xref: /freebsd/lib/libfigpar/figpar.3 (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
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25.Dd March 13, 2018
26.Dt FIGPAR 3
27.Os
28.Sh NAME
29.Nm figpar ,
30.Nm parse_config ,
31.Nm get_config_option
32.Nd configuration file parsing library
33.Sh LIBRARY
34.Lb libfigpar
35.Sh SYNOPSIS
36.In figpar.h
37.Ft int
38.Fo parse_config
39.Fa "struct figpar_config options[]"
40.Fa "const char *path"
41.Fa "int \*[lp]*unknown\*[rp]\*[lp]struct figpar_config *option"
42.Fa "uint32_t line"
43.Fa "char *directive"
44.Fa "char *value\*[rp]"
45.Fa "uint8_t processing_options"
46.Fc
47.Ft "struct figpar_config *"
48.Fo get_config_option
49.Fa "struct figpar_config options[]"
50.Fa "const char *directive"
51.Fc
52.In string_m.h
53.Ft int
54.Fo replaceall
55.Fa "char *source"
56.Fa "const char *find"
57.Fa "const char *replace"
58.Fc
59.Ft unsigned int
60.Fo strcount
61.Fa "const char *source"
62.Fa "const char *find"
63.Fc
64.Ft void
65.Fo strexpand
66.Fa "char *source"
67.Fc
68.Ft void
69.Fo strexpandnl
70.Fa "char *source"
71.Fc
72.Ft void
73.Fo strtolower
74.Fa "char *source"
75.Fc
76.Sh DESCRIPTION
77The
78.Nm
79library provides a light-weight,
80portable framework for parsing configuration
81files.
82The library uses
83.Xr open 2 ,
84.Xr read 2 ,
85and
86.Xr lseek 2
87within the file pointed to by
88.Fa path
89to find directives and values which are then made available to the application.
90.Pp
91Due to the fact that configuration files may have basic syntax differences,
92the library does not attempt to impose any structure on the data but instead
93provides raw data to a set of callback functions.
94These callback functions can in-turn initiate abort through their return value,
95allowing custom syntax validation during parsing.
96.Pp
97Configuration directives,
98types,
99and callback functions are provided through data structures defined in
100.In figpar.h :
101.Bd -literal -offset indent
102struct figpar_config {
103    enum figpar_cfgtype		type;		/* value type */
104    const char			*directive;	/* keyword */
105    union figpar_cfgvalue	value;		/* value */
106
107    /* Pointer to function used when directive is found */
108    int (*action)(struct figpar_config *option, uint32_t line,
109        char *directive, char *value);
110};
111
112enum figpar_cfgtype {
113    FIGPAR_TYPE_NONE      = 0x0000, /* directives with no value */
114    FIGPAR_TYPE_BOOL      = 0x0001, /* boolean */
115    FIGPAR_TYPE_INT       = 0x0002, /* signed 32 bit integer */
116    FIGPAR_TYPE_UINT      = 0x0004, /* unsigned 32 bit integer */
117    FIGPAR_TYPE_STR       = 0x0008, /* string pointer */
118    FIGPAR_TYPE_STRARRAY  = 0x0010, /* string array pointer */
119    FIGPAR_TYPE_DATA1     = 0x0020, /* void data type-1 (open) */
120    FIGPAR_TYPE_DATA2     = 0x0040, /* void data type-2 (open) */
121    FIGPAR_TYPE_DATA3     = 0x0080, /* void data type-3 (open) */
122    FIGPAR_TYPE_RESERVED1 = 0x0100, /* reserved data type-1 */
123    FIGPAR_TYPE_RESERVED2 = 0x0200, /* reserved data type-2 */
124    FIGPAR_TYPE_RESERVED3 = 0x0400, /* reserved data type-3 */
125};
126
127union figpar_cfgvalue {
128    void	*data;      /* Pointer to NUL-terminated string */
129    char	*str;       /* Pointer to NUL-terminated string */
130    char	**strarray; /* Pointer to an array of strings */
131    int32_t	num;        /* Signed 32-bit integer value */
132    uint32_t	u_num;      /* Unsigned 32-bit integer value */
133    uint32_t	boolean:1;  /* Boolean integer value (0 or 1) */
134};
135.Ed
136.Pp
137The
138.Fa processing_options
139argument to
140.Fn parse_config
141is a mask of bit fields which indicate various
142processing options.
