--- /dev/null
+/* lttd
+ *
+ * Linux Trace Toolkit Daemon
+ *
+ * This is a simple daemon that reads a few relay+debugfs channels and save
+ * them in a trace.
+ *
+ * CPU hot-plugging is supported using inotify.
+ *
+ * Copyright 2005 -
+ * Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "liblttd.h"
+
+#define _REENTRANT
+#define _GNU_SOURCE
+#include <features.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/poll.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <asm/ioctls.h>
+
+#include <linux/version.h>
+
+/* Relayfs IOCTL */
+#include <asm/ioctl.h>
+#include <asm/types.h>
+
+/* Get the next sub buffer that can be read. */
+#define RELAY_GET_SB _IOR(0xF5, 0x00,__u32)
+/* Release the oldest reserved (by "get") sub buffer. */
+#define RELAY_PUT_SB _IOW(0xF5, 0x01,__u32)
+/* returns the number of sub buffers in the per cpu channel. */
+#define RELAY_GET_N_SB _IOR(0xF5, 0x02,__u32)
+/* returns the size of the current sub buffer. */
+#define RELAY_GET_SB_SIZE _IOR(0xF5, 0x03, __u32)
+/* returns the size of data to consume in the current sub-buffer. */
+#define RELAY_GET_MAX_SB_SIZE _IOR(0xF5, 0x04, __u32)
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,14)
+#include <sys/inotify.h>
+
+#define HAS_INOTIFY
+#else
+static inline int inotify_init (void)
+{
+ return -1;
+}
+
+static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
+{
+ return 0;
+}
+
+static inline int inotify_rm_watch (int fd, __u32 wd)
+{
+ return 0;
+}
+#undef HAS_INOTIFY
+#endif
+
+struct liblttd_callbacks *callbacks;
+
+struct channel_trace_fd {
+ struct fd_pair *pair;
+ int num_pairs;
+};
+
+struct inotify_watch {
+ int wd;
+ char path_channel[PATH_MAX];
+ char *base_path_channel;
+};
+
+struct inotify_watch_array {
+ struct inotify_watch *elem;
+ int num;
+};
+
+struct channel_trace_fd fd_pairs = { NULL, 0 };
+int inotify_fd = -1;
+struct inotify_watch_array inotify_watch_array = { NULL, 0 };
+
+/* protects fd_pairs and inotify_watch_array */
+pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
+
+static char *channel_name = NULL;
+static unsigned long num_threads = 1;
+volatile static int quit_program = 0; /* For signal handler */
+static int dump_flight_only = 0;
+static int dump_normal_only = 0;
+static int verbose_mode = 0;
+
+#define printf_verbose(fmt, args...) \
+ do { \
+ if (verbose_mode) \
+ printf(fmt, ##args); \
+ } while (0)
+
+
+int open_buffer_file(char *filename, char *path_channel,
+ char *base_path_channel, struct channel_trace_fd *fd_pairs)
+{
+ int open_ret = 0;
+ int ret = 0;
+
+ if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
+ if(dump_flight_only) {
+ printf_verbose("Skipping normal channel %s\n",
+ path_channel);
+ return 0;
+ }
+ } else {
+ if(dump_normal_only) {
+ printf_verbose("Skipping flight channel %s\n",
+ path_channel);
+ return 0;
+ }
+ }
+ printf_verbose("Opening file.\n");
+
+ fd_pairs->pair = realloc(fd_pairs->pair,
+ ++fd_pairs->num_pairs * sizeof(struct fd_pair));
+
+ /* Open the channel in read mode */
+ fd_pairs->pair[fd_pairs->num_pairs-1].channel =
+ open(path_channel, O_RDONLY | O_NONBLOCK);
+ if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
+ perror(path_channel);
+ fd_pairs->num_pairs--;
+ return 0; /* continue */
+ }
+
+ if(callbacks->on_open_channel) ret = callbacks->on_open_channel(
+ callbacks, &fd_pairs->pair[fd_pairs->num_pairs-1],
+ base_path_channel);
+
+ if(ret != 0) {
+ open_ret = -1;
+ close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
