcmp(argv[1], "-h") == 0) { |
| 80 | return 1; |
| 81 | } |
| 82 | } |
| 83 | |
| 84 | while(argn < argc) { |
| 85 | |
| 86 | switch(argv[argn][0]) { |
| 87 | case '-': |
| 88 | switch(argv[argn][1]) { |
| 89 | case 't': |
| 90 | if(argn+1 < argc) { |
| 91 | trace_name = argv[argn+1]; |
| 92 | argn++; |
| 93 | } |
| 94 | break; |
| 95 | case 'c': |
| 96 | if(argn+1 < argc) { |
| 97 | channel_name = argv[argn+1]; |
| 98 | argn++; |
| 99 | } |
| 100 | break; |
| 101 | case 'd': |
| 102 | daemon_mode = 1; |
| 103 | break; |
| 104 | case 'a': |
| 105 | append_mode = 1; |
| 106 | break; |
| 107 | default: |
| 108 | printf("Invalid argument '%s'.\n", argv[argn]); |
| 109 | printf("\n"); |
| 110 | ret = -1; |
| 111 | } |
| 112 | break; |
| 113 | default: |
| 114 | printf("Invalid argument '%s'.\n", argv[argn]); |
| 115 | printf("\n"); |
| 116 | ret = -1; |
| 117 | } |
| 118 | argn++; |
| 119 | } |
| 120 | |
| 121 | if(trace_name == NULL) { |
| 122 | printf("Please specify a trace name.\n"); |
| 123 | printf("\n"); |
| 124 | ret = -1; |
| 125 | } |
| 126 | |
| 127 | if(channel_name == NULL) { |
| 128 | printf("Please specify a channel name.\n"); |
| 129 | printf("\n"); |
| 130 | ret = -1; |
| 131 | } |
| 132 | |
| 133 | return ret; |
| 134 | } |
| 135 | |
| 136 | void show_info(void) |
| 137 | { |
| 138 | printf("Linux Trace Toolkit Trace Daemon\n"); |
| 139 | printf("\n"); |
| 140 | printf("Reading from relayfs directory : %s\n", channel_name); |
| 141 | printf("Writing to trace directory : %s\n", trace_name); |
| 142 | printf("\n"); |
| 143 | } |
| 144 | |
| 145 | |
| 146 | int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name, |
| 147 | struct channel_trace_fd *fd_pairs) |
| 148 | { |
| 149 | DIR *channel_dir = opendir(subchannel_name); |
| 150 | struct dirent *entry; |
| 151 | struct stat stat_buf; |
| 152 | int ret; |
| 153 | char path_channel[PATH_MAX]; |
| 154 | int path_channel_len; |
| 155 | char *path_channel_ptr; |
| 156 | char path_trace[PATH_MAX]; |
| 157 | int path_trace_len; |
| 158 | char *path_trace_ptr; |
| 159 | |
| 160 | if(channel_dir == NULL) { |
| 161 | perror(subchannel_name); |
| 162 | return ENOENT; |
| 163 | } |
| 164 | |
| 165 | //FIXME : check if the directory already exist, and ask the user if he wants |
| 166 | //to append to the traces. |
| 167 | printf("Creating trace subdirectory %s\n", subtrace_name); |
| 168 | ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO); |
| 169 | if(ret == -1) { |
| 170 | if(errno == EEXIST && append_mode) { |
| 171 | printf("Appending to directory %s as resquested\n", subtrace_name); |
| 172 | } else { |
| 173 | perror(subtrace_name); |
| 174 | return -1; |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | strncpy(path_channel, subchannel_name, PATH_MAX-1); |
| 179 | path_channel_len = strlen(path_channel); |
| 180 | path_channel[path_channel_len] = '/'; |
| 181 | path_channel_len++; |
| 182 | path_channel_ptr = path_channel + path_channel_len; |
| 183 | |
| 184 | strncpy(path_trace, subtrace_name, PATH_MAX-1); |
