This matches the semantics the original hush code obtained by using the SA_RESTART flag when installing signal handlers, and avoids error messages about waitpid being interrupted.
The sigprocmask implementation in GNO 2.0.6 libc has bugs that cause it to never actually unblock signals that have been blocked. This was causing many signals to remain blocked when they shouldn't be, particularly after running signal handlers.
This problem combined with a kernel issue (wait() calls won't recognize that a child has finished if SIGCHLD is blocked) to cause hangs in certain conditions.
This patch works around these issues by defining our own non-buggy version of sigprocmask in place of libc's.
I think this problem is probably due to a bug in GNO's implementation of select().
The workaround is not to use poll (which calls select) when reading a key with no timeout (which is the normal case for command-line input).
The only substantive change is about when simple line input mode is used.
I also bumped the version number and included a GNO-version-specific component.
The problem seemed to be that it crashes if the t_intrc special character is set to -1 on a pty. I worked around this by setting it to an obscure control character instead in that case.
In vi-mode lineedit tries to detect some escape sequences.
After the ESC it reads the next character to check for certain
values. This read should have a timeout or a user-entered ESC to
switch to command mode doesn't properly handle the next character.
Signed-off-by: Ron Yorston <rmy@tigress.co.uk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The support for OA-left/right on GNO uses the OA2META ioctl option to map OA-x to ESC x.
VT100-type terminal emulators have significant variations in what modifier combinations they'll pass through and what escape sequences they produce. Hopefully at least one of them works on just about everything.
This was broken by the change to using CRMOD mode, which actually does mapping on input as well as output. The fix is to set the terminal to "vt100 arrow" mode, which is an undocumented option that translates arrows to vt100-style escape sequences (also used by gsh).
(Note that the earlier patch actually makes us use CRMOD mode most of the time, not non-CRMOD mode as the summary erroneously says.)
This is important because CRMOD mode prevents text from backgrounded programs from being printed properly. It also leaves the terminal in an inappropriate state if hush crashes or is killed.
For the time being, we still switch briefly to CRMOD mode when we want to print just a CR.
This is done by adding new memory allocation routines that use the current process's userID, so the memory will be deallocated when it quits or execs, even if it's a forked child process.
We do this by maintaining a mask (for each pid) giving the fds to be closed on exec. We wrap functions that close fds so that their close-on-exec bits can be cleared at that point.
This implementation may close the fds even if the execve operation ultimately fails.
Also, fix issue where callers of getopt32() weren't properly detecting errors on GNO due to a size mismatch.
This avoids strange behavior when commands using getopt32 (like export) are invoked multiple times, sometimes with invalid arguments.
This avoids a problem where one of the SIGALRM signals could be delivered after the original SIGALRM handler was restored, which would normally cause the process to terminate.
For now, we just rely on polling in a loop to determine when the child is done. This isn't optimal, but should be OK. If procsend() worked, we could use that in the child to signal the parent. However, procsend() is broken in GNO 2.0.6 -- it seems that it actually tries to invoke the send() call for sockets, but with the wrong arguments, leading to a crash.
Busybox already uses sendfile in httpd. This patch proposes to use it
globally to copy data between file descriptors.
It speeds up the copying on slow systems a lot - below are the times needed
to copy a 450Mb file with and without this option enabled on a BeagleBone
Black:
sendfile:
user 0m0.000s
sys 0m8.170s
read/write 4k:
user 0m0.470s
sys 0m16.300s
function old new delta
bb_full_fd_action 394 474 +80
Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Sometimes ARG_MAX is small (like 32k) yet sysconf(_SC_ARG_MAX)
is big, and people prefer using the bigger value.
OTOH, with sufficiently large ARG_MAX, further wins from
sysconf(_SC_ARG_MAX) being bigger are exponentially smaller:
you can see 4 times fewer fork+execs when you run find, but
when each execed process already takes a thousand parameters
it's likely execution time is dominated by what that process
does with each parameter.
Thus, with this change ARG_MAX is used if it's sufficiently big,
otherwise sysconf(_SC_ARG_MAX) is used.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
*Most significantly, we avoid using setpgid(), because it doesn't work and in fact corrupts the kernel's process group table.
*Also, work around tctpgrp() returning garbage instead of 0 on success.
This adds an implementation of tcsetpgrp that works by reading the process tables to find a process in the appropriate group. This isn't used for the main job control operations, though, since it might be relatively slow.
At this point, basic job control seems to work.
* Push/pop environment to make sure it is isolated from our parents and children.
* Make all environment vars (and shell vars) case-insensitive, consistent with GNO's internal handling of environment vars.
* Wrap putenv and unsetenv to make sure they are called with lower-case variable names, which is necessary to maintain consistency between the environ array and the kernel's internal representation of variables.
This should avoid strange behavior due to races when the parent has resumed but the child is still running the exec* code in libc, which mainly manifests itself when running at low speed.
We also change to signaling the child's completion with SIGALRM, and setting an extra alarm in the parent in case the child doesn't actually do it.
