Formerly, return always returned from a function if it was called from a
function, even if there was a closer dot script. This was for compatibility
with the Bourne shell which only allowed returning from functions.
Other modern shells and POSIX return from the function or the dot script,
whichever is closest.
Git 1.8.4's rebase --continue depends on the POSIX behaviour.
Reported by: Christoph Mallon, avg
The change in r238888 was incomplete. It was still possible for a trapped
signal to arrive before the shell went to sleep (sigsuspend()) because a
check was missing or because the signal arrived before in_waitcmd was set.
On SMP, this bug sometimes caused the builtins/wait4.0 test to take 1 second
to execute; it then might or might not fail. On UP, the test almost always
failed.
The erflag argument was only used by old-style (``) command substitutions.
We can remove it and handle the special case in the command substitution
code.
NEOF needs to be a non-null pointer distinct from valid union node pointers.
It is not dereferenced.
The new NEOF is much like SIG_ERR except that it is an object pointer
instead of a function pointer.
The variable tokpushback can now be static.
As per POSIX, a simple command must have at least one redirection,
assignment word or command word.
These occured in rare cases such as eval "f()" .
The extension of allowing no commands inside { }, if, while, for, etc.
remains.
POSIX does not require ++ and -- in arithmetic. It is probably more useful
to reject them than to treat ++x and --x as x silently.
Note that the behaviour of increment and decrement can be obtained via
(x+=1), ((x+=1)-1), (x-=1) and ((x-=1)+1).
PR: bin/176444
If a job is specified to 'wait', wait for it to complete. Formerly, in
interactive mode, the job was deleted if it stopped.
If no jobs are specified in interactive mode, 'wait' still waits for all jobs
to complete or stop.
In non-interactive mode, WUNTRACED is not passed to wait3() so stopped jobs
are not detected.
PR: bin/181435
Replace the RESET blocks with regular functions and a reset() function that
calls them all.
This code generation tool is unusual and does not appear to provide much
benefit. I do not think isolating the knowledge about which modules need to
be reset is worth an almost 500-line build tool and wider scope for
variables used by the reset functions.
Also, relying on reset functions is often wrong: the cleanup should be done
in exception handlers so that no stale state remains after 'command eval'
and the like.
These cleanup operations are not needed because they are already performed
after an optimized command substitution (whether there was an error or not).
Although using -i with -c does not seem very useful, it seems inappropriate
to read commands from the terminal in this case.
Side effect: if the -s -c extension is used and the -s option is turned off
using 'set +s' during the interactive part, the shell now exits after an
error or interrupt. Note that POSIX only specifies -s as option to sh, not
to set.
See also Austin Group issue #718.
This is required by POSIX, at least for pids that are not known child
processes.
Other problems with job specifications still cause wait to abort with
exit status 2.
PR: 176916
This is only part of the PR; the behaviour for unknown/invalid pids/jobs
remains unchanged (aborts the builtin with status 2).
PR: 176916
Submitted by: Vadim Goncharov
The linked list of stack marks may cause problems if the allocation stack is
used between an exception and a higher-level popstackmark(), as it may then
touch a stack mark that is local to a function which has returned.
Also, the adjustment compares to a pointer passed to realloc(), which is
undefined behaviour.
Instead of adjusting stack marks when reallocating stack blocks, ensure that
such an adjustment is never necessary by fixing a small piece of memory in
place at a stack mark. This also simplifies the code.
To avoid the problems reported in bin/175922, it remains necessary to call
setstackmark() after popstackmark() if the stack mark remains in use.
* If read -t times out, return status as if interrupted by SIGALRM
(formerly 1).
* If a trapped signal interrupts read, return status 128+sig (formerly 1).
* If [EINTR] occurs but there is no trap, retry the read (for example
because of a SIGWINCH in interactive mode).
* If a read error occurs, write an error message and return status 2.
As before, a variable assignment error returns 2 and discards the remaining
data read.
Use non-blocking I/O to write as much as the pipe will accept (often 64K,
but it can be as little as 4K), avoiding the need for the ugly PIPESIZE
constant. If PIPESIZE was set too high, a deadlock would occur.
It now passes WARNS=7 with clang on i386.
GCC 4.2.1 does not understand setjmp() properly so will always trigger
-Wuninitialized. I will not add the volatile keywords to suppress this.
In some other shells, things like $((a);(b)) are command substitutions.
Also, there are shells that have an extension ((ARITH)) that evaluates an
arithmetic expression and returns status 1 if the result is zero, 0
otherwise. This extension may lead to ambiguity with two subshells starting
in sequence.
If syntactically invalid job identifiers are to be taken as jobs that exited
with status 127, this should not apply to options, so that we can add
options later if need be.
This ensures 'return' in a trap returns the correct status to the caller.
If evalskip is not set or if it is overridden by a previous evalskip, keep
the old behaviour of restoring the exit status from before the trap.
If a stack mark is set while the current stack block is empty, the stack
block may move later on (because of realloc()) and the stack mark needs to
be updated. This updating does not happen after popstackmark() has been
called; therefore, call setstackmark() again if the stack mark is still
being used.
For some reason, this only affects a few users. I cannot reproduce it. The
situation seems quite rare as well because an empty stack block would
usually be freed (by popstackmark()) before execution reaches a
setstackmark() call.
PR: 175922
Tested by: KT Sin
Now it outputs fixed files, which use constants provided by the C standard
library to determine appropriate values for the target machine.
Before, mksyntax inspected the host machine which resulted in subtle
breakage if e.g. char is signed on the host and unsigned on the target such
as when cross-compiling on x86 for ARM.
Tested using -funsigned-char on amd64. Compiling build-tools without it and
sh itself with it causes various tests to fail without this change but not
with this change. With consistent -funsigned-char, tests pass with or
without this change.
The mksyntax program could be removed and syntax.c and syntax.h committed to
the repository.
Submitted by: Christoph Mallon
MFC after: 2 weeks
ISO/IEC 9899:1999 (E) 5.2.1p3 guarantees that the values of the characters
0123456789 are contiguous.
The generated syntax.c and syntax.h remain the same.
Submitted by: Christoph Mallon
Expand here documents at the same point other redirections are expanded but
use a non-fork subshell environment (like simple command substitutions) for
compatibility. Substitition errors result in an empty here document like
before.
As a result, a fork is avoided for short (<4K) expanded here documents.
Unexpanded here documents (with quoted end marker after <<) are not affected
by this change. They already only forked when >4K.
Side effects:
* Order of expansion is slightly different.
* Slow expansions are not executed in parallel with the redirected command.
* A non-fork subshell environment is subtly different from a forked process.
