1ber_encode(3LDAP) LDAP Library Functions ber_encode(3LDAP)
2
6 ber_encode, ber_alloc, ber_printf, ber_put_int, ber_put_ostring,
7 ber_put_string, ber_put_null, ber_put_boolean, ber_put_bitstring,
8 ber_start_seq, ber_start_set, ber_put_seq, ber_put_set - simplified
9 Basic Encoding Rules library encoding functions
10
12 cc[ flag... ] file... -lldap[ library... ]
13 #include <lber.h>
14 BerElement *ber_alloc();
16 ber_printf(BerElement *ber, char **fmt[, arg... ]);
19 ber_put_int(BerElement *ber, long num, char tag);
22 ber_put_ostring(BerElement *ber, char **str, unsigned long len,
25 char tag);
26 ber_put_string(BerElement *ber, char **str, char tag);
29 ber_put_null(BerElement *ber, char tag);
32 ber_put_boolean(BerElement *ber, int bool, char tag);
35 ber_put_bitstring(BerElement *ber, char *str, int blen, char tag);
38 ber_start_seq(BerElement *ber, char tag);
41 ber_start_set(BerElement *ber, char tag);
44 ber_put_seq(BerElement *ber);
47 ber_put_set(BerElement *ber);
50
53 These functions provide a subfunction interface to a simplified imple‐
54 mentation of the Basic Encoding Rules of ASN.1. The version of BER
55 these functions support is the one defined for the LDAP protocol. The
56 encoding rules are the same as BER, except that only definite form
57 lengths are used, and bitstrings and octet strings are always encoded
58 in primitive form. In addition, these lightweight BER functions
59 restrict tags and class to fit in a single octet (this means the actual
60 tag must be less than 31). When a "tag"is specified in the descriptions
61 below, it refers to the tag, class, and primitive or constructed bit in
62 the first octet of the encoding. This man page describes the encoding
63 functions in the lber library. See ber_decode(3LDAP) for details on
64 the corresponding decoding functions.
65 Normally, the only functions that need be called by an application are
68 ber_alloc(), to allocate a BER element, and ber_printf() to do the
69 actual encoding. The other functions are provided for those applica‐
70 tions that need more control than ber_printf() provides. In general,
71 these functions return the length of the element encoded, or −1 if an
72 error occurred.
73 The ber_alloc() function is used to allocate a new BER element.
76 The ber_printf() function is used to encode a BER element in much the
79 same way that sprintf(3S) works. One important difference, though, is
80 that some state information is kept with the ber parameter so that mul‐
81 tiple calls can be made to ber_printf() to append things to the end of
82 the BER element. Ber_printf() writes to ber, a pointer to a BerEle‐
83 ment such as returned by ber_alloc(). It interprets and formats its
84 arguments according to the format string fmt. The format string can
85 contain the following characters:
86 b Boolean. An integer parameter should be supplied. A boolean ele‐
88 ment is output.
89 B Bitstring. A char * pointer to the start of the bitstring is sup‐
92 plied, followed by the number of bits in the bitstring. A bit‐
93 string element is output.
94 i Integer. An integer parameter should be supplied. An integer
97 element is output.
98 n Null. No parameter is required. A null element is output.
101 o Octet string. A char * is supplied, followed by the length of the
104 string pointed to. An octet string element is output.
105 O Octet string. A struct berval * is supplied. An octet string
108 element is output.
109 s Octet string. A null-terminated string is supplied. An octet
112 string element is output, not including the trailing null octet.
113 t Tag. An int specifying the tag to give the next element is pro‐
116 vided. This works across calls.
117 v Several octet strings. A null-terminated array of char * is sup‐
120 plied. Note that a construct like '{v}' is required to get an
121 actual sequence of octet strings.
122 { Begin sequence. No parameter is required.
125 } End sequence. No parameter is required.
128 [ Begin set. No parameter is required.
131 ] End set. No parameter is required.
134 The ber_put_int() function writes the integer element num to the BER
138 element ber.
139 The ber_put_boolean() function writes the boolean value given by bool
142 to the BER element.
143 The ber_put_bitstring() function writes blen bits starting at str as a
146 bitstring value to the given BER element. Note that blen is the length
147 in bits of the bitstring.
148 The ber_put_ostring() function writes len bytes starting at str to the
151 BER element as an octet string.
152 The ber_put_string() function writes the null-terminated string (minus
155 the terminating '') to the BER element as an octet string.
156 The ber_put_null() function writes a NULL element to the BER element.
159 The ber_start_seq() function is used to start a sequence in the BER
162 element. The ber_start_set() function works similarly. The end of the
163 sequence or set is marked by the nearest matching call to
164 ber_put_seq() or ber_put_set(), respectively.
165 The ber_first_element() function is used to return the tag and length
168 of the first element in a set or sequence. It also returns in cookie a
169 magic cookie parameter that should be passed to subsequent calls to
170 ber_next_element(), which returns similar information.
171
173 Example 1 Assuming the following variable declarations, and that the
174 variables have been assigned appropriately, an BER encoding of the fol‐
175 lowing ASN.1 object:
176 AlmostASearchRequest := SEQUENCE {
178 baseObject DistinguishedName,
179 scope ENUMERATED {
180 baseObject (0),
181 singleLevel (1),
182 wholeSubtree (2)
183 },
184 derefAliases ENUMERATED {
185 neverDerefaliases (0),
186 derefInSearching (1),
187 derefFindingBaseObj (2),
188 alwaysDerefAliases (3N)
189 },
190 sizelimit INTEGER (0 .. 65535),
191 timelimit INTEGER (0 .. 65535),
192 attrsOnly BOOLEAN,
193 attributes SEQUENCE OF AttributeType
194 }
195 can be achieved like so:
199 int scope, ali, size, time, attrsonly;
201 char *dn, **attrs;
202 /* ... fill in values ... */
204 if ( (ber = ber_alloc()) == NULLBER )
205 /* error */
206 if ( ber_printf( ber, "{siiiib{v}}", dn, scope, ali,
208 size, time, attrsonly, attrs ) == -1 )
209 /* error */
210 else
211 /* success */
212
215 If an error occurs during encoding, ber_alloc() returns NULL; other
216 functions generally return −1.
217
219 See attributes(5) for a description of the following attributes:
220 ┌─────────────────────────────┬─────────────────────────────┐
225 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
226 ├─────────────────────────────┼─────────────────────────────┤
227 │Availability │SUNWcsl (32-bit) │
228 ├─────────────────────────────┼─────────────────────────────┤
229 │ │SUNWcslx (64-bit) │
230 ├─────────────────────────────┼─────────────────────────────┤
231 │Interface Stability │Committed │
232 └─────────────────────────────┴─────────────────────────────┘
233
235 ber_decode(3LDAP), attributes(5)
236 Yeong, W., Howes, T., and Hardcastle-Kille, S., "Lightweight Directory
239 Access Protocol", OSI-DS-26, April 1992.
240 Information Processing - Open Systems Interconnection - Model and Nota‐
243 tion - Service Definition - Specification of Basic Encoding Rules for
244 Abstract Syntax Notation One, International Organization for Standard‐
245 ization, International Standard 8825.
246
248 The return values for all of these functions are declared in <lber.h>.
249SunOS 5.11 6 Oct 2008 ber_encode(3LDAP)