ash: remove REDIR_SAVEFD2

function                                             old     new   delta
evalcommand                                         1364    1369      +5
redirect                                            1055    1014     -41
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 5/-41)             Total: -36 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 37 insertions, 32 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 52fcc7944..1e720aec4 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2030,7 +2030,7 @@ struct redirtab;
 struct globals_var {
         struct shparam shellparam;      /* $@ current positional parameters */
         struct redirtab *redirlist;
-        int preverrout_fd;   /* save fd2 before print debug if xflag is set. */
+        int preverrout_fd;   /* stderr fd: usually 2, unless redirect moved it */
         struct var *vartab[VTABSIZE];
         struct var varinit[ARRAY_SIZE(varinit_data)];
 };
@@ -5426,16 +5426,13 @@ is_hidden_fd(struct redirtab *rp, int fd)
  */
 /* flags passed to redirect */
 #define REDIR_PUSH    01        /* save previous values of file descriptors */
-#define REDIR_SAVEFD2 03        /* set preverrout */
 static void
 redirect(union node *redir, int flags)
 {
         struct redirtab *sv;
         int sv_pos;
-        int i;
         int fd;
         int newfd;
-        int copied_fd2 = -1;
 
         if (!redir)
                 return;
@@ -5479,37 +5476,38 @@ redirect(union node *redir, int flags)
                          * to the same fd as right side fd in N>&M */
                         int minfd = right_fd < 10 ? 10 : right_fd + 1;
 #if defined(F_DUPFD_CLOEXEC)
-                        i = fcntl(fd, F_DUPFD_CLOEXEC, minfd);
+                        int copy = fcntl(fd, F_DUPFD_CLOEXEC, minfd);
 #else
-                        i = fcntl(fd, F_DUPFD, minfd);
+                        int copy = fcntl(fd, F_DUPFD, minfd);
 #endif
-                        if (i == -1) {
-                                i = errno;
-                                if (i != EBADF) {
+                        if (copy == -1) {
+                                int e = errno;
+                                if (e != EBADF) {
                                         /* Strange error (e.g. "too many files" EMFILE?) */
                                         if (newfd >= 0)
                                                 close(newfd);
-                                        errno = i;
+                                        errno = e;
                                         ash_msg_and_raise_perror("%d", fd);
                                         /* NOTREACHED */
                                 }
                                 /* EBADF: it is not open - good, remember to close it */
  remember_to_close:
-                                i = CLOSED;
+                                copy = CLOSED;
                         } else { /* fd is open, save its copy */
 #if !defined(F_DUPFD_CLOEXEC)
-                                fcntl(i, F_SETFD, FD_CLOEXEC);
+                                fcntl(copy, F_SETFD, FD_CLOEXEC);
 #endif
                                 /* "exec fd>&-" should not close fds
                                  * which point to script file(s).
                                  * Force them to be restored afterwards */
                                 if (is_hidden_fd(sv, fd))
-                                        i |= COPYFD_RESTORE;
+                                        copy |= COPYFD_RESTORE;
                         }
-                        if (fd == 2)
-                                copied_fd2 = i;
+                        /* if we move stderr, let "set -x" code know */
+                        if (fd == preverrout_fd)
+                                preverrout_fd = copy;
                         sv->two_fd[sv_pos].orig = fd;
-                        sv->two_fd[sv_pos].copy = i;
+                        sv->two_fd[sv_pos].copy = copy;
                         sv_pos++;
                 }
                 if (newfd < 0) {
@@ -5537,10 +5535,16 @@ redirect(union node *redir, int flags)
                 }
 #endif
         } while ((redir = redir->nfile.next) != NULL);
-
         INT_ON;
-        if ((flags & REDIR_SAVEFD2) && copied_fd2 >= 0)
-                preverrout_fd = copied_fd2;
+
+//dash:#define REDIR_SAVEFD2 03        /* set preverrout */
+#define REDIR_SAVEFD2 0
+        // dash has a bug: since REDIR_SAVEFD2=3 and REDIR_PUSH=1, this test
+        // triggers for pure REDIR_PUSH too. Thus, this is done almost always,
+        // not only for calls with flags containing REDIR_SAVEFD2.
+        // We do this unconditionally (see code above).
+        //if ((flags & REDIR_SAVEFD2) && copied_fd2 >= 0)
+        //      preverrout_fd = copied_fd2;
 }
 
 static int
@@ -9655,9 +9659,7 @@ evalcommand(union node *cmd, int flags)
         int spclbltin;
         int status;
         char **nargv;
-        struct builtincmd *bcmd;
         smallint cmd_is_exec;
-        smallint pseudovarflag = 0;
 
         /* First expand the arguments. */
         TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
@@ -9674,21 +9676,24 @@ evalcommand(union node *cmd, int flags)
 
         argc = 0;
         if (cmd->ncmd.args) {
+                struct builtincmd *bcmd;
+                smallint pseudovarflag;
+
                 bcmd = find_builtin(cmd->ncmd.args->narg.text);
                 pseudovarflag = bcmd && IS_BUILTIN_ASSIGN(bcmd);
-        }
 
-        for (argp = cmd->ncmd.args; argp; argp = argp->narg.next) {
-                struct strlist **spp;
+                for (argp = cmd->ncmd.args; argp; argp = argp->narg.next) {
+                        struct strlist **spp;
 
-                spp = arglist.lastp;
-                if (pseudovarflag && isassignment(argp->narg.text))
-                        expandarg(argp, &arglist, EXP_VARTILDE);
-                else
-                        expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
+                        spp = arglist.lastp;
+                        if (pseudovarflag && isassignment(argp->narg.text))
+                                expandarg(argp, &arglist, EXP_VARTILDE);
+                        else
+                                expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
 
-                for (sp = *spp; sp; sp = sp->next)
-                        argc++;
+                        for (sp = *spp; sp; sp = sp->next)
+                                argc++;
+                }
         }
 
         /* Reserve one extra spot at the front for shellexec. */
@@ -9704,9 +9709,9 @@ evalcommand(union node *cmd, int flags)
         if (iflag && funcnest == 0 && argc > 0)
                 lastarg = nargv[-1];
 
-        preverrout_fd = 2;
         expredir(cmd->ncmd.redirect);
         redir_stop = pushredir(cmd->ncmd.redirect);
+        preverrout_fd = 2;
         status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH | REDIR_SAVEFD2);
 
         path = vpath.var_text;