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  * indent If other than 0 the XML will be pretty printed
  85  * with indentation and newline.
  86  *
  87  * Returns an instance of a configuration writer on success, NULL on
  88  * error.
  89  */
  90 LTTNG_HIDDEN
  91 struct config_writer *config_writer_create(int fd_output, int indent);
  92
  93 /*
  94  * Destroy an instance of a configuration writer.
  95  *
  96  * writer An instance of a configuration writer.
  97  *
  98  * Returns zero if the XML document could be closed cleanly. Negative values
  99  * indicate an error.
 100  */
 101 LTTNG_HIDDEN
 102 int config_writer_destroy(struct config_writer *writer);
 103
 104 /*
 105  * Open an element tag.
 106  *
 107  * writer An instance of a configuration writer.
 108  *
 109  * element_name Element tag name.
 110  *
 111  * Returns zero if the XML document could be closed cleanly.
 112  * Negative values indicate an error.
 113  */
 114 LTTNG_HIDDEN
 115 int config_writer_open_element(struct config_writer *writer,
 116                 const char *element_name);
 117
 118 /*
 119  * Close the current element tag.
 120  *
 121  * writer An instance of a configuration writer.
 122  *
 123  * Returns zero if the XML document could be closed cleanly.
 124  * Negative values indicate an error.
 125  */
 126 LTTNG_HIDDEN
 127 int config_writer_close_element(struct config_writer *writer);
 128
 129 /*
 130  * Write an element of type unsigned int.
 131  *
 132  * writer An instance of a configuration writer.
 133  *
 134  * element_name Element name.
 135  *
 136  * value Unsigned int value of the element
 137  *
 138  * Returns zero if the element's value could be written.
 139  * Negative values indicate an error.
 140  */
 141 LTTNG_HIDDEN
 142 int config_writer_write_element_unsigned_int(struct config_writer *writer,
 143                 const char *element_name, uint64_t value);
 144
 145 /*
 146  * Write an element of type signed int.
 147  *
 148  * writer An instance of a configuration writer.
 149  *
 150  * element_name Element name.
 151  *
 152  * value Signed int value of the element
 153  *
 154  * Returns zero if the element's value could be written.
 155  * Negative values indicate an error.
 156  */LTTNG_HIDDEN
 157 int config_writer_write_element_signed_int(struct config_writer *writer,
 158                 const char *element_name, int64_t value);
 159
 160 /*
 161  * Write an element of type boolean.
 162  *
 163  * writer An instance of a configuration writer.
 164  *
 165  * element_name Element name.
 166  *
 167  * value Boolean value of the element
 168  *
 169  * Returns zero if the element's value could be written.
 170  * Negative values indicate an error.
 171  */
 172 LTTNG_HIDDEN
 173 int config_writer_write_element_bool(struct config_writer *writer,
 174                 const char *element_name, int value);
 175
 176 /*
 177  * Write an element of type string.
 178  *
 179  * writer An instance of a configuration writer.
 180  *
 181  * element_name Element name.
 182  *
 183  * value String value of the element
 184  *
 185  * Returns zero if the element's value could be written.
 186  * Negative values indicate an error.
 187  */
 188 LTTNG_HIDDEN
 189 int config_writer_write_element_string(struct config_writer *writer,
 190                 const char *element_name, const char *value);
 191
 192 /*
 193  * Load session configurations from a file.
 194  *
 195  * path Path to an LTTng session configuration file. All *.lttng files
 196  * will be loaded if path is a directory. If path is NULL, the default
 197  * paths will be searched in the following order:
 198  *      1) $HOME/.lttng/sessions
 199  *      2) /etc/lttng/sessions
 200  *
 201  * session_name Name of the session to load. Will load all
 202  * sessions from path if NULL.
 203  *
 204  * override Override current session configuration if it exists.
 205  * autoload Tell to load the auto session(s).
 206  *
 207  * Returns zero if the session could be loaded successfully. Returns
 208  * a negative LTTNG_ERR code on error.
 209  */
 210 LTTNG_HIDDEN
 211 int config_load_session(const char *path, const char *session_name,
 212                 int override, unsigned int autoload);
 213
 214 #endif /* _CONFIG_H */