cgpt: Handle read errors gracefullystabilize-7019.Bstabilize-7018.B

When a read fails in getting the GPT, just zero the contents of the
buffer and carry on.

Some testing changes are required for this. When a read of the GPT
fails, it is no longer fatal, so tests of that have been adjusted.
Tests have been improved to show that the GPT is automatically
repaired when a read error occurs.
There was one test which checked that a zero-sized disk would fail
to load a kernel, but it was surrounded by a number of mocked
functions which normally do that error checking, and it amounted
to the same test as read failure; that test was deleted.

BUG=chrome-os-partner:35440
TEST=vboot tests pass
BRANCH=none

Change-Id: I0c05813e7492920433733947d3fb74a7e4aa66f2
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/266882
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 34 insertions, 22 deletions

diff --git a/tests/vboot_kernel_tests.c b/tests/vboot_kernel_tests.c
index 03e77f98..e690bc31 100644
--- a/tests/vboot_kernel_tests.c
+++ b/tests/vboot_kernel_tests.c
@@ -12,6 +12,7 @@
 
 #include "cgptlib.h"
 #include "cgptlib_internal.h"
+#include "crc32.h"
 #include "gbb_header.h"
 #include "gpt.h"
 #include "host_common.h"
@@ -467,27 +468,43 @@ static void ReadWriteGptTest(void)
 	/* Error reading */
 	ResetMocks();
 	disk_read_to_fail = 1;
-	TEST_NEQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
-	Memset(g.primary_header, '\0', g.sector_bytes);
-	WriteAndFreeGptData(handle, &g);
+	TEST_EQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
+	g.valid_headers = g.valid_entries = MASK_SECONDARY;
+	GptRepair(&g);
+	ResetCallLog();
+	TEST_EQ(WriteAndFreeGptData(handle, &g), 0, "WriteAndFree mod 1");
+	TEST_CALLS("VbExDiskWrite(h, 1, 1)\n"
+		   "VbExDiskWrite(h, 2, 32)\n");
 
 	ResetMocks();
 	disk_read_to_fail = 2;
-	TEST_NEQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
-	Memset(g.primary_header, '\0', g.sector_bytes);
-	WriteAndFreeGptData(handle, &g);
+	TEST_EQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
+	g.valid_headers = MASK_BOTH;
+	g.valid_entries = MASK_SECONDARY;
+	GptRepair(&g);
+	ResetCallLog();
+	TEST_EQ(WriteAndFreeGptData(handle, &g), 0, "WriteAndFree mod 1");
+	TEST_CALLS("VbExDiskWrite(h, 2, 32)\n");
 
 	ResetMocks();
 	disk_read_to_fail = 991;
-	TEST_NEQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
-	Memset(g.primary_header, '\0', g.sector_bytes);
-	WriteAndFreeGptData(handle, &g);
+	TEST_EQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
+	g.valid_headers = MASK_BOTH;
+	g.valid_entries = MASK_PRIMARY;
+	GptRepair(&g);
+	ResetCallLog();
+	TEST_EQ(WriteAndFreeGptData(handle, &g), 0, "WriteAndFree mod 2");
+	TEST_CALLS("VbExDiskWrite(h, 991, 32)\n");
 
 	ResetMocks();
 	disk_read_to_fail = 1023;
-	TEST_NEQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
-	Memset(g.primary_header, '\0', g.sector_bytes);
-	WriteAndFreeGptData(handle, &g);
+	TEST_EQ(AllocAndReadGptData(handle, &g), 0, "AllocAndRead disk fail");
+	g.valid_headers = g.valid_entries = MASK_PRIMARY;
+	GptRepair(&g);
+	ResetCallLog();
+	TEST_EQ(WriteAndFreeGptData(handle, &g), 0, "WriteAndFree mod 2");
+	TEST_CALLS("VbExDiskWrite(h, 1023, 1)\n"
+		   "VbExDiskWrite(h, 991, 32)\n");
 
 	/* Error writing */
 	ResetMocks();
@@ -543,20 +560,10 @@ static void InvalidParamsTest(void)
 		"Huge lba size");
 
 	ResetMocks();
-	disk_read_to_fail = 1;
-	TEST_EQ(LoadKernel(&lkp, &cparams), VBERROR_NO_KERNEL_FOUND,
-		"Can't read disk");
-
-	ResetMocks();
 	gpt_init_fail = 1;
 	TEST_EQ(LoadKernel(&lkp, &cparams), VBERROR_NO_KERNEL_FOUND,
 		"Bad GPT");
 
-	ResetMocks();
-	lkp.gpt_lba_count = 0;
-	TEST_EQ(LoadKernel(&lkp, &cparams), VBERROR_NO_KERNEL_FOUND,
-		"GPT size = 0");
-
 	/* This causes the stream open call to fail */
 	ResetMocks();
 	lkp.disk_handle = NULL;
@@ -765,6 +772,11 @@ static void LoadKernelTest(void)
 	lkp.boot_flags |= BOOT_FLAG_EXTERNAL_GPT;
 	TEST_EQ(LoadKernel(&lkp, &cparams), 0, "Succeed external GPT");
 	TEST_EQ(gpt_flag_external, 1, "GPT was external");
+
+	/* Check recovery from unreadble primary GPT */
+	ResetMocks();
+	disk_read_to_fail = 1;
+	TEST_EQ(LoadKernel(&lkp, &cparams), 0, "Can't read disk");
 }
 
 int main(void)