getpmsg - Linux
Overview
The getpmsg command is a Linux utility that retrieves and displays Protocol Message Buffers (Protobuf) data from a page cache. It is commonly used for debugging or maintenance purposes, particularly in the context of network communications or message processing systems.
Syntax
getpmsg [options] <page cache file>
Options/Flags
| Option | Description | Default |
|—|—|—|
| -a, –all | Display all available pages, even those that are not currently allocated. | false |
| -H, –hex | Display the data in hexadecimal format. | false |
| -j, –json | Display the data in JSON format. | false |
| -m, –message | Only display protobuf messages. | false |
| -p, –page | Specify the page number to retrieve. | -1 (all) |
| -r, –raw | Display the data in raw binary format. | false |
Examples
Example 1: Display all pages in a page cache file
getpmsg -a <page cache file>
Example 2: Display the first protobuf message in hexadecimal format
getpmsg -m -H -p 0 <page cache file>
Common Issues
- Cannot find page cache file: Ensure that the specified file exists and has read permissions.
- Protobuf decoding error: Verify that the protobuf message is valid and uses a supported encoding.
- Page number out of range: Specify a valid page number within the page cache file.
Integration
getpmsg can be combined with other Linux commands for advanced tasks:
- Use
grepto filter the output:getpmsg <page cache file> | grep "field_name" - Extract protobuf messages from a dump file:
binwalk -e <dump file> | getpmsg