hush: fix two redirection testcase failures
function old new delta
save_fds_on_redirect 183 256 +73
fcntl_F_DUPFD - 46 +46
restore_redirects 74 96 +22
xdup_and_close 51 72 +21
setup_redirects 196 200 +4
hush_main 988 983 -5
static.C 12 - -12
run_pipe 1595 1551 -44
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 4/2 up/down: 166/-61) Total: 105 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush.c b/shell/hush.c
index cf6d8cd..59bddbf 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -402,6 +402,7 @@
#define debug_printf_expand(...) do {} while (0)
#define debug_printf_varexp(...) do {} while (0)
#define debug_printf_glob(...) do {} while (0)
+#define debug_printf_redir(...) do {} while (0)
#define debug_printf_list(...) do {} while (0)
#define debug_printf_subst(...) do {} while (0)
#define debug_printf_clean(...) do {} while (0)
@@ -1146,6 +1147,10 @@
# define DEBUG_GLOB 0
#endif
+#ifndef debug_printf_redir
+# define debug_printf_redir(...) (indent(), fdprintf(2, __VA_ARGS__))
+#endif
+
#ifndef debug_printf_list
# define debug_printf_list(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
@@ -1381,12 +1386,30 @@
free(strings);
}
-
-static int xdup_and_close(int fd, int F_DUPFD_maybe_CLOEXEC)
+static int fcntl_F_DUPFD(int fd, int avoid_fd)
{
- /* We avoid taking stdio fds. Mimicking ash: use fds above 9 */
- int newfd = fcntl(fd, F_DUPFD_maybe_CLOEXEC, 10);
+ int newfd;
+ repeat:
+ newfd = fcntl(fd, F_DUPFD, avoid_fd + 1);
if (newfd < 0) {
+ if (errno == EBUSY)
+ goto repeat;
+ if (errno == EINTR)
+ goto repeat;
+ }
+ return newfd;
+}
+
+static int xdup_and_close(int fd, int F_DUPFD_maybe_CLOEXEC, int avoid_fd)
+{
+ int newfd;
+ repeat:
+ newfd = fcntl(fd, F_DUPFD_maybe_CLOEXEC, avoid_fd + 1);
+ if (newfd < 0) {
+ if (errno == EBUSY)
+ goto repeat;
+ if (errno == EINTR)
+ goto repeat;
/* fd was not open? */
if (errno == EBADF)
return fd;
@@ -1424,13 +1447,14 @@
}
fclose(fp);
}
-static int save_FILEs_on_redirect(int fd)
+static int save_FILEs_on_redirect(int fd, int avoid_fd)
{
struct FILE_list *fl = G.FILE_list;
while (fl) {
if (fd == fl->fd) {
/* We use it only on script files, they are all CLOEXEC */
- fl->fd = xdup_and_close(fd, F_DUPFD_CLOEXEC);
+ fl->fd = xdup_and_close(fd, F_DUPFD_CLOEXEC, avoid_fd);
+ debug_printf_redir("redirect_fd %d: matches a script fd, moving it to %d\n", fd, fl->fd);
return 1;
}
fl = fl->next;
@@ -1443,6 +1467,7 @@
while (fl) {
int should_be = fileno(fl->fp);
if (fl->fd != should_be) {
+ debug_printf_redir("restoring script fd from %d to %d\n", fl->fd, should_be);
xmove_fd(fl->fd, should_be);
fl->fd = should_be;
}
@@ -6518,77 +6543,108 @@
wait(NULL); /* wait till child has died */
}
+struct squirrel {
+ int orig_fd;
+ int moved_to;
+ /* moved_to = n: fd was moved to n; restore back to orig_fd after redir */
+ /* moved_to = -1: fd was opened by redirect; close orig_fd after redir */
+};
+
+static struct squirrel *add_squirrel(struct squirrel *sq, int fd, int avoid_fd)
+{
+ int i = 0;
+
+ if (sq) while (sq[i].orig_fd >= 0) {
+ /* If we collide with an already moved fd... */
+ if (fd == sq[i].moved_to) {
+ sq[i].moved_to = fcntl_F_DUPFD(sq[i].moved_to, avoid_fd);
+ debug_printf_redir("redirect_fd %d: already busy, moving to %d\n", fd, sq[i].moved_to);
+ if (sq[i].moved_to < 0) /* what? */
+ xfunc_die();
+ return sq;
+ }
+ if (fd == sq[i].orig_fd) {
+ /* Example: echo Hello >/dev/null 1>&2 */
+ debug_printf_redir("redirect_fd %d: already moved\n", fd);
+ return sq;
+ }
+ i++;
+ }
+
+ sq = xrealloc(sq, (i + 2) * sizeof(sq[0]));
+ sq[i].orig_fd = fd;
+ /* If this fd is open, we move and remember it; if it's closed, moved_to = -1 */
+ sq[i].moved_to = fcntl_F_DUPFD(fd, avoid_fd);
+ debug_printf_redir("redirect_fd %d: previous fd is moved to %d (-1 if it was closed)\n", fd, sq[i].moved_to);
+ if (sq[i].moved_to < 0 && errno != EBADF)
+ xfunc_die();
+ sq[i+1].orig_fd = -1; /* end marker */
+ return sq;
+}
+
/* fd: redirect wants this fd to be used (e.g. 3>file).
