[PATCH v1 1/6] makedumpfile: Add '--config' option to specify filter config file.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

This patch adds '--config' option to specify config file that contains filter
commands to filter out desired kernel data and it's members.

Updated makedumpfile man page with '--config' option info.

Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
Signed-off-by: Prerna Saxena <prerna at linux.vnet.ibm.com>
---

 makedumpfile.8 |   20 +++++++++++++++++++-
 makedumpfile.c |   17 +++++++++++++++++
 makedumpfile.h |    7 +++++++
 3 files changed, 43 insertions(+), 1 deletions(-)

diff --git a/makedumpfile.8 b/makedumpfile.8
index 4a0271d..a1aaa3e 100644
--- a/makedumpfile.8
+++ b/makedumpfile.8
@@ -6,6 +6,8 @@ makedumpfile \- make a small dumpfile of kdump
 .br
 \fBmakedumpfile\fR \-F [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR
 .br
+\fBmakedumpfile\fR   [\fIOPTION\fR] \-x \fIVMLINUX\fR \-\-config \fIFILTERCONFIGFILE\fR \fIVMCORE\fR \fIDUMPFILE\fR
+.br
 \fBmakedumpfile\fR \-R \fIDUMPFILE\fR
 .br
 \fBmakedumpfile\fR \-\-split [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE1\fR \fIDUMPFILE2\fR [\fIDUMPFILE3\fR ..]
@@ -55,6 +57,15 @@ compression support. The ELF format is readable with GDB and the crash utility.
 If a user wants to use GDB, \fIDUMPFILE\fR format has to be explicitly
 specified to be the ELF format.
 .PP
+Apart from the exclusion of unnecessary pages mentioned above, makedumpfile
+allows user to filter out targeted kernel data. The filter config file can
+be used to specify kernel/module symbols and its members that need to be
+filtered out through the erase command syntax. makedumpfile reads the filter
+config and builds the list of memory addresses and its sizes after processing
+filter commands. The memory locations that require to be filtered out are
+then poisoned with character 'X' (58 in Hex). Refer to \fBfilter.conf(8)\fR
+for file format.
+.PP
 To analyze the first kernel's memory usage, makedumpfile can refer to
 \fIVMCOREINFO\fR instead of \fIVMLINUX\fR. \fIVMCOREINFO\fR contains the first
 kernel's information (structure size, field offset, etc.), and \fIVMCOREINFO\fR
@@ -232,6 +243,13 @@ specified.
 # makedumpfile \-g vmcoreinfo \-x vmlinux
 
 .TP
+\fB\-\-config\fR \fIFILTERCONFIGFILE\fR
+Used in conjunction with \-x \fIVMLINUX\fR option, to specify the filter
+config file \fIFILTERCONFIGFILE\fR that contains erase commands to filter out
+desired kernel data from vmcore while creating \fIDUMPFILE\fR. For filter
+command syntax please refer to \fBfilter.conf(8)\fR.
+
+.TP
 \fB\-F\fR
 Output the dump data in the flattened format to the standard output for
 transporting the dump data by SSH.
@@ -482,5 +500,5 @@ Written by Masaki Tachibana, and Ken'ichi Ohmichi.
 
 .SH SEE ALSO
 .PP
-crash(8), gdb(1), kexec(8)
+crash(8), gdb(1), kexec(8), filter.conf(8)
 
diff --git a/makedumpfile.c b/makedumpfile.c
index 7d0c663..f136eba 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -636,6 +636,11 @@ print_usage(void)
 	MSG("  Creating DUMPFILE:\n");
 	MSG("  # makedumpfile    [-c|-E] [-d DL] [-x VMLINUX|-i VMCOREINFO] VMCORE DUMPFILE\n");
 	MSG("\n");
+	MSG("  Creating DUMPFILE with filtered kernel data specified through filter config\n");
+	MSG("  file:\n");
+	MSG("  # makedumpfile    [-c|-E] [-d DL] -x VMLINUX --config FILTERCONFIGFILE VMCORE\n");
+	MSG("    DUMPFILE\n");
+	MSG("\n");
 	MSG("  Outputting the dump data in the flattened format to the standard output:\n");
 	MSG("  # makedumpfile -F [-c|-E] [-d DL] [-x VMLINUX|-i VMCOREINFO] VMCORE\n");
 	MSG("\n");
@@ -714,6 +719,11 @@ print_usage(void)
 	MSG("      other system that is running the same first kernel. [-x VMLINUX] must\n");
 	MSG("      be specified.\n");
 	MSG("\n");
+	MSG("  [--config FILTERCONFIGFILE]:\n");
+	MSG("      Used in conjunction with -x VMLINUX option, to specify the filter config\n");
+	MSG("      file that contains filter commands to filter out desired kernel data\n");
+	MSG("      from vmcore while creating DUMPFILE.\n");
+	MSG("\n");
 	MSG("  [-F]:\n");
 	MSG("      Output the dump data in the flattened format to the standard output\n");
 	MSG("      for transporting the dump data by SSH.\n");
@@ -7729,6 +7739,9 @@ check_param_for_creating_dumpfile(int argc, char *argv[])
 	if (info->flag_flatten && info->flag_split)
 		return FALSE;
 
+	if (info->name_filterconfig && !info->name_vmlinux)
+		return FALSE;
+
 	if ((argc == optind + 2) && !info->flag_flatten
 				 && !info->flag_split) {
 		/*
@@ -7821,6 +7834,7 @@ static struct option longopts[] = {
 	{"message-level", required_argument, NULL, 'm'},
 	{"vtop", required_argument, NULL, 'V'},
 	{"dump-dmesg", no_argument, NULL, 'M'}, 
+	{"config", required_argument, NULL, 'C'},
 	{"help", no_argument, NULL, 'h'},
 	{0, 0, 0, 0}
 };
@@ -7851,6 +7865,9 @@ main(int argc, char *argv[])
 		case 'b':
 			info->block_order = atoi(optarg);
 			break;
+		case 'C':
+			info->name_filterconfig = optarg;
+			break;
 		case 'c':
 			info->flag_compress = 1;
 			break;
diff --git a/makedumpfile.h b/makedumpfile.h
index 11e1a93..342e419 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -888,6 +888,13 @@ struct DumpInfo {
 	unsigned long	vmemmap_end;
 
 	/*
+	 * Filter config file containing filter commands to filter out kernel
+	 * data from vmcore.
+	 */
+	char		*name_filterconfig;
+	FILE		*file_filterconfig;
+
+	/*
 	 * diskdimp info:
 	 */
 	int		block_order;