[PATCH] makedumpfile: Fix dmesg format after crash utility

[Atsushi Kumagai]

Hello Petr,

>On Fri, 29 Aug 2014 01:43:31 +0000
>Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote:
>
>> Hello,
>
>Hello Kumagai-san,
>
>> I made a trivial patch for v1.5.7.
>> This isn't essential but it's better than nothing.
>>[...]
>> diff --git a/makedumpfile.c b/makedumpfile.c
>> index b4b6eca..632daba 100644
>> --- a/makedumpfile.c
>> +++ b/makedumpfile.c
>> @@ -3950,6 +3950,7 @@ dump_log_entry(char *logptr, int fp)
>>  {
>>  	char *msg, *p, *bufp;
>>  	unsigned int i, text_len;
>> +	unsigned int indent_len;
>>  	unsigned long long ts_nsec;
>>  	char buf[BUFSIZE];
>>  	ulonglong nanos;
>> @@ -3965,6 +3966,7 @@ dump_log_entry(char *logptr, int fp)
>>
>>  	bufp = buf;
>>  	bufp += sprintf(buf, "[%5lld.%06ld] ", nanos, rem/1000);
>> +	indent_len = strlen(buf);
>>
>>  	for (i = 0, p = msg; i < text_len; i++, p++) {
>>  		/* 6bytes = "\\x%02x" + '\n' + '\0' */
>> @@ -3974,7 +3976,9 @@ dump_log_entry(char *logptr, int fp)
>>  			bufp = buf;
>>  		}
>>
>> -		if (isprint(*p) || isspace(*p))
>> +		if (*p == '\n')
>> +			bufp += sprintf(bufp, "\n%-*s", indent_len, "");
>> +		else if (isprint(*p) || isspace(*p))
>
>If you do this, you'll have to adjust the condition for growing the buffer above:
>
>	if (bufp - buf >= sizeof(buf) - 6) {

Yeah, I missed this.

>Let me send a cleanup patch for the "magic constant", which was never a
>good idea, it seems.

I've written the v2 patch based on your cleanup.


Thanks
Atsushi Kumagai

From: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
Date: Mon, 1 Sep 2014 14:23:01 +0900
Subject: [PATCH v2] Fix dmesg format after crash utility.

Add some spaces before a new line as much as the length
of the timestamp like crash utility as:

    $ diff -u  current.dmesg fixed.dmesg
    --- current.dmesg       2014-08-28 17:39:53.000000000 +0900
    +++ fixed.dmesg 2014-08-27 16:46:09.000000000 +0900
    @@ -150,8 +150,8 @@
     [    0.015251] Disabled fast string operations
     [    0.015285] mce: CPU supports 10 MCE banks
     [    0.015402] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
    -Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
    -tlb_flushall_shift: 6
    +               Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
    +               tlb_flushall_shift: 6
     [    0.015535] Freeing SMP alternatives memory: 20K (ffffffff81964000 - ffffffff81969000)
     [    0.018265] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
     [    0.028286] smpboot: CPU0: Intel QEMU Virtual CPU version (cpu64-rhel6) (fam: 06, model: 0d, stepping: 03)
    $

Signed-off-by: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
---
 makedumpfile.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/makedumpfile.c b/makedumpfile.c
index 37dea37..0a50175 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3949,7 +3949,7 @@ static int
 dump_log_entry(char *logptr, int fp)
 {
 	char *msg, *p, *bufp;
-	unsigned int i, text_len, buf_need;
+	unsigned int i, text_len, indent_len, buf_need;
 	unsigned long long ts_nsec;
 	char buf[BUFSIZE];
 	ulonglong nanos;
@@ -3965,9 +3965,10 @@ dump_log_entry(char *logptr, int fp)
 
 	bufp = buf;
 	bufp += sprintf(buf, "[%5lld.%06ld] ", nanos, rem/1000);
+	indent_len = strlen(buf);
 
 	/* How much buffer space is needed in the worst case */
-	buf_need = sizeof("\\xXX\n");
+	buf_need = MAX(sizeof("\\xXX\n"), sizeof("\n") + indent_len);
 
 	for (i = 0, p = msg; i < text_len; i++, p++) {
 		if (bufp - buf >= sizeof(buf) - buf_need) {
@@ -3976,7 +3977,9 @@ dump_log_entry(char *logptr, int fp)
 			bufp = buf;
 		}
 
-		if (isprint(*p) || isspace(*p))
+		if (*p == '\n')
+			bufp += sprintf(bufp, "\n%-*s", indent_len, "");
+		else if (isprint(*p) || isspace(*p))
 			*bufp++ = *p;
 		else
 			bufp += sprintf(bufp, "\\x%02x", *p);
-- 
1.9.0