Add initial unit test of erase_filesystem_signatures() (#220)

Initially just testing erasing of Intel Software RAID signatures.
Chosen because it was expected to work, but turned out not to be true in
all cases.

The code needs to initialise GParted_Core::mainthread, construct
Gtk::Main() and execute xvfb-run because of this call chain:
    GParted_Core::erase_filesystem_signatures()
      GParted_Core::settle_device()
        Utils::execute_command ("udevadm settle ...")
          status.foreground = (Glib::Thread::self() == GParted_Core::mainthread)
          Gtk::Main::run()
This was also needed when testing file system interface classes as
discussed in commits [1][2].

The test fails like this:
    $ ./test_EraseFileSystemSignatures
    ...
    [ RUN      ] EraseFileSystemSignaturesTest.IntelSoftwareRAIDAligned
    [       OK ] EraseFileSystemSignaturesTest.IntelSoftwareRAIDAligned (155 ms)
    [ RUN      ] EraseFileSystemSignaturesTest.IntelSoftwareRAIDUnaligned
    test_EraseFileSystemSignatures.cc:286: Failure
    Failed
    image_contains_all_zeros(): First non-zero bytes:
    0x00001A00  "Intel Raid ISM C"  49 6E 74 65 6C 20 52 61 69 64 20 49 53 4D 20 43
    test_EraseFileSystemSignatures.cc:320: Failure
    Value of: image_contains_all_zeros()
      Actual: false
    Expected: true
    [  FAILED  ] EraseFileSystemSignaturesTest.IntelSoftwareRAIDUnaligned (92 ms)

Manually write the same test image:
    $ python << 'EOF'
    signature = b'Intel Raid ISM Cfg Sig. '
    import os
    fd = os.open('/tmp/test.img', os.O_CREAT|os.O_WRONLY)
    os.ftruncate(fd, 16*1024*1024 - 512)
    os.lseek(fd, -(2*512), os.SEEK_END)
    os.write(fd, signature)
    os.close(fd)
    EOF

Run gpartedbin /tmp/test.img and Format to > Cleared.  GParted continues
to display the the image file as containing an ataraid signature.
    $ blkid /tmp/test.img
    /tmp/test.img: TYPE="isw_raid_member"
    $ hexdump -C /tmp/test.img
    00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
    *
    00fffa00  49 6e 74 65 6c 20 52 61  69 64 20 49 53 4d 20 43  |Intel Raid ISM C|
    00fffa10  66 67 20 53 69 67 2e 20  00 00 00 00 00 00 00 00  |fg Sig. ........|
    00fffa20  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
    *
    00fffe00

This signature is not being cleared when the device/partition/image size
is 512 bytes smaller than a whole MiB because the last 3.5 KiB is left
unwritten.  This is because the last block of zeros written is 8 KiB
aligned to 4 KiB at the end of the device.

[1] a97c23c57c
    Add initial create ext2 only FileSystem interface class test (!49)
[2] 8db9a83b39
    Run test program under xvfb-run to satisfy need for an X11 display (!49)

Closes #220 - Format to Cleared not clearing "pdc" ataraid signature

include/GParted_Core.h

@@ -40,6 +40,9 @@ namespace GParted
 
 class GParted_Core
 {
+friend class EraseFileSystemSignaturesTest;  // To allow unit testing to call private
+                                             // method.
+
 public:
 	static Glib::Thread *mainthread;
 	GParted_Core() ;

tests/Makefile.am

@@ -13,6 +13,7 @@ LDADD =  \
 check_PROGRAMS =  \
 	test_dummy                      \
 	test_BlockSpecial               \
+	test_EraseFileSystemSignatures  \
 	test_PasswordRAMStore           \
 	test_PipeCapture                \
 	test_SupportedFileSystems
@@ -20,10 +21,7 @@ check_PROGRAMS =  \
 # Test cases to be run by "make check"
 TESTS = $(check_PROGRAMS)
 
