[Crash-utility] [PATCH 2/4] parse NT_VMCOREDD ELF notes in KDUMP vmcore

[Surendra Mobiya]

Enhance help -D to parse NT_VMCOREDD ELF notes present in KDUMP vmcore.

Example:
crash> help -D
[...]
num_vmcoredd_notes: 2
            notes[0]: 7ff9a578d010 (NT_VMCOREDD)
                      name: "cxgb4_0000:02:00.4"
                      size: 33558464
            notes[1]: 7ff9a778e010 (NT_VMCOREDD)
                      name: "cxgb4_0000:03:00.4"
                      size: 33558464
[...]

Signed-off-by: Surendra Mobiya <surendra at chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy at chelsio.com>
---
rfc:
- No changes.

 diskdump.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/diskdump.c b/diskdump.c
index 8085712..6b7a91b 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -26,6 +26,7 @@
 #include "defs.h"
 #include "diskdump.h"
 #include "xen_dom0.h"
+#include "vmcore.h"
 
 #define BITMAP_SECT_LEN	4096
 
@@ -58,6 +59,8 @@ struct diskdump_data {
 	void	**nt_qemu_percpu;
 	void	**nt_qemucs_percpu;
 	uint	num_qemu_notes;
+	void	**nt_vmcoredd_array;
+	uint	num_vmcoredd_notes;
 
 	/* page cache */
 	struct page_cache_hdr {		/* header for each cached page */
@@ -279,6 +282,7 @@ process_elf32_notes(void *note_buf, unsigned long size_note)
 	Elf32_Nhdr *nt;
 	size_t index, len = 0;
 	int num = 0;
+	int vmcoredd_num = 0;
 	int qemu_num = 0;
 
 	for (index = 0; index < size_note; index += len) {
@@ -304,6 +308,12 @@ process_elf32_notes(void *note_buf, unsigned long size_note)
 			process_xen_note(nt->n_type, data, nt->n_descsz);
 		}
 
+		if (nt->n_type == NT_VMCOREDD &&
+		    vmcoredd_num < NR_DEVICE_DUMPS) {
+			dd->nt_vmcoredd_array[vmcoredd_num] = nt;
+			vmcoredd_num++;
+		}
+
 		len = roundup(len + nt->n_namesz, 4);
 		len = roundup(len + nt->n_descsz, 4);
 	}
@@ -317,6 +327,9 @@ process_elf32_notes(void *note_buf, unsigned long size_note)
 		pc->flags2 |= QEMU_MEM_DUMP_COMPRESSED;
 		dd->num_qemu_notes = qemu_num;
 	}
+	if (vmcoredd_num > 0)
+		dd->num_vmcoredd_notes = vmcoredd_num;
+
 	return;
 }
 
@@ -326,6 +339,7 @@ process_elf64_notes(void *note_buf, unsigned long size_note)
 	Elf64_Nhdr *nt;
 	size_t index, len = 0;
 	int num = 0;
+	int vmcoredd_num = 0;
 	int qemu_num = 0;
 
 	for (index = 0; index < size_note; index += len) {
@@ -357,6 +371,12 @@ process_elf64_notes(void *note_buf, unsigned long size_note)
 			process_xen_note(nt->n_type, data, nt->n_descsz);
 		}
 
+		if (nt->n_type == NT_VMCOREDD &&
+		    vmcoredd_num < NR_DEVICE_DUMPS) {
+			dd->nt_vmcoredd_array[vmcoredd_num] = nt;
+			vmcoredd_num++;
+		}
+
 		len = roundup(len + nt->n_namesz, 4);
 		len = roundup(len + nt->n_descsz, 4);
 	}
@@ -370,6 +390,9 @@ process_elf64_notes(void *note_buf, unsigned long size_note)
 		pc->flags2 |= QEMU_MEM_DUMP_COMPRESSED;
 		dd->num_qemu_notes = qemu_num;
 	}
+	if (vmcoredd_num > 0)
+		dd->num_vmcoredd_notes = vmcoredd_num;
+
 	return;
 }
 
@@ -778,6 +801,10 @@ restart:
 			error(FATAL, "qemu mem dump compressed: cannot malloc pointer"
 				" to QEMUCS notes\n");
 
+		if ((dd->nt_vmcoredd_array = malloc(NR_DEVICE_DUMPS * sizeof(void *))) == NULL)
+			error(FATAL, "compressed kdump: cannot malloc array for "
+				     "vmcore device dump notes\n");
+
 		if (FLAT_FORMAT()) {
 			if (!read_flattened_format(dd->dfd, offset, dd->notes_buf, size)) {
 				error(INFO, "compressed kdump: cannot read notes data"
@@ -875,6 +902,8 @@ err:
 		free(dd->nt_qemu_percpu);
 	if (dd->nt_qemucs_percpu)
 		free(dd->nt_qemucs_percpu);
+	if (dd->nt_vmcoredd_array)
+		free(dd->nt_vmcoredd_array);
 
 	dd->flags &= ~(DISKDUMP_LOCAL|KDUMP_CMPRS_LOCAL);
 	pc->flags2 &= ~ELF_NOTES;
@@ -1948,6 +1977,15 @@ __diskdump_memory_dump(FILE *fp)
 				dd->sub_header_kdump->size_note);
 			fprintf(fp, "           notes_buf: %lx\n",
 				(ulong)dd->notes_buf);
+			fprintf(fp, "  num_vmcoredd_notes: %d\n",
+				dd->num_vmcoredd_notes);
+			for (i = 0; i < dd->num_vmcoredd_notes; i++) {
+				fprintf(fp, "            notes[%d]: %lx %s\n",
+					i, (ulong)dd->nt_vmcoredd_array[i],
+					dd->nt_vmcoredd_array[i] ? "(NT_VMCOREDD)" : "");
+				display_vmcoredd_note(dd->nt_vmcoredd_array[i], fp);
+			}
+
 			fprintf(fp, "  num_prstatus_notes: %d\n",
 				dd->num_prstatus_notes);
 			for (i = 0; i < dd->num_prstatus_notes; i++) {
-- 
2.21.0