[Crash-utility] [PATCH v3 1/2] Crash-Utility: Enhance crash utilty to read elf notes content from DUMPFILE

[Mahesh J Salgaonkar]

This patch enables crash utility to handle elf notes content in DUMPFILE if
kdump hedaer version >= 4. The processing of data content will be architecture
dependent.

makedumpfile tool is enhanced to store elf notes content from vmcore to
DUMPFILE starting from kdump header version 4.

	---------------------------------------------------------------
	commit 1fb344e934f87b9c124e487a21e111c7bdc977ba
	Author: Ken'ichi Ohmichi <oomichi at mxs.nes.nec.co.jp>
	Date:   Fri Oct 8 09:18:59 2010 +0900

	    [PATCH] Add ELF note section to the kdump-compressed format.
	---------------------------------------------------------------

A new arch dependent interface has been added to machdep_table structure which
needs to be populated during machdep_init(SETUP_ENV) call.

struct machdep_table {
	...
	...
	void (*process_elf_notes)(void *, unsigned long);
}

ChangeLog:
- Modified __diskdump_memory_dump() function to display contents of
  all 4 additional fields in the kdump_sub_header.
- Modified __diskdump_memory_dump() to dump the vmcoreinfo ASCII strings.

Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
---
 defs.h     |    1 
 diskdump.c |   81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 diskdump.h |    4 +++
 3 files changed, 86 insertions(+)

Index: crash-5.0.9/diskdump.c
===================================================================
--- crash-5.0.9.orig/diskdump.c
+++ crash-5.0.9/diskdump.c
@@ -189,6 +189,7 @@ static int read_dump_header(char *file)
 	struct disk_dump_header *header = NULL;
 	struct disk_dump_sub_header *sub_header = NULL;
 	struct kdump_sub_header *sub_header_kdump = NULL;
+	unsigned char *notes_buf = NULL;
 	int bitmap_len;
 	int block_size = (int)sysconf(_SC_PAGESIZE);
 	off_t offset;
@@ -355,6 +356,31 @@ restart:
 		goto err;
 	}
 
+	/* process elf notes data */
+	if (KDUMP_CMPRS_VALID() && (dd->header->header_version >= 4) &&
+		(sub_header_kdump->offset_note) &&
+		(sub_header_kdump->size_note) && (machdep->process_elf_notes)) {
+		unsigned long size_note = sub_header_kdump->size_note;
+		offset = sub_header_kdump->offset_note;
+
+		if (lseek(dd->dfd, offset, SEEK_SET) == failed) {
+			error(INFO, "compressed kdump: cannot lseek dump elf"
+				" notes\n");
+			goto err;
+		}
+
+		if ((notes_buf = malloc(size_note)) == NULL)
+			error(FATAL, "compressed kdump: cannot malloc notes"
+				" buffer\n");
+
+		if (read(dd->dfd, notes_buf, size_note) < size_note) {
+			error(INFO, "compressed kdump: cannot read notes data"
+				"\n");
+			goto err;
+		}
+		machdep->process_elf_notes(notes_buf, size_note);
+	}
+
 	/* For split dumpfile */
 	if (KDUMP_CMPRS_VALID()) {
 		is_split = ((dd->header->header_version >= 2) &&
@@ -399,6 +425,8 @@ err:
 		free(sub_header);
 	if (sub_header_kdump)
 		free(sub_header_kdump);
+	if (notes_buf)
+		free(notes_buf);
 	if (dd->bitmap)
 		free(dd->bitmap);
 	if (dd->dumpable_bitmap)
@@ -786,6 +814,43 @@ int diskdump_memory_used(void)
         return 0;
 }
 
+void dump_vmcoreinfo(FILE *fp)
+{
+	char *buf = NULL;
+	unsigned long i = 0;
+	unsigned long size_vmcoreinfo = dd->sub_header_kdump->size_vmcoreinfo;
+	off_t offset = dd->sub_header_kdump->offset_vmcoreinfo;
+	const off_t failed = (off_t)-1;
+
+	if (lseek(dd->dfd, offset, SEEK_SET) == failed) {
+		error(INFO, "compressed kdump: cannot lseek dump vmcoreinfo\n");
+		return;
+	}
+
+	if ((buf = malloc(size_vmcoreinfo)) == NULL) {
+		error(FATAL, "compressed kdump: cannot malloc vmcoreinfo"
+				" buffer\n");
+	}
+
+	if (read(dd->dfd, buf, size_vmcoreinfo) < size_vmcoreinfo) {
+		error(INFO, "compressed kdump: cannot read vmcoreinfo data\n");
+		goto err;
+	}
+
+	fprintf(fp, "                      ");
+	for (i = 0; i < size_vmcoreinfo; i++) {
+		fprintf(fp, "%c", buf[i]);
+		if (buf[i] == '\n')
+			fprintf(fp, "                      ");
+	}
+	if (buf[i - 1] != '\n')
+		fprintf(fp, "\n");
+err:
+	if (buf)
+		free(buf);
+	return;
+}
+
 /*
  *  This function is dump-type independent, and could be used
  *  to dump the diskdump_data structure contents and perhaps
@@ -954,6 +1019,22 @@ __diskdump_memory_dump(FILE *fp)
 			fprintf(fp, "           start_pfn: %lu\n", dd->sub_header_kdump->start_pfn);
 			fprintf(fp, "             end_pfn: %lu\n", dd->sub_header_kdump->end_pfn);
 		}
+		if (dh->header_version >= 3) {
+			fprintf(fp, "   offset_vmcoreinfo: %lx\n",
+				dd->sub_header_kdump->offset_vmcoreinfo);
+			fprintf(fp, "     size_vmcoreinfo: %lu\n",
+				dd->sub_header_kdump->size_vmcoreinfo);
+			if (dd->sub_header_kdump->offset_vmcoreinfo &&
+				dd->sub_header_kdump->size_vmcoreinfo) {
+				dump_vmcoreinfo(fp);
+			}
+		}
+		if (dh->header_version >= 4) {
+			fprintf(fp, "         offset_note: %lx\n",
+				dd->sub_header_kdump->offset_note);
+			fprintf(fp, "           size_note: %lu\n",
+				dd->sub_header_kdump->size_note);
+		}
 		fprintf(fp, "\n");
 	} else
         	fprintf(fp, "(n/a)\n\n");
Index: crash-5.0.9/diskdump.h
===================================================================
--- crash-5.0.9.orig/diskdump.h
+++ crash-5.0.9/diskdump.h
@@ -63,6 +63,10 @@ struct kdump_sub_header {
 	int		split;       /* header_version 2 and later */
 	unsigned long start_pfn; /* header_version 2 and later */
 	unsigned long end_pfn;   /* header_version 2 and later */
+	off_t		offset_vmcoreinfo;/* header_version 3 and later */
+	unsigned long	size_vmcoreinfo;  /* header_version 3 and later */
+	off_t		offset_note;	/* header_version 4 and later */
+	unsigned long	size_note;	/* header_version 4 and later */
 };
 
 /* page flags */
Index: crash-5.0.9/defs.h
===================================================================
--- crash-5.0.9.orig/defs.h
+++ crash-5.0.9/defs.h
@@ -807,6 +807,7 @@ struct machdep_table {
 	int (*xen_kdump_p2m_create)(struct xen_kdump_data *);
 	int (*in_alternate_stack)(int, ulong);
 	void (*dumpfile_init)(int, void *);
+	void (*process_elf_notes)(void *, unsigned long);
 };
 
 /*