ash: fix bug where redirection of closed fd was leaving it open afterwards.
redirect 983 1024 +41
bb_echo 276 301 +25
popredir 118 132 +14
evalcommand 1163 1176 +13
bbunpack 358 366 +8
echocmd 13 5 -8
echo_main 13 5 -8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/2 up/down: 101/-16) Total: 85 bytes
text data bss dec hex filename
774999 962 9236 785197 bfb2d busybox_old
775084 962 9236 785282 bfb82 busybox_unstripped
diff --git a/shell/ash.c b/shell/ash.c
index bb930f5..4113ce8 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4567,6 +4567,7 @@
*/
#define EMPTY -2 /* marks an unused slot in redirtab */
+#define CLOSED -3 /* marks a slot of previously-closed fd */
#ifndef PIPE_BUF
# define PIPESIZE 4096 /* amount of buffering in a pipe */
#else
@@ -4791,7 +4792,7 @@
int i;
int fd;
int newfd;
- int *p;
+
nullredirs++;
if (!redir) {
return;
@@ -4799,15 +4800,13 @@
sv = NULL;
INT_OFF;
if (flags & REDIR_PUSH) {
- struct redirtab *q;
- q = ckmalloc(sizeof(struct redirtab));
- q->next = redirlist;
- redirlist = q;
- q->nullredirs = nullredirs - 1;
+ sv = ckmalloc(sizeof(*sv));
+ sv->next = redirlist;
+ redirlist = sv;
+ sv->nullredirs = nullredirs - 1;
for (i = 0; i < 10; i++)
- q->renamed[i] = EMPTY;
+ sv->renamed[i] = EMPTY;
nullredirs = 0;
- sv = q;
}
n = redir;
do {
@@ -4817,9 +4816,14 @@
continue; /* redirect from/to same file descriptor */
newfd = openredirect(n);
- if (fd == newfd)
+ if (fd == newfd) {
+ /* Descriptor wasn't open before redirect.
+ * Mark it for close in the future */
+ if (sv && sv->renamed[fd] == EMPTY)
+ sv->renamed[fd] = CLOSED;
continue;
- if (sv && *(p = &sv->renamed[fd]) == EMPTY) {
+ }
+ if (sv && sv->renamed[fd] == EMPTY) {
i = fcntl(fd, F_DUPFD, 10);
if (i == -1) {
@@ -4831,7 +4835,7 @@
/* NOTREACHED */
}
} else {
- *p = i;
+ sv->renamed[fd] = i;
close(fd);
}
} else {
@@ -4840,7 +4844,7 @@
dupredirect(n, newfd);
} while ((n = n->nfile.next));
INT_ON;
- if (flags & REDIR_SAVEFD2 && sv && sv->renamed[2] >= 0)
+ if ((flags & REDIR_SAVEFD2) && sv && sv->renamed[2] >= 0)
preverrout_fd = sv->renamed[2];
}
@@ -4858,6 +4862,11 @@
INT_OFF;
rp = redirlist;
for (i = 0; i < 10; i++) {
+ if (rp->renamed[i] == CLOSED) {
+ if (!drop)
+ close(i);
+ continue;
+ }
if (rp->renamed[i] != EMPTY) {
if (!drop) {
close(i);
@@ -10994,7 +11003,7 @@
static int
echocmd(int argc, char **argv)
{
- return bb_echo(argv);
+ return bb_echo(argc, argv);
}
#endif
diff --git a/shell/ash_test/ash-redir/redir.right b/shell/ash_test/ash-redir/redir.right
new file mode 100644
index 0000000..2a02d41
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir.right
@@ -0,0 +1 @@
+TEST
diff --git a/shell/ash_test/ash-redir/redir.tests b/shell/ash_test/ash-redir/redir.tests
new file mode 100644
index 0000000..7a1a668
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir.tests
@@ -0,0 +1,6 @@
+# test: closed fds should stay closed
+exec 1>&-
+echo TEST >TEST
+echo JUNK # lost: stdout is closed
+cat TEST >&2
+rm TEST