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ash: fix a bug where redirection fds were not closed afterwards.
optimize close+fcntl(DUPFD) into dup2. add testsuites. function old new delta copyfd 47 68 +21 argstr 1311 1298 -13 popredir 148 131 -17 redirect 1139 1107 -32 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/3 up/down: 21/-62) Total: -41 bytes
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parent
6fbb43bc3c
commit
5a867317bb
74
shell/ash.c
74
shell/ash.c
@ -4846,12 +4846,21 @@ openredirect(union node *redir)
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* if the source file descriptor is closed, EMPTY if there are no unused
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* file descriptors left.
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*/
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/* 0x800..00: bit to set in "to" to request dup2 instead of fcntl(F_DUPFD).
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* old code was doing close(to) prior to copyfd() to achieve the same */
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#define COPYFD_EXACT ((int)~INT_MAX)
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static int
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copyfd(int from, int to)
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{
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int newfd;
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newfd = fcntl(from, F_DUPFD, to);
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if (to & COPYFD_EXACT) {
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to &= ~COPYFD_EXACT;
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/*if (from != to)*/
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newfd = dup2(from, to);
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} else {
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newfd = fcntl(from, F_DUPFD, to);
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}
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if (newfd < 0) {
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if (errno == EMFILE)
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return EMPTY;
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@ -4947,11 +4956,7 @@ redirect(union node *redir, int flags)
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/* Descriptor wasn't open before redirect.
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* Mark it for close in the future */
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if (need_to_remember(sv, fd)) {
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if (fd == 2)
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copied_fd2 = CLOSED; /// do we need this?
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sv->two_fd[sv_pos].orig = fd;
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sv->two_fd[sv_pos].copy = CLOSED;
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sv_pos++;
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goto remember_to_close;
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}
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continue;
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}
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@ -4959,6 +4964,10 @@ redirect(union node *redir, int flags)
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if (need_to_remember(sv, fd)) {
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/* Copy old descriptor */
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i = fcntl(fd, F_DUPFD, 10);
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/* You'd expect copy to be CLOEXECed. Currently these extra "saved" fds
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* are closed in popredir() in the child, preventing them from leaking
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* into child. (popredir() also cleans up the mess in case of failures)
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*/
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if (i == -1) {
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i = errno;
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if (i != EBADF) {
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@ -4969,31 +4978,25 @@ redirect(union node *redir, int flags)
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ash_msg_and_raise_error("%d: %m", fd);
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/* NOTREACHED */
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}
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/* EBADF: it is not open - ok */
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} else {
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/* fd is open, save its copy */
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/* You'd expect copy to be CLOEXECed. Currently these extra "saved" fds
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* are closed in popredir() in the child, preventing them from leaking
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* into child. (popredir() also cleans up the mess in case of failures)
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*/
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if (fd == 2)
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copied_fd2 = i;
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sv->two_fd[sv_pos].orig = fd;
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sv->two_fd[sv_pos].copy = i;
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sv_pos++;
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close(fd);
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}
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} else {
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close(fd);
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/* EBADF: it is not open - good, remember to close it */
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remember_to_close:
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i = CLOSED;
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} /* else: fd is open, save its copy */
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if (fd == 2)
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copied_fd2 = i;
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sv->two_fd[sv_pos].orig = fd;
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sv->two_fd[sv_pos].copy = i;
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sv_pos++;
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}
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/* At this point fd is closed */
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if (newfd < 0) {
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/* NTOFD/NFROMFD: copy redir->ndup.dupfd to fd */
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if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
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copyfd(redir->ndup.dupfd, fd);
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if (redir->ndup.dupfd < 0) { /* "NN>&-" */
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close(fd);
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} else {
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copyfd(redir->ndup.dupfd, fd | COPYFD_EXACT);
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}
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} else { /* move newfd to fd */
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copyfd(newfd, fd);
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} else if (fd != newfd) { /* move newfd to fd */
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copyfd(newfd, fd | COPYFD_EXACT);
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close(newfd);
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}
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} while ((redir = redir->nfile.next) != NULL);
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@ -5025,8 +5028,8 @@ popredir(int drop)
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}
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if (rp->two_fd[i].copy != EMPTY) {
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if (!drop) {
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close(fd);
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copyfd(rp->two_fd[i].copy, fd);
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/*close(fd);*/
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copyfd(rp->two_fd[i].copy, fd | COPYFD_EXACT);
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}
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close(rp->two_fd[i].copy);
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}
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@ -5064,7 +5067,8 @@ redirectsafe(union node *redir, int flags)
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struct jmploc jmploc;
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SAVE_INT(saveint);
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err = setjmp(jmploc.loc) * 2;
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/* "echo 9>/dev/null; echo >&9; echo result: $?" - result should be 1, not 2! */
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err = setjmp(jmploc.loc); // huh?? was = setjmp(jmploc.loc) * 2;
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if (!err) {
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exception_handler = &jmploc;
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redirect(redir, flags);
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@ -5443,8 +5447,8 @@ evalbackcmd(union node *n, struct backcmd *result)
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FORCE_INT_ON;
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close(pip[0]);
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if (pip[1] != 1) {
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close(1);
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copyfd(pip[1], 1);
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/*close(1);*/
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copyfd(pip[1], 1 | COPYFD_EXACT);
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close(pip[1]);
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}
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eflag = 0;
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@ -10691,11 +10695,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
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len = out - (char *)stackblock();
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out = stackblock();
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if (eofmark == NULL) {
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if ((c == '>' || c == '<')
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&& quotef == 0
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// && len <= 2 // THIS LIMITS fd to 1 char: N>file, but no NN>file!
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// && (*out == '\0' || isdigit(*out))
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) {
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if ((c == '>' || c == '<') && quotef == 0) {
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int maxlen = 9 + 1; /* max 9 digit fd#: 999999999 */
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char *np = out;
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while (--maxlen && isdigit(*np))
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1
shell/ash_test/ash-redir/redir2.right
Normal file
1
shell/ash_test/ash-redir/redir2.right
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@ -0,0 +1 @@
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OK
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5
shell/ash_test/ash-redir/redir2.tests
Executable file
5
shell/ash_test/ash-redir/redir2.tests
Executable file
@ -0,0 +1,5 @@
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# ash once couldn't redirect above fd#9
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exec 1>/dev/null
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(echo LOST1 >&22) 22>&1
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(echo LOST2 >&22) 22>&1
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(echo OK >&22) 22>&2
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3
shell/ash_test/ash-redir/redir3.right
Normal file
3
shell/ash_test/ash-redir/redir3.right
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@ -0,0 +1,3 @@
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TEST
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./redir3.tests: line 4: 9: Bad file descriptor
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Output to fd#9: 1
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5
shell/ash_test/ash-redir/redir3.tests
Executable file
5
shell/ash_test/ash-redir/redir3.tests
Executable file
@ -0,0 +1,5 @@
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# redirects to closed descriptors should not leave these descriptors"
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# open afterwards
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echo TEST 9>/dev/null
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echo MUST ERROR OUT >&9
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echo "Output to fd#9: $?"
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@ -3,8 +3,8 @@
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TOPDIR=$PWD
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test -x ash || {
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echo "No ./ash?! Perhaps you want to run 'ln -s ../../busybox ash'"
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exit
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echo "No ./ash - creating a link to ../../busybox"
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ln -s ../../busybox ash
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}
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test -x printenv || gcc -O2 -o printenv printenv.c || exit $?
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test -x recho || gcc -O2 -o recho recho.c || exit $?
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