include/ust/ustconsumer.h

   1 /*
   2  * libustconsumer header file
   3  *
   4  * Copyright 2005-2010 -
   5  *               Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   6  * Copyright 2010-
   7  *               Oumarou Dicko <oumarou.dicko@polymtl.ca>
   8  *               Michael Sills-Lavoie <michael.sills-lavoie@polymtl.ca>
   9  *               Alexis Halle <alexis.halle@polymtl.ca>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #ifndef _USTCONSUMER_H
  27 #define _USTCONSUMER_H
  28
  29 #include <pthread.h>
  30 #include <dirent.h>
  31 #include <ust/kcompat/kcompat.h>
  32 #include <urcu/list.h>
  33
  34 #define USTCONSUMER_DEFAULT_TRACE_PATH "/tmp/usttrace"
  35
  36 struct ustcomm_sock;
  37
  38 struct buffer_info {
  39         char *name;
  40         char *trace;
  41         char *channel;
  42         int channel_cpu;
  43
  44         pid_t pid;
  45         int app_sock;
  46         /* The pipe file descriptor */
  47         int pipe_fd;
  48
  49         int shmid;
  50         int bufstruct_shmid;
  51
  52         /* the buffer memory */
  53         void *mem;
  54         /* buffer size */
  55         int memlen;
  56         /* number of subbuffers in buffer */
  57         int n_subbufs;
  58         /* size of each subbuffer */
  59         int subbuf_size;
  60         /* subbuf size count order */
  61         int subbuf_size_order;
  62         /* alloc size of all subbuf */
  63         int alloc_size;
  64
  65         /* the buffer information struct */
  66         void *bufstruct_mem;
  67
  68         long consumed_old;
  69
  70         s64 pidunique;
  71
  72         void *user_data;
  73 };
  74
  75 struct ustconsumer_callbacks;
  76
  77 /**
  78  * struct ustconsumer_instance - Contains the data associated with a trace instance.
  79  * The lib user can read but MUST NOT change any attributes but callbacks.
  80  * @callbacks: Contains the necessary callbacks for a tracing session.
  81  */
  82 struct ustconsumer_instance {
  83         struct ustconsumer_callbacks *callbacks;
  84         int quit_program;
  85         int is_init;
  86         struct cds_list_head connections;
  87         int epoll_fd;
  88         struct ustcomm_sock *listen_sock;
  89         char *sock_path;
  90         pthread_mutex_t mutex;
  91         int active_buffers;
  92 };
  93
  94 /**
  95 * struct ustconsumer_callbacks - Contains the necessary callbacks for a tracing
  96 * session. The user can set the unnecessary functions to NULL if he does not
  97 * need them.
  98 */
  99 struct ustconsumer_callbacks {
 100         /**
 101          * on_open_buffer - Is called after a buffer is attached to process memory
 102          *
 103          * @data: pointer to the callbacks structure that has been passed to the
 104          *        library.
 105          * @buf: structure that contains the data associated with the buffer
 106          *
 107          * Returns 0 if the callback succeeds else not 0.
 108          *
 109          * It has to be thread safe, because it is called by many threads.
 110          */
 111         int (*on_open_buffer)(struct ustconsumer_callbacks *data,
 112                                 struct buffer_info *buf);
 113
 114         /**
 115          * on_close_buffer - Is called after a buffer is detached from process memory
 116          *
 117          * @data: pointer to the callbacks structure that has been passed to the
 118          *        library.
 119          * @buf: structure that contains the data associated with the buffer
 120          *
 121          * Returns 0 if the callback succeeds else not 0.
 122          *
 123          * It has to be thread safe, because it is called by many threads.
 124          */
 125         int (*on_close_buffer)(struct ustconsumer_callbacks *data,
 126                                 struct buffer_info *buf);
 127
 128         /**
 129          * on_read_subbuffer - Is called after a subbuffer is a reserved.
 130          *
 131          * @data: pointer to the callbacks structure that has been passed to the
 132          *        library.
 133          * @buf: structure that contains the data associated with the buffer
 134          *
 135          * Returns 0 if the callback succeeds else not 0.
 136          *
 137          * It has to be thread safe, because it is called by many threads.
 138          */
 139         int (*on_read_subbuffer)(struct ustconsumer_callbacks *data,
 140                                 struct buffer_info *buf);
 141
 142         /**
 143          * on_read_partial_subbuffer - Is called when an incomplete subbuffer
 144          *                             is being salvaged from an app crash
 145          *
 146          * @data: pointer to the callbacks structure that has been passed to the
 147          *        library.
 148          * @buf: structure that contains the data associated with the buffer
 149          * @subbuf_index: index of the subbuffer to read in the buffer
 150          * @valid_length: number of bytes considered safe to read
 151          *
 152          * Returns 0 if the callback succeeds else not 0.
 153          *
 154          * It has to be thread safe, because it is called by many threads.
