1 files changed, 31 insertions, 27 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 647fc81b4..0490f7f7d 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -3760,12 +3760,12 @@ setjobctl(int on)
                                 if (--fd < 0)
                                         goto out;
                 }
+                /* fd is a tty at this point */
                 fd = fcntl(fd, F_DUPFD, 10);
-                if (ofd >= 0)
+                if (ofd >= 0) /* if it is "/dev/tty", close. If 0/1/2, dont */
                         close(ofd);
                 if (fd < 0)
-                        goto out;
-                /* fd is a tty at this point */
+                        goto out; /* F_DUPFD failed */
                 close_on_exec_on(fd);
                 while (1) { /* while we are in the background */
                         pgrp = tcgetpgrp(fd);
@@ -5181,26 +5181,31 @@ openredirect(union node *redir)
 }
 
 /*
- * Copy a file descriptor to be >= to. Throws exception on error.
+ * Copy a file descriptor to be >= 10. Throws exception on error.
  */
-/* 0x800..00: bit to set in "to" to request dup2 instead of fcntl(F_DUPFD).
- * old code was doing close(to) prior to copyfd() to achieve the same */
-enum {
-        COPYFD_EXACT   = (int)~(INT_MAX),
-        COPYFD_RESTORE = (int)((unsigned)COPYFD_EXACT >> 1),
-};
 static int
-copyfd(int from, int to)
+savefd(int from)
 {
         int newfd;
+        int err;
 
-        if (to & COPYFD_EXACT) {
-                to &= ~COPYFD_EXACT;
-                /*if (from != to)*/
-                        newfd = dup2(from, to);
-        } else {
-                newfd = fcntl(from, F_DUPFD, to);
+        newfd = fcntl(from, F_DUPFD, 10);
+        err = newfd < 0 ? errno : 0;
+        if (err != EBADF) {
+                if (err)
+                        ash_msg_and_raise_error("%d: %m", from);
+                close(from);
+                fcntl(newfd, F_SETFD, FD_CLOEXEC);
         }
+
+        return newfd;
+}
+static int
+dup2_or_raise(int from, int to)
+{
+        int newfd;
+
+        newfd = (from != to) ? dup2(from, to) : to;
         if (newfd < 0) {
                 /* Happens when source fd is not open: try "echo >&99" */
                 ash_msg_and_raise_error("%d: %m", from);
@@ -5218,6 +5223,9 @@ struct redirtab {
         struct two_fd_t two_fd[];
 };
 #define redirlist (G_var.redirlist)
+enum {
+        COPYFD_RESTORE = (int)~(INT_MAX),
+};
 
 static int
 need_to_remember(struct redirtab *rp, int fd)
@@ -5391,10 +5399,10 @@ redirect(union node *redir, int flags)
                                 if (fd != -1)
                                         close(fd);
                         } else {
-                                copyfd(redir->ndup.dupfd, fd | COPYFD_EXACT);
+                                dup2_or_raise(redir->ndup.dupfd, fd);
                         }
                 } else if (fd != newfd) { /* move newfd to fd */
-                        copyfd(newfd, fd | COPYFD_EXACT);
+                        dup2_or_raise(newfd, fd);
 #if ENABLE_ASH_BASH_COMPAT
                         if (!(redir->nfile.type == NTO2 && fd == 2))
 #endif
@@ -5440,7 +5448,7 @@ popredir(int drop, int restore)
                         if (!drop || (restore && (copy & COPYFD_RESTORE))) {
                                 copy &= ~COPYFD_RESTORE;
                                 /*close(fd);*/
-                                copyfd(copy, fd | COPYFD_EXACT);
+                                dup2_or_raise(copy, fd);
                         }
                         close(copy & ~COPYFD_RESTORE);
                 }
@@ -5894,7 +5902,7 @@ evalbackcmd(union node *n, struct backcmd *result)
                 close(pip[0]);
                 if (pip[1] != 1) {
                         /*close(1);*/
-                        copyfd(pip[1], 1 | COPYFD_EXACT);
+                        dup2_or_raise(pip[1], 1);
                         close(pip[1]);
                 }
 /* TODO: eflag clearing makes the following not abort:
@@ -10204,7 +10212,6 @@ static int
 setinputfile(const char *fname, int flags)
 {
         int fd;
-        int fd2;
 
         INT_OFF;
         fd = open(fname, O_RDONLY);
@@ -10214,11 +10221,8 @@ setinputfile(const char *fname, int flags)
                 exitstatus = 127;
                 ash_msg_and_raise_error("can't open '%s'", fname);
         }
-        if (fd < 10) {
-                fd2 = copyfd(fd, 10);
-                close(fd);
-                fd = fd2;
-        }
+        if (fd < 10)
+                fd = savefd(fd);
         setinputfd(fd, flags & INPUT_PUSH_FILE);
  out:
         INT_ON;