xref: /freebsd/lib/libfigpar/figpar.3 (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
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27.Dd Nov 2, 2015
28.Dt FIGPAR 3
29.Os
30.Sh NAME
31.Nm figpar ,
32.Nm parse_config ,
33.Nm get_config_option
34.Nd configuration file parsing library
35.Sh LIBRARY
36.Lb libfigpar
37.Sh SYNOPSIS
38.In figpar.h
39.Ft int
40.Fo parse_config
41.Fa "struct figpar_config options[], const char *path"
42.Fa "int \*[lp]*unknown\*[rp]\*[lp]struct figpar_config *option, uint32_t line"
43.Fa "char *directive, char *value\*[rp], uint8_t processing_options"
44.Fc
45.Ft "struct figpar_config *"
46.Fo get_config_option
47.Fa "struct figpar_config options[], const char *directive"
48.Fc
49.In string_m.h
50.Ft int
51.Fo replaceall
52.Fa "char *source, const char *find, const char *replace"
53.Fc
54.Ft unsigned int
55.Fo strcount
56.Fa "const char *source, const char *find"
57.Fc
58.Ft void
59.Fo strexpand
60.Fa "char *source"
61.Fc
62.Ft void
63.Fo strexpandnl
64.Fa "char *source"
65.Fc
66.Ft void
67.Fo strtolower
68.Fa "char *source"
69.Fc
70.Sh DESCRIPTION
71The
72.Nm
73library provides a light-weight, portable framework for parsing configuration
74files.
75The library uses
76.Xr open 2 ,
77.Xr read 2 ,
78and
79.Xr lseek 2
80within the file pointed to by
81.Fa path
82to find directives and values which are then made available to the application.
83.Pp
84Due to the fact that configuration files may have basic syntax differences,
85the library does not attempt to impose any structure on the data but instead
86provides raw data to a set of callback functions.
87These callback functions can in-turn initiate abort through their return value,
88allowing custom syntax validation during parsing.
89.Pp
90Configuration directives, types, and callback functions are provided through
91data structures defined in
92.In figpar.h :
93.Bd -literal -offset indent
94struct figpar_config {
95    enum figpar_cfgtype		type;		/* value type */
96    const char			*directive;	/* keyword */
97    union figpar_cfgvalue	value;		/* value */
98
99    /* Pointer to function used when directive is found */
100    int (*action)(struct figpar_config *option, uint32_t line,
101        char *directive, char *value);
102};
103
104enum figpar_cfgtype {
105    FIGPAR_TYPE_NONE      = 0x0000, /* directives with no value */
106    FIGPAR_TYPE_BOOL      = 0x0001, /* boolean */
107    FIGPAR_TYPE_INT       = 0x0002, /* signed 32 bit integer */
108    FIGPAR_TYPE_UINT      = 0x0004, /* unsigned 32 bit integer */
109    FIGPAR_TYPE_STR       = 0x0008, /* string pointer */
110    FIGPAR_TYPE_STRARRAY  = 0x0010, /* string array pointer */
111    FIGPAR_TYPE_DATA1     = 0x0020, /* void data type-1 (open) */
112    FIGPAR_TYPE_DATA2     = 0x0040, /* void data type-2 (open) */
113    FIGPAR_TYPE_DATA3     = 0x0080, /* void data type-3 (open) */
114    FIGPAR_TYPE_RESERVED1 = 0x0100, /* reserved data type-1 */
115    FIGPAR_TYPE_RESERVED2 = 0x0200, /* reserved data type-2 */
116    FIGPAR_TYPE_RESERVED3 = 0x0400, /* reserved data type-3 */
117};
118
119union figpar_cfgvalue {
120    void	*data;      /* Pointer to NUL-terminated string */
121    char	*str;       /* Pointer to NUL-terminated string */
122    char	**strarray; /* Pointer to an array of strings */
123    int32_t	num;        /* Signed 32-bit integer value */
124    uint32_t	u_num;      /* Unsigned 32-bit integer value */
125    uint32_t	boolean:1;  /* Boolean integer value (0 or 1) */
126};
127.Ed
128.Pp
129The
130.Fa processing_options
131argument to
132.Fn parse_config
133is a mask of bit fields which indicate various
134processing options.
