- LDAP search operations
cc [ flag... ] file... -lldap[ library...] #include <sys/time.h> /* for struct timeval definition */ #include <lber.h> #include <ldap.h> int ldap_search(LDAP *ld, char *base, int scope, char *filter, char *attrs, int attrsonly);
int ldap_search_s(LDAP *ld, char *base, int scope, char *filter, char *attrs,int attrsonly, LDAPMessage **res);
int ldap_search_st(LDAP *ld, char *base, int scope, char *filter, char *attrs, int attrsonly, struct timeval *timeout, LDAPMessage **res);
int ldap_search_ext(LDAP *ld, char *base, int scope, char *filter, char **attrs, int attrsonly, LDAPControl **serverctrls, LDAPControl **clientctrls, struct timeval *timeoutp, int sizelimit, int *msgidp);
int ldap_search_ext_s(LDAP *ld,char *base, int scope, char *filter, char **attrs, int attrsonly, LDAPControl **serverctrls, LDAPControl **clientctrls, struct timeval *timeoutp, int sizelimit, LDAPMessage **res);
These functions are used to perform LDAP search operations. The ldap_search_s() function does the search synchronously (that is, not returning until the operation completes). The ldap_search_st() function does the same, but allows a timeout to be specified. The ldap_search() function is the asynchronous version, initiating the search and returning the message ID of the operation it initiated.
The base is the DN of the entry at which to start the search. The scope is the scope of the search and should be one of LDAP_SCOPE_BASE, to search the object itself, LDAP_SCOPE_ONELEVEL, to search the object's immediate children, or LDAP_SCOPE_SUBTREE, to search the object and all its descendents.
The filter is a string representation of the filter to apply in the search. Simple filters can be specified as attributetype=attributevalue. More complex filters are specified using a prefix notation according to the following BNF:
<filter> ::= '(' <filtercomp> ')' <filtercomp> ::= <and> | <or> | <not> | <simple> <and> ::= '&' <filterlist> <or> ::= '|' <filterlist> <not> ::= '!' <filter> <filterlist> ::= <filter> | <filter> <filterlist> <simple> ::= <attributetype> <filtertype> <attributevalue> <filtertype> ::= '=' | '~=' | '<=' | '>='
The '~=' construct is used to specify approximate matching. The representation for <attributetype> and <attributevalue> are as described in RFC 1778. In addition, <attributevalue> can be a single * to achieve an attribute existence test, or can contain text and *'s interspersed to achieve substring matching.
For example, the filter mail=* finds entries that have a mail attribute. The filter firstname.lastname@example.org finds entries that have a mail attribute ending in the specified string. Use a backslash (\\) to escape parentheses characters in a filter. See RFC 1588 for a more complete description of the filters that are allowed. See ldap_getfilter(3LDAP) for functions to help construct search filters automatically.
The attrs is a null-terminated array of attribute types to return from entries that match filter. If NULL is specified, all attributes are returned. The attrsonly is set to 1 when attribute types only are wanted. The attrsonly is set to 0 when both attributes types and attribute values are wanted.
The sizelimit argument returns the number of matched entries specified for a search operation. When sizelimit is set to 50, for example, no more than 50 entries are returned. When sizelimit is set to 0, all matched entries are returned. The LDAP server can be configured to send a maximum number of entries, different from the size limit specified. If 5000 entries are matched in the database of a server configured to send a maximum number of 500 entries, no more than 500 entries are returned even when sizelimit is set to 0.
The ldap_search_ext() function initiates an asynchronous search operation and returns LDAP_SUCCESS when the request is successfully sent to the server. Otherwise, ldap_search_ext() returns an LDAP error code. See ldap_error(3LDAP). If successful, ldap_search_ext() places the message ID of the request in *msgidp. A subsequent call to ldap_result(3LDAP) can be used to obtain the result of the add request.
The ldap_search_ext_s() function initiates a synchronous search operation and returns the result of the operation itself.
The ldap_search_s() and ldap_search_st() functions return the LDAP error code that results from a search operation. See ldap_error(3LDAP) for details.
The ldap_search() function returns -1 when the operation terminates unsuccessfully.
See attributes(5) for a description of the following attributes:
Howes, T., Kille, S., Yeong, W., Robbins, C., Wenn, J. RFC 1778, The String Representation of Standard Attribute Syntaxes. Network Working Group. March 1995.
Postel, J., Anderson, C. RFC 1588, White Pages Meeting Report. Network Working Group. February 1994.
The read and list functionality are subsumed by ldap_search() functions, when a filter such as objectclass=* is used with the scope LDAP_SCOPE_BASE to emulate read or the scope LDAP_SCOPE_ONELEVEL to emulate list.
The ldap_search() functions may allocate memory which must be freed by the calling application. Return values are contained in <ldap.h>.