Difference between revisions of "CRIT"

Latest revision as of 16:31, 4 November 2022

This page describes the CRIT Python tool. For the Go library, see CRIT (Go library).

CRiu Image Tool is a feature-rich replacement for existing "criu show". It is written completely in Python, so it is quite easy to read the code and extend its features.

Usage[edit]

usage: crit [-h] {decode,encode,info,x,show} ...

CRiu Image Tool

positional arguments:
  {decode,encode,info,x,show}
                        Use crit CMD --help for command-specific help
    decode              convert criu image from binary type to json
    encode              convert criu image from json type to binary
    info                show info about image
    x                   explore image dir
    show                convert criu image from binary to human-readable json

optional arguments:
  -h, --help            show this help message and exit

Pretty output[edit]

crit decode prints JSON text in one line. This can be read by any further JSON-aware tool for parsing. For human eyes it's more convenient to read JSON multi-line with indentation. CRIT can do this when using the show action or the --pretty option.

Wend doing pretty optput CRIT does a little bit more, than just multiline indented JSON.

Addresses and registers: VM addresses and core.img register values are all printed in hex. Since JSON doesn't support this form of numbers, such fields are encoded as strings.

Bit-fields: Such things as flags and masks (e.g. sig-block mask) are also better understood when written in hex, so CRIT does this.

IP addresses: By default those a printed in decimal, but the "1.2.3.4" for v4 or "::1" for v6 can be seen in the --pretty mode.

Symbolic names for flags: Some known bit sets (e.g. MAP_PRIVATE, MAP_ANONYMOUS, etc. for vma->flags) are shown with names.

Device numbers: If the field is known to be of dev_t type, it's printed in the major:minor manner

Functionality[edit]

Convert images from IMG to JSON[edit]

crit decode is the replacement for the (rather nasty) criu show code. This is also the way to edit the images before restoring from them.

It uses text_format as a human-readable format for protobuf messages.

The output file is structured in the following way.

Without "--pretty":

{ "magic" : "FOO", "entries" : [{"foo": "bar", "bar": "foo", "extra": "abc"}, {"foo": "bar", "bar" : "foo", "extra" : "abc"} ]}

With "--pretty":

{
    "magic" : "FOO",
    "entries" : [
        {
            "foo" : "bar",
            "bar" : "foo",
            "extra" : "abc"
        },
        {
            "foo" : "bar",
            "bar" : "foo",
            "extra" : "abc"
        }
    ]
}

Example("crit decode -i core-5679.img --pretty")

{
    "magic": "CORE", 
    "entries": [
        {
            "mtype": "X86_64", 
            "thread_core": {
                "futex_rla_len": 24, 
                "sched_policy": 0, 
                "sched_nice": 0, 
                "futex_rla": 0, 
                "signals_p": {}, 
                "sas": {
                    "ss_size": 0, 
                    "ss_sp": 0, 
                    "ss_flags": 2
                }
            }, 
            "thread_info": {
                "fpregs": {
                    "st_space": [
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0
                    ], 
                    "fop": 0, 
                    "rdp": 0, 
                    "twd": 0, 
                    "mxcsr": 8064, 
                    "swd": 0, 
                    "rip": 0, 
                    "xsave": {
                        "ymmh_space": [
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0, 
                            0
                        ], 
                        "xstate_bv": 2
                    }, 
                    "xmm_space": [
                        0, 
                        4278190080, 
                        4294967295, 
                        4294967295, 
                        1701145715, 
                        3219568, 
                        0, 
                        0, 
                        0, 
                        0, 
                        33, 
                        0, 
                        792358505, 
                        1953460082, 
                        1852400175, 
                        0, 
                        942882145, 
                        876295483, 
                        774519349, 
                        1031303283, 
                        893073459, 
                        976565307, 
                        1937255978, 
                        859661936, 
                        993344312, 
                        3814708, 
                        65, 
                        0, 
                        37049520, 
                        0, 
                        37049632, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        4294901760, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0, 
                        0
                    ], 
                    "cwd": 0, 
                    "mxcsr_mask": 65535
                }, 
                "clear_tid_addr": 0, 
                "gpregs": {
                    "gs": "0x0", 
                    "ip": "0x7f172cf1ea04", 
                    "cx": "0xffffffffffffffff", 
                    "cs": "0x33", 
                    "ax": "0x38", 
                    "orig_ax": "0x38", 
                    "di": "0x1200011", 
                    "es": "0x0", 
                    "gs_base": "0x0", 
                    "r14": "0x0", 
                    "r15": "0x2355e00", 
                    "r12": "0x7ffffdbf74f0", 
                    "r13": "0x0", 
                    "r10": "0x7f172d83d9d0", 
                    "r11": "0x246", 
                    "fs_base": "0x7f172d83d700", 
                    "bp": "0x7ffffdbf7530", 
                    "dx": "0x0", 
                    "bx": "0x0", 
                    "ds": "0x0", 
                    "ss": "0x2b", 
                    "sp": "0x7ffffdbf74f0", 
                    "r8": "0x0", 
                    "r9": "0x0", 
                    "fs": "0x0", 
                    "si": "0x0", 
                    "flags": "0x246"
                }
            }, 
            "tc": {
                "timers": {
                    "real": {
                        "isec": 0, 
                        "vusec": 0, 
                        "iusec": 0, 
                        "vsec": 0
                    }, 
                    "virt": {
                        "isec": 0, 
                        "vusec": 0, 
                        "iusec": 0, 
                        "vsec": 0
                    }, 
                    "prof": {
                        "isec": 0, 
                        "vusec": 0, 
                        "iusec": 0, 
                        "vsec": 0
                    }
                }, 
                "cg_set": 1, 
                "signals_s": {}, 
                "blk_sigset": "0x10002", 
                "exit_code": 0, 
                "rlimits": {
                    "rlimits": [
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 8388608
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 0
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 62844, 
                            "cur": 62844
                        }, 
                        {
                            "max": 4096, 
                            "cur": 1024
                        }, 
                        {
                            "max": 65536, 
                            "cur": 65536
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }, 
                        {
                            "max": 62844, 
                            "cur": 62844
                        }, 
                        {
                            "max": 819200, 
                            "cur": 819200
                        }, 
                        {
                            "max": 0, 
                            "cur": 0
                        }, 
                        {
                            "max": 0, 
                            "cur": 0
                        }, 
                        {
                            "max": 18446744073709551615, 
                            "cur": 18446744073709551615
                        }
                    ]
                }, 
                "comm": "loop.sh", 
                "flags": 1077960704, 
                "task_state": 1, 
                "personality": 0
            }
        }
    ]
}

