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ash: fix bug where redirection of closed fd was leaving it open afterwards.
redirect 983 1024 +41 bb_echo 276 301 +25 popredir 118 132 +14 evalcommand 1163 1176 +13 bbunpack 358 366 +8 echocmd 13 5 -8 echo_main 13 5 -8 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 5/2 up/down: 101/-16) Total: 85 bytes text data bss dec hex filename 774999 962 9236 785197 bfb2d busybox_old 775084 962 9236 785282 bfb82 busybox_unstripped
This commit is contained in:
Denis Vlasenko
parent
705eaf8b40
commit
7d75a96b15
141
coreutils/echo.c
141
coreutils/echo.c
@ -25,7 +25,9 @@
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#include "libbb.h"
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int bb_echo(char **argv)
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/* argc is unused, but removing it precludes compiler from
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* using call -> jump optimization */
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int bb_echo(int argc, char **argv)
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{
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const char *arg;
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#if !ENABLE_FEATURE_FANCY_ECHO
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@ -33,6 +35,18 @@ int bb_echo(char **argv)
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eflag = '\\',
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nflag = 1, /* 1 -- print '\n' */
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};
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/* We must check that stdout is not closed.
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* The reason for this is highly non-obvious.
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* bb_echo is used from shell. Shell must correctly handle "echo foo"
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* if stdout is closed. With stdio, output gets shoveled into
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* stdout buffer, and even fflush cannot clear it out. It seems that
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* even if libc receives EBADF on write attempts, it feels determined
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* to output data no matter what. So it will try later,
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* and possibly will clobber future output. Not good. */
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if (dup2(1, 1) != 1)
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return -1;
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arg = *++argv;
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if (!arg)
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goto newline_ret;
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@ -41,6 +55,10 @@ int bb_echo(char **argv)
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char nflag = 1;
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char eflag = 0;
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/* We must check that stdout is not closed. */
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if (dup2(1, 1) != 1)
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return -1;
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while (1) {
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arg = *++argv;
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if (!arg)
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@ -122,7 +140,7 @@ int bb_echo(char **argv)
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int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int echo_main(int argc, char **argv)
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{
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return bb_echo(argv);
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return bb_echo(argc, argv);
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}
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/*-
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@ -163,3 +181,122 @@ int echo_main(int argc, char **argv)
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*
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* @(#)echo.c 8.1 (Berkeley) 5/31/93
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*/
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#ifdef VERSION_WITH_WRITEV
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/* We can't use stdio.
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* The reason for this is highly non-obvious.
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* bb_echo is used from shell. Shell must correctly handle "echo foo"
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* if stdout is closed. With stdio, output gets shoveled into
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* stdout buffer, and even fflush cannot clear it out. It seems that
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* even if libc receives EBADF on write attempts, it feels determined
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* to output data no matter what. So it will try later,
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* and possibly will clobber future output. Not good.
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*
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* Using writev instead, with 'direct' conversion of argv vector.
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*/
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int bb_echo(int argc, char **argv)
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{
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struct iovec io[argc];
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struct iovec *cur_io = io;
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char *arg;
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char *p;
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#if !ENABLE_FEATURE_FANCY_ECHO
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enum {
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eflag = '\\',
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nflag = 1, /* 1 -- print '\n' */
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};
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arg = *++argv;
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if (!arg)
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goto newline_ret;
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#else
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char nflag = 1;
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char eflag = 0;
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while (1) {
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arg = *++argv;
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if (!arg)
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goto newline_ret;
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if (*arg != '-')
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break;
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/* If it appears that we are handling options, then make sure
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* that all of the options specified are actually valid.
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* Otherwise, the string should just be echoed.
