1 cfa37a7b 2004-04-10 devnull .TH 9PCMDBUF 3
  2 cfa37a7b 2004-04-10 devnull .SH NAME
  3 cfa37a7b 2004-04-10 devnull Cmdbuf, parsecmd, respondcmderror, lookupcmd \- control message parsing
  4 cfa37a7b 2004-04-10 devnull .SH SYNOPSIS
  5 cfa37a7b 2004-04-10 devnull .ft L
  6 cfa37a7b 2004-04-10 devnull .nf
  7 cfa37a7b 2004-04-10 devnull #include <u.h>
  8 cfa37a7b 2004-04-10 devnull #include <libc.h>
  9 cfa37a7b 2004-04-10 devnull #include <fcall.h>
 10 cfa37a7b 2004-04-10 devnull #include <thread.h>
 11 cfa37a7b 2004-04-10 devnull #include <9p.h>
 12 cfa37a7b 2004-04-10 devnull .fi
 13 cfa37a7b 2004-04-10 devnull .PP
 14 cfa37a7b 2004-04-10 devnull .ft L
 15 cfa37a7b 2004-04-10 devnull .nf
 16 cfa37a7b 2004-04-10 devnull .ta \w'\fL1234'u +\w'\fL12345678'u
 17 cfa37a7b 2004-04-10 devnull typedef struct Cmdbuf
 18 cfa37a7b 2004-04-10 devnull {
 19 cfa37a7b 2004-04-10 devnull 	char	*buf;
 20 cfa37a7b 2004-04-10 devnull 	char	**f;
 21 cfa37a7b 2004-04-10 devnull 	int	nf;
 22 cfa37a7b 2004-04-10 devnull } Cmdbuf;
 23 cfa37a7b 2004-04-10 devnull 
 24 cfa37a7b 2004-04-10 devnull typedef struct Cmdtab
 25 cfa37a7b 2004-04-10 devnull {
 26 cfa37a7b 2004-04-10 devnull 	int	index;
 27 cfa37a7b 2004-04-10 devnull 	char	*cmd;
 28 cfa37a7b 2004-04-10 devnull 	int	narg;
 29 cfa37a7b 2004-04-10 devnull };
 30 cfa37a7b 2004-04-10 devnull 
 31 cfa37a7b 2004-04-10 devnull Cmdbuf	*parsecmd(char *p, int n)
 32 cfa37a7b 2004-04-10 devnull Cmdtab	*lookupcmd(Cmdbuf *cb, Cmdtab *tab, int ntab)
 33 cfa37a7b 2004-04-10 devnull void	respondcmderror(Req *r, Cmdbuf *cb, char *fmt, ...)
 34 cfa37a7b 2004-04-10 devnull .fi
 35 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
 36 cfa37a7b 2004-04-10 devnull These data structures and functions provide parsing of textual control messages.
 37 cfa37a7b 2004-04-10 devnull .PP
 38 cfa37a7b 2004-04-10 devnull .I Parsecmd
 39 cfa37a7b 2004-04-10 devnull treats the
 40 cfa37a7b 2004-04-10 devnull .I n
 41 cfa37a7b 2004-04-10 devnull bytes at
 42 cfa37a7b 2004-04-10 devnull .I p
 43 cfa37a7b 2004-04-10 devnull (which need not be NUL-terminated) as a UTF string and splits it
 44 cfa37a7b 2004-04-10 devnull using
 45 bf8a59fa 2004-04-11 devnull .IR tokenize (3).
 46 cfa37a7b 2004-04-10 devnull It returns a
 47 cfa37a7b 2004-04-10 devnull .B Cmdbuf
 48 cfa37a7b 2004-04-10 devnull structure holding pointers to each field in the message.
 49 cfa37a7b 2004-04-10 devnull .PP
 50 cfa37a7b 2004-04-10 devnull .I Lookupcmd
 51 cfa37a7b 2004-04-10 devnull walks through the array
 52 cfa37a7b 2004-04-10 devnull .IR ctab ,
 53 cfa37a7b 2004-04-10 devnull which has
 54 cfa37a7b 2004-04-10 devnull .I ntab
 55 cfa37a7b 2004-04-10 devnull entries,
 56 cfa37a7b 2004-04-10 devnull looking for the first
 57 cfa37a7b 2004-04-10 devnull .B Cmdtab
 58 cfa37a7b 2004-04-10 devnull that matches the parsed command.