Decode also supports input via STDIN instead of the "-i" flag.

cat "core-5679.img" | crit decode

Convert images from JSON to IMG[edit]

crit encode converts the image from JSON to IMG. Standard usage would look like:

crit encode -i core-5679.json -o core-5679.img

Encode also supports input via STDIN instead of the "-i" flag.

cat "core-5679.json" | crit encode

Incase a "-o" flag is not specified the input is piped out to STDOUT.

Generate core files out of task images[edit]

Moved into separate project called criu-coredump.

Show images statistics[edit]

crit x allows you to explore image statistics. E.g. Total number of processes, files, memory, sockets, etc.

crit x $directory_with_images <explore type>

Supported explorers are

'ps': to show process tree

'fds': to show files used by tasks

'mems': to show memory mappings info

Show images Info[edit]

Image of a info such as its "COUNT" and "MAGIC" can be displayed using the INFO command.

Example("crit info core-5679.img")

{
    "count": 1, 
    "magic": "CORE"
}

Planned functionality[edit]

On-the-fly conversion[edit]

There's an idea to make CRIU spawn CRIT and read images "through" it, to allow for at-the-restore-time modifications. For details, see https://github.com/checkpoint-restore/criu/issues/59.

Convert between different image versions[edit]

Right now we store the images version in inventory.img and collect info about what's bad with V1 images. If some day we have v2, CRIT will convert from v1. And for backward compatibility we'll use on-the-fly conversion when restoring from old images.

Check/validate images[edit]

Check that

all images are present
the inter-images IDs are in consistent state

For details, see https://github.com/checkpoint-restore/criu/issues/44.

Anonymize image files[edit]

Since images contain raw memory dumps people may refuse to send us images for debugging. Need to anonymize them, i.e. -- remove this sensitive information.