-test_dummy_SOURCES        = test_dummy.cc
+gparted_core_OBJECTS =  \
-
-test_SupportedFileSystems_SOURCES = test_SupportedFileSystems.cc
-test_SupportedFileSystems_LDADD   =  \
 	$(top_builddir)/src/BCache_Info.$(OBJEXT)           \
 	$(top_builddir)/src/BlockSpecial.$(OBJEXT)          \
 	$(top_builddir)/src/CopyBlocks.$(OBJEXT)            \
@@ -65,15 +63,21 @@ test_SupportedFileSystems_LDADD   =  \
 	$(top_builddir)/src/reiser4.$(OBJEXT)               \
 	$(top_builddir)/src/reiserfs.$(OBJEXT)              \
 	$(top_builddir)/src/udf.$(OBJEXT)                   \
-	$(top_builddir)/src/xfs.$(OBJEXT)                   \
+	$(top_builddir)/src/xfs.$(OBJEXT)
-	$(GTEST_LIBS)                                       \
+
-	$(top_builddir)/lib/gtest/lib/libgtest.la
+test_dummy_SOURCES        = test_dummy.cc
 
 test_BlockSpecial_SOURCES = test_BlockSpecial.cc
 test_BlockSpecial_LDADD   =  \
 	$(top_builddir)/src/BlockSpecial.$(OBJEXT)  \
 	$(LDADD)
 
+test_EraseFileSystemSignatures_SOURCES = test_EraseFileSystemSignatures.cc
+test_EraseFileSystemSignatures_LDADD =  \
+	$(gparted_core_OBJECTS)                    \
+	$(GTEST_LIBS)                              \
+	$(top_builddir)/lib/gtest/lib/libgtest.la
+
 test_PasswordRAMStore_SOURCES = test_PasswordRAMStore.cc
 test_PasswordRAMStore_LDADD   =  \
 	$(top_builddir)/src/PasswordRAMStore.$(OBJEXT)  \
@@ -83,3 +87,9 @@ test_PipeCapture_SOURCES  = test_PipeCapture.cc
 test_PipeCapture_LDADD    =  \
 	$(top_builddir)/src/PipeCapture.$(OBJEXT)  \
 	$(LDADD)
+
+test_SupportedFileSystems_SOURCES = test_SupportedFileSystems.cc
+test_SupportedFileSystems_LDADD   =  \
+	$(gparted_core_OBJECTS)                    \
+	$(GTEST_LIBS)                              \
+	$(top_builddir)/lib/gtest/lib/libgtest.la

