diff options
Diffstat (limited to 'shell/ash.c')
| -rw-r--r-- | shell/ash.c | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/shell/ash.c b/shell/ash.c index 08ad0f4..067feb1 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -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); } |