+ fd_pairs->num_pairs--;
+ goto end;
+ }
+
+end:
+ return open_ret;
+}
+
+int open_channel_trace_pairs(char *subchannel_name,
+ char *base_subchannel_name,
+ struct channel_trace_fd *fd_pairs, int *inotify_fd,
+ struct inotify_watch_array *iwatch_array)
+{
+ DIR *channel_dir = opendir(subchannel_name);
+ struct dirent *entry;
+ struct stat stat_buf;
+ int ret;
+ char path_channel[PATH_MAX];
+ int path_channel_len;
+ char *path_channel_ptr;
+ char *base_subchannel_ptr;
+
+ int open_ret = 0;
+
+ if(channel_dir == NULL) {
+ perror(subchannel_name);
+ open_ret = ENOENT;
+ goto end;
+ }
+
+ printf_verbose("Calling on new channels folder");
+ if(callbacks->on_new_channels_folder) ret = callbacks->
+ on_new_channels_folder(callbacks,
+ base_subchannel_name);
+ if(ret == -1) {
+ open_ret = -1;
+ goto end;
+ }
+
+ strncpy(path_channel, subchannel_name, PATH_MAX-1);
+ path_channel_len = strlen(path_channel);
+ path_channel[path_channel_len] = '/';
+ path_channel_len++;
+ path_channel_ptr = path_channel + path_channel_len;
+ base_subchannel_ptr = path_channel +
+ (base_subchannel_name - subchannel_name);
+
+#ifdef HAS_INOTIFY
+ iwatch_array->elem = realloc(iwatch_array->elem,
+ ++iwatch_array->num * sizeof(struct inotify_watch));
+
+ printf_verbose("Adding inotify for channel %s\n", path_channel);
+ iwatch_array->elem[iwatch_array->num-1].wd = inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
+ strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel, path_channel);
+ iwatch_array->elem[iwatch_array->num-1].base_path_channel =
+ iwatch_array->elem[iwatch_array->num-1].path_channel +
+ (base_subchannel_name - subchannel_name);
+ printf_verbose("Added inotify for channel %s, wd %u\n",
+ iwatch_array->elem[iwatch_array->num-1].path_channel,
+ iwatch_array->elem[iwatch_array->num-1].wd);
+#endif
+
+ while((entry = readdir(channel_dir)) != NULL) {
+
+ if(entry->d_name[0] == '.') continue;
+
+ strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
+
+ ret = stat(path_channel, &stat_buf);
+ if(ret == -1) {
+ perror(path_channel);
+ continue;
+ }
+
+ printf_verbose("Channel file : %s\n", path_channel);
+
+ if(S_ISDIR(stat_buf.st_mode)) {
+
+ printf_verbose("Entering channel subdirectory...\n");
+ ret = open_channel_trace_pairs(path_channel, base_subchannel_ptr, fd_pairs,
+ inotify_fd, iwatch_array);
+ if(ret < 0) continue;
+ } else if(S_ISREG(stat_buf.st_mode)) {
+ open_ret = open_buffer_file(entry->d_name, path_channel, base_subchannel_ptr,
+ fd_pairs);
+ if(open_ret)
+ goto end;
+ }
+ }
+
+end:
+ closedir(channel_dir);
+
+ return open_ret;
+}
+
+
+int read_subbuffer(struct fd_pair *pair)
+{
+ unsigned int consumed_old, len;
+ int err;
+ long ret;
+ off_t offset;
+
+
+ err = ioctl(pair->channel, RELAY_GET_SB, &consumed_old);
+ printf_verbose("cookie : %u\n", consumed_old);
+ if(err != 0) {
+ ret = errno;
+ perror("Reserving sub buffer failed (everything is normal, it is due to concurrency)");
+ goto get_error;
+ }
+
+ err = ioctl(pair->channel, RELAY_GET_SB_SIZE, &len);
+ if(err != 0) {
+ ret = errno;
+ perror("Getting sub-buffer len failed.");
+ goto get_error;
+ }
+
+ if(callbacks->on_read_subbuffer) ret = callbacks->on_read_subbuffer(
+ callbacks, pair, len);
+
+write_error:
+ ret = 0;
+ err = ioctl(pair->channel, RELAY_PUT_SB, &consumed_old);
+ if(err != 0) {
+ ret = errno;
+ if(errno == EFAULT) {
+ perror("Error in unreserving sub buffer\n");
+ } else if(errno == EIO) {
