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hush: fix two redirection testcase failures

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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>
This commit is contained in:
Denys Vlasenko
2017-07-07 22:07:28 +02:00
parent 69a5ec9dcc
commit 2db74610cd
3 changed files with 118 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

181
shell/hush.c
View File

@@ -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 @@ static const struct built_in_command bltins2[] = {
# 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 @@ static void free_strings(char **strings)
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 @@ static void fclose_and_forget(FILE *fp)
}
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 @@ static void restore_redirected_FILEs(void)
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 @@ static void setup_heredoc(struct redir_struct *redir)
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 @@ static int setup_redirects(struct command *prog, int squirrel[])
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 @@ static int setup_redirects(struct command *prog, int squirrel[])
}
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 checkjobs_and_fg_shell(struct pipe *fg_pipe)
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 @@ static NOINLINE int run_pipe(struct pipe *pi)
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 @@ static NOINLINE int run_pipe(struct pipe *pi)
/* { 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 @@ static NOINLINE int run_pipe(struct pipe *pi)
/* 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 @@ static NOINLINE int run_pipe(struct pipe *pi)
#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 @@ static NOINLINE int run_pipe(struct pipe *pi)
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 @@ static NOINLINE int run_pipe(struct pipe *pi)
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 @@ static NOINLINE int run_pipe(struct pipe *pi)
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 @@ int hush_main(int argc, char **argv)
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 @@ int hush_main(int argc, char **argv)
#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);

3
shell/hush_test/hush-redir/redir3.right
View File

@@ -1,3 +1,2 @@
TEST
./redir3.tests: line 4: 9: Bad file descriptor
Output to fd#9: 1
hush: can't duplicate file descriptor: Bad file descriptor

3
shell/hush_test/hush-redir/redir_to_bad_fd.right
View File

@@ -1,2 +1 @@
./redir_to_bad_fd.tests: line 2: 10: Bad file descriptor
OK
hush: can't duplicate file descriptor: Bad file descriptor