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hush: restore redirected stdin

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function                                             old     new   delta
restore_redirects                                     52      95     +43
save_fd_on_redirect                                  243     253     +10
hfopen                                                90      99      +9
fgetc_interactive                                    259     261      +2
builtin_type                                         117     115      -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 64/-2)              Total: 62 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2019-11-01 14:16:07 +01:00
parent ea096d6c13
commit 21806562ca
5 changed files with 42 additions and 7 deletions
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3
shell/ash_test/ash-redir/redir_stdin1.right Normal file
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@ -0,0 +1,3 @@
#Testing that stdin redirect is restored
read2
Ok:0

7
shell/ash_test/ash-redir/redir_stdin1.tests Executable file
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@ -0,0 +1,7 @@
#Testing that stdin redirect is restored
echo read2 | $THIS_SH -c 'read r <redir_stdin1.tests
echo $r
read r
echo $r
'
echo Ok:$?

29
shell/hush.c
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@ -573,7 +573,6 @@ typedef struct HFILE {
char *cur;
char *end;
struct HFILE *next_hfile;
int is_stdin;
int fd;
char buf[1024];
} HFILE;
@ -973,6 +972,7 @@ struct globals {
unsigned execute_lineno;
#endif
HFILE *HFILE_list;
HFILE *HFILE_stdin;
/* Which signals have non-DFL handler (even with no traps set)?
* Set at the start to:
* (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOBSTOP_SIGS)
@ -1603,7 +1603,8 @@ static HFILE *hfopen(const char *name)
}
fp = xmalloc(sizeof(*fp));
fp->is_stdin = (name == NULL);
if (name == NULL)
G.HFILE_stdin = fp;
fp->fd = fd;
fp->cur = fp->end = fp->buf;
fp->next_hfile = G.HFILE_list;
@ -2666,7 +2667,7 @@ static int fgetc_interactive(struct in_str *i)
{
int ch;
/* If it's interactive stdin, get new line. */
if (G_interactive_fd && i->file->is_stdin) {
if (G_interactive_fd && i->file == G.HFILE_stdin) {
/* Returns first char (or EOF), the rest is in i->p[] */
ch = get_user_input(i);
G.promptmode = 1; /* PS2 */
@ -7605,7 +7606,9 @@ static int save_fd_on_redirect(int fd, int avoid_fd, struct squirrel **sqp)
avoid_fd = 9;
#if ENABLE_HUSH_INTERACTIVE
if (fd == G_interactive_fd) {
if (fd != 0 /* don't trigger for G_interactive_fd == 0 (that's "not interactive" flag) */
&& fd == G_interactive_fd
) {
/* Testcase: "ls -l /proc/$$/fd 255>&-" should work */
G_interactive_fd = xdup_CLOEXEC_and_close(G_interactive_fd, avoid_fd);
debug_printf_redir("redirect_fd %d: matches interactive_fd, moving it to %d\n", fd, G_interactive_fd);
@ -7619,7 +7622,7 @@ static int save_fd_on_redirect(int fd, int avoid_fd, struct squirrel **sqp)
/* No need to move script fds.
* For NOMMU case, it's actively wrong: we'd change ->fd
* fields in memory for the parent, but parent's fds
* aren't be moved, it would use wrong fd!
* aren't moved, it would use wrong fd!
* Reproducer: "cmd 3>FILE" in script.
* If we would call move_HFILEs_on_redirect(), child would:
* fcntl64(3, F_DUPFD_CLOEXEC, 10) = 10
@ -7683,6 +7686,20 @@ static void restore_redirects(struct squirrel *sq)
}
free(sq);
}
if (G.HFILE_stdin
&& G.HFILE_stdin->fd != STDIN_FILENO
) {
/* Testcase: interactive "read r <FILE; echo $r; read r; echo $r".
* Redirect moves ->fd to e.g. 10,
* and it is not restored above (we do not restore script fds
* after redirects, we just use new, "moved" fds).
* However for stdin, get_user_input() -> read_line_input(),
* and read builtin, depend on fd == STDIN_FILENO.
*/
debug_printf_redir("restoring %d to stdin\n", G.HFILE_stdin->fd);
xmove_fd(G.HFILE_stdin->fd, STDIN_FILENO);
G.HFILE_stdin->fd = STDIN_FILENO;
}
/* If moved, G_interactive_fd stays on new fd, not restoring it */
}
@ -10214,8 +10231,6 @@ int hush_main(int argc, char **argv)
G_saved_tty_pgrp = 0;
}
}
// TODO: track & disallow any attempts of user
// to (inadvertently) close/redirect G_interactive_fd
}
debug_printf("interactive_fd:%d\n", G_interactive_fd);
if (G_interactive_fd) {

3
shell/hush_test/hush-redir/redir_stdin1.right Normal file
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@ -0,0 +1,3 @@
#Testing that stdin redirect is restored
read2
Ok:0

7
shell/hush_test/hush-redir/redir_stdin1.tests Executable file
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@ -0,0 +1,7 @@
#Testing that stdin redirect is restored
echo read2 | $THIS_SH -c 'read r <redir_stdin1.tests
echo $r
read r
echo $r
'
echo Ok:$?