dump: add API to write dump header

the functions are used to write header of kdump-compressed format to vmcore.
Header of kdump-compressed format includes:
1. common header: DiskDumpHeader32 / DiskDumpHeader64
2. sub header: KdumpSubHeader32 / KdumpSubHeader64
3. extra information: only elf notes here

Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 223 insertions, 0 deletions

diff --git a/dump.c b/dump.c
index 3a1944e381..4b2799f80f 100644
--- a/dump.c
+++ b/dump.c
@@ -778,6 +778,229 @@ static int buf_write_note(const void *buf, size_t size, void *opaque)
     return 0;
 }
 
+/* write common header, sub header and elf note to vmcore */
+static int create_header32(DumpState *s)
+{
+    int ret = 0;
+    DiskDumpHeader32 *dh = NULL;
+    KdumpSubHeader32 *kh = NULL;
+    size_t size;
+    int endian = s->dump_info.d_endian;
+    uint32_t block_size;
+    uint32_t sub_hdr_size;
+    uint32_t bitmap_blocks;
+    uint32_t status = 0;
+    uint64_t offset_note;
+
+    /* write common header, the version of kdump-compressed format is 6th */
+    size = sizeof(DiskDumpHeader32);
+    dh = g_malloc0(size);
+
+    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
+    dh->header_version = cpu_convert_to_target32(6, endian);
+    block_size = s->page_size;
+    dh->block_size = cpu_convert_to_target32(block_size, endian);
+    sub_hdr_size = sizeof(struct KdumpSubHeader32) + s->note_size;
+    sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
+    dh->sub_hdr_size = cpu_convert_to_target32(sub_hdr_size, endian);
+    /* dh->max_mapnr may be truncated, full 64bit is in kh.max_mapnr_64 */
+    dh->max_mapnr = cpu_convert_to_target32(MIN(s->max_mapnr, UINT_MAX),
+                                            endian);
+    dh->nr_cpus = cpu_convert_to_target32(s->nr_cpus, endian);
+    bitmap_blocks = DIV_ROUND_UP(s->len_dump_bitmap, block_size) * 2;
+    dh->bitmap_blocks = cpu_convert_to_target32(bitmap_blocks, endian);
+    memcpy(&(dh->utsname.machine), "i686", 4);
+
+    if (s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) {
+        status |= DUMP_DH_COMPRESSED_ZLIB;
+    }
+#ifdef CONFIG_LZO
+    if (s->flag_compress & DUMP_DH_COMPRESSED_LZO) {
+        status |= DUMP_DH_COMPRESSED_LZO;
+    }
+#endif
+#ifdef CONFIG_SNAPPY
+    if (s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) {
+        status |= DUMP_DH_COMPRESSED_SNAPPY;
+    }
+#endif
+    dh->status = cpu_convert_to_target32(status, endian);
+
+    if (write_buffer(s->fd, 0, dh, size) < 0) {
+        dump_error(s, "dump: failed to write disk dump header.\n");
+        ret = -1;
+        goto out;
+    }
+
+    /* write sub header */
+    size = sizeof(KdumpSubHeader32);
+    kh = g_malloc0(size);
+
+    /* 64bit max_mapnr_64 */
+    kh->max_mapnr_64 = cpu_convert_to_target64(s->max_mapnr, endian);
+    kh->phys_base = cpu_convert_to_target32(PHYS_BASE, endian);
+    kh->dump_level = cpu_convert_to_target32(DUMP_LEVEL, endian);
+
+    offset_note = DISKDUMP_HEADER_BLOCKS * block_size + size;
+    kh->offset_note = cpu_convert_to_target64(offset_note, endian);
+    kh->note_size = cpu_convert_to_target32(s->note_size, endian);
+
+    if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS *
+                     block_size, kh, size) < 0) {
+        dump_error(s, "dump: failed to write kdump sub header.\n");
+        ret = -1;
+        goto out;
+    }
+
+    /* write note */
+    s->note_buf = g_malloc0(s->note_size);
+    s->note_buf_offset = 0;
+
+    /* use s->note_buf to store notes temporarily */
+    if (write_elf32_notes(buf_write_note, s) < 0) {
+        ret = -1;
+        goto out;
+    }
+
+    if (write_buffer(s->fd, offset_note, s->note_buf,
+                     s->note_size) < 0) {
+        dump_error(s, "dump: failed to write notes");
+        ret = -1;
+        goto out;
+    }
+
+    /* get offset of dump_bitmap */
+    s->offset_dump_bitmap = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size) *
+                             block_size;
+
+    /* get offset of page */
+    s->offset_page = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size + bitmap_blocks) *
