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void init_mib(void);
int add_mibdir(char *dirname);
int add_module_replacement(char *old_module, char *new_module, char *tag, int len);
void init_mib_internals(void);
struct tree *read_module(char *name);
struct tree *read_mib(char *filename);
struct tree *read_all_mibs(void);
void shutdown_mib(void);
void print_mib(FILE *fp);
int read_objid(char *input, oid *output, int *out_len);
int get_module_node(char *name, char *module, oid *objid, int *objidlen);
void print_variable(const oid *objid, size_t objidlen, struct variable_list *variable);
void fprint_variable(FILE *fp, const oid *objid, size_t objidlen, struct variable_list *variable);
int snprint_variable(char *buf, size_t len, const oid *objid, size_t objidlen, struct variable_list *variable);
int sprint_realloc_variable(u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const oid *objid, size_t objidlen, struct variable_list *variable);
void print_value(oid *objid, size_t objidlen, struct variable_list *variable)
void fprint_value(FILE *fp, const oid *objid, size_t objidlen, struct variable_list *variable);
int snprint_value(char *buf, size_t len, const oid *objid, size_t objidlen, struct variable_list *variable);
int sprint_realloc_value(u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const oid *objid, size_t objidlen, struct variable_list *variable);
void print_objid(const oid *objid, size_t objidlen);
void fprint_objid(FILE *fp, const oid *objid, size_t objidlen);
int snprint_objid(char *buf, size_t len, const oid *objid, size_t objidlen);
int sprint_realloc_objid(u_char **buf, size_t *buf_len, size_t *out_len, int allow_realloc, const oid *objid, size_t objidlen);
void print_description(const oid *objid, size_t objidlen);
void fprint_description(FILE *fp, const oid *objid, size_t objidlen);
void snmp_set_mib_warnings(int level);
void snmp_set_save_descriptions(int save);
add_mibdir is used to define the range of directory locations which are searched for files containing MIB modules (one module per file). By default, this will be set to the directory /usr/local/share/mibs but this can be overridden by setting the environment variable MIBDIRS to a (colon-separated) list of directories to search. Note that this does not actually load the MIB modules located in that directory, but is an initialisation step to make them available. This function returns a count of files found in the directory, or a -1 if there is an error.
init_mib_internals sets up the internal structures, preparatory to reading in MIB modules. It should be called after all calls to add_mibdir, and before and calls to read_module. This is called automatically if init_mib is used.
shutdown_mib will clear the information that was gathered by read_module, add_mibdir and add_module_replacement. It is strongly recommended that one does not invoke shutdown_mib while there are SNMP sessions being actively managed.
| tag | len |
load the new module when: |
| NULL | 0 | always (the old module is a strict subset of the new) |
| name | 0 | for the given tag only |
| name | non-0 | for any identifier with this prefix |
read_module locates and parses the module specified, together with any modules that it imports from, and adds the contents of these modules to the active MIB tree. Note that add_mibdir must first be called to add the directory containing the file with the module definition, if this is not in the standard path.
By default, the following MIB modules will be loaded: IP-MIB, IF-MIB, TCP-MIB, UDP-MIB, SNMPv2-MIB, RFC1213-MIB, UCD-SNMP-MIB. This can be overridden by setting the environment variable MIBS to a (colon-separated) list of modules to load. If this variable starts with a plus character, then the specified modules are added to the default list. Otherwise only those modules listed are loaded (together with any others they import from). If MIBS is set to ALL, read_all_mibs is called to load all the MIB files found in all the specified MIBDIRS.
read_mib parses the file specified, together with any modules that it imports from, and adds the contents to the active MIB tree. Such a file can contain more then one module, though care must be taken that any imports occur earlier in the file, if they are not to be read from the installed modules. Note that the file specified does not need to be in any of the directories initialised by add_mibdir (or the default setup), though any imported modules do.
The environment variable MIBFILES can be set to a (colon-separated) list of files containing MIBs to load.
read_objid takes a string containing a textual version of an object identifier (in either numeric or descriptor form), and transforms this into the corresponding list of sub-identifiers. This is returned in the output parameter, with the number of sub-identifiers returned via out_len. When called, out_len must hold the maximum length of the output array. This function returns a value of 1 if it succeeds in parsing the string and 0 otherwise.
print_variable will take an object identifier (as returned by read_objid or get_module_node) and an instance of such a variable, and prints to the standard output the textual form of the object identifier together with the value of the variable. fprint_variable does the same, but prints to the FILE pointer specified by the initial parameter.
snprint_variable prints the same information into the buffer pointed to by buf which is of length len and returns either the number of characters printed, or -1 if the buffer was not large enough. In the latter case, buf will typically contained a truncated version of the information (but this behaviour is not guaranteed). This function replaces the obsolete function sprint_variable.
sprint_realloc_variable is the low-level function used to implement all these functions. It prints to a specified offset in a string buffer. The buf parameter points to a pointer to that buffer; buf_len points to a variable holding the current size of that buffer, and out_len points to a variable holding the offset to which to print. out_len will be updated to hold the offset of the character following the last one added to the buffer. If allow_realloc is 1, the buffer will be dynamically expanded, as necessary, to hold the output; the variables pointed to by buf and buf_len will be updated. If allow_realloc is 0, the buffer will not be dynamically expanded. sprint_realloc_variable returns 0 if allow_realloc is 1 and an attempt to allocate memory to expand the buffer fails, or if allow_realloc is 0 and the output wouldn't fit in the buffer. Otherwise it returns 1. When using this function you should be careful to call free(3) on *buf when you have finished with it.
print_value, fprint_value, snprint_value and sprint_realloc_value do the same as the equivalent print_variable routines, but only displaying the value of the variable, without the corresponding object identifier.
print_objid, fprint_objid, snprint_objid, and sprint_realloc_objid take an object identifier (without an accompanying variable instance) and print out the textual representation.
print_description and fprint_description take an object identifier (as for print_objid above) and print out the associated DESCRIPTION clause.
Note that there are no corresponding routines snprint_description or sprint_realloc_description. By default the parser does not save descriptions since they may be huge. In order to be able to print them, you must call snmp_set_save_descriptions(1).
In general the parser is silent about what strangenesses it sees in the MIB files. To get warnings reported, call snmp_set_mib_warnings with a level of 1 (or 2 for even more warnings).