shell: split read builtin from ash

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

12 files changed, 379 insertions, 213 deletions

diff --git a/shell/Kbuild b/shell/Kbuild
index 03960a8ea..155ac6f0f 100644
--- a/shell/Kbuild
+++ b/shell/Kbuild
@@ -5,7 +5,7 @@
 # Licensed under the GPL v2, see the file LICENSE in this tarball.
 
 lib-y:=
-lib-$(CONFIG_ASH)      += ash.o ash_ptr_hack.o
+lib-$(CONFIG_ASH)      += ash.o ash_ptr_hack.o shell_common.o builtin_read.o
 lib-$(CONFIG_HUSH)     += hush.o match.o
 lib-$(CONFIG_CTTYHACK) += cttyhack.o
 
diff --git a/shell/ash.c b/shell/ash.c
index e668f41e1..c7deffd08 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2,18 +2,18 @@
 /*
  * ash shell port for busybox
  *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Original BSD copyright notice is retained at the end of this file.
+ *
  * Copyright (c) 1989, 1991, 1993, 1994
  *      The Regents of the University of California.  All rights reserved.
  *
  * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
  * was re-ported from NetBSD and debianized.
  *
- * This code is derived from software contributed to Berkeley by
- * Kenneth Almquist.
- *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
- *
- * Original BSD copyright notice is retained at the end of this file.
  */
 
 /*
@@ -34,8 +34,6 @@
 
 #define PROFILE 0
 
-#define IFS_BROKEN
-
 #define JOBS ENABLE_ASH_JOB_CONTROL
 
 #if DEBUG
@@ -50,6 +48,9 @@
 #include <paths.h>
 #include <setjmp.h>
 #include <fnmatch.h>
+
+#include "shell_common.h"
+#include "builtin_read.h"
 #include "math.h"
 #if ENABLE_ASH_RANDOM_SUPPORT
 # include "random.h"
@@ -1737,13 +1738,6 @@ struct localvar {
 # define VDYNAMIC       0
 #endif
 
-#ifdef IFS_BROKEN
-static const char defifsvar[] ALIGN1 = "IFS= \t\n";
-#define defifs (defifsvar + 4)
-#else
-static const char defifs[] ALIGN1 = " \t\n";
-#endif
-
 