* Move all conflicting internally used fds,
* and remember them so that we can restore them later.
*/
-static int save_fds_on_redirect(int fd, int squirrel[3])
+static int save_fds_on_redirect(int fd, int avoid_fd, struct squirrel **sqp)
{
- if (squirrel) {
- /* Handle redirects of fds 0,1,2 */
-
- /* If we collide with an already moved stdio fd... */
- if (fd == squirrel[0]) {
- squirrel[0] = xdup_and_close(squirrel[0], F_DUPFD);
- return 1;
- }
- if (fd == squirrel[1]) {
- squirrel[1] = xdup_and_close(squirrel[1], F_DUPFD);
- return 1;
- }
- if (fd == squirrel[2]) {
- squirrel[2] = xdup_and_close(squirrel[2], F_DUPFD);
- return 1;
- }
- /* If we are about to redirect stdio fd, and did not yet move it... */
- if (fd <= 2 && squirrel[fd] < 0) {
- /* We avoid taking stdio fds */
- squirrel[fd] = fcntl(fd, F_DUPFD, 10);
- if (squirrel[fd] < 0 && errno != EBADF)
- xfunc_die();
- return 0; /* "we did not close fd" */
- }
- }
+ if (avoid_fd < 9) /* the important case here is that it can be -1 */
+ avoid_fd = 9;
#if ENABLE_HUSH_INTERACTIVE
if (fd != 0 && fd == G.interactive_fd) {
- G.interactive_fd = xdup_and_close(G.interactive_fd, F_DUPFD_CLOEXEC);
- return 1;
+ G.interactive_fd = xdup_and_close(G.interactive_fd, F_DUPFD_CLOEXEC, avoid_fd);
+ debug_printf_redir("redirect_fd %d: matches interactive_fd, moving it to %d\n", fd, G.interactive_fd);
+ return 1; /* "we closed fd" */
}
#endif
-
/* Are we called from setup_redirects(squirrel==NULL)? Two cases:
* (1) Redirect in a forked child. No need to save FILEs' fds,
* we aren't going to use them anymore, ok to trash.
- * (2) "exec 3>FILE". Bummer. We can save FILEs' fds,
- * but how are we doing to use them?
+ * (2) "exec 3>FILE". Bummer. We can save script FILEs' fds,
+ * but how are we doing to restore them?
* "fileno(fd) = new_fd" can't be done.
*/
- if (!squirrel)
+ if (!sqp)
return 0;
- return save_FILEs_on_redirect(fd);
+ /* If this one of script's fds? */
+ if (save_FILEs_on_redirect(fd, avoid_fd))
+ return 1; /* yes. "we closed fd" */
+
+ /* Check whether it collides with any open fds (e.g. stdio), save fds as needed */
+ *sqp = add_squirrel(*sqp, fd, avoid_fd);
+ return 0; /* "we did not close fd" */
}
-static void restore_redirects(int squirrel[3])
+static void restore_redirects(struct squirrel *sq)
{
- int i, fd;
- for (i = 0; i <= 2; i++) {
- fd = squirrel[i];
- if (fd != -1) {
- /* We simply die on error */
- xmove_fd(fd, i);
+
+ if (sq) {
+ int i = 0;
+ while (sq[i].orig_fd >= 0) {
+ if (sq[i].moved_to >= 0) {
+ /* We simply die on error */
+ debug_printf_redir("restoring redirected fd from %d to %d\n", sq[i].moved_to, sq[i].orig_fd);
+ xmove_fd(sq[i].moved_to, sq[i].orig_fd);
+ } else {
+ /* cmd1 9>FILE; cmd2_should_see_fd9_closed */
+ debug_printf_redir("restoring redirected fd %d: closing it\n", sq[i].orig_fd);
+ close(sq[i].orig_fd);
+ }
+ i++;
}
+ free(sq);
}
- /* Moved G.interactive_fd stays on new fd, not doing anything for it */
+ /* If moved, G.interactive_fd stays on new fd, not restoring it */
restore_redirected_FILEs();
}
/* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
-static int setup_redirects(struct command *prog, int squirrel[])
+static int setup_redirects(struct command *prog, struct squirrel **sqp)
{
int openfd, mode;
struct redir_struct *redir;
@@ -6596,7 +6652,7 @@
for (redir = prog->redirects; redir; redir = redir->next) {
if (redir->rd_type == REDIRECT_HEREDOC2) {
/* "rd_fd<<HERE" case */
- save_fds_on_redirect(redir->rd_fd, squirrel);
+ save_fds_on_redirect(redir->rd_fd, /*avoid:*/ 0, sqp);
/* for REDIRECT_HEREDOC2, rd_filename holds _contents_
* of the heredoc */
debug_printf_parse("set heredoc '%s'\n",
@@ -6635,7 +6691,7 @@
}
if (openfd != redir->rd_fd) {
- int closed = save_fds_on_redirect(redir->rd_fd, squirrel);
+ int closed = save_fds_on_redirect(redir->rd_fd, /*avoid:*/ openfd, sqp);
if (openfd == REDIRFD_CLOSE) {
/* "rd_fd >&-" means "close me" */
if (!closed) {
@@ -7497,14 +7553,14 @@
static int redirect_and_varexp_helper(char ***new_env_p,
struct variable **old_vars_p,
struct command *command,
- int squirrel[3],
+ struct squirrel **sqp,
char **argv_expanded)
{
/* setup_redirects acts on file descriptors, not FILEs.
