08d8b3cee
Denys Vlasenko
2010-06-03
Subject
ash: fix redirection of fd 0 in scripts are sourced from interactive ash
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shell/ash.c +25 -10shell/ash_test/ash-signals/signal5.right +2 -2shell/ash_test/ash-signals/signal5.tests +1 -1
shell/ash.c+25 -10
| @@ -1070,7 +1070,7 @@ ash_vmsg(const char *msg, va_list ap) | |
| if (commandname) { | |
| if (strcmp(arg0, commandname)) | |
| fprintf(stderr, "%s: ", commandname); | |
| - | if (!iflag || g_parsefile->fd) |
| + | if (!iflag || g_parsefile->fd > 0) |
| fprintf(stderr, "line %d: ", startlinno); | |
| } | |
| vfprintf(stderr, msg, ap); | |
| @@ -5063,15 +5063,26 @@ static int is_hidden_fd(struct redirtab *rp, int fd) | |
| if (fd == -1) | |
| return 0; | |
| + | /* Check open scripts' fds */ |
| pf = g_parsefile; | |
| while (pf) { | |
| - | if (fd == pf->fd) { |
| + | /* We skip fd == 0 case because of the following case: |
| + | * $ ash # running ash interactively |
| + | * $ . ./script.sh |
| + | * and in script.sh: "exec 9>&0". |
| + | * Even though top-level fd _is_ 0, |
| + | * it's still ok to use it: "read" builtin uses it, |
| + | * why should we cripple "exec" builtin? |
| + | */ |
| + | if (pf->fd > 0 && fd == pf->fd) { |
| return 1; | |
| } | |
| pf = pf->prev; | |
| } | |
| + | |
| if (!rp) | |
| return 0; | |
| + | /* Check saved fds of redirects */ |
| fd |= COPYFD_RESTORE; | |
| for (i = 0; i < rp->pair_count; i++) { | |
| if (rp->two_fd[i].copy == fd) { | |
| @@ -5084,9 +5095,7 @@ static int is_hidden_fd(struct redirtab *rp, int fd) | |
| /* | |
| * Process a list of redirection commands. If the REDIR_PUSH flag is set, | |
| * old file descriptors are stashed away so that the redirection can be | |
| - | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the |
| - | * standard output, and the standard error if it becomes a duplicate of |
| - | * stdout, is saved in memory. |
| + | * undone by calling popredir. |
| */ | |
| /* flags passed to redirect */ | |
| #define REDIR_PUSH 01 /* save previous values of file descriptors */ | |
| @@ -5132,13 +5141,15 @@ redirect(union node *redir, int flags) | |
| } | |
| do { | |
| + | int right_fd = -1; |
| fd = redir->nfile.fd; | |
| if (redir->nfile.type == NTOFD || redir->nfile.type == NFROMFD) { | |
| - | int right_fd = redir->ndup.dupfd; |
| + | right_fd = redir->ndup.dupfd; |
| + | //bb_error_msg("doing %d > %d", fd, right_fd); |
| /* redirect from/to same file descriptor? */ | |
| if (right_fd == fd) | |
| continue; | |
| - | /* echo >&10 and 10 is a fd opened to the sh script? */ |
| + | /* "echo >&10" and 10 is a fd opened to a sh script? */ |
| if (is_hidden_fd(sv, right_fd)) { | |
| errno = EBADF; /* as if it is closed */ | |
| ash_msg_and_raise_error("%d: %m", right_fd); | |
| @@ -5160,7 +5171,10 @@ redirect(union node *redir, int flags) | |
| #endif | |
| if (need_to_remember(sv, fd)) { | |
| /* Copy old descriptor */ | |
| - | i = fcntl(fd, F_DUPFD, 10); |
| + | /* Careful to not accidentally "save" |
| + | * to the same fd as right side fd in N>&M */ |
| + | int minfd = right_fd < 10 ? 10 : right_fd + 1; |
| + | i = fcntl(fd, F_DUPFD, minfd); |
| /* You'd expect copy to be CLOEXECed. Currently these extra "saved" fds | |
| * are closed in popredir() in the child, preventing them from leaking | |
| * into child. (popredir() also cleans up the mess in case of failures) | |
| @@ -12994,8 +13008,9 @@ int ash_main(int argc UNUSED_PARAM, char **argv) | |
| * Ensure we don't falsely claim that 0 (stdin) | |
| * is one of stacked source fds. | |
| * Testcase: ash -c 'exec 1>&0' must not complain. */ | |
| - | if (!sflag) |
| - | g_parsefile->fd = -1; |
| + | // if (!sflag) g_parsefile->fd = -1; |
| + | // ^^ not necessary since now we special-case fd 0 |
| + | // in is_hidden_fd() to not be considered "hidden fd" |
| evalstring(minusc, 0); | |
| } | |
shell/ash_test/ash-signals/signal5.right+2 -2
| @@ -1,5 +1,5 @@ | |
| - | sleeping for 3 sec |
| - | sleeping for 2 sec |
| + | Sleeping |
| + | Sleeping |
| Waiting | |
| 2 sec passed, sending USR1 to parent | |
| USR1 received | |
shell/ash_test/ash-signals/signal5.tests+1 -1
| @@ -1,6 +1,6 @@ | |
| trap "echo USR1 received" USR1 | |
| stub() { | |
| - | echo "sleeping for $1 sec" |
| + | echo "Sleeping" |
| sleep $1 | |
| echo "$1 sec passed, sending USR1 to parent" | |
| kill -USR1 $$ | |