| 185 | path_trace_len = strlen(path_trace); |
| 186 | path_trace[path_trace_len] = '/'; |
| 187 | path_trace_len++; |
| 188 | path_trace_ptr = path_trace + path_trace_len; |
| 189 | |
| 190 | while((entry = readdir(channel_dir)) != NULL) { |
| 191 | |
| 192 | if(entry->d_name[0] == '.') continue; |
| 193 | |
| 194 | strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len); |
| 195 | strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len); |
| 196 | |
| 197 | ret = stat(path_channel, &stat_buf); |
| 198 | if(ret == -1) { |
| 199 | perror(path_channel); |
| 200 | continue; |
| 201 | } |
| 202 | |
| 203 | printf("Channel file : %s\n", path_channel); |
| 204 | |
| 205 | if(S_ISDIR(stat_buf.st_mode)) { |
| 206 | |
| 207 | printf("Entering channel subdirectory...\n"); |
| 208 | ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs); |
| 209 | if(ret < 0) continue; |
| 210 | } else if(S_ISREG(stat_buf.st_mode)) { |
| 211 | printf("Opening file.\n"); |
| 212 | |
| 213 | fd_pairs->pair = realloc(fd_pairs->pair, |
| 214 | ++fd_pairs->num_pairs * sizeof(struct fd_pair)); |
| 215 | |
| 216 | /* Open the channel in read mode */ |
| 217 | fd_pairs->pair[fd_pairs->num_pairs-1].channel = |
| 218 | open(path_channel, O_RDONLY | O_NONBLOCK); |
| 219 | if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) { |
| 220 | perror(path_channel); |
| 221 | } |
| 222 | /* Open the trace in write mode, only append if append_mode */ |
| 223 | ret = stat(path_trace, &stat_buf); |
| 224 | if(ret == 0) { |
| 225 | if(append_mode) { |
| 226 | printf("Appending to file %s as resquested\n", path_trace); |
| 227 | |
| 228 | fd_pairs->pair[fd_pairs->num_pairs-1].trace = |
| 229 | open(path_trace, O_WRONLY|O_APPEND, |
| 230 | S_IRWXU|S_IRWXG|S_IRWXO); |
| 231 | |
| 232 | if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) { |
| 233 | perror(path_trace); |
| 234 | } |
| 235 | } else { |
| 236 | printf("File %s exists, cannot open. Try append mode.\n", path_trace); |
| 237 | return -1; |
| 238 | } |
| 239 | } else { |
| 240 | if(errno == ENOENT) { |
| 241 | fd_pairs->pair[fd_pairs->num_pairs-1].trace = |
| 242 | open(path_trace, O_WRONLY|O_CREAT|O_EXCL, |
| 243 | S_IRWXU|S_IRWXG|S_IRWXO); |
| 244 | if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) { |
| 245 | perror(path_trace); |
| 246 | } |
| 247 | } |
| 248 | } |
| 249 | } |
| 250 | } |
| 251 | |
| 252 | closedir(channel_dir); |
| 253 | |
| 254 | return 0; |
| 255 | } |
| 256 | |
| 257 | /* read_channels |
| 258 | * |
| 259 | * Read the realyfs channels and write them in the paired tracefiles. |
| 260 | * |
| 261 | * @fd_pairs : paired channels and trace files. |
| 262 | * |
| 263 | * returns 0 on success, -1 on error. |
| 264 | * |
| 265 | * Note that the high priority polled channels are consumed first. We then poll |
| 266 | * again to see if these channels are still in priority. Only when no |
| 267 | * high priority channel is left, we start reading low priority channels. |
| 268 | * |
| 269 | * Note that a channel is considered high priority when the buffer is almost |
