Date: Sat, 4 Mar 2017 22:58:35 +0000 (UTC) From: Jilles Tjoelker <jilles@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r314686 - in head/bin/sh: . tests/expansion Message-ID: <201703042258.v24MwZmp017067@repo.freebsd.org>
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Author: jilles Date: Sat Mar 4 22:58:34 2017 New Revision: 314686 URL: https://svnweb.freebsd.org/changeset/base/314686 Log: sh: Fix crash if a -T trap is taken during command substitution. Code like t=$(stat -f %m "$file") segfaulted if -T was active and a trap was taken while the shell was waiting for the child process to finish. What happened was that the dotrap() call in waitforjob() was hit. This re-entered command execution (including expand.c) at a point not expected by expbackq(), and global state (unallocated stack string and argbackq) was corrupted. To fix this, change expbackq() to prepare for command execution to be re-entered. Reported by: bdrewery MFC after: 1 week Added: head/bin/sh/tests/expansion/cmdsubst21.0 (contents, props changed) head/bin/sh/tests/expansion/cmdsubst22.0 (contents, props changed) Modified: head/bin/sh/expand.c head/bin/sh/tests/expansion/Makefile Modified: head/bin/sh/expand.c ============================================================================== --- head/bin/sh/expand.c Sat Mar 4 22:38:10 2017 (r314685) +++ head/bin/sh/expand.c Sat Mar 4 22:58:34 2017 (r314686) @@ -460,7 +460,6 @@ expbackq(union node *cmd, int quoted, in p = grabstackstr(dest); evalbackcmd(cmd, &in); ungrabstackstr(p, dest); - argbackq = saveargbackq; p = in.buf; nnl = 0; @@ -514,12 +513,16 @@ expbackq(union node *cmd, int quoted, in close(in.fd); if (in.buf) ckfree(in.buf); - if (in.jp) + if (in.jp) { + p = grabstackstr(dest); exitstatus = waitforjob(in.jp, (int *)NULL); + ungrabstackstr(p, dest); + } TRACE(("expbackq: size=%td: \"%.*s\"\n", ((dest - stackblock()) - startloc), (int)((dest - stackblock()) - startloc), stackblock() + startloc)); + argbackq = saveargbackq; expdest = dest; INTON; } Modified: head/bin/sh/tests/expansion/Makefile ============================================================================== --- head/bin/sh/tests/expansion/Makefile Sat Mar 4 22:38:10 2017 (r314685) +++ head/bin/sh/tests/expansion/Makefile Sat Mar 4 22:58:34 2017 (r314686) @@ -42,6 +42,8 @@ ${PACKAGE}FILES+= cmdsubst17.0 ${PACKAGE}FILES+= cmdsubst18.0 ${PACKAGE}FILES+= cmdsubst19.0 ${PACKAGE}FILES+= cmdsubst20.0 +${PACKAGE}FILES+= cmdsubst21.0 +${PACKAGE}FILES+= cmdsubst22.0 ${PACKAGE}FILES+= export1.0 ${PACKAGE}FILES+= export2.0 ${PACKAGE}FILES+= export3.0 Added: head/bin/sh/tests/expansion/cmdsubst21.0 ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/bin/sh/tests/expansion/cmdsubst21.0 Sat Mar 4 22:58:34 2017 (r314686) @@ -0,0 +1,6 @@ +# $FreeBSD$ + +set -T +trapped='' +trap "trapped=x$trapped" TERM +[ "x$($SH -c "kill $$")y" = xy ] && [ "$trapped" = x ] Added: head/bin/sh/tests/expansion/cmdsubst22.0 ============================================================================== --- /dev/null 00:00:00 1970 (empty, because file is newly added) +++ head/bin/sh/tests/expansion/cmdsubst22.0 Sat Mar 4 22:58:34 2017 (r314686) @@ -0,0 +1,6 @@ +# $FreeBSD$ + +set -T +trapped='' +trap "trapped=x$trapped" TERM +[ "x$(:; kill $$)y" = xy ] && [ "$trapped" = x ]
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