From ebada311aaf6393b027f9b12ae835626dea6762c Mon Sep 17 00:00:00 2001 From: Ethan Pini Date: Sat, 27 Jun 2026 20:19:23 -0700 Subject: [PATCH 2/3] add regression test for pipe capacity behavior on Mac --- Makefile.in | 8 ++- support/Makefile.in | 2 +- support/fillpipekva.c | 140 ++++++++++++++++++++++++++++++++++++++++++ tests/heredoc.right | 10 ++- tests/heredoc.tests | 3 + tests/heredoc11.sub | 43 +++++++++++++ 6 files changed, 202 insertions(+), 4 deletions(-) create mode 100644 support/fillpipekva.c create mode 100644 tests/heredoc11.sub diff --git a/Makefile.in b/Makefile.in index c4a882f7..a55a540e 100644 --- a/Makefile.in +++ b/Makefile.in @@ -595,9 +595,10 @@ PO_DIR = $(dot)/po/ SUPPORT_SRC = $(srcdir)/support/ SUPPORT_DIR = $(dot)/support -TESTS_SUPPORT = recho$(EXEEXT) zecho$(EXEEXT) printenv$(EXEEXT) xcase$(EXEEXT) +TESTS_SUPPORT = recho$(EXEEXT) zecho$(EXEEXT) printenv$(EXEEXT) xcase$(EXEEXT) \ + fillpipekva$(EXEEXT) CREATED_SUPPORT = signames.h recho$(EXEEXT) zecho$(EXEEXT) printenv$(EXEEXT) \ - tests/recho$(EXEEXT) tests/zecho$(EXEEXT) \ + tests/recho$(EXEEXT) tests/zecho$(EXEEXT) tests/fillpipekva$(EXEEXT) \ tests/printenv$(EXEEXT) xcase$(EXEEXT) tests/xcase$(EXEEXT) \ mksignames$(EXEEXT) lsignames.h \ mksyntax${EXEEXT} syntax.c $(VERSPROG) $(VERSOBJ) \ @@ -1076,6 +1077,9 @@ printenv$(EXEEXT): $(SUPPORT_SRC)printenv.c xcase$(EXEEXT): $(SUPPORT_SRC)xcase.c @$(CC_FOR_BUILD) $(CCFLAGS_FOR_BUILD) ${LDFLAGS_FOR_BUILD} -o $@ $(SUPPORT_SRC)xcase.c ${LIBS_FOR_BUILD} +fillpipekva$(EXEEXT): $(SUPPORT_SRC)fillpipekva.c + @$(CC_FOR_BUILD) $(CCFLAGS_FOR_BUILD) ${LDFLAGS_FOR_BUILD} -o $@ $(SUPPORT_SRC)fillpipekva.c ${LIBS_FOR_BUILD} + test tests check: force $(Program) $(TESTS_SUPPORT) @-test -d tests || mkdir tests @cp $(TESTS_SUPPORT) tests diff --git a/support/Makefile.in b/support/Makefile.in index 28fa610e..4dc9a502 100644 --- a/support/Makefile.in +++ b/support/Makefile.in @@ -2,7 +2,7 @@ # Simple Makefile for the support programs. # # documentation support: man2html -# testing support: printenv recho zecho xcase +# testing support: printenv recho zecho xcase fillpipekva # # bashbug.sh lives here (created by configure), but bashbug is created by # the top-level makefile diff --git a/support/fillpipekva.c b/support/fillpipekva.c new file mode 100644 index 00000000..327e1b71 --- /dev/null +++ b/support/fillpipekva.c @@ -0,0 +1,140 @@ +/* fillpipekva.c -- push amountpipekva past maxpipekva on macOS. */ + +/* Copyright (C) 2026 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see . +*/ + +#ifdef MACOSX +#include +#include +#include +#include +#include +#include + +/* Defined in apple-oss-distributions/xnu @ ff8ca1ea. + bsd/sys/pipe.h:74 -- `#define PIPE_SIZE 16384` + bsd/kern/sys_pipe.c:307 -- `PIPE_SIZE * 4` + */ +#define XNU_PIPESIZE_BLOCKS_MAX (1024*64) + +/* Defined in apple-oss-distributions/xnu @ ff8ca1ea. + bsd/sys/pipe.h:77 -- `#define PIPE_KVAMAX (1024 * 1024 * 16)` + */ +#define XNU_PIPE_KVAMAX (1024*1024*16) + +#define PIPES_NEEDED ((XNU_PIPE_KVAMAX / XNU_PIPESIZE_BLOCKS_MAX) + 1) +#define FDS_NEEDED (PIPES_NEEDED * 2) + +int +set_nonblock (int fd) +{ + int fl; + fl = fcntl (fd, F_GETFL, 0); + if (fl < 0) + { + return fl; + } + + return fcntl (fd, F_SETFL, fl | O_NONBLOCK); +} + +int +main (int argc, char **argv) +{ + char* buf; + int* fds; + size_t nw; + size_t nw_total; + ssize_t remains; + int npipes, nfds; + int pipefds[2]; + + buf = calloc (XNU_PIPESIZE_BLOCKS_MAX, 1); + if (buf == NULL) + { + printf ("error allocating buffer: %s\n", strerror (errno)); + exit (1); + } + + fds = calloc (FDS_NEEDED, sizeof(int)); + if (fds == NULL) + { + printf ("error allocating buffer: %s\n", strerror (errno)); + exit (1); + } + + printf ("creating %d %d-byte pipes...