tests/test_EraseFileSystemSignatures.cc

@@ -0,0 +1,388 @@
+/* Copyright (C) 2023 Mike Fleetwood
+ *
+ *  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
+ *  (at your option) 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, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Test GParted_Core::erase_filesystem_signatures()
+ */
+
+
+#include "GParted_Core.h"
+#include "OperationDetail.h"
+#include "Partition.h"
+#include "Utils.h"
+#include "gtest/gtest.h"
+
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <iomanip>
+#include <stddef.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <gtkmm.h>
+#include <parted/parted.h>
+#include <glibmm/ustring.h>
+#include <glibmm/thread.h>
+
+
+namespace GParted
+{
+
+
+// Hacky XML parser which strips italic and bold markup added in
+// OperationDetail::set_description() and reverts just these 5 characters &<>'" encoded by
+// Glib::Markup::escape_text() -> g_markup_escape_text() -> append_escaped_text().
+Glib::ustring strip_markup(const Glib::ustring& str)
+{
+	size_t len = str.length();
+	size_t i = 0;
+	Glib::ustring ret;
+	ret.reserve(len);
+	while (i < len)
+	{
+		if (str.compare(i, 3, "<i>") == 0)
+			i += 3;
+		else if (str.compare(i, 4, "</i>") == 0)
+			i += 4;
+		else if (str.compare(i, 3, "<b>") == 0)
+			i += 3;
+		else if (str.compare(i, 4, "</b>") == 0)
+			i += 4;
+		else if (str.compare(i, 5, "&amp;") == 0)
+		{
+			ret.push_back('&');
+			i += 5;
+		}
+		else if (str.compare(i, 4, "&lt;") == 0)
+		{
+			ret.push_back('<');
+			i += 4;
+		}
+		else if (str.compare(i, 4, "&gt;") == 0)
+		{
+			ret.push_back('>');
+			i += 4;
+		}
+		else if (str.compare(i, 6, "&apos;") == 0)
+		{
+			ret.push_back('\'');
+			i += 6;
+		}
+		else if (str.compare(i, 6, "&quot;") == 0)
+		{
+			ret.push_back('"');
+			i += 6;
+		}
+		else
+		{
+			ret.push_back(str[i]);
+			i++;
+		}
+	}
+	return ret;
+}
+
+
+// Print method for OperationDetailStatus.
+std::ostream& operator<<(std::ostream& out, const OperationDetailStatus od_status)
+{
+	switch (od_status)
+	{
+		case STATUS_NONE:     out << "NONE";     break;
+		case STATUS_EXECUTE:  out << "EXECUTE";  break;
+		case STATUS_SUCCESS:  out << "SUCCESS";  break;
+		case STATUS_ERROR:    out << "ERROR";    break;
+		case STATUS_INFO:     out << "INFO";     break;
+		case STATUS_WARNING:  out << "WARNING";  break;
+		default:                                 break;
+	}
+	return out;
+}
+
+
+// Print method for an OperationDetail object.
+std::ostream& operator<<(std::ostream& out, const OperationDetail& od)
+{
+	out << strip_markup(od.get_description());
+	Glib::ustring elapsed = od.get_elapsed_time();
+	if (! elapsed.empty())
+		out << "    " << elapsed;
+	if (od.get_status() != STATUS_NONE)
+		out << "  (" << od.get_status() << ")";
+	out << "\n";
+
+	for (size_t i = 0; i < od.get_childs().size(); i++)
+	{
+		out << *od.get_childs()[i];
+	}
+	return out;
+}
+
+
+// Explicit test fixture class for common variables and methods used in each test.
+// Reference:
+//     Google Test, Primer, Test Fixtures: Using the Same Data Configuration for Multiple Tests
+class EraseFileSystemSignaturesTest : public ::testing::Test
+{
+protected:
+	virtual void create_image_file(Byte_Value size);
+	virtual void write_intel_software_raid_signature();
+	virtual bool image_contains_all_zeros();
+	virtual void TearDown();
+
+	bool erase_filesystem_signatures(const Partition& partition, OperationDetail& operationdetail)
+		{ return m_gparted_core.erase_filesystem_signatures(partition, operationdetail); };
+
+	static const char* s_image_name;
