[coreboot-gerrit] Change in coreboot[master]: cbmem: Add new command line flag to dump console for one boo...

[Julius Werner (Code Review)]

Hello Aaron Durbin, Furquan Shaikh,

I'd like you to do a code review.  Please visit

    https://review.coreboot.org/19497

to review the following change.


Change subject: cbmem: Add new command line flag to dump console for one boot only
......................................................................

cbmem: Add new command line flag to dump console for one boot only

Even though the persistent CBMEM console is obviously awesome, there may
be cases where we only want to look at console output from the last boot.
It's easy to tell where one boot ends and another begins from the banner
message that coreboot prints at the start of every stage, but in order
to make it easier to find that point (especially for external tools),
let's put that functionality straight into the cbmem utility with a new
command line flag. Use the POSIX/libc regular expression API to find the
banner string for maximum compatilibity, even though it's kinda icky.

Change-Id: Ic17383507a884d84de9a2a880380cb15b25708a1
Signed-off-by: Julius Werner <jwerner at chromium.org>
---
M util/cbmem/cbmem.c
1 file changed, 37 insertions(+), 4 deletions(-)


  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/97/19497/1

diff --git a/util/cbmem/cbmem.c b/util/cbmem/cbmem.c
index 7b7f10d..c1b1caa 100644
--- a/util/cbmem/cbmem.c
+++ b/util/cbmem/cbmem.c
@@ -31,6 +31,7 @@
 #include <sys/mman.h>
 #include <libgen.h>
 #include <assert.h>
+#include <regex.h>
 #include <commonlib/cbmem_id.h>
 #include <commonlib/timestamp_serialized.h>
 #include <commonlib/coreboot_tables.h>
@@ -611,7 +612,7 @@
 #define CBMC_OVERFLOW (1 << 31)
 
 /* dump the cbmem console */
-static void dump_console(void)
+static void dump_console(int one_boot_only)
 {
 	struct cbmem_console *console_p;
 	char *console_c;
@@ -659,8 +660,32 @@
 	for (cursor = 0; cursor < size; cursor++)
 		if (!isprint(console_c[cursor]) && !isspace(console_c[cursor]))
 			console_c[cursor] = '?';
-	printf("%s\n", console_c);
 
+	/* We detect the last boot by looking for a bootblock, romstage or
+	   ramstage banner, in that order (to account for platforms without
+	   CONFIG_BOOTBLOCK_CONSOLE and/or CONFIG_EARLY_CONSOLE). Once we find
+	   a banner, store the last match for that stage in cursor and stop. */
+	cursor = 0;
+	if (one_boot_only) {
+#define BANNER_REGEX(stage) "\n\ncoreboot-[^\n]* " stage " starting\\.\\.\\.\n"
+		const char *regex[] = { BANNER_REGEX("bootblock"),
+					BANNER_REGEX("romstage"),
+					BANNER_REGEX("ramstage")};
+		int i;
+
+		for (i = 0; !cursor && i < ARRAY_SIZE(regex); i++) {
+			regex_t re;
+			regmatch_t match;
+			assert(!regcomp(&re, regex[i], 0));
+
+			/* Keep looking for matches so we find the last one. */
+			while (!regexec(&re, console_c + cursor, 1, &match, 0))
+				cursor += match.rm_so + 1;
+			regfree(&re);
+		}
+	}
+
+	puts(console_c + cursor);
 	free(console_c);
 	unmap_memory();
 }
@@ -936,6 +961,7 @@
 	printf("usage: %s [-cCltTxVvh?]\n", name);
 	printf("\n"
 	     "   -c | --console:                   print cbmem console\n"
+	     "   -1 | --oneboot:                   print cbmem console for last boot only\n"
 	     "   -C | --coverage:                  dump coverage information\n"
 	     "   -l | --list:                      print cbmem table of contents\n"
 	     "   -x | --hexdump:                   print hexdump of cbmem area\n"
@@ -1074,11 +1100,13 @@
 	int print_rawdump = 0;
 	int print_timestamps = 0;
 	int machine_readable_timestamps = 0;
+	int one_boot_only = 0;
 	unsigned int rawdump_id = 0;
 
 	int opt, option_index = 0;
 	static struct option long_options[] = {
 		{"console", 0, 0, 'c'},
+		{"oneboot", 0, 0, '1'},
 		{"coverage", 0, 0, 'C'},
 		{"list", 0, 0, 'l'},
 		{"timestamps", 0, 0, 't'},
@@ -1090,11 +1118,16 @@
 		{"help", 0, 0, 'h'},
 		{0, 0, 0, 0}
 	};
-	while ((opt = getopt_long(argc, argv, "cCltTxVvh?r:",
+	while ((opt = getopt_long(argc, argv, "c1CltTxVvh?r:",
 				  long_options, &option_index)) != EOF) {
 		switch (opt) {
 		case 'c':
 			print_console = 1;
+			print_defaults = 0;
+			break;
+		case '1':
+			print_console = 1;
+			one_boot_only = 1;
 			print_defaults = 0;
 			break;
 		case 'C':
@@ -1211,7 +1244,7 @@
 #endif
 
 	if (print_console)
-		dump_console();
+		dump_console(one_boot_only);
 
 	if (print_coverage)
 		dump_coverage();

-- 
To view, visit https://review.coreboot.org/19497
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ic17383507a884d84de9a2a880380cb15b25708a1
Gerrit-PatchSet: 1
Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-Owner: Julius Werner <jwerner at chromium.org>
Gerrit-Reviewer: Aaron Durbin <adurbin at chromium.org>
Gerrit-Reviewer: Furquan Shaikh <furquan at google.com>