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/macros.h>
  23 #include <stdint.h>
  24
  25 struct config_entry {
  26         /* section is NULL if the entry is not in a section */
  27         const char *section;
  28         const char *name;
  29         const char *value;
  30 };
  31
  32 /* Instance of a configuration writer. */
  33 struct config_writer;
  34
  35 /*
  36  * A config_entry_handler_cb receives config_entry structures belonging to the
  37  * sections the handler has been registered to.
  38  *
  39  * The config_entry and its members are only valid for the duration of the call
  40  * and must not be freed.
  41  *
  42  * config_entry_handler_cb may return negative value to indicate an error in
  43  * the configuration file.
  44  */
  45 typedef int (*config_entry_handler_cb)(const struct config_entry *, void *);
  46
  47 /*
  48  * Read a section's entries in an INI configuration file.
  49  *
  50  * path may be NULL, in which case the following paths will be tried:
  51  *      1) $HOME/.lttng/lttng.conf
  52  *      2) /etc/lttng/lttng.conf
  53  *
  54  * handler will only be called with entries belonging to the provided section.
  55  * If section is NULL, all entries will be relayed to handler. If section is
  56  * "", only the global entries are relayed.
  57  *
  58  * Returns 0 on success. Negative values are error codes. If the return value
  59  * is positive, it represents the line number on which a parsing error occured.
  60  */
  61 LTTNG_HIDDEN
  62 int config_get_section_entries(const char *path, const char *section,
  63                 config_entry_handler_cb handler, void *user_data);
  64
  65 /*
  66  * Parse a configuration value.
  67  *
  68  * This function expects either an unsigned integer or a boolean text option.
  69  * The following strings are recognized: true, yes, on, false, no and off.
  70  *
  71  * Returns either the value of the parsed integer, or 0/1 if a boolean text
  72  * string was recognized. Negative values indicate an error.
  73  */
  74 LTTNG_HIDDEN
  75 int config_parse_value(const char *value);
  76
  77 /*
  78  * Create an instance of a configuration writer.
  79  *
  80  * fd_output File to which the XML content must be written. The file will be
  81  * closed once the config_writer has been destroyed.
  82  *
  83  * Returns an instance of a configuration writer on success, NULL on
  84  * error.
  85  */
  86 LTTNG_HIDDEN
  87 struct config_writer *config_writer_create(int fd_output);
  88
  89 /*
  90  * Destroy an instance of a configuration writer.
  91  *
  92  * writer An instance of a configuration writer.
  93  *
  94  * Returns zero if the XML document could be closed cleanly. Negative values
  95  * indicate an error.
  96  */
  97 LTTNG_HIDDEN
  98 int config_writer_destroy(struct config_writer *writer);
  99
 100 /*
 101  * Open an element tag.
 102  *
 103  * writer An instance of a configuration writer.
 104  *
 105  * element_name Element tag name.
 106  *
 107  * Returns zero if the XML document could be closed cleanly.
 108  * Negative values indicate an error.
 109  */
 110 LTTNG_HIDDEN
 111 int config_writer_open_element(struct config_writer *writer,
 112                 const char *element_name);
 113
 114 /*
 115  * Close the current element tag.
 116  *
 117  * writer An instance of a configuration writer.
 118  *
 119  * Returns zero if the XML document could be closed cleanly.
 120  * Negative values indicate an error.
 121  */
 122 LTTNG_HIDDEN
 123 int config_writer_close_element(struct config_writer *writer);
 124
 125 /*
 126  * Write an element of type unsigned int.
 127  *
 128  * writer An instance of a configuration writer.
 129  *
 130  * element_name Element name.
 131  *
 132  * value Unsigned int value of the element
 133  *
 134  * Returns zero if the element's value could be written.
 135  * Negative values indicate an error.
 136  */
 137 LTTNG_HIDDEN
 138 int config_writer_write_element_unsigned_int(struct config_writer *writer,
 139                 const char *element_name, uint64_t value);
 140
 141 /*
 142  * Write an element of type signed int.
 143  *
 144  * writer An instance of a configuration writer.
 145  *
 146  * element_name Element name.
 147  *
 148  * value Signed int value of the element
 149  *
 150  * Returns zero if the element's value could be written.
 151  * Negative values indicate an error.
 152  */LTTNG_HIDDEN
 153 int config_writer_write_element_signed_int(struct config_writer *writer,
 154                 const char *element_name, int64_t value);
 155
 156 /*
 157  * Write an element of type boolean.
 158  *
 159  * writer An instance of a configuration writer.
 160  *
 161  * element_name Element name.
 162  *
 163  * value Boolean value of the element
 164  *
 165  * Returns zero if the element's value could be written.
 166  * Negative values indicate an error.
 167  */
 168 LTTNG_HIDDEN
 169 int config_writer_write_element_bool(struct config_writer *writer,
 170                 const char *element_name, int value);
 171
 172 /*
 173  * Write an element of type string.
 174  *
 175  * writer An instance of a configuration writer.
 176  *
 177  * element_name Element name.
 178  *
 179  * value String value of the element
 180  *
 181  * Returns zero if the element's value could be written.
 182  * Negative values indicate an error.
 183  */
 184 LTTNG_HIDDEN
 185 int config_writer_write_element_string(struct config_writer *writer,
 186                 const char *element_name, const char *value);
 187
 188 #endif /* _CONFIG_H */