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>

MAINTAINERS

@@ -786,6 +786,11 @@ M:	Simon Glass <sjg@chromium.org>
 S:	Maintained
 F:	tools/buildman/
 
+CAT
+M:	Roger Knecht <rknecht@pm.me>
+S:	Maintained
+F:	cmd/cat.c
+
 CFI FLASH
 M:	Stefan Roese <sr@denx.de>
 S:	Maintained

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
+);

configs/sandbox64_defconfig

@@ -22,6 +22,7 @@ CONFIG_CONSOLE_RECORD=y
 CONFIG_CONSOLE_RECORD_OUT_SIZE=0x1000
 CONFIG_PRE_CONSOLE_BUFFER=y
 CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_CMD_CAT=y
 CONFIG_CMD_CPU=y
 CONFIG_CMD_LICENSE=y
 CONFIG_CMD_BOOTZ=y

configs/sandbox_defconfig

@@ -36,6 +36,7 @@ CONFIG_LOG_DEFAULT_LEVEL=6
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_STACKPROTECTOR=y
 CONFIG_ANDROID_AB=y
+CONFIG_CMD_CAT=y
 CONFIG_CMD_CPU=y
 CONFIG_CMD_LICENSE=y
 CONFIG_CMD_BOOTM_PRE_LOAD=y

doc/usage/cmd/cat.rst

@@ -0,0 +1,49 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+cat command
+===============
+
+Synopsis
+--------
+
+::
+
+    cat <interface> <dev[:part]> <file>
+
+Description
+-----------
+
+The cat command prints the file content to standard out.
+
+interface
+    interface for accessing the block device (mmc, sata, scsi, usb, ....)
+
+dev
+    device number
+
+part
+    partition number, defaults to 1
+
+file
+    path to file
+
+Example
+-------
+
+Here is the output for a example text file:
+
+::
+
+    => cat mmc 0:1 hello
+    hello world
+    =>
+
+Configuration
+-------------
+
+The cat command is only available if CONFIG_CMD_CAT=y.
+
+Return value
+------------
+
+The return value $? is set to 0 (true) if the file is readable, otherwise it returns a non-zero error code.

doc/usage/index.rst

@@ -31,6 +31,7 @@ Shell commands
    cmd/bootmeth
    cmd/button
    cmd/bootz
+   cmd/cat
    cmd/cbsysinfo
    cmd/cls
    cmd/conitrace

test/py/tests/test_cat/conftest.py

@@ -0,0 +1,35 @@
+# SPDX-License-Identifier:      GPL-2.0+
+
+"""Fixture for cat command test
+"""
+
+import os
+import shutil
+from subprocess import check_call, CalledProcessError
+import pytest
+
+@pytest.fixture(scope='session')
+def cat_data(u_boot_config):
+    """Set up a file system to be used in cat tests
+
+    Args:
+        u_boot_config -- U-boot configuration.
+    """
+    mnt_point = u_boot_config.persistent_data_dir + '/test_cat'
+    image_path = u_boot_config.persistent_data_dir + '/cat.img'
+
+    try:
+        os.mkdir(mnt_point, mode = 0o755)
+
+        with open(mnt_point + '/hello', 'w', encoding = 'ascii') as file:
+            file.write('hello world\n')
+
+        check_call(f'virt-make-fs --partition=gpt --size=+1M --type=vfat {mnt_point} {image_path}',
+                   shell=True)
+
+        yield image_path
+    except CalledProcessError:
+        pytest.skip('Setup failed')
+    finally:
+        shutil.rmtree(mnt_point)
+        os.remove(image_path)

test/py/tests/test_cat/test_cat.py

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier:      GPL-2.0+
+
+""" Unit test for cat command
+"""
+
+import pytest
+
+@pytest.mark.boardspec('sandbox')
+@pytest.mark.buildconfigspec('cmd_cat')
+def test_cat(u_boot_console, cat_data):
+    """ Unit test for cat
+
+    Args:
+        u_boot_console -- U-Boot console
+        cat_data -- Path to the disk image used for testing.
+    """
+    response = u_boot_console.run_command_list([
+        f'host bind 0 {cat_data}',
+        'cat host 0 hello'])
+    assert 'hello world' in response