Copyright (c) 2007, 2012 Reyk Floeter <reyk@openbsd.org>
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.Dd $Mdocdate: March 3 2021 $ .Dt OBER_GET_STRING 3 .Os .Sh NAME .Nm ober_get_null , .Nm ober_get_eoc , .Nm ober_get_integer , .Nm ober_get_enumerated , .Nm ober_get_boolean , .Nm ober_get_string , .Nm ober_get_nstring , .Nm ober_get_ostring , .Nm ober_get_bitstring , .Nm ober_get_oid , .Nm ober_getpos , .Nm ober_scanf_elements .Nd access properties of ASN.1 objects decoded from BER .Sh SYNOPSIS n sys/types.h n ber.h .Ft "int" .Fn "ober_get_null" "struct ber_element *root" .Ft "int" .Fn "ober_get_eoc" "struct ber_element *root" .Ft "int" .Fn "ober_get_integer" "struct ber_element *root" "long long *val" .Ft "int" .Fn "ober_get_enumerated" "struct ber_element *root" "long long *val" .Ft "int" .Fn "ober_get_boolean" "struct ber_element *root" "int *bool" .Ft "int" .Fn "ober_get_string" "struct ber_element *root" "char **charbuf" .Ft "int" .Fn "ober_get_nstring" "struct ber_element *root" "void **buf" "size_t *size" .Ft "int" .Fn "ober_get_ostring" "struct ber_element *root" "struct ber_octetstring *ostring" .Ft "int" .Fn "ober_get_bitstring" "struct ber_element *root" "void **buf" "size_t *size" .Ft "int" .Fn "ober_get_oid" "struct ber_element *root" "struct ber_oid *oid" .Ft off_t .Fn "ober_getpos" "struct ber_element *elm" .Ft "int" .Fn "ober_scanf_elements" "struct ber_element *root" "char *format" "..." .Sh DESCRIPTION Functions which take two arguments save the value contained in the .Fa root element into the storage location pointed to by the second argument. If the storage location is .Dv NULL then only a type check is performed. Additionally, .Fn ober_get_nstring and .Fn ober_get_bitstring save the number of bytes contained in the string into
f * Fa size . If .Fa buf is .Dv NULL and size is not .Dv NULL , size is set. .Fa size must not be .Dv NULL to return a valid .Fa buf .
p .Fn ober_scanf_elements retrieves the values from zero or more elements starting at .Fa root . For each character in .Fa fmt , arguments of the types given in the following table are consumed and passed to the function listed, processing one .Vt ber_element per character. The following characters are valid: l -column -offset indent\ characte ober_get_enumerated_ "1: struct ber_element **" t Sy character Ta Sy function Ta Sy arguments t $ Ta see below Ta 0 t B Ta Fn ober_get_bitstring Ta 2: Vt void ** , size_t * t b Ta Fn ober_get_boolean Ta 1: Vt int * t d Ta Fn ober_get_integer Ta 1: Vt int * t E Ta Fn ober_get_enumerated Ta 1: Vt long long * t e Ta see below Ta 1: Vt struct ber_element ** t i Ta Fn ober_get_integer Ta 1: Vt long long * t o Ta Fn ober_get_oid Ta 1: Vt struct ber_oid * t p Ta Fn ober_getpos Ta 1: Vt off_t * t S Ta see below Ta 0 t s Ta Fn ober_get_string Ta 1: Vt char ** t t Ta see below Ta 2: Vt int * , unsigned int * t x Ta Fn ober_get_nstring Ta 2: Vt void **, size_t * t ( or { Ta see below Ta 0 t ) or } Ta see below Ta 0 t . Ta Fn ober_get_eoc Ta 0 t 0 Ta Fn ober_get_null Ta 0 .El
p For .Sq e , .Sq p , .Sq S , and .Sq t , the type of the element is not checked. For .Sq p and .Sq t , the pointer is not incremented to the next element. For .Sq e , a pointer to the element is stored in the corresponding pointer variable. For .Sq S , the element is skipped without extracting any information from it. For .Sq t , the class and type of the element are stored in the two corresponding variables, but if the element contains a value, that value is ignored. A .Sq $ mandates the end of a sequence or set.
p For an opening parenthesis or brace, it is checked that the element is a sequence or a set, and parsing continues with its children. For a closing parenthesis or brace, parsing of the current sequence or set is ended and parsing continues with the element following the sequence or set. .Sh RETURN VALUES .Fn ober_getpos returns the value of .Vt be_offs .
p .Fn ober_scanf_elements returns 0 for success or -1 when encountering elements that do not agree with the expectations of .Fa fmt or when .Fa fmt is syntactically invalid. Even when .Fn ober_scanf_elements fails, some of the arguments may already have been filled in.
p The other functions return 0 if .Va root is of the requested type or -1 otherwise. .Sh SEE ALSO .Xr ober_add_string 3 , .Xr ober_oid_cmp 3 , .Xr ober_read_elements 3 , .Xr ober_set_header 3 .Sh STANDARDS ITU-T Recommendation X.690, also known as ISO/IEC 8825-1: Information technology - ASN.1 encoding rules. .Sh HISTORY These functions first appeared as internal functions in .Xr snmpd 8 in .Ox 4.2 and were moved to libutil in .Ox 6.6 . .Sh AUTHORS .An -nosplit The BER library was written by .An Claudio Jeker Aq Mt claudio@openbsd.org , .An Marc Balmer Aq Mt marc@openbsd.org and .An Reyk Floeter Aq Mt reyk@openbsd.org .