util/ec_parse_panicinfo: Parse older structures

For devices on older FW branches, we need to be able to parse
panicinfo even if the size of the structures don't match.

Realign trailer (struct_size and magic) for that purpose.

Also, add WARNING/ERROR tags to messages so that we can
grep for those in a test.

Make a similar change in ectool (use the return value that
indicates the size).

BUG=b:182087232
TEST=make build/bds/util/ec_parse_panicinfo
TEST=build/bds/util/ec_parse_panicinfo < \
      ./upload_file_eccrash-857e3693bfce1e1f.eccrash
BRANCH=none

Change-Id: I97650aa3085e753b0a2256058402e33d11238f52
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2738577
Reviewed-by: Eric Yilun Lin <yllin@chromium.org>

4 files changed, 75 insertions, 21 deletions

diff --git a/util/ec_panicinfo.c b/util/ec_panicinfo.c
index b919cc6df7..ad6867fdc9 100644
--- a/util/ec_panicinfo.c
+++ b/util/ec_panicinfo.c
@@ -5,7 +5,9 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include <string.h>
 #include "compile_time_macros.h"
+
 #include "ec_panicinfo.h"
 
 static void print_panic_reg(int regnum, const uint32_t *regs, int index)
@@ -123,34 +125,67 @@ static int parse_panic_info_rv32i(const struct panic_data *pdata)
 	return 0;
 }
 
-int parse_panic_info(const struct panic_data *pdata)
+int parse_panic_info(const char *data, size_t size)
 {
+	/* Size of the panic information "header". */
+	const size_t header_size = 4;
+	/* Size of the panic information "trailer" (struct_size and magic). */
+	const size_t trailer_size = sizeof(struct panic_data) -
+				 offsetof(struct panic_data, struct_size);
+
+	struct panic_data pdata = { 0 };
+	size_t copy_size;
+
+	if (size < (header_size + trailer_size)) {
+		fprintf(stderr, "ERROR: Panic data too short (%zd).\n", size);
+		return -1;
+	}
+
+	if (size > sizeof(pdata)) {
+		fprintf(stderr, "WARNING: Panic data too large (%zd > %zd). "
+			"Following data may be incorrect!\n",
+			size, sizeof(pdata));
+		copy_size = sizeof(pdata);
+	} else {
+		copy_size = size;
+	}
+	/* Copy the data into pdata, as the struct size may have changed. */
+	memcpy(&pdata, data, copy_size);
+	/* Then copy the trailer in position. */
+	memcpy((char *)&pdata + (sizeof(struct panic_data) - trailer_size),
+		data + (size - trailer_size), trailer_size);
+
 	/*
 	 * We only understand panic data with version <= 2. Warn the user
 	 * of higher versions.
 	 */
-	if (pdata->struct_version > 2)
-		fprintf(stderr,
-			"Unknown panic data version (%d). "
+	if (pdata.struct_version > 2)
+		fprintf(stderr, "WARNING: Unknown panic data version (%d). "
 			"Following data may be incorrect!\n",
-			pdata->struct_version);
+			pdata.struct_version);
 
 	/* Validate magic number */
-	if (pdata->magic != PANIC_DATA_MAGIC)
+	if (pdata.magic != PANIC_DATA_MAGIC)
+		fprintf(stderr, "WARNING: Incorrect panic magic (%d). "
+			"Following data may be incorrect!\n",
+			pdata.magic);
+
+	if (pdata.struct_size != size)
 		fprintf(stderr,
-			"Incorrect panic magic (%d). "
+			"WARNING: Panic struct size inconsistent (%u vs %zd). "
 			"Following data may be incorrect!\n",
-			pdata->magic);
+			pdata.struct_size, size);
 
-	switch (pdata->arch) {
+	switch (pdata.arch) {
 	case PANIC_ARCH_CORTEX_M:
-		return parse_panic_info_cm(pdata);
+		return parse_panic_info_cm(&pdata);
 	case PANIC_ARCH_NDS32_N8:
-		return parse_panic_info_nds32(pdata);
+		return parse_panic_info_nds32(&pdata);
 	case PANIC_ARCH_RISCV_RV32I:
-		return parse_panic_info_rv32i(pdata);
+		return parse_panic_info_rv32i(&pdata);
 	default:
-		fprintf(stderr, "Unknown architecture (%d).\n", pdata->arch);
+		fprintf(stderr, "ERROR: Unknown architecture (%d).\n",
+			pdata.arch);
 		break;
 	}
 	return -1;
diff --git a/util/ec_panicinfo.h b/util/ec_panicinfo.h
index f70c58e59f..c61cf797e6 100644
--- a/util/ec_panicinfo.h
+++ b/util/ec_panicinfo.h
@@ -14,6 +14,6 @@
  * @param pdata  Panic information to print
  * @return 0 if success or non-zero error code if error.
  */
-int parse_panic_info(const struct panic_data *pdata);
+int parse_panic_info(const char *data, size_t size);
 
 #endif /* EC_PANICINFO_H */
diff --git a/util/ec_parse_panicinfo.c b/util/ec_parse_panicinfo.c
index 5db8ed2e05..a3fefcf7b5 100644
--- a/util/ec_parse_panicinfo.c
+++ b/util/ec_parse_panicinfo.c
@@ -7,16 +7,36 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include "compile_time_macros.h"
 #include "ec_panicinfo.h"
 
 int main(int argc, char *argv[])
 {
-	struct panic_data pdata;
+	/*
+	 * panic_data size could change with time, as new architecture are
+	 * added (or, less likely, removed).
+	 */
+	char pdata[4096];
+	size_t size = 0;
+	size_t read;
 
-	if (fread(&pdata, sizeof(pdata), 1, stdin) != 1) {
-		fprintf(stderr, "Error reading panicinfo from stdin.\n");
-		return 1;
+	BUILD_ASSERT(sizeof(pdata) > sizeof(struct panic_data)*2);
+
+	while (1) {
+		read = fread(&pdata[size], 1, sizeof(pdata)-size, stdin);
+		if (read < 0) {
+			fprintf(stderr, "Cannot read panicinfo from stdin.\n");
+			return 1;
+		}
+		if (read == 0)
+			break;
+
+		size += read;
+		if (size == sizeof(pdata)) {
+			fprintf(stderr, "Too much panicinfo data in stdin.\n");
+			return 1;
+		}
 	}
 
-	return parse_panic_info(&pdata) ? 1 : 0;
+	return parse_panic_info(pdata, size) ? 1 : 0;
 }
diff --git a/util/ectool.c b/util/ectool.c
index a85166ebe7..459a7158b5 100644
--- a/util/ectool.c
+++ b/util/ectool.c
@@ -6448,7 +6448,6 @@ int cmd_keyboard_factory_test(int argc, char *argv[])
 int cmd_panic_info(int argc, char *argv[])
 {
 	int rv;
-	struct panic_data *pdata = (struct panic_data *)ec_inbuf;
 
 	rv = ec_command(EC_CMD_GET_PANIC_INFO, 0, NULL, 0,
 			ec_inbuf, ec_max_insize);
@@ -6460,7 +6459,7 @@ int cmd_panic_info(int argc, char *argv[])
 		return 0;
 	}
 
-	return parse_panic_info(pdata);
+	return parse_panic_info(ec_inbuf, rv);
 }