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ash: do not abort interactive mode on >&9999 redirect 

With very large fd#, the error code path is different
from one for closed but small fd#.

Make it not abort if we are interactive:

$ echo text >&99    # this wasn't buggy
ash: dup2(9,1): Bad file descriptor
$ echo text >&9999  # this was
ash: fcntl(1,F_DUPFD,10000): Invalid argument

function                                             old     new   delta
.rodata                                           105637  105661     +24
dup2_or_raise                                         35      38      +3
redirect                                            1084    1044     -40
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 27/-40)            Total: -13 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
master
Denys Vlasenko 2024-07-12 21:58:04 +02:00
parent 1ad2f5cd9f
commit 0829fce079
1 changed files with 16 additions and 4 deletions
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20
shell/ash.c
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@ -5621,10 +5621,13 @@ dup2_or_raise(int from, int to)
newfd = (from != to) ? dup2(from, to) : to;
if (newfd < 0) {
/* Happens when source fd is not open: try "echo >&99" */
ash_msg_and_raise_perror("%d", from);
ash_msg_and_raise_perror("dup2(%d,%d)", from, to);
}
return newfd;
}
/* The only possible error return is EBADF (fd wasn't open).
* Transient errors retry, other errors raise exception.
*/
static int
dup_CLOEXEC(int fd, int avoid_fd)
{
@ -5639,6 +5642,16 @@ dup_CLOEXEC(int fd, int avoid_fd)
goto repeat;
if (errno == EINTR)
goto repeat;
if (errno != EBADF) {
/* "echo >&9999" gets EINVAL trying to save fd 1 to above 9999.
* We could try saving it _below_ 9999 instead (how?), but
* this probably means that dup2(9999,1) to effectuate >&9999
* would also not work: fd 9999 can't exist. Gracefully bail out.
* (This differs from "echo >&99" where saving works, but
* subsequent dup2(99,1) fails if fd 99 is not open).
*/
ash_msg_and_raise_perror("fcntl(%d,F_DUPFD,%d)", fd, avoid_fd + 1);
}
}
return newfd;
}
@ -5754,7 +5767,7 @@ save_fd_on_redirect(int fd, int avoid_fd, struct redirtab *sq)
new_fd = dup_CLOEXEC(fd, avoid_fd);
sq->two_fd[i].moved_to = new_fd;
TRACE(("redirect_fd %d: already busy, moving to %d\n", fd, new_fd));
if (new_fd < 0) /* what? */
if (new_fd < 0) /* EBADF? what? */
xfunc_die();
return 0; /* "we did not close fd" */
}
@ -5769,8 +5782,7 @@ save_fd_on_redirect(int fd, int avoid_fd, struct redirtab *sq)
new_fd = dup_CLOEXEC(fd, avoid_fd);
TRACE(("redirect_fd %d: previous fd is moved to %d (-1 if it was closed)\n", fd, new_fd));
if (new_fd < 0) {
if (errno != EBADF)
xfunc_die();
/* EBADF (fd is not open) */
/* new_fd = CLOSED; - already is -1 */
}
sq->two_fd[i].moved_to = new_fd;