 /* Need to be before varinit_data[] */
 #if ENABLE_LOCALE_SUPPORT
@@ -1774,7 +1768,7 @@ static const struct {
         const char *text;
         void (*func)(const char *) FAST_FUNC;
 } varinit_data[] = {
-#ifdef IFS_BROKEN
+#if IFS_BROKEN
         { VSTRFIXED|VTEXTFIXED       , defifsvar   , NULL            },
 #else
         { VSTRFIXED|VTEXTFIXED|VUNSET, "IFS\0"     , NULL            },
@@ -12499,211 +12493,53 @@ typedef enum __rlimit_resource rlim_t;
 static int FAST_FUNC
 readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
-        static const char *const arg_REPLY[] = { "REPLY", NULL };
-
-        char **ap;
-        int backslash;
-        char c;
-        int rflag;
-        char *prompt;
-        const char *ifs;
-        char *p;
-        int startword;
-        int status;
+        char *opt_n = NULL;
+        char *opt_p = NULL;
+        char *opt_t = NULL;
+        char *opt_u = NULL;
+        int read_flags = 0;
+        const char *r;
         int i;
-        int fd = 0;
-#if ENABLE_ASH_READ_NCHARS
-        int nchars = 0; /* if != 0, -n is in effect */
-        int silent = 0;
-        struct termios tty, old_tty;
-#endif
-#if ENABLE_ASH_READ_TIMEOUT
-        unsigned end_ms = 0;
-        unsigned timeout = 0;
-#endif
-
-        rflag = 0;
-        prompt = NULL;
-        while ((i = nextopt("p:u:r"
-                IF_ASH_READ_TIMEOUT("t:")
-                IF_ASH_READ_NCHARS("n:s")
-        )) != '\0') {
+
+        while ((i = nextopt("p:u:rt:n:s")) != '\0') {
                 switch (i) {
                 case 'p':
-                        prompt = optionarg;
+                        opt_p = optionarg;
                         break;
-#if ENABLE_ASH_READ_NCHARS
                 case 'n':
-                        nchars = bb_strtou(optionarg, NULL, 10);
-                        if (nchars < 0 || errno)
-                                ash_msg_and_raise_error("invalid count");
-                        /* nchars == 0: off (bash 3.2 does this too) */
+                        opt_n = optionarg;
                         break;
                 case 's':
-                        silent = 1;
+                        read_flags |= BUILTIN_READ_SILENT;
                         break;
-#endif
-#if ENABLE_ASH_READ_TIMEOUT
                 case 't':
-                        timeout = bb_strtou(optionarg, NULL, 10);
-                        if (errno || timeout > UINT_MAX / 2048)
-                                ash_msg_and_raise_error("invalid timeout");
-                        timeout *= 1000;
-#if 0 /* even bash have no -t N.NNN support */
-                        ts.tv_sec = bb_strtou(optionarg, &p, 10);
-                        ts.tv_usec = 0;
-                        /* EINVAL means number is ok, but not terminated by NUL */
-                        if (*p == '.' && errno == EINVAL) {
-                                char *p2;
-                                if (*++p) {
-                                        int scale;
-                                        ts.tv_usec = bb_strtou(p, &p2, 10);
-                                        if (errno)
-                                                ash_msg_and_raise_error("invalid timeout");
-                                        scale = p2 - p;
-                                        /* normalize to usec */
-                                        if (scale > 6)
-                                                ash_msg_and_raise_error("invalid timeout");
-                                        while (scale++ < 6)
-                                                ts.tv_usec *= 10;
-                                }
-                        } else if (ts.tv_sec < 0 || errno) {
-                                ash_msg_and_raise_error("invalid timeout");
-                        }
-                        if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
-                                ash_msg_and_raise_error("invalid timeout");
-                        }
-#endif /* if 0 */
+                        opt_t = optionarg;
                         break;
-#endif
                 case 'r':
-                        rflag = 1;
+                        read_flags |= BUILTIN_READ_RAW;
                         break;
                 case 'u':
-                        fd = bb_strtou(optionarg, NULL, 10);
-                        if (fd < 0 || errno)
-                                ash_msg_and_raise_error("invalid file descriptor");
+                        opt_u = optionarg;
                         break;
                 default:
                         break;
                 }
         }
-        if (prompt && isatty(fd)) {
-                out2str(prompt);
-        }
-        ap = argptr;
-        if (*ap == NULL)
-                ap = (char**)arg_REPLY;
-        ifs = bltinlookup("IFS");
-        if (ifs == NULL)
-                ifs = defifs;
-#if ENABLE_ASH_READ_NCHARS
-        tcgetattr(fd, &tty);
-        old_tty = tty;
-        if (nchars || silent) {
-                if (nchars) {
-                        tty.c_lflag &= ~ICANON;
-                        tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
-                }
-                if (silent) {
-                        tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
-                }
-                /* if tcgetattr failed, tcsetattr will fail too.
-                 * Ignoring, it's harmless. */
-                tcsetattr(fd, TCSANOW, &tty);
-        }
-#endif
 
-        status = 0;
-        startword = 1;
-        backslash = 0;
-#if ENABLE_ASH_READ_TIMEOUT
-        if (timeout) /* NB: ensuring end_ms is nonzero */
-                end_ms = ((unsigned)monotonic_ms() + timeout) | 1;
-#endif
-        STARTSTACKSTR(p);
-        do {
-                const char *is_ifs;
-
-#if ENABLE_ASH_READ_TIMEOUT
-                if (end_ms) {
-                        struct pollfd pfd[1];
-                        pfd[0].fd = fd;
-                        pfd[0].events = POLLIN;
-                        timeout = end_ms - (unsigned)monotonic_ms();
-                        if ((int)timeout <= 0 /* already late? */
-                         || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
-                        ) { /* timed out! */
-#if ENABLE_ASH_READ_NCHARS
-                                tcsetattr(fd, TCSANOW, &old_tty);
-#endif
-                                return 1;
-                        }
-                }
-#endif
-                if (nonblock_safe_read(fd, &c, 1) != 1) {
-                        status = 1;
-                        break;
-                }
-                if (c == '\0')
-                        continue;
-                if (backslash) {
-                        backslash = 0;
-                        if (c != '\n')
-                                goto put;
-                        continue;
-                }
-                if (!rflag && c == '\\') {
-                        backslash = 1;
-                        continue;
-                }
-                if (c == '\n')
-                        break;
-                /* $IFS splitting */
-/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
-                is_ifs = strchr(ifs, c);
-                if (startword && is_ifs) {
-                        if (isspace(c))
-                                continue;
-                        /* it is a non-space ifs char */
-                        startword--;
-                        if (startword == 1) /* first one? */
-                                continue; /* yes, it is not next word yet */
-                }
-                startword = 0;
-                if (ap[1] != NULL && is_ifs) {
-                        const char *beg;
-                        STACKSTRNUL(p);
-                        beg = stackblock();
-                        setvar(*ap, beg, 0);
-                        ap++;
-                        /* can we skip one non-space ifs char? (2: yes) */
-                        startword = isspace(c) ? 2 : 1;
-                        STARTSTACKSTR(p);
-                        continue;
-                }
- put:
-                STPUTC(c, p);
-        }
-/* end of do {} while: */
-#if ENABLE_ASH_READ_NCHARS
-        while (--nchars);
-#else
-        while (1);
-#endif
+        r = builtin_read(setvar,
+                argptr,
+                bltinlookup("IFS"), /* can be NULL */
+                read_flags,
+                opt_n,
+                opt_p,
+                opt_t,
+                opt_u
+        );
 
