NAME
ccggeetteenntt, ccggeettsseett, ccggeettmmaattcchh, ccggeettccaapp, ccggeettnnuumm, ccggeettssttrr, ccggeettuussttrr,ccggeettffiirrsstt, ccggeettnneexxtt, ccggeettcclloossee - capability database access routines
LLIIBBRRAARRYYStandard C Library (libc, -lc)
SYNOPSIS
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int ccggeetteenntt(char **buf, char **dbarray, char *name); int ccggeettsseett(char *ent); int ccggeettmmaattcchh(char *buf, char *name); char * ccggeettccaapp(char *buf, char *cap, int type); int ccggeettnnuumm(char *buf, char *cap, long *num); int ccggeettssttrr(char *buf, char *cap, char **str); int ccggeettuussttrr(char *buf, char *cap, char **str); int ccggeettffiirrsstt(char **buf, char **dbarray); int ccggeettnneexxtt(char **buf, char **dbarray); int ccggeettcclloossee(void);> DESCRIPTION
The ccggeetteenntt() function extracts the capability name from the database specified by the NULL terminated file array dbarray and returns a pointer to a malloc(3)'d copy of it in buf. The ccggeetteenntt() function will first look for files ending in .db (see capmkdb(1)) before accessing the ASCII file. The buf argument must be retained through all subsequent calls to ccggeettmmaattcchh(), ccggeettccaapp(), ccggeettnnuumm(), ccggeettssttrr(), and ccggeettuussttrr(), but may then be free(3)'d. On success 0 is returned, 1 if the returnedrecord contains an unresolved ttcc expansion, -1 if the requested record
couldn't be found, -2 if a system error was encountered (couldn't
open/read a file, etc.) also setting errno, and -3 if a potential refer-
ence loop is detected (see ttcc== comments below).The ccggeettsseett() function enables the addition of a character buffer con-
taining a single capability record entry to the capability database. Conceptually, the entry is added as the first ``file'' in the database, and is therefore searched first on the call to ccggeetteenntt(). The entry is passed in ent. If ent is NULL, the current entry is removed from the database. A call to ccggeettsseett() must precede the database traversal. It must be called before the ccggeetteenntt() call. If a sequential access isbeing performed (see below), it must be called before the first sequen-
tial access call (ccggeettffiirrsstt() or ccggeettnneexxtt()), or be directly preceded bya ccggeettcclloossee() call. On success 0 is returned and -1 on failure.
The ccggeettmmaattcchh() function will return 0 if name is one of the names of thecapability record buf, -1 if not.
The ccggeettccaapp() function searches the capability record buf for the capa-
bility cap with type type. A type is specified using any single charac-
ter. If a colon (`:') is used, an untyped capability will be searched for (see below for explanation of types). A pointer to the value of cap in buf is returned on success, NULL if the requested capability couldn't be found. The end of the capability value is signaled by a `:' or ASCII NUL (see below for capability database syntax). The ccggeettnnuumm() function retrieves the value of the numeric capability cap from the capability record pointed to by buf. The numeric value isreturned in the long pointed to by num. 0 is returned on success, -1 if
the requested numeric capability couldn't be found. The ccggeettssttrr() function retrieves the value of the string capability cap from the capability record pointed to by buf. A pointer to a decoded, NUL terminated, malloc(3)'d copy of the string is returned in the char * pointed to by str. The number of characters in the decoded string notincluding the trailing NUL is returned on success, -1 if the requested
string capability couldn't be found, -2 if a system error was encountered
(storage allocation failure). The ccggeettuussttrr() function is identical to ccggeettssttrr() except that it does notexpand special characters, but rather returns each character of the capa-
bility string literally. The ccggeettffiirrsstt() and ccggeettnneexxtt() functions comprise a function group that provides for sequential access of the NULL pointer terminated array of file names, dbarray. The ccggeettffiirrsstt() function returns the first record in the database and resets the access to the first record. The ccggeettnneexxtt() function returns the next record in the database with respect to the record returned by the previous ccggeettffiirrsstt() or ccggeettnneexxtt() call. If there is no such previous call, the first record in the database is returned. Each record is returned in a malloc(3)'d copy pointed to by buf. TTcc expansion is done (see ttcc== comments below). Upon completion of the database 0 is returned, 1 is returned upon successful return of record with possibly more remaining (we haven't reached the end of the database yet), 2 is returned if the record contains an unresolved ttccexpansion, -1 is returned if a system error occurred, and -2 is returned
if a potential reference loop is detected (see ttcc== comments below). Upon completion of database (0 return) the database is closed.The ccggeettcclloossee() function closes the sequential access and frees any mem-
ory and file descriptors being used. Note that it does not erase the buffer pushed by a call to ccggeettsseett(). CCAAPPAABBIILLIITTYY DDAATTAABBAASSEE SSYYNNTTAAXX Capability databases are normally ASCII and may be edited with standardtext editors. Blank lines and lines beginning with a `#' are comments
and are ignored. Lines ending with a `\' indicate that the next line is a continuation of the current line; the `\' and following newline are ignored. Long lines are usually continued onto several physical lines by ending each line except the last with a `\'. Capability databases consist of a series of records, one per logicalline. Each record contains a variable number of `:'-separated fields
(capabilities). Empty fields consisting entirely of white space charac-
ters (spaces and tabs) are ignored. The first capability of each record specifies its names, separated by `|' characters. These names are used to reference records in the database. By convention, the last name is usually a comment and is not intended as a lookup tag. For example, the vt100 record from the termcap(5) database begins:d0|vt100|vt100-am|vt100am|dec vt100:
giving four names that can be used to access the record.The remaining non-empty capabilities describe a set of (name, value)