+ /* Should never happen with newer LTTng versions */
+ perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+ }
+ goto get_error;
+ }
+
+get_error:
+ return ret;
+}
+
+
+int map_channels(struct channel_trace_fd *fd_pairs,
+ int idx_begin, int idx_end)
+{
+ int i,j;
+ int ret=0;
+
+ if(fd_pairs->num_pairs <= 0) {
+ printf("No channel to read\n");
+ goto end;
+ }
+
+ /* Get the subbuf sizes and number */
+
+ for(i=idx_begin;i<idx_end;i++) {
+ struct fd_pair *pair = &fd_pairs->pair[i];
+
+ ret = ioctl(pair->channel, RELAY_GET_N_SB, &pair->n_sb);
+ if(ret != 0) {
+ perror("Error in getting the number of sub-buffers");
+ goto end;
+ }
+ ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE,
+ &pair->max_sb_size);
+ if(ret != 0) {
+ perror("Error in getting the max sub-buffer size");
+ goto end;
+ }
+ ret = pthread_mutex_init(&pair->mutex, NULL); /* Fast mutex */
+ if(ret != 0) {
+ perror("Error in mutex init");
+ goto end;
+ }
+ }
+
+end:
+ return ret;
+}
+
+int unmap_channels(struct channel_trace_fd *fd_pairs)
+{
+ int j;
+ int ret=0;
+
+ /* Munmap each FD */
+ for(j=0;j<fd_pairs->num_pairs;j++) {
+ struct fd_pair *pair = &fd_pairs->pair[j];
+ int err_ret;
+
+ err_ret = pthread_mutex_destroy(&pair->mutex);
+ if(err_ret != 0) {
+ perror("Error in mutex destroy");
+ }
+ ret |= err_ret;
+ }
+
+ return ret;
+}
+
+#ifdef HAS_INOTIFY
+/* Inotify event arrived.
+ *
+ * Only support add file for now.
+ */
+
+int read_inotify(int inotify_fd,
+ struct channel_trace_fd *fd_pairs,
+ struct inotify_watch_array *iwatch_array)
+{
+ char buf[sizeof(struct inotify_event) + PATH_MAX];
+ char path_channel[PATH_MAX];
+ ssize_t len;
+ struct inotify_event *ievent;
+ size_t offset;
+ unsigned int i;
+ int ret;
+ int old_num;
+
+ offset = 0;
+ len = read(inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
+ if(len < 0) {
+
+ if(errno == EAGAIN)
+ return 0; /* another thread got the data before us */
+
+ printf("Error in read from inotify FD %s.\n", strerror(len));
+ return -1;
+ }
+ while(offset < len) {
+ ievent = (struct inotify_event *)&(buf[offset]);
+ for(i=0; i<iwatch_array->num; i++) {
+ if(iwatch_array->elem[i].wd == ievent->wd &&
+ ievent->mask == IN_CREATE) {
+ printf_verbose(
+ "inotify wd %u event mask : %u for %s%s\n",
+ ievent->wd, ievent->mask,
+ iwatch_array->elem[i].path_channel,
+ ievent->name);
+ old_num = fd_pairs->num_pairs;
+ strcpy(path_channel, iwatch_array->elem[i].path_channel);
+ strcat(path_channel, ievent->name);
+ if(ret = open_buffer_file(ievent->name, path_channel,
+ path_channel + (iwatch_array->elem[i].base_path_channel -
+ iwatch_array->elem[i].path_channel), fd_pairs)) {
+ printf("Error opening buffer file\n");
+ return -1;
+ }
+ if(ret = map_channels(fd_pairs, old_num, fd_pairs->num_pairs)) {
+ printf("Error mapping channel\n");
+ return -1;
+ }
+
+ }
+ }
+ offset += sizeof(*ievent) + ievent->len;
+ }
+}
+#endif //HAS_INOTIFY
+
+/* read_channels
+ *
+ * Thread worker.
+ *
+ * Read the debugfs channels and write them in the paired tracefiles.
+ *
+ * @fd_pairs : paired channels and trace files.
+ *
+ * returns 0 on success, -1 on error.
+ *
+ * Note that the high priority polled channels are consumed first. We then poll
+ * again to see if these channels are still in priority. Only when no
+ * high priority channel is left, we start reading low priority channels.
+ *
+ * Note that a channel is considered high priority when the buffer is almost
+ * full.
