[coreboot-gerrit] Change in coreboot[master]: libpayload: Read from cbmem console

[Yu-Ping Wu (Code Review)]

Yu-Ping Wu has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/37667 )

Change subject: libpayload: Read from cbmem console
......................................................................

libpayload: Read from cbmem console

To support the new recovery ui (the Groot project) and show cbmem log on
the screen, add a function cbmem_console_read() to read from cbmem
console. Non-printable characters are automatically replaced with '?' to
ensure that the returned string is printable.

BRANCH=none
BUG=b:146105976
TEST=emerge-nami libpayload

Change-Id: Ie324055f5fd8276f1d833fc9d04f60a792dbb9f6
Signed-off-by: Yu-Ping Wu 
---
M payloads/libpayload/drivers/cbmem_console.c
M payloads/libpayload/include/libpayload.h
2 files changed, 48 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/67/37667/1

diff --git a/payloads/libpayload/drivers/cbmem_console.c b/payloads/libpayload/drivers/cbmem_console.c
index 9435e1c..c6d7ee1 100644
--- a/payloads/libpayload/drivers/cbmem_console.c
+++ b/payloads/libpayload/drivers/cbmem_console.c
@@ -75,3 +75,50 @@

do_write(buffer, count);
 }
+
+void cbmem_console_read(void **buffer_p, size_t *count)
+{
+	const struct cbmem_console *console_p = cbmem_console_p;
+	char *console_c;
+	uint32_t size, cursor, overflow;
+
+	if (!console_p) {
+		printf("ERROR: No cbmem console found in coreboot table.\n");
+		return;
+	}
+
+	cursor = console_p->cursor & CURSOR_MASK;
+	overflow = console_p->cursor & OVERFLOW;
+	if (!overflow && cursor < console_p->size)
+		size = cursor;
+	else
+		size = console_p->size;
+
+	console_c = malloc(size + 1);
+	if (!console_c) {
+		printf("ERROR: Not enough memory for console.\n");
+		return;
+	}
+	console_c[size] = '\0';
+
+	if (overflow) {
+		if (cursor >= size) {
+			printf("cbmem: ERROR: CBMEM console struct is illegal, "
+			       "output may be corrupt or out of order!\n\n");
+			cursor = 0;
+		}
+		memcpy(console_c, console_p->body + cursor, size - cursor);
+		memcpy(console_c + size - cursor, console_p->body, cursor);
+	} else {
+		memcpy(console_c, console_p->body, size);
+	}
+
+	/* Slight memory corruption may occur between reboots and give us a few
+	   unprintable characters like '\0'. Replace them with '?' on output. */
+	for (cursor = 0; cursor < size; cursor++)
+		if (!isprint(console_c[cursor]) && !isspace(console_c[cursor]))
+			console_c[cursor] = '?';
+
+	*buffer_p = console_c;
+	*count = size;
+}
diff --git a/payloads/libpayload/include/libpayload.h b/payloads/libpayload/include/libpayload.h
index 934c368..6d814f1 100644
--- a/payloads/libpayload/include/libpayload.h
+++ b/payloads/libpayload/include/libpayload.h
@@ -313,6 +313,7 @@
  */
 void cbmem_console_init(void);
 void cbmem_console_write(const void *buffer, size_t count);
+void cbmem_console_read(void **buffer_p, size_t *count);
 /** @} */

/* drivers/option.c */