busybox/shell/ash_test/ash-redir/redir_script.tests
Denys Vlasenko 41ef41b3e0 hush: fix nested redirects colliding with script fds
This necessitates switch from libc FILE api to a simple
homegrown replacement.
The change which fixes the bug here is the deleting of

	restore_redirected_FILEs();

line. It was prematurely moving (restoring) script fd#3.
The fix is: we don't even _want_ to restore scrit fds,
we are perfectly fine with them being moved.
The only reason we tried to restore them is that FILE api
did not allow moving of FILE->fd.

function                                             old     new   delta
refill_HFILE_and_getc                                  -      93     +93
hfopen                                                 -      90     +90
hfclose                                                -      66     +66
pseudo_exec_argv                                     591     597      +6
hush_main                                           1089    1095      +6
builtin_source                                       209     214      +5
save_fd_on_redirect                                  197     200      +3
setup_redirects                                      320     321      +1
fgetc_interactive                                    235     236      +1
i_peek_and_eat_bkslash_nl                             99      97      -2
expand_vars_to_list                                 1103    1100      -3
restore_redirects                                     99      52     -47
fclose_and_forget                                     57       -     -57
remember_FILE                                         63       -     -63
------------------------------------------------------------------------------
(add/remove: 3/2 grow/shrink: 6/3 up/down: 271/-172)           Total: 99 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2018-07-24 16:54:41 +02:00

39 lines
1.1 KiB
Plaintext
Executable File

# Builds a " 3>&- 4>&-" string.
# Note: one of these fds is a directory opened to /proc/self/fd
# for globbing. It is unwanted, but I don't know how to filter it out.
find_fds() {
fds=""
for f in /proc/self/fd/*; do
test "$f" = "/proc/self/fd/0" && continue
test "$f" = "/proc/self/fd/1" && continue
test "$f" = "/proc/self/fd/2" && continue
fds="$fds ${f##*/}>&-"
done
}
find_fds
fds1="$fds"
# One of the fds is open to the script body
# Close it while executing something.
eval "find_fds $fds"
# Shell should not lose that fd. Did it?
find_fds
test x"$fds1" = x"$fds" \
&& { echo "Ok: script fd is not closed"; exit 0; }
# One legit way to handle it is to move script fd. For example, if we see that fd 10 moved to fd 11:
test x"$fds1" = x" 10>&- 3>&-" && \
test x"$fds" = x" 11>&- 3>&-" \
&& { echo "Ok: script fd is not closed"; exit 0; }
# or we see that fd 3 moved to fd 10:
test x"$fds1" = x" 3>&- 4>&-" && \
test x"$fds" = x" 10>&- 3>&-" \
&& { echo "Ok: script fd is not closed"; exit 0; }
echo "Bug: script fd is closed"
echo "fds1:$fds1"
echo "fds2:$fds"
exit 1