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Martin Vogel
7122298421
Why: arming the hook-augment deadline opens its breadcrumb log with
O_CREAT. The path came from raw getenv("HOME") as
"%s/.cache/codebase-memory-mcp/logs" in 1 KiB buffers with no length
check. A HOME near 1 KiB therefore created a file at the cut-off name
(".../logs/hook-augme") on every hook call, and a longer one created a
cut-off directory. The hook also ignored CBM_CACHE_DIR, which every
other cbm component honours for its cache and logs. The index skip log
had the same defect in its CBM_INDEX_LOG override: an override longer
than 1 KiB was copied in unchecked and opened "wb", which created or
truncated the file at its cut-off prefix and reported that name as the
run's logfile.
Fix: the breadcrumb log now resolves through cbm_resolve_cache_dir()
(CBM_CACHE_DIR, else HOME, else USERPROFILE, plus the default) to
<cache_dir>/logs/hook-augment-timeouts.log. Every snprintf into the
1 KiB buffers is checked, including the one for the CBM_HOOK_TIMEOUT_LOG
override. A path that does not fit means no breadcrumb, and the logs
directory is created only for a path that fits. The hook still exits 0
(it never fails the agent's hook call) and allocates nothing new. The
CBM_INDEX_LOG override gets the same check: an override that does not
fit writes no logfile and warns index.logfile_path_too_long, and the
index still completes. With a normal HOME the log stays where it was.
Proof (dev binary, synthetic roots, isolated CBM_RUNTIME_DIR, no-op
Bash payload on stdin; "created" = find over the synthetic root minus
the pre-made HOME/cache chains):
- 980-byte HOME. Before: exit 0, plus three directories and a file at
the cut-off name <HOME>/.cache/codebase-memory-mcp/logs/hook-augme
(1023 bytes). After: exit 0, nothing created.
- CBM_CACHE_DIR=<root>/cache. Before: the log landed under HOME.
After: <root>/cache/logs/hook-augment-timeouts.log.
- 1000-byte CBM_CACHE_DIR. After: exit 0, nothing created.
- Normal HOME: <HOME>/.cache/codebase-memory-mcp/logs/
hook-augment-timeouts.log before and after.
- 1096-byte CBM_INDEX_LOG via `cli index_repository`. Before: a file
at the 1023-byte cut-off name, reported as the logfile. After: status
indexed, skipped_count 1, no logfile, nothing written.
Tests: RED 3x on the unfixed code for the reasons above, green with
the fix, RED again with the fix reverted:
- cli: cli_hook_augment_log_long_home_creates_no_cut_path,
cli_hook_augment_log_honours_cache_dir, plus the positive control
cli_hook_augment_log_default_location_unchanged (green before and
after).
- index_resilience: index_long_log_override_writes_no_cut_path.
The fixtures sit under link-resolved temp roots: the kernel bounds the
expanded path, so under macOS's /tmp -> /private/tmp link a near-1 KiB
path can be neither created nor probed, and the bug stays hidden.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>