-#if ENABLE_ASH_READ_NCHARS
-        tcsetattr(fd, TCSANOW, &old_tty);
-#endif
+        if ((uintptr_t)r > 1)
+                ash_msg_and_raise_error(r);
 
-        STACKSTRNUL(p);
-        /* Remove trailing space ifs chars */
-        while ((char *)stackblock() <= --p && isspace(*p) && strchr(ifs, *p) != NULL)
-                *p = '\0';
-        setvar(*ap, stackblock(), 0);
-        while (*++ap != NULL)
-                setvar(*ap, nullstr, 0);
-        return status;
+        return (uintptr_t)r;
 }
 
 static int FAST_FUNC
diff --git a/shell/ash_test/ash-read/read_REPLY.right b/shell/ash_test/ash-read/read_REPLY.right
new file mode 100644
index 000000000..59f5d5487
--- /dev/null
+++ b/shell/ash_test/ash-read/read_REPLY.right
@@ -0,0 +1,5 @@
+test 1: |  abc1  def  |
+test 2: |  \abc2  d\ef  |
+test 3: |abc3  def|
+test 4: |\abc4  d\ef|
+Done
diff --git a/shell/ash_test/ash-read/read_REPLY.tests b/shell/ash_test/ash-read/read_REPLY.tests
new file mode 100755
index 000000000..ba20cae8d
--- /dev/null
+++ b/shell/ash_test/ash-read/read_REPLY.tests
@@ -0,0 +1,5 @@
+echo '  \abc1  d\ef  ' | ( read         ; echo "test 1: |$REPLY|" )
+echo '  \abc2  d\ef  ' | ( read -r      ; echo "test 2: |$REPLY|" )
+echo '  \abc3  d\ef  ' | ( read    REPLY; echo "test 3: |$REPLY|" )
+echo '  \abc4  d\ef  ' | ( read -r REPLY; echo "test 4: |$REPLY|" )
+echo Done
diff --git a/shell/builtin_read.c b/shell/builtin_read.c
new file mode 100644
index 000000000..7f667e9c1
--- /dev/null
+++ b/shell/builtin_read.c
@@ -0,0 +1,205 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Adapted from ash applet code
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Copyright (c) 1989, 1991, 1993, 1994
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
+ * was re-ported from NetBSD and debianized.
+ *
+ * Copyright (c) 2010 Denys Vlasenko
+ * Split from ash.c
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ */
+#include "libbb.h"
+#include "shell_common.h"
+#include "builtin_read.h"
+
+const char* FAST_FUNC
+builtin_read(void (*setvar)(const char *name, const char *val, int flags),
+        char       **argv,
+        const char *ifs,
+        int        read_flags,
+        const char *opt_n,
+        const char *opt_p,
+        const char *opt_t,
+        const char *opt_u
+)
+{
+        static const char *const arg_REPLY[] = { "REPLY", NULL };
+
+        unsigned end_ms; /* -t TIMEOUT */
+        int fd; /* -u FD */
+        int nchars; /* -n NUM */
+        char *buffer;
+        struct termios tty, old_tty;
+        const char *retval;
+        int bufpos; /* need to be able to hold -1 */
+        int startword;
+        smallint backslash;
+
+        nchars = 0; /* if != 0, -n is in effect */
+        if (opt_n) {
+                nchars = bb_strtou(opt_n, NULL, 10);
+                if (nchars < 0 || errno)
+                        return "invalid count";
+                /* note: "-n 0": off (bash 3.2 does this too) */
+        }
+        end_ms = 0;
+        if (opt_t) {
+                end_ms = bb_strtou(opt_t, NULL, 10);
+                if (errno || end_ms > UINT_MAX / 2048)
+                        return "invalid timeout";
+                end_ms *= 1000;
+#if 0 /* even bash has no -t N.NNN support */
+                ts.tv_sec = bb_strtou(opt_t, &p, 10);
+                ts.tv_usec = 0;
+                /* EINVAL means number is ok, but not terminated by NUL */
+                if (*p == '.' && errno == EINVAL) {
+                        char *p2;
+                        if (*++p) {
+                                int scale;
+                                ts.tv_usec = bb_strtou(p, &p2, 10);
+                                if (errno)
+                                        return "invalid timeout";
+                                scale = p2 - p;
+                                /* normalize to usec */
+                                if (scale > 6)
+                                        return "invalid timeout";
+                                while (scale++ < 6)
+                                        ts.tv_usec *= 10;
+                        }
+                } else if (ts.tv_sec < 0 || errno) {
+                        return "invalid timeout";
+                }
+                if (!(ts.tv_sec | ts.tv_usec)) { /* both are 0? */
+                        return "invalid timeout";
+                }
+#endif /* if 0 */
+        }
+        fd = STDIN_FILENO;
+        if (opt_u) {
+                fd = bb_strtou(opt_u, NULL, 10);
+                if (fd < 0 || errno)
+                        return "invalid file descriptor";
+        }
+
+        if (opt_p && isatty(fd)) {
+                fputs(opt_p, stderr);
+                fflush_all();
+        }
+
+        if (argv[0] == NULL)
+                argv = (char**)arg_REPLY;
+        if (ifs == NULL)
+                ifs = defifs;
+
+        if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
+                tcgetattr(fd, &tty);
+                old_tty = tty;
+                if (nchars) {
+                        tty.c_lflag &= ~ICANON;
+                        tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
+                }
+                if (read_flags & BUILTIN_READ_SILENT) {
+                        tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
+                }
+                /* This forces execution of "restoring" tcgetattr later */
