[parseopt] Add generic option-parsing library

Command implementations tend to include a substantial amount of common
boilerplate code revolving around the parsing of command-line options
and arguments.  This increases the size cost of each command.

Introduce an option-parsing library that abstracts out the common
operations involved in command implementations.  This enables the size
of each individual command to be reduced, and also enhances
consistency between commands.

Total size of the library is 704 bytes, to be amortised across all
command implementations.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 219 insertions, 0 deletions

diff --git a/src/core/parseopt.c b/src/core/parseopt.c
new file mode 100644
index 00000000..ccaed374
--- /dev/null
+++ b/src/core/parseopt.c
@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <getopt.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/image.h>
+#include <ipxe/parseopt.h>
+
+/** @file
+ *
+ * Command line option parsing
+ *
+ */
+
+/** Return status code for "--help" option */
+#define ECANCELED_NO_OP __einfo_error ( EINFO_ECANCELED_NO_OP )
+#define EINFO_ECANCELED_NO_OP \
+	__einfo_uniqify ( EINFO_ECANCELED, 0x01, "Nothing to do" )
+
+/**
+* Parse string value
+ *
+ * @v text		Text
+ * @ret value		String value
+ * @ret rc		Return status code
+ */
+int parse_string ( const char *text, const char **value ) {
+
+	/* Sanity check */
+	assert ( text != NULL );
+
+	/* Parse string */
+	*value = text;
+
+	return 0;
+}
+
+/**
+ * Parse integer value
+ *
+ * @v text		Text
+ * @ret value		Integer value
+ * @ret rc		Return status code
+ */
+int parse_integer ( const char *text, unsigned int *value ) {
+	char *endp;
+
+	/* Sanity check */
+	assert ( text != NULL );
+
+	/* Parse integer */
+	*value = strtoul ( text, &endp, 10 );
+	if ( *endp ) {
+		printf ( "\"%s\": invalid integer value\n", text );
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * Parse network device name
+ *
+ * @v text		Text
+ * @ret netdev		Network device
+ * @ret rc		Return status code
+ */
+int parse_netdev ( const char *text, struct net_device **netdev ) {
+
+	/* Sanity check */
+	assert ( text != NULL );
+
+	/* Find network device */
+	*netdev = find_netdev ( text );
+	if ( ! *netdev ) {
+		printf ( "\"%s\": no such network device\n", text );
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/**
+ * Parse image name
+ *
+ * @v text		Text
+ * @ret image		Image
+ * @ret rc		Return status code
+ */
+int parse_image ( const char *text, struct image **image ) {
+
+	/* Sanity check */
+	assert ( text != NULL );
+
+	/* Find network device */
+	*image = find_image ( text );
+	if ( ! *image ) {
+		printf ( "\"%s\": no such image\n", text );
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+/**
+ * Print command usage message
+ *
+ * @v cmd		Command descriptor
+ * @v argv		Argument list
+ */
+void print_usage ( struct command_descriptor *cmd, char **argv ) {
+	printf ( "Usage:\n\n  %s %s\n", argv[0], cmd->usage_description );
+}
+
+/**
+ * Parse command-line options
+ *
+ * @v argc		Argument count
+ * @v argv		Argument list
+ * @v cmd		Command descriptor
+ * @v opts		Options
+ * @ret rc		Return status code
+ */
+int parse_options ( int argc, char **argv, struct command_descriptor *cmd,
+		    void *opts ) {
+	struct option longopts[ cmd->num_options + 1 /* help */ + 1 /* end */ ];
+	char shortopts[ cmd->num_options * 3 /* possible "::" */ + 1 /* "h" */
+			+ 1 /* NUL */ ];
+	unsigned int shortopt_idx = 0;
+	int ( * parse ) ( const char *text, void *value );
+	void *value;
+	unsigned int i;
+	unsigned int j;
+	unsigned int num_args;
+	int c;
+	int rc;
+
+	/* Construct long and short option lists for getopt_long() */
+	memset ( longopts, 0, sizeof ( longopts ) );
+	for ( i = 0 ; i < cmd->num_options ; i++ ) {
+		longopts[i].name = cmd->options[i].longopt;
+		longopts[i].has_arg = cmd->options[i].has_arg;
+		longopts[i].val = cmd->options[i].shortopt;
+		shortopts[shortopt_idx++] = cmd->options[i].shortopt;
+		assert ( cmd->options[i].has_arg <= optional_argument );
+		for ( j = cmd->options[i].has_arg ; j > 0 ; j-- )
+			shortopts[shortopt_idx++] = ':';
+	}
+	longopts[i].name = "help";
+	longopts[i].val = 'h';
+	shortopts[shortopt_idx++] = 'h';
+	shortopts[shortopt_idx++] = '\0';
+	assert ( shortopt_idx <= sizeof ( shortopts ) );
+	DBGC ( cmd,  "Command \"%s\" has options \"%s\", %d-%d args, len %d\n",
+	       argv[0], shortopts, cmd->min_args, cmd->max_args, cmd->len );
+
+	/* Clear options */
+	memset ( opts, 0, cmd->len );
+
+	/* Parse options */
+	while ( ( c = getopt_long ( argc, argv, shortopts, longopts,
+				    NULL ) ) >= 0 ) {
+		switch ( c ) {
+		case 'h' :
+			/* Print help */
+			print_usage ( cmd, argv );
+			return -ECANCELED_NO_OP;
+		case '?' :
+		case ':' :
+			/* Print usage message */
+			print_usage ( cmd, argv );
+			return -EINVAL;
+		default:
+			/* Search for an option to parse */
+			for ( i = 0 ; i < cmd->num_options ; i++ ) {
+				if ( c != cmd->options[i].shortopt )
+					continue;
+				parse = cmd->options[i].parse;
+				value = ( opts + cmd->options[i].offset );
+				if ( ( rc = parse ( optarg, value ) ) != 0 )
+					return rc;
+				break;
+			}
+			assert ( i < cmd->num_options );
+		}
+	}
+
+	/* Check remaining arguments */
+	num_args = ( argc - optind );
+	if ( ( num_args < cmd->min_args ) || ( num_args > cmd->max_args ) ) {
+		print_usage ( cmd, argv );
+		return -ERANGE;
+	}
+
+	return 0;
+}