Blame makedumpfile-1.7.2-0003-IMPLEMENTAION-Add-a-description-of-the-flatten.patch

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From 42955c0b4d9c0723de72a810f80e4b3543053631 Mon Sep 17 00:00:00 2001
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From: Kazuhito Hagio <k-hagio-ab@nec.com>
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Date: Wed, 30 Nov 2022 12:02:44 +0900
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Subject: [PATCH 3/7] [PATCH] IMPLEMENTAION: Add a description of the flattened
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 format
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Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
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---
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 IMPLEMENTATION | 45 +++++++++++++++++++++++++++++++++++++++++++++
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 1 file changed, 45 insertions(+)
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diff --git a/makedumpfile-1.7.2/IMPLEMENTATION b/makedumpfile-1.7.2/IMPLEMENTATION
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index 589c5bf..b7a1603 100644
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--- a/makedumpfile-1.7.2/IMPLEMENTATION
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+++ b/makedumpfile-1.7.2/IMPLEMENTATION
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@@ -280,3 +280,48 @@
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     If there is no segment dumped into the DUMPFILE, the DUMPFILE can't be
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     analysed by crash.
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+
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+
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+* The flattened format
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+
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+  This format is mostly used to send dump data to a remote host via SSH.
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+  The kdump-compressed format and ELF format require random access to create
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+  a DUMPFILE, so it cannot be written directly to standard output.
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+  The flattened format adds the original offset and size of each data block,
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+  and it can be rearranged to the original format on the remote host.
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+
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+  - File structure
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+
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+    This is the case of the kdump-compressed format.
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+                                                 File offset
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+    +------------------------------------------+ 0x0
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+    | flat header (struct makedumpfile_header) |
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+    |                                          |
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+    |------------------------------------------| 0x1000 (4096)
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+    | flat data header                         |
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+    |     (struct makedumpfile_data_header)    |
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+    |   main header (struct disk_dump_header)  |
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+    |------------------------------------------| (not aligned)
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+    | flat data header                         |
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+    |                    :                     |
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+
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+    Note: For the ELF format, ELF header is not always the first data.
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+
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+  - flat header
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+
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+    struct makedumpfile_header {
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+            char    signature[SIG_LEN_MDF]; /* = "makedumpfile\0\0\0\0" */
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+            int64_t type;                   /* = TYPE_FLAT_HEADER (1) */
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+            int64_t version;                /* = VERSION_FLAT_HEADER (1) */
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+    };
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+
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+    Note: the type and version are big endian.
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+
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+  - flat data header
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+
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+    struct makedumpfile_data_header {
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+            int64_t offset;
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+            int64_t buf_size;
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+    };
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+
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+    Note: the offset and buf_size are big endian.
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-- 
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2.33.1
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