+ */
+
+int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
+ int inotify_fd, struct inotify_watch_array *iwatch_array)
+{
+ struct pollfd *pollfd = NULL;
+ int num_pollfd;
+ int i,j;
+ int num_rdy, num_hup;
+ int high_prio;
+ int ret = 0;
+ int inotify_fds;
+ unsigned int old_num;
+
+#ifdef HAS_INOTIFY
+ inotify_fds = 1;
+#else
+ inotify_fds = 0;
+#endif
+
+ pthread_rwlock_rdlock(&fd_pairs_lock);
+
+ /* Start polling the FD. Keep one fd for inotify */
+ pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
+
+#ifdef HAS_INOTIFY
+ pollfd[0].fd = inotify_fd;
+ pollfd[0].events = POLLIN|POLLPRI;
+#endif
+
+ for(i=0;i<fd_pairs->num_pairs;i++) {
+ pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
+ pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
+ }
+ num_pollfd = inotify_fds + fd_pairs->num_pairs;
+
+
+ pthread_rwlock_unlock(&fd_pairs_lock);
+
+ while(1) {
+ high_prio = 0;
+ num_hup = 0;
+#ifdef DEBUG
+ printf("Press a key for next poll...\n");
+ char buf[1];
+ read(STDIN_FILENO, &buf, 1);
+ printf("Next poll (polling %d fd) :\n", num_pollfd);
+#endif //DEBUG
+
+ /* Have we received a signal ? */
+ if(quit_program) break;
+
+ num_rdy = poll(pollfd, num_pollfd, -1);
+
+ if(num_rdy == -1) {
+ perror("Poll error");
+ goto free_fd;
+ }
+
+ printf_verbose("Data received\n");
+#ifdef HAS_INOTIFY
+ switch(pollfd[0].revents) {
+ case POLLERR:
+ printf_verbose(
+ "Error returned in polling inotify fd %d.\n",
+ pollfd[0].fd);
+ break;
+ case POLLHUP:
+ printf_verbose(
+ "Polling inotify fd %d tells it has hung up.\n",
+ pollfd[0].fd);
+ break;
+ case POLLNVAL:
+ printf_verbose(
+ "Polling inotify fd %d tells fd is not open.\n",
+ pollfd[0].fd);
+ break;
+ case POLLPRI:
+ case POLLIN:
+ printf_verbose(
+ "Polling inotify fd %d : data ready.\n",
+ pollfd[0].fd);
+
+ pthread_rwlock_wrlock(&fd_pairs_lock);
+ read_inotify(inotify_fd, fd_pairs, iwatch_array);
+ pthread_rwlock_unlock(&fd_pairs_lock);
+
+ break;
+ }
+#endif
+
+ for(i=inotify_fds;i<num_pollfd;i++) {
+ switch(pollfd[i].revents) {
+ case POLLERR:
+ printf_verbose(
+ "Error returned in polling fd %d.\n",
+ pollfd[i].fd);
+ num_hup++;
+ break;
+ case POLLHUP:
+ printf_verbose(
+ "Polling fd %d tells it has hung up.\n",
+ pollfd[i].fd);
+ num_hup++;
+ break;
+ case POLLNVAL:
+ printf_verbose(
+ "Polling fd %d tells fd is not open.\n",
+ pollfd[i].fd);
+ num_hup++;
+ break;
+ case POLLPRI:
+ pthread_rwlock_rdlock(&fd_pairs_lock);
+ if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
+ printf_verbose(
+ "Urgent read on fd %d\n",
+ pollfd[i].fd);
+ /* Take care of high priority channels first. */
+ high_prio = 1;
+ /* it's ok to have an unavailable sub-buffer */
+ ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
+ if(ret == EAGAIN) ret = 0;
+
+ ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
+ if(ret)
+ printf("Error in mutex unlock : %s\n", strerror(ret));
+ }
+ pthread_rwlock_unlock(&fd_pairs_lock);
+ break;
+ }
+ }
+ /* If every buffer FD has hung up, we end the read loop here */
+ if(num_hup == num_pollfd - inotify_fds) break;
+
+ if(!high_prio) {
+ for(i=inotify_fds;i<num_pollfd;i++) {
+ switch(pollfd[i].revents) {
+ case POLLIN:
+ pthread_rwlock_rdlock(&fd_pairs_lock);
+ if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
+ /* Take care of low priority channels. */
+ printf_verbose(
+ "Normal read on fd %d\n",
+ pollfd[i].fd);
+ /* it's ok to have an unavailable subbuffer */
+ ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
+ if(ret == EAGAIN) ret = 0;
+
+ ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
+ if(ret)
+ printf("Error in mutex unlock : %s\n", strerror(ret));
+ }
+ pthread_rwlock_unlock(&fd_pairs_lock);
+ break;
+ }
+ }
+ }
+
+ /* Update pollfd array if an entry was added to fd_pairs */
+ pthread_rwlock_rdlock(&fd_pairs_lock);
+ if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
+ pollfd = realloc(pollfd,
+ (inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
+ for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
+ pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
+ pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
+ }
+ num_pollfd = fd_pairs->num_pairs + inotify_fds;
+ }
+ pthread_rwlock_unlock(&fd_pairs_lock);
+
+ /* NB: If the fd_pairs structure is updated by another thread from this
+ * point forward, the current thread will wait in the poll without
+ * monitoring the new channel. However, this thread will add the
+ * new channel on next poll (and this should not take too much time
+ * on a loaded system).