135The possible flags are as follows:
136.Bl -tag -width FIGPAR_BREAK_ON_SEMICOLON
137.It Dv FIGPAR_BREAK_ON_EQUALS
138An equals sign
139.Pq Ql Li =
140is normally considered part of the directive.
141This flag enables terminating the directive at the equals sign.
142Also makes equals sign optional and transient.
143.It Dv FIGPAR_BREAK_ON_SEMICOLON
144A semicolon
145.Pq Ql Li \;
146is normally considered part of the value.
147This flag enables terminating the value at the semicolon.
148Also allows multiple statements on a single line separated by semicolon.
149.It Dv FIGPAR_CASE_SENSITIVE
150Normally directives are matched case insensitively using
151.Xr fnmatch 3 .
152This flag enables directive matching to be case sensitive.
153.It Dv FIGPAR_REQUIRE_EQUALS
154If a directive is not followed by an equals, processing is aborted.
155.It Dv FIGPAR_STRICT_EQUALS
156Equals must be part of the directive to be considered a delimiter between
157directive and value.
158.El
159.Pp
160The
161.Fa options
162struct array pointer can be NULL and every directive will invoke the
163.Fn unknown
164function argument.
165.Pp
166The directive for each figpar_config item in the
167.Fn parse_config
168options argument is matched against each parsed directive using
169.Xr fnmatch 3
170until a match is found.
171If a match is found, the
172.Fn action
173function for that figpar_config directive is invoked with the line number,
174directive, and value.
175Otherwise if no match, the
176.Fn unknown
177function is invoked
178.Pq with the same arguments .
179.Pp
180If either
181.Fa action
182or
183.Fa unknown
184return non-zero,
185.Fn parse_config
186aborts reading the file and returns the error value to its caller.
187.Pp
188.Fn get_config_option
189traverses the options-array and returns the option that matches via
190.Xr strcmp 3 ,
191or if no match a pointer to a static dummy struct is returned
192.Pq whose values are all zero or NULL .
193.Pp
194The use of
195.Fa "struct figpar_config"
196is entirely optional as-is the use of
197.Fa "enum figpar_cfgtype"
198or
199.Fa "union figpar_cfgvalue" .
200For example, you could choose to pass a NULL pointer to
201.Fn parse_config
202for the first argument and then provide a simple
203.Fa unknown
204function based on
205.Xr queue 3
206that populates a singly-linked list of your own struct containing the
207.Fa directive
208and
209.Fa value .
210.Pp
211In addition, the following miscellaneous string manipulation routines are
212provided by
213.In string_m.h :
214.Bl -tag -width strexpandnl()
215.It Fn replaceall
216Replace all occurrences of
217.Fa find
218in
219.Fa source
220with
221.Fa replace .
222.It Fn strcount
223Count the number of occurrences of one string that appear in the
224.Fa source
225string.
226Return value is the total count.
227An example use would be if you need to know how large a block of memory needs
228to be for a
229.Fn replaceall
230series.
231.It Fn strexpand
232Expand escape sequences in a buffer pointed to by
233.Fa source .
234.It Fn strexpandnl
235Expand only the escaped newlines in a buffer pointed to by
236.Fa source .
237.It Fn strtolower
238Convert a string to lower case.
239.El
240.Sh SEE ALSO
241.Xr queue 3
242.Sh HISTORY
243The
244.Nm
245library first appeared in
246.Fx 10.2 .
247.Sh AUTHORS
248.An Devin Teske Aq dteske@FreeBSD.org
249.Sh BUGS
250This is the first implementation of the library,
251and the interface may be subject to refinement.
252