src/common/config/config.h

   1 /*
   2  * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #ifndef _CONFIG_H
  19 #define _CONFIG_H
  20
  21 #include <common/config/ini.h>
  22 #include <common/config/config-session-abi.h>
  23 #include <common/macros.h>
  24 #include <stdint.h>
  25
  26 struct config_entry {
  27         /* section is NULL if the entry is not in a section */
  28         const char *section;
  29         const char *name;
  30         const char *value;
  31 };
  32
  33 /* Instance of a configuration writer. */
  34 struct config_writer;
  35
  36 /*
  37  * A config_entry_handler_cb receives config_entry structures belonging to the
  38  * sections the handler has been registered to.
  39  *
  40  * The config_entry and its members are only valid for the duration of the call
  41  * and must not be freed.
  42  *
  43  * config_entry_handler_cb may return negative value to indicate an error in
  44  * the configuration file.
  45  */
  46 typedef int (*config_entry_handler_cb)(const struct config_entry *, void *);
  47
  48 /*
  49  * Read a section's entries in an INI configuration file.
  50  *
  51  * path may be NULL, in which case the following paths will be tried:
  52  *      1) $HOME/.lttng/lttng.conf
  53  *      2) /etc/lttng/lttng.conf
  54  *
  55  * handler will only be called with entries belonging to the provided section.
  56  * If section is NULL, all entries will be relayed to handler. If section is
  57  * "", only the global entries are relayed.
  58  *
  59  * Returns 0 on success. Negative values are error codes. If the return value
  60  * is positive, it represents the line number on which a parsing error occured.
  61  */
  62 LTTNG_HIDDEN
  63 int config_get_section_entries(const char *path, const char *section,
  64                 config_entry_handler_cb handler, void *user_data);
  65
  66 /*
  67  * Parse a configuration value.
  68  *
  69  * This function expects either an unsigned integer or a boolean text option.
  70  * The following strings are recognized: true, yes, on, false, no and off.
  71  *
  72  * Returns either the value of the parsed integer, or 0/1 if a boolean text
  73  * string was recognized. Negative values indicate an error.
  74  */
  75 LTTNG_HIDDEN
  76 int config_parse_value(const char *value);
  77
  78 /*
  79  * Create an instance of a configuration writer.
  80  *
  81  * fd_output File to which the XML content must be written. The file will be
  82  * closed once the config_writer has been destroyed.
  83  *
  84  * Returns an instance of a configuration writer on success, NULL on
  85  * error.
  86  */
  87 LTTNG_HIDDEN
  88 struct config_writer *config_writer_create(int fd_output);
  89
  90 /*
  91  * Destroy an instance of a configuration writer.
  92  *
  93  * writer An instance of a configuration writer.
  94  *
  95  * Returns zero if the XML document could be closed cleanly. Negative values
  96  * indicate an error.
  97  */
  98 LTTNG_HIDDEN
  99 int config_writer_destroy(struct config_writer *writer);
 100
 101 /*
 102  * Open an element tag.
 103  *
 104  * writer An instance of a configuration writer.
 105  *
 106  * element_name Element tag name.
 107  *
 108  * Returns zero if the XML document could be closed cleanly.
 109  * Negative values indicate an error.
 110  */
 111 LTTNG_HIDDEN
 112 int config_writer_open_element(struct config_writer *writer,
 113                 const char *element_name);
 114
 115 /*
 116  * Close the current element tag.
 117  *
 118  * writer An instance of a configuration writer.
 119  *
 120  * Returns zero if the XML document could be closed cleanly.
 121  * Negative values indicate an error.
 122  */
 123 LTTNG_HIDDEN
 124 int config_writer_close_element(struct config_writer *writer);
 125
 126 /*
 127  * Write an element of type unsigned int.
 128  *
 129  * writer An instance of a configuration writer.
 130  *
 131  * element_name Element name.
 132  *
 133  * value Unsigned int value of the element
 134  *
 135  * Returns zero if the element's value could be written.
 136  * Negative values indicate an error.
 137  */
 138 LTTNG_HIDDEN
 139 int config_writer_write_element_unsigned_int(struct config_writer *writer,
 140                 const char *element_name, uint64_t value);
 141
 142 /*
 143  * Write an element of type signed int.
 144  *
 145  * writer An instance of a configuration writer.
 146  *
 147  * element_name Element name.
 148  *
 149  * value Signed int value of the element
 150  *
 151  * Returns zero if the element's value could be written.
 152  * Negative values indicate an error.
 153  */LTTNG_HIDDEN
 154 int config_writer_write_element_signed_int(struct config_writer *writer,
 155                 const char *element_name, int64_t value);
 156
 157 /*
 158  * Write an element of type boolean.
 159  *
 160  * writer An instance of a configuration writer.
 161  *
 162  * element_name Element name.
 163  *
 164  * value Boolean value of the element
 165  *
 166  * Returns zero if the element's value could be written.
 167  * Negative values indicate an error.
 168  */
 169 LTTNG_HIDDEN
 170 int config_writer_write_element_bool(struct config_writer *writer,
 171                 const char *element_name, int value);
 172
 173 /*
 174  * Write an element of type string.
 175  *
 176  * writer An instance of a configuration writer.
 177  *
 178  * element_name Element name.
 179  *
 180  * value String value of the element
 181  *
 182  * Returns zero if the element's value could be written.
 183  * Negative values indicate an error.
 184  */
 185 LTTNG_HIDDEN
 186 int config_writer_write_element_string(struct config_writer *writer,
 187                 const char *element_name, const char *value);
 188
 189 /*
 190  * Load session configurations from a file.
 191  *
 192  * path Path to an LTTng session configuration file. All *.lttng files
 193  * will be loaded if path is a directory. If path is NULL, the default
 194  * paths will be searched in the following order:
 195  *      1) $HOME/.lttng/sessions
 196  *      2) /etc/lttng/sessions
 197  *
 198  * session_name Name of the session to load. Will load all
 199  * sessions from path if NULL.
 200  *
 201  * override Override current session configuration if it exists.
 202  *
 203  * Returns zero if the session could be loaded successfully. Returns
 204  * a negative LTTNG_ERR code on error.
 205  */
 206 LTTNG_HIDDEN
 207 int config_load_session(const char *path, const char *session_name,
 208                 int override);
 209
 210 #endif /* _CONFIG_H */