+ *
+ * This event is quite unlikely and can only occur if a CPU is
+ * hot-plugged while multple lttd threads are running.
+ */
+ }
+
+free_fd:
+ free(pollfd);
+
+end:
+ return ret;
+}
+
+
+void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int inotify_fd,
+ struct inotify_watch_array *iwatch_array)
+{
+ int i;
+ int ret;
+
+ for(i=0;i<fd_pairs->num_pairs;i++) {
+ ret = close(fd_pairs->pair[i].channel);
+ if(ret == -1) perror("Close error on channel");
+ if(callbacks->on_close_channel) {
+ ret = callbacks->on_close_channel(
+ callbacks, &fd_pairs->pair[i]);
+ if(ret != 0) perror("Error on close channel callback");
+ }
+ }
+ free(fd_pairs->pair);
+ free(iwatch_array->elem);
+}
+
+/* Thread worker */
+void * thread_main(void *arg)
+{
+ long ret = 0;
+ unsigned long thread_num = (unsigned long)arg;
+
+ if(callbacks->on_new_thread)
+ ret = callbacks->on_new_thread(callbacks, thread_num);
+
+ if (ret < 0) {
+ return (void*)ret;
+ }
+ ret = read_channels(thread_num, &fd_pairs, inotify_fd, &inotify_watch_array);
+
+ if(callbacks->on_close_thread)
+ callbacks->on_close_thread(callbacks, thread_num);
+
+ return (void*)ret;
+}
+
+/*on_close_thread has to be reentrant, it'll be called by many threads*/
+int(*on_close_thread)(struct liblttd_callbacks *data, unsigned long thread_num);
+
+int channels_init()
+{
+ int ret = 0;
+
+ inotify_fd = inotify_init();
+ fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
+
+ if(ret = open_channel_trace_pairs(channel_name,
+ channel_name + strlen(channel_name), &fd_pairs,
+ &inotify_fd, &inotify_watch_array))
+ goto close_channel;
+ if (fd_pairs.num_pairs == 0) {
+ printf("No channel available for reading, exiting\n");
+ ret = -ENOENT;
+ goto close_channel;
+ }
+ if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
+ goto close_channel;
+ return 0;
+
+close_channel:
+ close_channel_trace_pairs(&fd_pairs, inotify_fd, &inotify_watch_array);
+ if(inotify_fd >= 0)
+ close(inotify_fd);
+ return ret;
+}
+
+int liblttd_start(char *channel_path, unsigned long n_threads,
+ int flight_only, int normal_only, int verbose,
+ struct liblttd_callbacks *user_data){
+ int ret = 0;
+ pthread_t *tids;
+ unsigned long i;
+ void *tret;
+
+ channel_name = channel_path;
+ num_threads = n_threads;
+ dump_flight_only = flight_only;
+ dump_normal_only = normal_only;
+ verbose_mode = verbose;
+ callbacks = user_data;
+
+ if(ret = channels_init())
+ return ret;
+
+ tids = malloc(sizeof(pthread_t) * num_threads);
+ for(i=0; i<num_threads; i++) {
+
+ ret = pthread_create(&tids[i], NULL, thread_main, (void*)i);
+ if(ret) {
+ perror("Error creating thread");
+ break;
+ }
+ }
+
+ for(i=0; i<num_threads; i++) {
+ ret = pthread_join(tids[i], &tret);
+ if(ret) {
+ perror("Error joining thread");
+ break;
+ }
+ if((long)tret != 0) {
+ printf("Error %s occured in thread %ld\n",
+ strerror((long)tret), i);
+ }
+ }
+
+ free(tids);
+ ret = unmap_channels(&fd_pairs);
+ close_channel_trace_pairs(&fd_pairs, inotify_fd, &inotify_watch_array);
+ if(inotify_fd >= 0)
+ close(inotify_fd);
+
+ if(callbacks->on_trace_end) callbacks->on_trace_end(callbacks);
+
+ return ret;
+}
+
+int liblttd_stop() {
+ quit_program = 1;
+ return 0;
+}
+
projects / ltt-control.git / blobdiff