143The possible flags are:
144.Bl -tag -width FIGPAR_BREAK_ON_SEMICOLON
145.It Dv FIGPAR_BREAK_ON_EQUALS
146An equals sign
147.Pq Ql Li =
148is normally considered part of the directive.
149This flag enables terminating the directive at the equals sign.
150Also makes equals sign optional and transient.
151.It Dv FIGPAR_BREAK_ON_SEMICOLON
152A semicolon
153.Pq Ql Li \;
154is normally considered part of the value.
155This flag enables terminating the value at the semicolon.
156Also allows multiple statements on a single line separated by semicolon.
157.It Dv FIGPAR_CASE_SENSITIVE
158Normally directives are matched case insensitively using
159.Xr fnmatch 3 .
160This flag enables directive matching to be case sensitive.
161.It Dv FIGPAR_REQUIRE_EQUALS
162If a directive is not followed by an equals,
163processing is aborted.
164.It Dv FIGPAR_STRICT_EQUALS
165Equals must be part of the directive to be considered a delimiter between
166directive and value.
167.El
168.Pp
169The
170.Fa options
171struct array pointer can be NULL and every directive will run the
172.Fn unknown
173function argument.
174.Pp
175The directive for each figpar_config item in the
176.Fn parse_config
177options argument is matched against each parsed directive using
178.Xr fnmatch 3
179until a match is found.
180If a match is found,
181the
182.Fn action
183function for that figpar_config directive is run with the line number,
184directive,
185and value.
186Otherwise if no match,
187the
188.Fn unknown
189function is run
190.Pq with the same arguments .
191.Pp
192If either
193.Fa action
194or
195.Fa unknown
196return non-zero,
197.Fn parse_config
198aborts reading the file and returns the error value to its caller.
199.Pp
200.Fn get_config_option
201traverses the options-array and returns the option that matches via
202.Xr strcmp 3 ,
203or if no match a pointer to a static dummy struct is returned
204.Pq whose values are all zero or NULL .
205.Pp
206The use of
207.Fa "struct figpar_config"
208is entirely optional as-is the use of
209.Fa "enum figpar_cfgtype"
210or
211.Fa "union figpar_cfgvalue" .
212For example,
213a NULL pointer can be passed to
214.Fn parse_config
215for the first argument while providing a simple
216.Fa unknown
217function based on
218.Xr queue 3
219that populates a singly-linked list of a struct containing the
220.Fa directive
221and
222.Fa value .
223.Pp
224In addition,
225miscellaneous string manipulation routines are provided by
226.In string_m.h :
227.Bl -tag -width strexpandnl()
228.It Fn replaceall
229Replace all occurrences of
230.Fa find
231in
232.Fa source
233with
234.Fa replace .
235.It Fn strcount
236Count the number of occurrences of one string that appear in the
237.Fa source
238string.
239Return value is the total count.
240An example use would be to show how large a block of memory needs to be for a
241.Fn replaceall
242series.
243.It Fn strexpand
244Expand escape sequences in a buffer pointed to by
245.Fa source .
246.It Fn strexpandnl
247Expand only the escaped newlines in a buffer pointed to by
248.Fa source .
249.It Fn strtolower
250Convert a string to lower case.
251.El
252.Sh SEE ALSO
253.Xr queue 3
254.Sh HISTORY
255The
256.Nm
257library first appeared in
258.Fx 10.2 .
259.Sh AUTHORS
260.An Devin Teske Aq dteske@FreeBSD.org
261.Sh BUGS
262This is the first implementation of the library,
263and the interface may be subject to refinement.
264