\n", + PIPES_NEEDED, XNU_PIPESIZE_BLOCKS_MAX); + + for (npipes = 0; npipes < PIPES_NEEDED; npipes++) + { + if (pipe (pipefds) < 0) + { + printf ("could not create more pipes: %s\n", strerror (errno)); + printf ("try increasing descriptor limit via ulimit\n"); + exit (1); + } + + fds[nfds] = pipefds[0]; + fds[nfds+1] = pipefds[1]; + nfds += 2; + + if (set_nonblock(pipefds[1]) < 0) + { + printf ("error setting pipe as nonblocking: %s\n", strerror (errno)); + exit (1); + } + + /* If amountpipekva < maxpipekva, the full 64K will be written. */ + nw = write (pipefds[1], buf, XNU_PIPESIZE_BLOCKS_MAX); + if (nw == XNU_PIPESIZE_BLOCKS_MAX) + { + nw_total += nw; + continue; + } + + /* If not, we have pushed amountpipekva past maxpipekva. */ + printf ("filled with %ld bytes (%d pipes)\n", nw_total, npipes); + + /* Other processes closing pipes can cause amountpipekva to go back + below maxpipekva. Keep trying to fill it until this process is + intentionally interrupted by the user. */ + ssize_t remains = XNU_PIPESIZE_BLOCKS_MAX - nw; + while (remains > 0) + { + nw = write (pipefds[1], buf, remains); + if (nw >= 0) + { + remains -= nw; + } + } + } + + exit (0); +} + + +#else /* ifdef MACOSX */ + +int main() +{ + /* This is only relevant to the XNU kernel's behavior. */ + return 0; +} + +#endif /* ifdef MACOSX */ diff --git a/tests/heredoc.right b/tests/heredoc.right index 214ef520..9935265e 100644 --- a/tests/heredoc.right +++ b/tests/heredoc.right @@ -161,8 +161,16 @@ here-doc line 1 here-doc line 2 here-document here-document +checking 512-byte heredoc for hang +checking 1024-byte heredoc for hang +checking 2048-byte heredoc for hang +checking 4096-byte heredoc for hang +checking 8192-byte heredoc for hang +checking 16384-byte heredoc for hang +checking 65536-byte heredoc for hang +checking 65537-byte heredoc for hang comsub here-string -./heredoc.tests: line 184: warning: here-document at line 181 delimited by end-of-file (wanted `') +./heredoc.tests: line 187: warning: here-document at line 184 delimited by end-of-file (wanted `') hi there '' diff --git a/tests/heredoc.tests b/tests/heredoc.tests index d6431b8a..ef0a7a32 100644 --- a/tests/heredoc.tests +++ b/tests/heredoc.tests @@ -171,6 +171,9 @@ ${THIS_SH} ./heredoc9.sub # test various combinations of here-documents and aliases ${THIS_SH} ./heredoc10.sub +# regression test for bash's interaction with macOS dynamic pipe capacities +${THIS_SH} ./heredoc11.sub + echo $( cat <<< "comsub here-string" ) diff --git a/tests/heredoc11.sub b/tests/heredoc11.sub new file mode 100644 index 00000000..fba1c778 --- /dev/null +++ b/tests/heredoc11.sub @@ -0,0 +1,43 @@ +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# +# Test here documents to ensure they don't hang at various sizes. +# This is a regression test for how bash interacts with macOS's dynamic +# pipe capacities. + +# start background test helper to fill pipekva +(fillpipekva >/dev/null) & +fillpipekva_pid=$! +sleep 1 + +# start background subshell to fail the test after 5 seconds +( + sleep 5 + echo timeout + kill -PIPE $$ &>/dev/null + kill $fillpipekva_pid &>/dev/null +) & +timeout_pid=$! + +# Try writing at every pipesize block (and past it) +# See bsd/kern/sys_pipe.c line 307 at commit ff8ca1ea +# of apple-oss-distributions/xnu for the list of sizes. +for size in 512 1024 2048 4096 8192 16384 65536 65537 +do + echo "checking ${size}-byte heredoc for hang" + cat >/dev/null <<<$(printf "%0$((size-1))d" 0) +done + +# Cleanup +kill $fillpipekva_pid &>/dev/null +kill $timeout_pid &>/dev/null -- 2.49.0