tac: use temp file for stdin to respect TMPDIR and handle disk-full errors#10094
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ChrisDryden
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Promise I'm not just rebasing for the sake of rebasing, all of the ones I've rebased right now all have merge conflicts that I'm sorting out |
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| curl -L ${repo}/raw/refs/heads/master/tests/runcon/runcon-compute.sh > tests/runcon/runcon-compute.sh | ||
| curl -L ${repo}/raw/refs/heads/master/tests/tac/tac-continue.sh > tests/tac/tac-continue.sh | ||
| # Add tac-continue.sh to root tests (it requires root to mount tmpfs) | ||
| sed -i 's|tests/split/l-chunk-root.sh.*|tests/split/l-chunk-root.sh\t\t\t\\\n tests/tac/tac-continue.sh\t\t\t\\|' tests/local.mk |
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sed -i does not work on macOS. So I changed it to -i.bak at #10201
DarthStrom
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tac memory-mapped regular files. If another process truncated such a file while it was mapped (e.g. during log rotation), accessing the now-invalid pages raised SIGBUS and killed the process. Read regular files into memory up front instead, so a concurrent truncation can no longer crash tac. The stdin path had the same hole by a different route: `tac < file` mapped the raw stdin fd -- the caller's regular file -- directly. Remove that direct-stdin mmap and always route stdin through a process-owned temp file (already used to bound memory on large stdin, see uutils#10094). The temp file is created unlinked, so no other process can truncate it and mapping it stays sound. Adds regression tests that truncate a file mid-read, via both an argument and stdin redirection, and assert tac is not killed by a signal. Fixes uutils#9748 Co-authored-by: easonysliu <easonysliu@tencent.com> Co-authored-by: Charlie Tonneslan <cst0520@gmail.com>
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tac memory-mapped regular files. If another process truncated such a file while it was mapped (e.g. during log rotation), accessing the now-invalid pages raised SIGBUS and killed the process. Read regular files into memory up front instead, so a concurrent truncation can no longer crash tac. The stdin path had the same hole by a different route: `tac < file` mapped the raw stdin fd -- the caller's regular file -- directly. Remove that direct-stdin mmap and always route stdin through a process-owned temp file (already used to bound memory on large stdin, see uutils#10094). The temp file is created unlinked, so no other process can truncate it and mapping it stays sound. Adds regression tests that truncate a file mid-read, via both an argument and stdin redirection, and assert tac is not killed by a signal. Fixes uutils#9748 Co-authored-by: easonysliu <easonysliu@tencent.com> Co-authored-by: Charlie Tonneslan <cst0520@gmail.com>
DarthStrom
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Jul 3, 2026
tac memory-mapped regular files. If another process truncated such a file while it was mapped (e.g. during log rotation), accessing the now-invalid pages raised SIGBUS and killed the process. Read regular files into memory up front instead, so a concurrent truncation can no longer crash tac. The stdin path had the same hole by a different route: `tac < file` mapped the raw stdin fd -- the caller's regular file -- directly. Remove that direct-stdin mmap and always route stdin through a process-owned temp file (already used to bound memory on large stdin, see uutils#10094). The temp file is created unlinked, so no other process can truncate it and mapping it stays sound. Adds regression tests that truncate a file mid-read, via both an argument and stdin redirection, and assert tac is not killed by a signal. Fixes uutils#9748 Co-authored-by: easonysliu <easonysliu@tencent.com> Co-authored-by: Charlie Tonneslan <cst0520@gmail.com>
DarthStrom
added a commit
to DarthStrom/coreutils
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Jul 3, 2026
tac memory-mapped regular files. If another process truncated such a file while it was mapped (e.g. during log rotation), accessing the now-invalid pages raised SIGBUS and killed the process. Read regular files into memory up front instead, so a concurrent truncation can no longer crash tac. The stdin path had the same hole by a different route: `tac < file` mapped the raw stdin fd -- the caller's regular file -- directly. Remove that direct-stdin mmap and always route stdin through a process-owned temp file (already used to bound memory on large stdin, see uutils#10094). The temp file is created unlinked, so no other process can truncate it and mapping it stays sound. Adds regression tests that truncate a file mid-read, via both an argument and stdin redirection, and assert tac is not killed by a signal. Fixes uutils#9748 Co-authored-by: easonysliu <easonysliu@tencent.com> Co-authored-by: Charlie Tonneslan <cst0520@gmail.com>
DarthStrom
added a commit
to DarthStrom/coreutils
that referenced
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Jul 3, 2026
tac memory-mapped regular files. If another process truncated such a file while it was mapped (e.g. during log rotation), accessing the now-invalid pages raised SIGBUS and killed the process. Read regular files into memory up front instead, so a concurrent truncation can no longer crash tac. The stdin path had the same hole by a different route: `tac < file` mapped the raw stdin fd -- the caller's regular file -- directly. Remove that direct-stdin mmap and always route stdin through a process-owned temp file (already used to bound memory on large stdin, see uutils#10094). The temp file is created unlinked, so no other process can truncate it and mapping it stays sound. Adds regression tests that truncate a file mid-read, via both an argument and stdin redirection, and assert tac is not killed by a signal. Fixes uutils#9748 Co-authored-by: easonysliu <easonysliu@tencent.com> Co-authored-by: Charlie Tonneslan <cst0520@gmail.com>
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The tac-continue test used to rely on having an accessible TMP_DIR, the test was changed and now it was updated to be more flexible. Ultimately the functionality of tac in our implementation compared to the GNU implementation was just different from the context that the stdin is buffered to a TMP_DIR in the GNU implementation and not in the uutils implementation. This can cause issues with large STDIN because it will always max out the memory and timeout instead of erroring and it takes up significantly more memory.