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Display memory mapped files for processes#7

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propertone merged 6 commits intodeshaw:mainfrom
herbierand:memory-maps
Oct 14, 2025
Merged

Display memory mapped files for processes#7
propertone merged 6 commits intodeshaw:mainfrom
herbierand:memory-maps

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@herbierand herbierand commented Sep 13, 2025

Resolves #4.

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If you compare the output of procfd and lsof for memory maps, procfd includes an extra entry for the executable. Is there a way to make them match? Also, I don't think it's correct to include mmaps for --type=path, it should be a separate filter.

herbierand
herbierand commented Sep 14, 2025
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herbierand commented Sep 14, 2025

Example of inspecting a bash process with procfd:

$ ./target/debug/procfd -p 252759
 PID    | User | Name | Type | FD  | Target
--------+------+------+------+-----+-----------------------------------------------------
 252759 | rand | bash | path | 0   | /dev/pts/1
 252759 | rand | bash | path | 1   | /dev/pts/1
 252759 | rand | bash | path | 2   | /dev/pts/1
 252759 | rand | bash | path | 255 | /dev/pts/1
 252759 | rand | bash | exe  |     | /usr/bin/bash
 252759 | rand | bash | cwd  |     | /home/rand/oss/procfd
 252759 | rand | bash | root |     | /
 252759 | rand | bash | mmap |     | /usr/lib/locale/locale-archive
 252759 | rand | bash | mmap |     | /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
 252759 | rand | bash | mmap |     | /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
 252759 | rand | bash | mmap |     | /usr/lib/x86_64-linux-gnu/libc.so.6
 252759 | rand | bash | mmap |     | /usr/lib/x86_64-linux-gnu/libtinfo.so.6.4

Inspecting the same process with lsof:

$ lsof -p 252759
COMMAND    PID USER  FD   TYPE DEVICE SIZE/OFF     NODE NAME
bash    252759 rand cwd    DIR  259,7     4096  2930887 /home/rand/oss/procfd
bash    252759 rand rtd    DIR  259,7     4096        2 /
bash    252759 rand txt    REG  259,7  1380656 11666857 /usr/bin/bash
bash    252759 rand mem    REG  259,7  3063024 11670577 /usr/lib/locale/locale-archive
bash    252759 rand mem    REG  259,7  2003408 11678163 /usr/lib/x86_64-linux-gnu/libc.so.6
bash    252759 rand mem    REG  259,7   204088 11668749 /usr/lib/x86_64-linux-gnu/libtinfo.so.6.4
bash    252759 rand mem    REG  259,7    27028 11678152 /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
bash    252759 rand mem    REG  259,7   225600 11678160 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
bash    252759 rand   0u   CHR  136,1      0t0        4 /dev/pts/1
bash    252759 rand   1u   CHR  136,1      0t0        4 /dev/pts/1
bash    252759 rand   2u   CHR  136,1      0t0        4 /dev/pts/1
bash    252759 rand 255u   CHR  136,1      0t0        4 /dev/pts/1

Filtering with --type mmap:

$ ./target/debug/procfd -p 252759 --type mmap
 PID    | User | Name | Type | FD | Target
--------+------+------+------+----+-----------------------------------------------------
 252759 | rand | bash | mmap |    | /usr/lib/locale/locale-archive
 252759 | rand | bash | mmap |    | /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
 252759 | rand | bash | mmap |    | /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
 252759 | rand | bash | mmap |    | /usr/lib/x86_64-linux-gnu/libc.so.6
 252759 | rand | bash | mmap |    | /usr/lib/x86_64-linux-gnu/libtinfo.so.6.4

Grepping for mem with lsof:

$ lsof -p 252759 | grep mem
bash    252759 rand mem    REG  259,7  3063024 11670577 /usr/lib/locale/locale-archive
bash    252759 rand mem    REG  259,7  2003408 11678163 /usr/lib/x86_64-linux-gnu/libc.so.6
bash    252759 rand mem    REG  259,7   204088 11668749 /usr/lib/x86_64-linux-gnu/libtinfo.so.6.4
bash    252759 rand mem    REG  259,7    27028 11678152 /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
bash    252759 rand mem    REG  259,7   225600 11678160 /usr/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2

@propertone propertone requested a review from Copilot September 20, 2025 21:56
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Pull Request Overview

This PR adds support for displaying memory-mapped files for processes by implementing a new "mmap" file descriptor type. This enhancement allows users to view which files are memory-mapped by each process, providing additional insight into process resource usage.

  • Adds MMap variant to FDType and FDTarget enums
  • Implements memory map querying and filtering functionality
  • Excludes process executables from memory map results to avoid duplication

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propertone
propertone requested changes Sep 20, 2025
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herbierand
herbierand commented Sep 21, 2025
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@propertone propertone merged commit 7393434 into deshaw:main Oct 14, 2025
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Show memory maps

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