fix: replace subprocess which with shutil.which() in Process.exists()#524
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kimocoder merged 2 commits intoJun 3, 2026
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…or precedence bug `not stdout == stderr == ''` is evaluated as `not (stdout == stderr == '')` which returns True when stderr is non-empty (e.g. "service not found"), causing wifite to believe the tool exists and then crash with FileNotFoundError. Replace with `bool(stdout)` — which is non-empty only when `which` actually found the binary. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The previous approach shelled out to the `which` binary via Popen, which has three problems: - `which` is not present on all systems (Alpine, minimal Docker images), causing an unhandled FileNotFoundError on every exists() call - any non-path text on stdout (e.g. zsh built-in printing "foo not found" to stdout) produced a false positive - spawning a subprocess for a PATH lookup is unnecessary overhead shutil is already imported and shutil.which() is already used by _resolve_tool() in the same class, as well as system_check.py and dependency.py. Using it here is consistent and correct on all platforms.
vlkumiloslearning
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Summary
Process.exists()inwifite/util/process.pyshelled out to thewhichbinary viaPopento check if a tool is installed. This had three problems:1. Operator precedence bug (original crash)
Evaluated as
not (stdout == stderr == ''). Whenwhich servicefails, stdout is''but stderr is'service not found'— so the chain returnsFalse,not False→True, and wifite crashes trying to exec a missing binary.2. Fragile on minimal systems
whichis not present on Alpine, minimal Docker images, or some chroots.Popen(['which', ...])raises an unhandledFileNotFoundError, crashing everyexists()call site.3. Inconsistent with the rest of the codebase
shutilis already imported in this file._resolve_tool()in the same class usesshutil.which(). So doessystem_check.pyanddependency.py. The subprocess approach was the only outlier.Fix
Replace the entire subprocess block with a single in-process call:
This is correct, portable, and consistent with every other tool-detection pattern in the codebase.
Test plan
wifite --killon a system whereserviceis not installed (e.g. Arch Linux) — should no longer crashaircrack-ng,tshark, etc.)Falsecorrectly