+                read_flags |= BUILTIN_READ_SILENT;
+                /* if tcgetattr failed, tcsetattr will fail too.
+                 * Ignoring, it's harmless. */
+                tcsetattr(fd, TCSANOW, &tty);
+        }
+
+        retval = (const char *)(uintptr_t)0;
+        startword = 1;
+        backslash = 0;
+        if (end_ms) /* NB: end_ms stays nonzero: */
+                end_ms = ((unsigned)monotonic_ms() + end_ms) | 1;
+        buffer = NULL;
+        bufpos = 0;
+        do {
+                char c;
+                const char *is_ifs;
+
+                if (end_ms) {
+                        int timeout;
+                        struct pollfd pfd[1];
+
+                        pfd[0].fd = fd;
+                        pfd[0].events = POLLIN;
+                        timeout = end_ms - (unsigned)monotonic_ms();
+                        if (timeout <= 0 /* already late? */
+                         || safe_poll(pfd, 1, timeout) != 1 /* no? wait... */
+                        ) { /* timed out! */
+                                retval = (const char *)(uintptr_t)1;
+                                goto ret;
+                        }
+                }
+
+                if ((bufpos & 0xff) == 0)
+                        buffer = xrealloc(buffer, bufpos + 0x100);
+                if (nonblock_safe_read(fd, &buffer[bufpos], 1) != 1) {
+                        retval = (const char *)(uintptr_t)1;
+                        break;
+                }
+                c = buffer[bufpos];
+                if (c == '\0')
+                        continue;
+                if (backslash) {
+                        backslash = 0;
+                        if (c != '\n')
+                                goto put;
+                        continue;
+                }
+                if (!(read_flags & BUILTIN_READ_RAW) && c == '\\') {
+                        backslash = 1;
+                        continue;
+                }
+                if (c == '\n')
+                        break;
+                /* $IFS splitting */
+/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
+                is_ifs = strchr(ifs, c);
+                if (startword && is_ifs) {
+                        if (isspace(c))
+                                continue;
+                        /* it is a non-space ifs char */
+                        startword--;
+                        if (startword == 1) /* first one? */
+                                continue; /* yes, it is not next word yet */
+                }
+                startword = 0;
+                if (argv[1] != NULL && is_ifs) {
+                        buffer[bufpos] = '\0';
+                        bufpos = 0;
+                        setvar(*argv, buffer, 0);
+                        argv++;
+                        /* can we skip one non-space ifs char? (2: yes) */
+                        startword = isspace(c) ? 2 : 1;
+                        continue;
+                }
+ put:
+                bufpos++;
+        } while (--nchars);
+
+        /* Remove trailing space ifs chars */
+        while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
+                continue;
+        buffer[bufpos + 1] = '\0';
+
+        setvar(*argv, buffer, 0);
+
+        while (*++argv != NULL)
+                setvar(*argv, "", 0);
+ ret:
+        free(buffer);
+        if (read_flags & BUILTIN_READ_SILENT)
+                tcsetattr(fd, TCSANOW, &old_tty);
+        return retval;
+}
diff --git a/shell/builtin_read.h b/shell/builtin_read.h
new file mode 100644
index 000000000..930d01428
--- /dev/null
+++ b/shell/builtin_read.h
@@ -0,0 +1,42 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Adapted from ash applet code
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Copyright (c) 1989, 1991, 1993, 1994
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
+ * was re-ported from NetBSD and debianized.
+ *
+ * Copyright (c) 2010 Denys Vlasenko
+ * Split from ash.c
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ */
+#ifndef SHELL_BUILTIN_READ_H
+#define SHELL_BUILTIN_READ_H 1
+
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
+
+enum {
+        BUILTIN_READ_SILENT = 1 << 0,
+        BUILTIN_READ_RAW    = 1 << 1,
+};
+
+const char* FAST_FUNC
+builtin_read(void (*setvar)(const char *name, const char *val, int flags),
+        char       **argv,
+        const char *ifs,
+        int        read_flags,
+        const char *opt_n,
+        const char *opt_p,
+        const char *opt_t,
+        const char *opt_u
+);
+
+POP_SAVED_FUNCTION_VISIBILITY
+
+#endif
diff --git a/shell/match.c b/shell/match.c
index a7101ef7e..fb6a38ef1 100644
--- a/shell/match.c
+++ b/shell/match.c
@@ -1,16 +1,16 @@
 /*
  * ##/%% variable matching code ripped out of ash shell for code sharing
  *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ *
  * Copyright (c) 1989, 1991, 1993, 1994
  *      The Regents of the University of California.  All rights reserved.
  *
  * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
  * was re-ported from NetBSD and debianized.
- *
- * This code is derived from software contributed to Berkeley by
- * Kenneth Almquist.
- *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 #ifdef STANDALONE
 # include <stdbool.h>
diff --git a/shell/match.h b/shell/match.h
index 90597ee54..98ff8745a 100644
--- a/shell/match.h
+++ b/shell/match.h
@@ -1,5 +1,8 @@
 /* match.h - interface to shell ##/%% matching code */
 
