ash: teach ash about 123>file. It could take only 0..9 before

function                                             old     new   delta
redirect                                            1052    1139     +87
need_to_remember                                       -      36     +36
popredir                                             132     148     +16
fixredir                                              86     101     +15
readtoken1                                          3130    3143     +13
evalvar                                             1374    1376      +2
popstring                                            140     134      -6
cmdtxt                                               592     561     -31
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/2 up/down: 169/-37)           Total: 132 bytes

1 files changed, 97 insertions, 45 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 6de71f6d7..22575ffbc 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -62,6 +62,10 @@
 #include <termios.h>
 #endif
 
+#ifndef PIPE_BUF
+#define PIPE_BUF 4096           /* amount of buffering in a pipe */
+#endif
+
 #if defined(__uClinux__)
 #error "Do not even bother, ash will not run on uClinux"
 #endif
@@ -4285,7 +4289,6 @@ cmdtxt(union node *n)
         union node *np;
         struct nodelist *lp;
         const char *p;
-        char s[2];
 
         if (!n)
                 return;
@@ -4417,14 +4420,11 @@ cmdtxt(union node *n)
         case NFROMTO:
                 p = "<>";
  redir:
-                s[0] = n->nfile.fd + '0';
-                s[1] = '\0';
-                cmdputs(s);
+                cmdputs(utoa(n->nfile.fd));
                 cmdputs(p);
                 if (n->type == NTOFD || n->type == NFROMFD) {
-                        s[0] = n->ndup.dupfd + '0';
-                        p = s;
-                        goto dotail2;
+                        cmdputs(utoa(n->ndup.dupfd));
+                        break;
                 }
                 n = n->nfile.fname;
                 goto donode;
@@ -4675,11 +4675,6 @@ stoppedjobs(void)
 
 #define EMPTY -2                /* marks an unused slot in redirtab */
 #define CLOSED -3               /* marks a slot of previously-closed fd */
-#ifndef PIPE_BUF
-# define PIPESIZE 4096          /* amount of buffering in a pipe */
-#else
-# define PIPESIZE PIPE_BUF
-#endif
 
 /*
  * Open a file in noclobber mode.
@@ -4756,7 +4751,7 @@ openhere(union node *redir)
                 ash_msg_and_raise_error("pipe call failed");
         if (redir->type == NHERE) {
                 len = strlen(redir->nhere.doc->narg.text);
-                if (len <= PIPESIZE) {
+                if (len <= PIPE_BUF) {
                         full_write(pip[1], redir->nhere.doc->narg.text, len);
                         goto out;
                 }
@@ -4860,19 +4855,40 @@ copyfd(int from, int to)
         if (newfd < 0) {
                 if (errno == EMFILE)
                         return EMPTY;
+                /* Happens when source fd is not open: try "echo >&99" */
                 ash_msg_and_raise_error("%d: %m", from);
         }
         return newfd;
 }
 
 /* Struct def and variable are moved down to the first usage site */
+struct two_fd_t {
+        int orig, copy;
+};
 struct redirtab {
         struct redirtab *next;
-        int renamed[10];
         int nullredirs;
+        int pair_count;
+        struct two_fd_t two_fd[0];
 };
 #define redirlist (G_var.redirlist)
 
+static int need_to_remember(struct redirtab *rp, int fd)
+{
+        int i;
+
+        if (!rp) /* remebering was not requested */
+                return 0;
+
+        for (i = 0; i < rp->pair_count; i++) {
+                if (rp->two_fd[i].orig == fd) {
+                        /* already remembered */
+                        return 0;
+                }
+        }
+        return 1;
+}
+
 /*
  * 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
@@ -4887,24 +4903,36 @@ static void
 redirect(union node *redir, int flags)
 {
         struct redirtab *sv;
+        int sv_pos;
         int i;
         int fd;
         int newfd;
+        int copied_fd2 = -1;
 
         g_nullredirs++;
         if (!redir) {
                 return;
         }
+
         sv = NULL;
+        sv_pos = 0;
         INT_OFF;
         if (flags & REDIR_PUSH) {
-                sv = ckmalloc(sizeof(*sv));
+                union node *tmp = redir;
+                do {
+                        sv_pos++;
+                        tmp = tmp->nfile.next;
+                } while (tmp);
+                sv = ckmalloc(sizeof(*sv) + sv_pos * sizeof(sv->two_fd[0]));
                 sv->next = redirlist;
+                sv->pair_count = sv_pos;
                 redirlist = sv;
                 sv->nullredirs = g_nullredirs - 1;
                 g_nullredirs = 0;
-                for (i = 0; i < 10; i++)
-                        sv->renamed[i] = EMPTY;
+                while (sv_pos > 0) {
+                        sv_pos--;
+                        sv->two_fd[sv_pos].orig = sv->two_fd[sv_pos].copy = EMPTY;
+                }
         }
 