bindings, consisting of a names optionally followed by a typed value: name typeless [boolean] capability name is present [true] nameTvalue capability (name, T) has value value name@ no capability name exists nameT@ capability (name, T) does not exist Names consist of one or more characters. Names may contain any characterexcept `:', but it's usually best to restrict them to the printable char-
acters and avoid use of graphics like `#', `=', `%', `@', etc. Types are
single characters used to separate capability names from their associated typed values. Types may be any character except a `:'. Typically,graphics like `#', `=', `%', etc. are used. Values may be any number of
characters and may contain any character except `:'. CCAAPPAABBIILLIITTYY DDAATTAABBAASSEE SSEEMMAANNTTIICCSS Capability records describe a set of (name, value) bindings. Names mayhave multiple values bound to them. Different values for a name are dis-
tinguished by their types. The ccggeettccaapp() function will return a pointer to a value of a name given the capability name and the type of the value.The types `#' and `=' are conventionally used to denote numeric and
string typed values, but no restriction on those types is enforced. Thefunctions ccggeettnnuumm() and ccggeettssttrr() can be used to implement the tradi-
tional syntax and semantics of `#' and `='. Typeless capabilities are
typically used to denote boolean objects with presence or absence indi-
cating truth and false values respectively. This interpretation is con-
veniently represented by: (getcap(buf, name, ':') != NULL)A special capability, ttcc== nnaammee, is used to indicate that the record spec-
ified by name should be substituted for the ttcc capability. TTcc capabili-
ties may interpolate records which also contain ttcc capabilities and more than one ttcc capability may be used in a record. A ttcc expansion scope (i.e., where the argument is searched for) contains the file in which the ttcc is declared and all subsequent files in the file array. When a database is searched for a capability record, the first matchingrecord in the search is returned. When a record is scanned for a capa-
bility, the first matching capability is returned; the capability ::nnaammeeTT@@:: will hide any following definition of a value of type T for name; and the capability ::nnaammee@@:: will prevent any following values of name from being seen. These features combined with ttcc capabilities can be used to generatevariations of other databases and records by either adding new capabili-
ties, overriding definitions with new definitions, or hiding following definitions via `@' capabilities. EEXXAAMMPPLLEESS example|an example of binding multiple values to names:\:foo%bar:foo^blah:foo@:\
:abc%xyz:abc^frap:abc$@:\
:tc=more:The capability foo has two values bound to it (bar of type `%' and blah
of type `^') and any other value bindings are hidden. The capability abcalso has two values bound but only a value of type `$' is prevented from
being defined in the capability record more. file1: new|newrecord|a modification of "old":\:fript=bar:who-cares@:tc=old:blah:tc=extensions:
file2: old|oldrecord|an old database record:\:fript=foo:who-cares:glork#200:
The records are extracted by calling ccggeetteenntt() with file1 preceding file2. In the capability record new in file1, fript=bar overrides the definition of fript=foo interpolated from the capability record old infile2, who-cares@ prevents the definition of any who-cares definitions in
old from being seen, glork#200 is inherited from old, and blah and any-
thing defined by the record extensions is added to those definitions inold. Note that the position of the fript=bar and who-cares@ definitions
before tc=old is important here. If they were after, the definitions in old would take precedence. CCGGEETTNNUUMM AANNDD CCGGEETTSSTTRR SSYYNNTTAAXX AANNDD SSEEMMAANNTTIICCSS Two types are predefined by ccggeettnnuumm() and ccggeettssttrr():name#number numeric capability name has value number
name=string string capability name has value stringname#@ the numeric capability name does not exist
name=@ the string capability name does not exist Numeric capability values may be given in one of three numeric bases. Ifthe number starts with either `0x' or `0X' it is interpreted as a hexa-
decimal number (both upper and lower case a-f may be used to denote the
extended hexadecimal digits). Otherwise, if the number starts with a `0'it is interpreted as an octal number. Otherwise the number is inter-
preted as a decimal number.String capability values may contain any character. Non-printable ASCII
codes, new lines, and colons may be conveniently represented by the use of escape sequences:^X ('X' & 037) control-X
\b, \B (ASCII 010) backspace \t, \T (ASCII 011) tab \n, \N (ASCII 012) line feed (newline) \f, \F (ASCII 014) form feed \r, \R (ASCII 015) carriage return \e, \E (ASCII 027) escape \c, \C (:) colon \\ (\) back slash \^ (^) caret \nnn (ASCII octal nnn) A `\' may be followed by up to three octal digits directly specifies the numeric code for a character. The use of ASCII NULs, while easily encoded, causes all sorts of problems and must be used with care since NULs are typically used to denote the end of strings; many applications use `\200' to represent a NUL. DIAGNOSTICS The ccggeetteenntt(), ccggeettsseett(), ccggeettmmaattcchh(), ccggeettnnuumm(), ccggeettssttrr(), ccggeettuussttrr(), ccggeettffiirrsstt(), and ccggeettnneexxtt() functions return a value greater than or equal to 0 on success and a value less than 0 on failure. The ccggeettccaapp() function returns a character pointer on success and a NULL on failure. The ccggeetteenntt(), and ccggeettsseeqq() functions may fail and set errno for any of the errors specified for the library functions: fopen(3), fclose(3), open(2), and close(2). The ccggeetteenntt(), ccggeettsseett(), ccggeettssttrr(), and ccggeettuussttrr() functions may fail and set errno as follows: [ENOMEM] No memory to allocate.SEE ALSO
capmkdb(1), malloc(3)BUGS
Colons (`:') can't be used in names, types, or values. There are no checks for ttcc=nnaammee loops in ccggeetteenntt(). The buffer added to the database by a call to ccggeettsseett() is not unique to the database but is rather prepended to any database used. BSD May 13, 1994 BSD