 155          */
 156         int (*on_read_partial_subbuffer)(struct ustconsumer_callbacks *data,
 157                                         struct buffer_info *buf,
 158                                         long subbuf_index,
 159                                         unsigned long valid_length);
 160
 161         /**
 162          * on_put_error - Is called when a put error has occured and the last
 163          *                subbuffer read is no longer safe to keep
 164          *
 165          * @data: pointer to the callbacks structure that has been passed to the
 166          *        library.
 167          * @buf: structure that contains the data associated with the buffer
 168          *
 169          * Returns 0 if the callback succeeds else not 0.
 170          *
 171          * It has to be thread safe, because it is called by many threads.
 172          */
 173         int (*on_put_error)(struct ustconsumer_callbacks *data,
 174                                 struct buffer_info *buf);
 175
 176         /**
 177          * on_new_thread - Is called when a new thread is created
 178          *
 179          * @data: pointer to the callbacks structure that has been passed to the
 180          *        library.
 181          *
 182          * Returns 0 if the callback succeeds else not 0.
 183          *
 184          * It has to be thread safe, because it is called by many threads.
 185          */
 186         int (*on_new_thread)(struct ustconsumer_callbacks *data);
 187
 188         /**
 189          * on_close_thread - Is called just before a thread is destroyed
 190          *
 191          * @data: pointer to the callbacks structure that has been passed to the
 192          *        library.
 193          *
 194          * Returns 0 if the callback succeeds else not 0.
 195          *
 196          * It has to be thread safe, because it is called by many threads.
 197          */
 198         int (*on_close_thread)(struct ustconsumer_callbacks *data);
 199
 200         /**
 201          * on_trace_end - Is called at the very end of the tracing session. At
 202          * this time, everything has been closed and the threads have
 203          * been destroyed.
 204          *
 205          * @instance: pointer to the instance structure that has been passed to
 206          *            the library.
 207          *
 208          * Returns 0 if the callback succeeds else not 0.
 209          *
 210          * After this callback is called, no other callback will be called
 211          * again and the tracing instance will be deleted automatically by
 212          * libustconsumer. After this call, the user must not use the libustconsumer instance.
 213          */
 214         int (*on_trace_end)(struct ustconsumer_instance *instance);
 215
 216         /**
 217          * The library's data.
 218          */
 219         void *user_data;
 220 };
 221
 222 /**
 223  * ustconsumer_new_instance - Is called to create a new tracing session.
 224  *
 225  * @callbacks:    Pointer to a callbacks structure that contain the user
 226  *                callbacks and data.
 227  * @sock_path:    Path to the socket used for communication with the traced app
 228  *
 229  * Returns the instance if the function succeeds else NULL.
 230  */
 231 struct ustconsumer_instance *
 232 ustconsumer_new_instance(
 233         struct ustconsumer_callbacks *callbacks, char *sock_path);
 234
 235 /**
 236  * ustconsumer_delete_instance - Is called to free a ustconsumer_instance struct
 237  *
 238  * @instance: The tracing session instance that needs to be freed.
 239  *
 240  * This function should only be called if the instance has not been started,
 241  * as it will automatically be called at the end of ustconsumer_start_instance.
 242  */
 243 void ustconsumer_delete_instance(struct ustconsumer_instance *instance);
 244
 245 /**
 246  * ustconsumer_init_instance - Is called to initiliaze a new tracing session
 247  *
 248  * @instance: The tracing session instance that needs to be started.
 249  *
 250  * Returns 0 if the function succeeds.
 251  *
 252  * This function must be called between ustconsumer_new_instance and
 253  * ustconsumer_start_instance. It sets up the communication between the library
 254  * and the tracing application.
 255  */
 256 int ustconsumer_init_instance(struct ustconsumer_instance *instance);
 257
 258 /**
 259  * ustconsumer_start_instance - Is called to start a new tracing session.
 260  *
 261  * @instance: The tracing session instance that needs to be started.
 262  *
 263  * Returns 0 if the function succeeds.
 264  *
 265  * This is a blocking function. The caller will be blocked on it until the
 266  * tracing session is stopped by the user using ustconsumer_stop_instance or until
 267  * the traced application terminates
 268  */
 269 int ustconsumer_start_instance(struct ustconsumer_instance *instance);
 270
 271 /**
 272  * ustconsumer_stop_instance - Is called to stop a tracing session.
 273  *
 274  * @instance: The tracing session instance that needs to be stoped.
 275  * @send_msg: If true, a message will be sent to the listening thread through
 276  *            the daemon socket to force it to return from the poll syscall
 277  *            and realize that it must close. This is not necessary if the
 278  *            instance is being stopped as part of an interrupt handler, as
 279  *            the interrupt itself will cause poll to return.
 280  *
 281  * Returns 0 if the function succeeds.
 282  *
 283  * This function returns immediately, it only tells libustconsumer to stop the
 284  * instance. The on_trace_end callback will be called when the tracing session
 285  * will really be stopped. The instance is deleted automatically by libustconsumer
 286  * after on_trace_end is called.
 287  */
 288 int ustconsumer_stop_instance(struct ustconsumer_instance *instance, int send_msg);
 289
 290 #endif /* _USTCONSUMER_H */
 291