| 270 | * full. |
| 271 | */ |
| 272 | |
| 273 | int read_channels(struct channel_trace_fd *fd_pairs) |
| 274 | { |
| 275 | struct pollfd *pollfd; |
| 276 | int i; |
| 277 | int num_rdy; |
| 278 | |
| 279 | pollfd = malloc(fd_pairs->num_pairs * sizeof(struct pollfd)); |
| 280 | |
| 281 | for(i=0;i<fd_pairs->num_pairs;i++) { |
| 282 | pollfd[i].fd = fd_pairs->pair[i].channel; |
| 283 | pollfd[i].events = POLLIN|POLLPRI; |
| 284 | } |
| 285 | |
| 286 | while(1) { |
| 287 | |
| 288 | num_rdy = poll(pollfd, fd_pairs->num_pairs, -1); |
| 289 | if(num_rdy == -1) { |
| 290 | perror("Poll error"); |
| 291 | return -1; |
| 292 | } |
| 293 | |
| 294 | printf("Data received\n"); |
| 295 | |
| 296 | for(i=0;i<fd_pairs->num_pairs;i++) { |
| 297 | switch(pollfd[i].revents) { |
| 298 | case POLLERR: |
| 299 | printf("Error returned in polling fd %d.\n", pollfd[i].fd); |
| 300 | break; |
| 301 | case POLLHUP: |
| 302 | printf("Polling fd %d tells it has hung up.\n", pollfd[i].fd); |
| 303 | break; |
| 304 | case POLLNVAL: |
| 305 | printf("Polling fd %d tells fd is not open.\n", pollfd[i].fd); |
| 306 | break; |
| 307 | case POLLPRI: |
| 308 | /* Take care of high priority channels first. */ |
| 309 | break; |
| 310 | default: |
| 311 | } |
| 312 | |
| 313 | for(i=0;i<fd_pairs->num_pairs;i++) { |
| 314 | switch(pollfd[i].revents) { |
| 315 | case POLLIN: |
| 316 | /* Take care of low priority channels. */ |
| 317 | break; |
| 318 | default: |
| 319 | } |
| 320 | |
| 321 | } |
| 322 | |
| 323 | free(pollfd); |
| 324 | |
| 325 | return 0; |
| 326 | } |
| 327 | |
| 328 | |
| 329 | void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs) |
| 330 | { |
| 331 | int i; |
| 332 | int ret; |
| 333 | |
| 334 | for(i=0;i<fd_pairs->num_pairs;i++) { |
| 335 | ret = close(fd_pairs->pair[i].channel); |
| 336 | if(ret == -1) perror("Close error on channel"); |
| 337 | ret = close(fd_pairs->pair[i].trace); |
| 338 | if(ret == -1) perror("Close error on trace"); |
| 339 | } |
| 340 | free(fd_pairs->pair); |
| 341 | } |
| 342 | |
| 343 | int main(int argc, char ** argv) |
| 344 | { |
| 345 | int ret; |
| 346 | pid_t pid; |
| 347 | struct channel_trace_fd fd_pairs = { NULL, 0 }; |
| 348 | |
| 349 | ret = parse_arguments(argc, argv); |
| 350 | |
| 351 | if(ret != 0) show_arguments(); |
| 352 | if(ret < 0) return EINVAL; |
| 353 | if(ret > 0) return 0; |
| 354 | |
| 355 | show_info(); |
| 356 | |
| 357 | if(daemon_mode) { |
| 358 | pid = fork(); |
| 359 | |
| 360 | if(pid > 0) { |
| 361 | /* parent */ |
| 362 | return 0; |
| 363 | } else if(pid < 0) { |
| 364 | /* error */ |
| 365 | printf("An error occured while forking.\n"); |
| 366 | return -1; |
| 367 | } |
| 368 | /* else, we are the child, continue... */ |
| 369 | } |
| 370 | |
| 371 | if(ret = open_channel_trace_pairs(channel_name, trace_name, &fd_pairs)) |
| 372 | goto close_channel; |
| 373 | |
| 374 | ret = read_channels(&fd_pairs); |
| 375 | |
| 376 | close_channel: |
| 377 | close_channel_trace_pairs(&fd_pairs); |
| 378 | |
| 379 | return ret; |
| 380 | } |