Public bug reported:
Using uutils `chmod -R` with an invalid mode will spam standard error
with duplicate diagnostics.
Using `strace` to inject a successful return value from ioctl, so that
it the pipe into `wc` is treated as a terminal, we can see 31504 lines
are emitted to standard error:
```
$ lsb_release -rd
Description: Ubuntu 26.10
Release: 26.10
$ chmod --version
chmod (uutils coreutils) 0.12.0
$ strace -e inject=ioctl:retval=0 -o /dev/null chmod -R invalid
/home/collin/coreutils/ 2>&1 | wc -l
31504
```
It seems the warning is printed for every visited file:
```
$ strace -e inject=ioctl:retval=0 -o /dev/null chmod -R invalid
/home/collin/coreutils/ 2>&1 | grep -F 'Help' | wc -l
3938
$ find /home/collin/coreutils | wc -l
3938
```
This also means that uutils `chmod` can take an unreasonably long time
to execute, depending on the number of files visited. Here are the
results from a minimal Docker image:
```
$ time chmod -R invalid /
[...]
real 0m4.364s
user 0m1.264s
sys 0m2.514s
$ strace -c chmod -R invalid /
[...]
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ------------------
50.44 5.548258 9 615432 write
19.83 2.181529 10 211320 218 statx
10.14 1.115335 5 205144 umask
8.50 0.935452 9 102582 newfstatat
6.07 0.667635 6 102574 ioctl
1.94 0.213929 10 20560 getdents64
1.18 0.129649 12 10271 8 openat
0.76 0.083392 8 10263 close
0.60 0.066164 6 10262 fstat
0.53 0.058565 5 10252 lseek
0.00 0.000170 6 27 read
0.00 0.000056 9 6 brk
0.00 0.000034 3 9 rt_sigaction
0.00 0.000022 22 1 munmap
0.00 0.000019 19 1 readlink
0.00 0.000018 6 3 sigaltstack
0.00 0.000017 5 3 fcntl
0.00 0.000014 0 52 mmap
0.00 0.000014 1 13 mprotect
0.00 0.000010 5 2 2 access
0.00 0.000008 8 1 poll
0.00 0.000007 7 1 sched_getaffinity
0.00 0.000006 3 2 prlimit64
0.00 0.000005 5 1 gettid
0.00 0.000002 1 2 rt_sigprocmask
0.00 0.000001 0 3 getrandom
0.00 0.000000 0 1 execve
0.00 0.000000 0 2 1 statfs
0.00 0.000000 0 1 arch_prctl
0.00 0.000000 0 1 set_tid_address
0.00 0.000000 0 1 set_robust_list
0.00 0.000000 0 1 rseq
------ ----------- ----------- --------- --------- ------------------
100.00 11.000311 8 1298794 229 total
```
In this case, GNU coreutils properly realizes there is nothing to do and
simply exits:
```
$ time gnuchmod -R invalid /
gnuchmod: invalid mode: 'invalid'
Try 'gnuchmod --help' for more information.
real 0m0.006s
user 0m0.000s
sys 0m0.002s
$ strace -c gnuchmod -R invalid /
gnuchmod: invalid mode: 'invalid'
Try 'gnuchmod --help' for more information.
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
55.00 0.000253 253 1 execve
11.74 0.000054 6 8 mmap
5.43 0.000025 6 4 write
4.57 0.000021 7 3 mprotect
3.70 0.000017 4 4 close
3.48 0.000016 8 2 openat
2.83 0.000013 4 3 brk
2.83 0.000013 6 2 newfstatat
1.74 0.000008 4 2 fstat
1.74 0.000008 4 2 getrandom
1.09 0.000005 5 1 1 access
0.87 0.000004 4 1 read
0.87 0.000004 4 1 fcntl
0.87 0.000004 4 1 set_tid_address
0.87 0.000004 4 1 set_robust_list
0.87 0.000004 4 1 prlimit64
0.87 0.000004 4 1 rseq
0.65 0.000003 3 1 arch_prctl
------ ----------- ----------- --------- --------- ----------------
100.00 0.000460 11 39 1 total
```
** Affects: rust-coreutils (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2170507
Title:
uutils `chmod -R` with an invalid mode spams standard error
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