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*/
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p = arg + 1;
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if (!*p) /* A single '-', so echo it. */
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goto just_echo;
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do {
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if (!strrchr("neE", *p))
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goto just_echo;
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} while (*++p);
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/* All of the options in this arg are valid, so handle them. */
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p = arg + 1;
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do {
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if (*p == 'n')
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nflag = 0;
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if (*p == 'e')
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eflag = '\\';
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} while (*++p);
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}
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just_echo:
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#endif
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while (1) {
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/* arg is already == *argv and isn't NULL */
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int c;
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cur_io->iov_base = p = arg;
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if (!eflag) {
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/* optimization for very common case */
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p += strlen(arg);
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} else while ((c = *arg++)) {
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if (c == eflag) { /* Check for escape seq. */
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if (*arg == 'c') {
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/* '\c' means cancel newline and
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* ignore all subsequent chars. */
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cur_io->iov_len = p - (char*)cur_io->iov_base;
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cur_io++;
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goto ret;
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}
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#if !ENABLE_FEATURE_FANCY_ECHO
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/* SUSv3 specifies that octal escapes must begin with '0'. */
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if ( (((unsigned char)*arg) - '1') >= 7)
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#endif
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{
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/* Since SUSv3 mandates a first digit of 0, 4-digit octals
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* of the form \0### are accepted. */
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if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
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arg++;
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}
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/* bb_process_escape_sequence can handle nul correctly */
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c = bb_process_escape_sequence( (void*) &arg);
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}
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}
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*p++ = c;
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}
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arg = *++argv;
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if (arg)
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*p++ = ' ';
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cur_io->iov_len = p - (char*)cur_io->iov_base;
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cur_io++;
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if (!arg)
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break;
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}
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newline_ret:
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if (nflag) {
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cur_io->iov_base = (char*)"\n";
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cur_io->iov_len = 1;
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cur_io++;
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}
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ret:
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/* TODO: implement and use full_writev? */
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return writev(1, io, (cur_io - io)) >= 0;
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}
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#endif
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@ -728,7 +728,7 @@ extern void bb_verror_msg(const char *s, va_list p, const char *strerr);
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/* applets which are useful from another applets */
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int bb_cat(char** argv);
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int bb_echo(char** argv);
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int bb_echo(int argc, char** argv);
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int test_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int kill_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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#if ENABLE_ROUTE
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35
shell/ash.c
35
shell/ash.c
@ -4567,6 +4567,7 @@ stoppedjobs(void)
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*/
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#define EMPTY -2 /* marks an unused slot in redirtab */
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#define CLOSED -3 /* marks a slot of previously-closed fd */
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#ifndef PIPE_BUF
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# define PIPESIZE 4096 /* amount of buffering in a pipe */
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#else
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@ -4791,7 +4792,7 @@ redirect(union node *redir, int flags)
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int i;
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int fd;
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int newfd;
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int *p;
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nullredirs++;
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if (!redir) {
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return;
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@ -4799,15 +4800,13 @@ redirect(union node *redir, int flags)
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sv = NULL;
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INT_OFF;
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if (flags & REDIR_PUSH) {
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struct redirtab *q;
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q = ckmalloc(sizeof(struct redirtab));
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q->next = redirlist;
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redirlist = q;
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q->nullredirs = nullredirs - 1;
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sv = ckmalloc(sizeof(*sv));
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sv->next = redirlist;
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redirlist = sv;
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sv->nullredirs = nullredirs - 1;
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for (i = 0; i < 10; i++)
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q->renamed[i] = EMPTY;
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sv->renamed[i] = EMPTY;
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nullredirs = 0;
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sv = q;
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}
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n = redir;
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do {
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@ -4817,9 +4816,14 @@ redirect(union node *redir, int flags)
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continue; /* redirect from/to same file descriptor */
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newfd = openredirect(n);
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if (fd == newfd)
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if (fd == newfd) {
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/* Descriptor wasn't open before redirect.
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* Mark it for close in the future */
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if (sv && sv->renamed[fd] == EMPTY)
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sv->renamed[fd] = CLOSED;
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continue;
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if (sv && *(p = &sv->renamed[fd]) == EMPTY) {
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}
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if (sv && sv->renamed[fd] == EMPTY) {
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i = fcntl(fd, F_DUPFD, 10);
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if (i == -1) {
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@ -4831,7 +4835,7 @@ redirect(union node *redir, int flags)
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/* NOTREACHED */
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}
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} else {
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*p = i;
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sv->renamed[fd] = i;
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close(fd);
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}
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} else {
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@ -4840,7 +4844,7 @@ redirect(union node *redir, int flags)
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dupredirect(n, newfd);
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} while ((n = n->nfile.next));
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INT_ON;
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if (flags & REDIR_SAVEFD2 && sv && sv->renamed[2] >= 0)
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if ((flags & REDIR_SAVEFD2) && sv && sv->renamed[2] >= 0)
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preverrout_fd = sv->renamed[2];
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}
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@ -4858,6 +4862,11 @@ popredir(int drop)
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INT_OFF;
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rp = redirlist;
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for (i = 0; i < 10; i++) {
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if (rp->renamed[i] == CLOSED) {
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if (!drop)
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close(i);
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continue;
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}
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if (rp->renamed[i] != EMPTY) {
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if (!drop) {
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close(i);
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@ -10994,7 +11003,7 @@ exitcmd(int argc, char **argv)
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static int
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echocmd(int argc, char **argv)
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{
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return bb_echo(argv);
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return bb_echo(argc, argv);
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}
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#endif
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1
shell/ash_test/ash-redir/redir.right
Normal file
1
shell/ash_test/ash-redir/redir.right
Normal file
@ -0,0 +1 @@
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TEST
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6
shell/ash_test/ash-redir/redir.tests
Normal file
6
shell/ash_test/ash-redir/redir.tests
Normal file
@ -0,0 +1,6 @@
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# test: closed fds should stay closed
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exec 1>&-
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echo TEST >TEST
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echo JUNK # lost: stdout is closed
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cat TEST >&2
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rm TEST
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