645b5f8724
in addition to the pages, there's also changes to the mkfile to generate the index for the new section.
107 lines
2 KiB
Text
107 lines
2 KiB
Text
.TH PARSECMD 9
|
|
.SH NAME
|
|
parsecmd, cmderror, lookupcmd
|
|
\- parse device commands
|
|
.SH SYNOPSIS
|
|
.ta \w'\fLCmdbuf* 'u
|
|
.B
|
|
Cmdbuf* parsecmd(char *a, int n)
|
|
.PP
|
|
.B
|
|
void cmderror(Cmdbuf *cb, char *s)
|
|
.PP
|
|
.B
|
|
Cmdtab* lookupcmd(Cmdbuf *cb, Cmdtab *ctab, int nctab)
|
|
.SH DESCRIPTION
|
|
.I Parsecmd
|
|
is an interface to
|
|
.I tokenize
|
|
(see
|
|
.IR getfields (2)),
|
|
that safely parses a command, with blank-separated fields, as might be
|
|
written to a device's
|
|
.B ctl
|
|
file.
|
|
The buffer
|
|
.I a
|
|
and count
|
|
.I n
|
|
can be those passed to the driver's
|
|
.I write
|
|
function.
|
|
.I Parsecmd
|
|
converts the byte array (which might not be null-terminated) to a null-terminated string,
|
|
trimming any trailing new line,
|
|
before invoking
|
|
.I tokenize
|
|
to break the string into arguments, interpreting blank and tab as field separators
|
|
when they are not quoted
|
|
(in the style of
|
|
.IR rc (1)).
|
|
It returns a pointer to a dynamically-allocated
|
|
.B Cmdbuf
|
|
structure,
|
|
which holds a copy of the string and the resulting fields; it is
|
|
defined as follows:
|
|
.IP
|
|
.EX
|
|
.ta 6n +\w'char* 'u
|
|
typedef
|
|
struct Cmdbuf
|
|
{
|
|
char *buf;
|
|
char **f;
|
|
int nf;
|
|
} Cmdbuf;
|
|
.EE
|
|
.PP
|
|
The array
|
|
.B f
|
|
holds the field pointers;
|
|
.B nf
|
|
gives the number of fields.
|
|
.B Cmdbuf
|
|
is allocated by
|
|
.I smalloc
|
|
(see
|
|
.IR malloc (9)),
|
|
and the caller is responsible for freeing it using
|
|
.IR free .
|
|
.I Cmderror
|
|
prepends the given format with the original command,
|
|
then calls
|
|
.IR error (9).
|
|
.PP
|
|
Command strings may be turned into a (typically enumerated)
|
|
integer with
|
|
.IR lookupcmd .
|
|
The catchall
|
|
.L *
|
|
matches any text. Unrecognized commands, or commands
|
|
given an unacceptable number of arguments generate a
|
|
call to
|
|
.IR error .
|
|
The definition is as follows
|
|
.IP
|
|
.EX
|
|
.ta 6n +\w'char* 'u
|
|
typedef
|
|
struct Cmdtab
|
|
{
|
|
int index; /* used by client to switch on result */
|
|
char *cmd; /* command name */
|
|
int narg; /* expected #args; 0 ==> variadic */
|
|
} Cmdtab;
|
|
.EE
|
|
.PP
|
|
The integer
|
|
.B index
|
|
is the number returned on command match.
|
|
The string
|
|
.B cmd
|
|
is the command name, and
|
|
.B narg
|
|
is 0 (indicating a variadic function) or the
|
|
number of arguments.
|
|
.SH SOURCE
|
|
.B /sys/src/9/port/parse.c
|