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author | Denys Vlasenko <vda.linux@googlemail.com> | 2016-08-19 21:22:45 +0300 |
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committer | Denys Vlasenko <vda.linux@googlemail.com> | 2016-08-19 21:24:49 +0300 |
commit | ca26f1c238c51b3b2f80dd25fd7fcf8774f38ca4 (patch) | |
tree | 77765ce82ef68797ff53fb0efede7ff45bd2b932 /modutils | |
parent | 8191abd146989652ce376f0e36c5e1adbea99fe1 (diff) |
hush: fix a bug with "stdio rewind on exit". Closes 9186
With FEATURE_SH_STANDALONE=y, run this in a "sh SCRIPT":
sha256sum /dev/null
echo END
sha256sum is a NOEXEC applet. It runs in a forked child. Then child exit()s.
By this time, entire script is read, and buffered in a FILE object
from fopen("SCRIPT"). But fgetc() did not consume entire input.
exit() lseeks back by -9 bytes, from <eof> to 'e' in 'echo'.
(this may be libc-specific).
This change of fd position *is shared with the parent*!
Now parent can read more, and it thinks there is another "echo END".
End result: two "echo END"s are run.
`cmd` and arithmetic also need the fix for this, even without
FEATURE_SH_STANDALONE.
Fix this by _exit()ing instead.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'modutils')
0 files changed, 0 insertions, 0 deletions