@@ Line 1: / Line 1: @@
-This page describes the CRiu Image Tool. CRIT is a feature-rich replacement for existing "criu show".
+''This page describes the CRIT Python tool. For the Go library, see [[CRIT (Go library)]]''.
+CRiu Image Tool is a feature-rich replacement for existing "criu show".
 It is written completely in Python, so it is quite easy to read the code and extend its features.
 == Usage ==
 <pre>
-usage: crit [-h] [-i IN] [-o OUT] [--pretty] {decode,encode}
+usage: crit [-h] {decode,encode,info,x,show} ...
 CRiu Image Tool
 positional arguments:
-   {decode,encode}       decode/encode - convert criu image from/to binary type
+   {decode,encode,info,x,show}
-                        to/from json
+                        Use crit CMD --help for command-specific help
+    decode              convert criu image from binary type to json
+    encode              convert criu image from json type to binary
+    info                show info about image
+    x                   explore image dir
+    show                convert criu image from binary to human-readable json
 optional arguments:
    -h, --help            show this help message and exit
-  -i IN, --in IN        input file (stdin by default)
-  -o OUT, --out OUT     output file (stdout by default)
-  --pretty              multi-line with indentation and some fields printed in more human-readable format
 </pre>
 === Pretty output ===
-By default CRIT prints JSON text in one line. This can be read by any further JSON-aware tool for parsing. For human eyes it's more convenient to read JSON multi-line with indentation. However, CRIT does a little bit more and prints some fields in even more pretty manner.
+<code>crit decode</code> prints JSON text in one line. This can be read by any further JSON-aware tool for parsing. For human eyes it's more convenient to read JSON multi-line with indentation. CRIT can do this when using the <code>show</code> action or the <code>--pretty</code> option.
+Wend doing pretty optput CRIT does a little bit more, than just multiline indented JSON.
 ; Addresses and registers
@@ Line 32: / Line 38: @@
 : By default those a printed in decimal, but the "1.2.3.4" for v4 or "::1" for v6 can be seen in the --pretty mode.
-==== TODO ====
+; Symbolic names for flags
+: Some known bit sets (e.g. MAP_PRIVATE, MAP_ANONYMOUS, etc. for vma->flags) are shown with names.
-; Symbolic names for flags
+; Device numbers
-: Some known bits (e.g. MAP_PRIVATE, MAP_ANONYMOUS, etc. for vma->flags) can be shown with names.
+: If the field is known to be of <code>dev_t</code> type, it's printed in the <code>major:minor</code> manner
 == Functionality ==
-=== Convert images to JSON and back ===
+=== Convert images from IMG to JSON ===
-{{Status|ready}}
-This is the replacement for (rather nasty) criu show code. Also this is the way to edit the images before restoring from them.
+<code>crit decode</code> is the replacement for the (rather nasty) <code>criu show</code> code. This is also the way to edit the images before restoring from them.
 It uses [https://developers.google.com/protocol-buffers/docs/reference/python/google.protobuf.text_format-module text_format] as a human-readable format for protobuf messages.
@@ Line 409: / Line 415: @@
 </div>
 </div>
+Decode also supports input via STDIN instead of the "-i" flag.
+<pre>
+cat "core-5679.img" | crit decode
+</pre>
+=== Convert images from JSON to IMG ===
+<code>crit encode</code> converts the image from JSON to IMG. Standard usage would look like:
+<pre>
+crit encode -i core-5679.json -o core-5679.img
+</pre>
+Encode also supports input via STDIN instead of the "-i" flag.
+<pre>
+cat "core-5679.json" | crit encode
+</pre>
+Incase a "-o" flag is not specified the input is piped out to STDOUT.
 === Generate core files out of task images ===
-{{Status|ready}}
+Moved into separate project called [[criu-coredump]].
-Moved into separate project called [[criu-coredump]].
+=== Show images statistics ===
+<code>crit x</code> allows you to explore image statistics.
+E.g. Total number of processes, files, memory, sockets, etc.
+<pre>
+crit x $directory_with_images <explore type>
+</pre>
+Supported explorers are
+;'ps'
+:to show process tree
-=== On-the-fly conversion ===
+;'fds'
+:to show files used by tasks
-{{Status|not ready}}
+;'mems'
+:to show memory mappings info
-There's an idea to make CRIU spawn CRIT and read images "through" it, to allow for at-the-restore-time modifications
+=== Show images Info ===
-=== Convert between different image versions ===
+Image of a info such as its "COUNT" and "MAGIC" can be displayed using the INFO command.
+<div class="toccolours mw-collapsible mw-collapsed" style="width:800px">
+<b>Example("crit info core-5679.img")</b>
+<div class="mw-collapsible-content">
+<pre>
+{
+    "count": 1,
+    "magic": "CORE"
+}
+</pre>
+</div>
+</div>
-{{Status|not ready}}
+== Planned functionality ==
-Right now we store the images version in inventory.img and collect info about [[what's bad with V1 images]]. If some day we have v2, CRIT will convert from v1. And for backward compatibility we'll use on-the-fly conversion when restoring from old images.
+=== On-the-fly conversion ===
-=== Show images statistics ===
+There's an idea to make CRIU spawn CRIT and read images "through" it, to allow for at-the-restore-time modifications. For details, see https://github.com/checkpoint-restore/criu/issues/59.
-{{Status|not ready}}
+=== Convert between different image versions ===
-E.g. -- total number of processes, files, memory, sockets, etc.
+Right now we store the images version in inventory.img and collect info about [[what's bad with V1 images]]. If some day we have v2, CRIT will convert from v1. And for backward compatibility we'll use on-the-fly conversion when restoring from old images.
 === Check/validate images ===
-{{Status|not ready}}
 Check that
 * all images are present
 * the inter-images IDs are in consistent state
+For details, see https://github.com/checkpoint-restore/criu/issues/44.
+=== [[Anonymize image files]] ===
+Since images contain raw memory dumps people may refuse to send us images for debugging. Need to anonymize them, i.e. -- remove this sensitive information.
 [[Category:Images]]
 [[Category:API]]