cmd: cat: add new command

Add cat command to print file content to standard out

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Roger Knecht <rknecht@pm.me>

cmd/Kconfig

@@ -1533,6 +1533,11 @@ endmenu
 
 menu "Shell scripting commands"
 
+config CMD_CAT
+	bool "cat"
+	help
+	  Print file to standard output
+
 config CMD_ECHO
 	bool "echo"
 	default y

cmd/Makefile

@@ -38,6 +38,7 @@ obj-$(CONFIG_CMD_BOOTZ) += bootz.o
 obj-$(CONFIG_CMD_BOOTI) += booti.o
 obj-$(CONFIG_CMD_BTRFS) += btrfs.o
 obj-$(CONFIG_CMD_BUTTON) += button.o
+obj-$(CONFIG_CMD_CAT) += cat.o
 obj-$(CONFIG_CMD_CACHE) += cache.o
 obj-$(CONFIG_CMD_CBFS) += cbfs.o
 obj-$(CONFIG_CMD_CLK) += clk.o

cmd/cat.c

@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2022
+ * Roger Knecht <rknecht@pm.de>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <fs.h>
+#include <malloc.h>
+#include <mapmem.h>
+
+static int do_cat(struct cmd_tbl *cmdtp, int flag, int argc,
+		  char *const argv[])
+{
+	char *ifname;
+	char *dev;
+	char *file;
+	char *buffer;
+	phys_addr_t addr;
+	loff_t file_size;
+
+	if (argc < 4)
+		return CMD_RET_USAGE;
+
+	ifname = argv[1];
+	dev = argv[2];
+	file = argv[3];
+
+	// check file exists
+	if (fs_set_blk_dev(ifname, dev, FS_TYPE_ANY))
+		return CMD_RET_FAILURE;
+
+	if (!fs_exists(file)) {
+		log_err("File does not exist: ifname=%s dev=%s file=%s\n", ifname, dev, file);
+		return CMD_RET_FAILURE;
+	}
+
+	// get file size
+	if (fs_set_blk_dev(ifname, dev, FS_TYPE_ANY))
+		return CMD_RET_FAILURE;
+
+	if (fs_size(file, &file_size)) {
+		log_err("Cannot read file size: ifname=%s dev=%s file=%s\n", ifname, dev, file);
+		return CMD_RET_FAILURE;
+	}
+
+	// allocate memory for file content
+	buffer = calloc(sizeof(char), file_size + 1);
+	if (!buffer) {
+		log_err("Out of memory\n");
+		return CMD_RET_FAILURE;
+	}
+
+	// map pointer to system memory
+	addr = map_to_sysmem(buffer);
+
+	// read file to memory
+	if (fs_set_blk_dev(ifname, dev, FS_TYPE_ANY))
+		return CMD_RET_FAILURE;
+
+	if (fs_read(file, addr, 0, 0, &file_size)) {
+		log_err("Cannot read file: ifname=%s dev=%s file=%s\n", ifname, dev, file);
+		return CMD_RET_FAILURE;
+	}
+
+	// print file content
+	buffer[file_size] = '\0';
+	puts(buffer);
+
+	free(buffer);
+
+	return 0;
+}
+
+#ifdef CONFIG_SYS_LONGHELP
+static char cat_help_text[] =
+	"<interface> <dev[:part]> <file>\n"
+	"  - Print file from 'dev' on 'interface' to standard output\n";
+#endif
+
+U_BOOT_CMD(cat, 4, 1, do_cat,
+	   "Print file to standard output",
+	   cat_help_text
+);