* This is perfect for work that comes after exec().
* Is it really safe for inline use? Experimentally,
* things seem to work. */
- int rcode = setup_redirects(command, squirrel);
+ int rcode = setup_redirects(command, sqp);
if (rcode == 0) {
char **new_env = expand_assignments(command->argv, command->assignment_cnt);
*new_env_p = new_env;
@@ -7524,8 +7580,7 @@
struct command *command;
char **argv_expanded;
char **argv;
- /* it is not always needed, but we aim to smaller code */
- int squirrel[] = { -1, -1, -1 };
+ struct squirrel *squirrel = NULL;
int rcode;
debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
@@ -7582,7 +7637,7 @@
/* { list } */
debug_printf("non-subshell group\n");
rcode = 1; /* exitcode if redir failed */
- if (setup_redirects(command, squirrel) == 0) {
+ if (setup_redirects(command, &squirrel) == 0) {
debug_printf_exec(": run_list\n");
rcode = run_list(command->group) & 0xff;
}
@@ -7609,7 +7664,7 @@
/* Ensure redirects take effect (that is, create files).
* Try "a=t >file" */
#if 0 /* A few cases in testsuite fail with this code. FIXME */
- rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, squirrel, /*argv_expanded:*/ NULL);
+ rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, &squirrel, /*argv_expanded:*/ NULL);
/* Set shell variables */
if (new_env) {
argv = new_env;
@@ -7631,7 +7686,7 @@
#else /* Older, bigger, but more correct code */
- rcode = setup_redirects(command, squirrel);
+ rcode = setup_redirects(command, &squirrel);
restore_redirects(squirrel);
/* Set shell variables */
if (G_x_mode)
@@ -7694,7 +7749,7 @@
goto clean_up_and_ret1;
}
}
- rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
+ rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, &squirrel, argv_expanded);
if (rcode == 0) {
if (!funcp) {
debug_printf_exec(": builtin '%s' '%s'...\n",
@@ -7723,10 +7778,6 @@
unset_vars(new_env);
add_vars(old_vars);
/* clean_up_and_ret0: */
-
-//FIXME: this restores stdio fds, but does not close other redirects!
-//Example: after "echo TEST 9>/dev/null" fd#9 is not closed!
-//The squirreling code needs rework to remember all fds, not just 0,1,2.
restore_redirects(squirrel);
clean_up_and_ret1:
free(argv_expanded);
@@ -7739,7 +7790,7 @@
if (ENABLE_FEATURE_SH_NOFORK) {
int n = find_applet_by_name(argv_expanded[0]);
if (n >= 0 && APPLET_IS_NOFORK(n)) {
- rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
+ rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, &squirrel, argv_expanded);
if (rcode == 0) {
debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
argv_expanded[0], argv_expanded[1]);
@@ -8694,7 +8745,7 @@
G_saved_tty_pgrp = 0;
/* try to dup stdin to high fd#, >= 255 */
- G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
+ G_interactive_fd = fcntl_F_DUPFD(STDIN_FILENO, 254);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);
@@ -8767,7 +8818,7 @@
#elif ENABLE_HUSH_INTERACTIVE
/* No job control compiled in, only prompt/line editing */
if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
- G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
+ G_interactive_fd = fcntl_F_DUPFD(STDIN_FILENO, 254);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);