+
+	GParted_Core    m_gparted_core;
+	Partition       m_partition;
+	OperationDetail m_operation_detail;
+};
+
+
+const char* EraseFileSystemSignaturesTest::s_image_name = "test_EraseFileSystemSignatures.img";
+
+
+void EraseFileSystemSignaturesTest::create_image_file(Byte_Value size)
+{
+	// Create new image file to work with.
+	unlink(s_image_name);
+	int fd = open(s_image_name, O_WRONLY|O_CREAT|O_NONBLOCK, 0666);
+	ASSERT_GE(fd, 0) << "Failed to create image file '" << s_image_name << "'.  errno="
+	                 << errno << "," << strerror(errno);
+	ASSERT_EQ(ftruncate(fd, (off_t)size), 0) << "Failed to set image file '" << s_image_name << "' to size "
+	                                         << size << ".  errno=" << errno << "," << strerror(errno);
+	close(fd);
+
+	// Initialise m_partition as a Partition object spanning the whole of the image file.
+	m_partition.Reset();
+
+	PedDevice* lp_device = ped_device_get(s_image_name);
+	ASSERT_TRUE(lp_device != NULL);
+
+	m_partition.set_unpartitioned(s_image_name,
+	                              lp_device->path,
+	                              FS_UNALLOCATED,
+	                              lp_device->length,
+	                              lp_device->sector_size,
+	                              false);
+
+	ped_device_destroy(lp_device);
+	lp_device = NULL;
+}
+
+
+void EraseFileSystemSignaturesTest::write_intel_software_raid_signature()
+{
+	int fd = open(s_image_name, O_WRONLY|O_NONBLOCK);
+	ASSERT_GE(fd, 0) << "Failed to open image file '" << s_image_name << "'.  errno="
+	                 << errno << "," << strerror(errno);
+	const char* signature = "Intel Raid ISM Cfg Sig. ";
+	size_t len_signature = strlen(signature);
+
+	// Write Intel Software RAID signature at -2 sectors before the end.  Hard codes
+	// sector size to 512 bytes for a file.
+	// Reference:
+	//     .../util-linux/libblkid/src/superblocks/isw_raid.c:probe_iswraid().
+	ASSERT_GE(lseek(fd, 2 * -512, SEEK_END), 0) << "Failed to seek in image file '" << s_image_name
+	                                            << "'.  errno=" << errno << "," << strerror(errno);
+	ASSERT_EQ(write(fd, signature, len_signature), (ssize_t)len_signature)
+	        << "Failed to write to image file '" << s_image_name << "'.  errno="
+	        << errno << "," << strerror(errno);
+	close(fd);
+}
+
+
+const char* first_non_zero_byte(const char* buf, size_t size)
+{
+	while (size > 0)
+	{
+		if (*buf != '\0')
+			return buf;
+		buf++;
+		size--;
+	}
+	return NULL;
+}
+
+
+// Number of bytes of binary data to report.
+const size_t BinaryStringChunkSize = 16;
+
+
+// Format up to BinaryStringChunkSize (16) bytes of binary data ready for printing as:
+//      Hex offset     ASCII text          Hex bytes
+//     "0x000000000  \"ABCDEFGHabcdefgh\"  41 42 43 44 45 46 47 48 61 62 63 64 65 66 67 68"
+std::string binary_string_to_print(size_t offset, const char* s, size_t len)
+{
+	std::ostringstream result;
+
+	result << "0x";
+	result.fill('0');
+	result << std::setw(8) << std::hex << std::uppercase << offset << "  \"";
+
+	size_t i;
+	for (i = 0; i < BinaryStringChunkSize && i < len; i++)
+		result.put((isprint(s[i])) ? s[i] : '.');
+	result.put('\"');
+
+	if (len > 0)
+	{
+		for (; i < BinaryStringChunkSize; i++)
+			result.put(' ');
+		result.put(' ');
+
+		for (i = 0 ; i < BinaryStringChunkSize && i < len; i++)
+			result << " "
+			       << std::setw(2) << std::hex << std::uppercase
+			       << (unsigned int)(unsigned char)s[i];
+	}
+
+	return result.str();
+}
+
+
+bool EraseFileSystemSignaturesTest::image_contains_all_zeros()
