add filetype command support

This adds support for a filetype detection command. It can be
used to print a filename on the console or to set a variable
with the detection result for use in shell scripts.
The command also has an option to print the known filetypes
so that a user knows what to match for.

Based on an earlier version from Jean-Christophe.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

commands/Kconfig

@@ -230,6 +230,11 @@ config CMD_TFTP
 	  barebox can mount tftp as a filesystem. This command is only needed to
 	  preserve backward compatibility to the old tftp command.
 
+config CMD_FILETYPE
+	tristate
+	select FILETYPE
+	prompt "filetype"
+
 endmenu
 
 menu "console                       "

commands/Makefile

@@ -76,3 +76,4 @@ obj-$(CONFIG_CMD_READLINK)	+= readlink.o
 obj-$(CONFIG_CMD_LN)		+= ln.o
 obj-$(CONFIG_CMD_CLK)		+= clk.o
 obj-$(CONFIG_CMD_TFTP)		+= tftp.o
+obj-$(CONFIG_CMD_FILETYPE)	+= filetype.o

commands/filetype.c

@@ -0,0 +1,97 @@
+/*
+ * (C) Copyright 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * Under GPLv2 Only
+ */
+
+#include <common.h>
+#include <command.h>
+#include <fs.h>
+#include <filetype.h>
+#include <environment.h>
+#include <magicvar.h>
+#include <getopt.h>
+#include <linux/stat.h>
+#include <fs.h>
+
+static int do_filetype(int argc, char *argv[])
+{
+	int opt;
+	enum filetype type;
+	char *filename = NULL;
+	int verbose = -1, list = 0;
+	const char *varname = NULL;
+	struct stat s;
+	int ret;
+
+	while ((opt = getopt(argc, argv, "vls:")) > 0) {
+		switch (opt) {
+		case 'v':
+			verbose = 1;
+			break;
+		case 'l':
+			list = 1;
+			break;
+		case 's':
+			varname = optarg;
+			/* in scripting mode default to nonverbose */
+			if (verbose < 0)
+				verbose = 0;
+			break;
+		default:
+			return COMMAND_ERROR_USAGE;
+		}
+	}
+
+	if (verbose < 0)
+		verbose = 1;
+
+	if (list) {
+		int i;
+
+		printf("known filetypes:\n");
+
+		for (i = 1; i < filetype_max; i++)
+			printf("%-16s: %s\n", file_type_to_short_string(i),
+					file_type_to_string(i));
+		return 0;
+	}
+
+	if (argc - optind < 1)
+		return COMMAND_ERROR_USAGE;
+
+	filename = argv[optind];
+
+	ret = stat(filename, &s);
+	if (ret)
+		return ret;
+
+	if (S_ISDIR(s.st_mode))
+		return -EISDIR;
+
+	type = file_name_detect_type(filename);
+
+	if (verbose)
+		printf("%s: %s (%s)\n", filename,
+				file_type_to_string(type),
+				file_type_to_short_string(type));
+
+	if (varname)
+		setenv(varname, file_type_to_short_string(type));
+
+	return 0;
+}
+
+BAREBOX_CMD_HELP_START(filetype)
+BAREBOX_CMD_HELP_USAGE("filetype [OPTIONS] <file>\n")
+BAREBOX_CMD_HELP_SHORT("detect type of a file and export result to a variable\n")
+BAREBOX_CMD_HELP_OPT("-v", "verbose\n")
+BAREBOX_CMD_HELP_OPT("-s <v>", "set <v> to shortname\n")
+BAREBOX_CMD_HELP_OPT("-l", "list known filetypes\n")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(filetype)
+	.cmd		= do_filetype,
+	.usage		= "detect file type",
+	BAREBOX_CMD_HELP(cmd_filetype_help)
+BAREBOX_CMD_END