 59 cfa37a7b 2004-04-10 devnull (If the parsed command is empty,
 60 cfa37a7b 2004-04-10 devnull .I lookupcmd
 61 cfa37a7b 2004-04-10 devnull returns nil immediately.)
 62 cfa37a7b 2004-04-10 devnull A
 63 cfa37a7b 2004-04-10 devnull .B Cmdtab
 64 cfa37a7b 2004-04-10 devnull matches the command if
 65 cfa37a7b 2004-04-10 devnull .I cmd
 66 cfa37a7b 2004-04-10 devnull is equal to
 67 cfa37a7b 2004-04-10 devnull .IB cb -> f [0]
 68 cfa37a7b 2004-04-10 devnull or if
 69 cfa37a7b 2004-04-10 devnull .I cmd
 70 cfa37a7b 2004-04-10 devnull is 
 71 cfa37a7b 2004-04-10 devnull .LR * .
 72 cfa37a7b 2004-04-10 devnull Once a matching
 73 cfa37a7b 2004-04-10 devnull .B Cmdtab
 74 cfa37a7b 2004-04-10 devnull has been found, if
 75 cfa37a7b 2004-04-10 devnull .I narg
 76 cfa37a7b 2004-04-10 devnull is not zero, then the parsed command
 77 cfa37a7b 2004-04-10 devnull must have exactly
 78 cfa37a7b 2004-04-10 devnull .I narg
 79 cfa37a7b 2004-04-10 devnull fields (including the command string itself).
 80 cfa37a7b 2004-04-10 devnull If the command has the wrong number of arguments,
 81 cfa37a7b 2004-04-10 devnull .I lookupcmd
 82 cfa37a7b 2004-04-10 devnull returns nil.
 83 cfa37a7b 2004-04-10 devnull Otherwise, it returns a pointer to the
 84 cfa37a7b 2004-04-10 devnull .B Cmdtab
 85 cfa37a7b 2004-04-10 devnull entry.
 86 cfa37a7b 2004-04-10 devnull If
 87 cfa37a7b 2004-04-10 devnull .I lookupcmd
 88 cfa37a7b 2004-04-10 devnull does not find a matching command at all,
 89 cfa37a7b 2004-04-10 devnull it returns nil.
 90 cfa37a7b 2004-04-10 devnull Whenever
 91 cfa37a7b 2004-04-10 devnull .I lookupcmd
 92 cfa37a7b 2004-04-10 devnull returns nil, it sets the system error string.
 93 cfa37a7b 2004-04-10 devnull .PP
 94 cfa37a7b 2004-04-10 devnull .I Respondcmderror
 95 cfa37a7b 2004-04-10 devnull resoponds to request
 96 cfa37a7b 2004-04-10 devnull .I r
 97 cfa37a7b 2004-04-10 devnull with an error of the form
 98 cfa37a7b 2004-04-10 devnull `\fIfmt\fB:\fI cmd\fR,'
 99 cfa37a7b 2004-04-10 devnull where
100 cfa37a7b 2004-04-10 devnull .I fmt
101 cfa37a7b 2004-04-10 devnull is the formatted string and
102 cfa37a7b 2004-04-10 devnull .I cmd
103 cfa37a7b 2004-04-10 devnull is a reconstruction of the parsed command.
104 cfa37a7b 2004-04-10 devnull Fmt
105 cfa37a7b 2004-04-10 devnull is often simply
106 cfa37a7b 2004-04-10 devnull .B "%r" .
107 cfa37a7b 2004-04-10 devnull .SH EXAMPLES
108 cfa37a7b 2004-04-10 devnull This interface is not used in any distributed 9P servers.
109 cfa37a7b 2004-04-10 devnull It was lifted from the Plan 9 kernel.
110 cfa37a7b 2004-04-10 devnull Almost any kernel driver
111 cfa37a7b 2004-04-10 devnull .RB ( /sys/src/9/*/dev*.c )
112 cfa37a7b 2004-04-10 devnull is a good example.
113 cfa37a7b 2004-04-10 devnull .SH SOURCE
114 cfa37a7b 2004-04-10 devnull .B /sys/src/lib9p/parse.c
115 cfa37a7b 2004-04-10 devnull .SH SEE ALSO
116 bf8a59fa 2004-04-11 devnull .IR 9p (3)