+{
+	int fd = open(s_image_name, O_RDONLY|O_NONBLOCK);
+	if (fd < 0)
+	{
+		ADD_FAILURE() << __func__ << "(): Failed to open image file '" << s_image_name << "'.  errno="
+		              << errno << "," << strerror(errno);
+		return false;
+	}
+
+	ssize_t bytes_read = 0;
+	size_t offset = 0;
+	do
+	{
+		char buf[BUFSIZ];
+		bytes_read = read(fd, buf, sizeof(buf));
+		if (bytes_read < 0)
+		{
+			ADD_FAILURE() << __func__ << "(): Failed to read from image file '" << s_image_name
+			              << "'.  errno=" << errno << "," << strerror(errno);
+			close(fd);
+			return false;
+		}
+		const char* p = first_non_zero_byte(buf, bytes_read);
+		if (p != NULL)
+		{
+			ADD_FAILURE() << __func__ << "(): First non-zero bytes:\n"
+			              << binary_string_to_print(offset + (p - buf), p, buf + bytes_read - p);
+			close(fd);
+			return false;
+		}
+	}
+	while (bytes_read > 0);
+	close(fd);
+	return true;
+}
+
+
+void EraseFileSystemSignaturesTest::TearDown()
+{
+	unlink(s_image_name);
+}
+
+
+TEST_F(EraseFileSystemSignaturesTest, IntelSoftwareRAIDAligned)
+{
+	create_image_file(16 * MEBIBYTE);
+	write_intel_software_raid_signature();
+
+	EXPECT_TRUE(erase_filesystem_signatures(m_partition, m_operation_detail)) << m_operation_detail;
+	EXPECT_TRUE(image_contains_all_zeros());
+}
+
+
+TEST_F(EraseFileSystemSignaturesTest, IntelSoftwareRAIDUnaligned)
+{
+	create_image_file(16 * MEBIBYTE - 512);
+	write_intel_software_raid_signature();
+
+	EXPECT_TRUE(erase_filesystem_signatures(m_partition, m_operation_detail)) << m_operation_detail;
+	EXPECT_TRUE(image_contains_all_zeros());
+}
+
+
+}  // namespace GParted
+
+
+// Re-execute current executable using xvfb-run so that it provides a virtual X11 display.
+void exec_using_xvfb_run(int argc, char** argv)
+{
+	// argc+2 = Space for "xvfb-run" command, existing argc strings plus NULL pointer.
+	size_t size = sizeof(char*) * (argc+2);
+	char** new_argv = (char**)malloc(size);
+	if (new_argv == NULL)
+	{
+		fprintf(stderr, "Failed to allocate %lu bytes of memory.  errno=%d,%s\n",
+			(unsigned long)size, errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	new_argv[0] = strdup("xvfb-run");
+	if (new_argv[0] == NULL)
+	{
+		fprintf(stderr, "Failed to allocate %lu bytes of memory.  errno=%d,%s\n",
+		        (unsigned long)strlen(new_argv[0])+1, errno, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+
+	// Copy argv pointers including final NULL pointer.
+	for (unsigned int i = 0; i <= (unsigned)argc; i++)
+		new_argv[i+1] = argv[i];
+
+	execvp(new_argv[0], new_argv);
+	fprintf(stderr, "Failed to execute '%s %s ...'.  errno=%d,%s\n", new_argv[0], new_argv[1],
+		errno, strerror(errno));
+	exit(EXIT_FAILURE);
+}
+
+
+// Custom Google Test main().
+// Reference:
+// *   Google Test, Primer, Writing the main() function
+//     https://github.com/google/googletest/blob/master/googletest/docs/primer.md#writing-the-main-function
+int main(int argc, char** argv)
+{
+	printf("Running main() from %s\n", __FILE__);
+
+	const char* display = getenv("DISPLAY");
+	if (display == NULL)
+	{
+		printf("DISPLAY environment variable unset.  Executing 'xvfb-run %s ...'\n", argv[0]);
+		exec_using_xvfb_run(argc, argv);
+	}
+	printf("DISPLAY=\"%s\"\n", display);
+
+	// Initialise threading in GParted to successfully use Utils:: and
+	// FileSystem::execute_command().  Must be before InitGoogleTest().
+	GParted::GParted_Core::mainthread = Glib::Thread::self();
+	Gtk::Main gtk_main = Gtk::Main();
+
+	testing::InitGoogleTest(&argc, argv);
+
+	return RUN_ALL_TESTS();
+}