0829fce07
Denys Vlasenko
2024-07-12
Subject
ash: do not abort interactive mode on >&9999 redirect
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shell/ash.c+16 -4
| @@ -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; | |