         do {
@@ -4918,19 +4946,25 @@ redirect(union node *redir, int flags)
                         if (fd == newfd) {
                                 /* Descriptor wasn't open before redirect.
                                  * Mark it for close in the future */
-                                if (sv && sv->renamed[fd] == EMPTY)
-                                        sv->renamed[fd] = CLOSED;
+                                if (need_to_remember(sv, fd)) {
+                                        if (fd == 2)
+                                                copied_fd2 = CLOSED; /// do we need this?
+                                        sv->two_fd[sv_pos].orig = fd;
+                                        sv->two_fd[sv_pos].copy = CLOSED;
+                                        sv_pos++;
+                                }
                                 continue;
                         }
                 }
-                if (sv && sv->renamed[fd] == EMPTY) {
+                if (need_to_remember(sv, fd)) {
                         /* Copy old descriptor */
                         i = fcntl(fd, F_DUPFD, 10);
                         if (i == -1) {
                                 i = errno;
                                 if (i != EBADF) {
                                         /* Strange error (e.g. "too many files" EMFILE?) */
-                                        /*if (newfd >= 0)*/ close(newfd);
+                                        if (newfd >= 0)
+                                                close(newfd);
                                         errno = i;
                                         ash_msg_and_raise_error("%d: %m", fd);
                                         /* NOTREACHED */
@@ -4938,10 +4972,15 @@ redirect(union node *redir, int flags)
                                 /* EBADF: it is not open - ok */
                         } else {
                                 /* fd is open, save its copy */
-//TODO: CLOEXEC the copy? 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)
-                                sv->renamed[fd] = i;
+/* 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)
+ */
+                                if (fd == 2)
+                                        copied_fd2 = i;
+                                sv->two_fd[sv_pos].orig = fd;
+                                sv->two_fd[sv_pos].copy = i;
+                                sv_pos++;
                                 close(fd);
                         }
                 } else {
@@ -4960,8 +4999,8 @@ redirect(union node *redir, int flags)
         } while ((redir = redir->nfile.next) != NULL);
 
         INT_ON;
-        if ((flags & REDIR_SAVEFD2) && sv && sv->renamed[2] >= 0)
-                preverrout_fd = sv->renamed[2];
+        if ((flags & REDIR_SAVEFD2) && copied_fd2 >= 0)
+                preverrout_fd = copied_fd2;
 }
 
 /*
@@ -4977,18 +5016,19 @@ popredir(int drop)
                 return;
         INT_OFF;
         rp = redirlist;
-        for (i = 0; i < 10; i++) {
-                if (rp->renamed[i] == CLOSED) {
+        for (i = 0; i < rp->pair_count; i++) {
+                int fd = rp->two_fd[i].orig;
+                if (rp->two_fd[i].copy == CLOSED) {
                         if (!drop)
-                                close(i);
+                                close(fd);
                         continue;
                 }
-                if (rp->renamed[i] != EMPTY) {
+                if (rp->two_fd[i].copy != EMPTY) {
                         if (!drop) {
-                                close(i);
-                                copyfd(rp->renamed[i], i);
+                                close(fd);
+                                copyfd(rp->two_fd[i].copy, fd);
                         }
-                        close(rp->renamed[i]);
+                        close(rp->two_fd[i].copy);
                 }
         }
         redirlist = rp->next;
@@ -10003,12 +10043,15 @@ makename(void)
 static void
 fixredir(union node *n, const char *text, int err)
 {
+        int fd;
+
         TRACE(("Fix redir %s %d\n", text, err));
         if (!err)
                 n->ndup.vname = NULL;
 
-        if (isdigit(text[0]) && text[1] == '\0')
-                n->ndup.dupfd = text[0] - '0';
+        fd = bb_strtou(text, NULL, 10);
+        if (!errno && fd >= 0)
+                n->ndup.dupfd = fd;
         else if (LONE_DASH(text))
                 n->ndup.dupfd = -1;
         else {
@@ -10630,7 +10673,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
 
                         }
                         c = pgetc_macro();
-                } /* for(;;) */
+                } /* for (;;) */
         }
  endword:
 #if ENABLE_ASH_MATH_SUPPORT
@@ -10650,12 +10693,20 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
         if (eofmark == NULL) {
                 if ((c == '>' || c == '<')
                  && quotef == 0
-                 && len <= 2 // THIS LIMITS fd to 1 char: N>file, but no NN>file!
-                 && (*out == '\0' || isdigit(*out))
+                // && len <= 2 // THIS LIMITS fd to 1 char: N>file, but no NN>file!
+                // && (*out == '\0' || isdigit(*out))
                 ) {
-                        PARSEREDIR();
-                        lasttoken = TREDIR;
-                        return lasttoken;
+                        int maxlen = 9 + 1; /* max 9 digit fd#: 999999999 */
+                        char *np = out;
+                        while (--maxlen && isdigit(*np))
+                                np++;
+                        if (*np == '\0') {
+                                PARSEREDIR(); /* passed as params: out, c */
+                                lasttoken = TREDIR;
+                                return lasttoken;
+                        }
+                        /* else: non-number X seen, interpret it
+                         * as "NNNX>file" = "NNNX >file" */
                 }
                 pungetc();
         }
@@ -10710,7 +10761,8 @@ checkend: {
  * first character of the redirection operator.
  */
 parseredir: {
-        char fd = *out;
+        /* out is already checked to be a valid number or "" */
+        int fd = (*out == '\0' ? -1 : atoi(out));
         union node *np;
 
         np = stzalloc(sizeof(struct nfile));
@@ -10762,8 +10814,8 @@ parseredir: {
                         break;
                 }
         }
-        if (fd != '\0')
-                np->nfile.fd = fd - '0';
+        if (fd >= 0)
+                np->nfile.fd = fd;
         redirnode = np;
         goto parseredir_return;
 }