+                     block_size;
+
+out:
+    g_free(dh);
+    g_free(kh);
+    g_free(s->note_buf);
+
+    return ret;
+}
+
+/* write common header, sub header and elf note to vmcore */
+static int create_header64(DumpState *s)
+{
+    int ret = 0;
+    DiskDumpHeader64 *dh = NULL;
+    KdumpSubHeader64 *kh = NULL;
+    size_t size;
+    int endian = s->dump_info.d_endian;
+    uint32_t block_size;
+    uint32_t sub_hdr_size;
+    uint32_t bitmap_blocks;
+    uint32_t status = 0;
+    uint64_t offset_note;
+
+    /* write common header, the version of kdump-compressed format is 6th */
+    size = sizeof(DiskDumpHeader64);
+    dh = g_malloc0(size);
+
+    strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));
+    dh->header_version = cpu_convert_to_target32(6, endian);
+    block_size = s->page_size;
+    dh->block_size = cpu_convert_to_target32(block_size, endian);
+    sub_hdr_size = sizeof(struct KdumpSubHeader64) + s->note_size;
+    sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);
+    dh->sub_hdr_size = cpu_convert_to_target32(sub_hdr_size, endian);
+    /* dh->max_mapnr may be truncated, full 64bit is in kh.max_mapnr_64 */
+    dh->max_mapnr = cpu_convert_to_target32(MIN(s->max_mapnr, UINT_MAX),
+                                            endian);
+    dh->nr_cpus = cpu_convert_to_target32(s->nr_cpus, endian);
+    bitmap_blocks = DIV_ROUND_UP(s->len_dump_bitmap, block_size) * 2;
+    dh->bitmap_blocks = cpu_convert_to_target32(bitmap_blocks, endian);
+    memcpy(&(dh->utsname.machine), "x86_64", 6);
+
+    if (s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) {
+        status |= DUMP_DH_COMPRESSED_ZLIB;
+    }
+#ifdef CONFIG_LZO
+    if (s->flag_compress & DUMP_DH_COMPRESSED_LZO) {
+        status |= DUMP_DH_COMPRESSED_LZO;
+    }
+#endif
+#ifdef CONFIG_SNAPPY
+    if (s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) {
+        status |= DUMP_DH_COMPRESSED_SNAPPY;
+    }
+#endif
+    dh->status = cpu_convert_to_target32(status, endian);
+
+    if (write_buffer(s->fd, 0, dh, size) < 0) {
+        dump_error(s, "dump: failed to write disk dump header.\n");
+        ret = -1;
+        goto out;
+    }
+
+    /* write sub header */
+    size = sizeof(KdumpSubHeader64);
+    kh = g_malloc0(size);
+
+    /* 64bit max_mapnr_64 */
+    kh->max_mapnr_64 = cpu_convert_to_target64(s->max_mapnr, endian);
+    kh->phys_base = cpu_convert_to_target64(PHYS_BASE, endian);
+    kh->dump_level = cpu_convert_to_target32(DUMP_LEVEL, endian);
+
+    offset_note = DISKDUMP_HEADER_BLOCKS * block_size + size;
+    kh->offset_note = cpu_convert_to_target64(offset_note, endian);
+    kh->note_size = cpu_convert_to_target64(s->note_size, endian);
+
+    if (write_buffer(s->fd, DISKDUMP_HEADER_BLOCKS *
+                     block_size, kh, size) < 0) {
+        dump_error(s, "dump: failed to write kdump sub header.\n");
+        ret = -1;
+        goto out;
+    }
+
+    /* write note */
+    s->note_buf = g_malloc0(s->note_size);
+    s->note_buf_offset = 0;
+
+    /* use s->note_buf to store notes temporarily */
+    if (write_elf64_notes(buf_write_note, s) < 0) {
+        ret = -1;
+        goto out;
+    }
+
+    if (write_buffer(s->fd, offset_note, s->note_buf,
+                     s->note_size) < 0) {
+        dump_error(s, "dump: failed to write notes");
+        ret = -1;
+        goto out;
+    }
+
+    /* get offset of dump_bitmap */
+    s->offset_dump_bitmap = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size) *
+                             block_size;
+
+    /* get offset of page */
+    s->offset_page = (DISKDUMP_HEADER_BLOCKS + sub_hdr_size + bitmap_blocks) *
+                     block_size;
+
+out:
+    g_free(dh);
+    g_free(kh);
+    g_free(s->note_buf);
+
+    return ret;
+}
+
+static int write_dump_header(DumpState *s)
+{
+    if (s->dump_info.d_machine == EM_386) {
+        return create_header32(s);
+    } else {
+        return create_header64(s);
+    }
+}
+
 static ram_addr_t get_start_block(DumpState *s)
 {
     GuestPhysBlock *block;