+#ifndef SHELL_MATCH_H
+#define SHELL_MATCH_H 1
+
 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
 typedef char *(*scan_t)(char *string, char *match, bool match_at_left);
@@ -24,3 +27,5 @@ static inline scan_t pick_scan(char op1, char op2, bool *match_at_left)
 }
 
 POP_SAVED_FUNCTION_VISIBILITY
+
+#endif
diff --git a/shell/math.c b/shell/math.c
index fc20def62..76159b299 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -1,20 +1,17 @@
 /*
  * arithmetic code ripped out of ash shell for code sharing
  *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Original BSD copyright notice is retained at the end of this file.
+ *
  * Copyright (c) 1989, 1991, 1993, 1994
  *      The Regents of the University of California.  All rights reserved.
  *
  * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
  * was re-ported from NetBSD and debianized.
  *
- * This code is derived from software contributed to Berkeley by
- * Kenneth Almquist.
- *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
- *
- * Original BSD copyright notice is retained at the end of this file.
- */
-/*
  * rewrite arith.y to micro stack based cryptic algorithm by
  * Copyright (c) 2001 Aaron Lehmann <aaronl@vitelus.com>
  *
@@ -25,6 +22,8 @@
  * used in busybox and size optimizations,
  * rewrote arith (see notes to this), added locale support,
  * rewrote dynamic variables.
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 #include "libbb.h"
 #include "math.h"
diff --git a/shell/random.h b/shell/random.h
index e22a2e88b..08563402c 100644
--- a/shell/random.h
+++ b/shell/random.h
@@ -6,6 +6,10 @@
  *
  * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
+#ifndef SHELL_RANDOM_H
+#define SHELL_RANDOM_H 1
+
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
 typedef struct random_t {
         /* Random number generators */
@@ -23,3 +27,7 @@ typedef struct random_t {
         ((rnd)->galois_LFSR = 0)
 
 uint32_t next_random(random_t *rnd) FAST_FUNC;
+
+POP_SAVED_FUNCTION_VISIBILITY
+
+#endif
diff --git a/shell/shell_common.c b/shell/shell_common.c
new file mode 100644
index 000000000..99bb91c6f
--- /dev/null
+++ b/shell/shell_common.c
@@ -0,0 +1,26 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Adapted from ash applet code
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Copyright (c) 1989, 1991, 1993, 1994
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
+ * was re-ported from NetBSD and debianized.
+ *
+ * Copyright (c) 2010 Denys Vlasenko
+ * Split from ash.c
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ */
+#include "libbb.h"
+#include "shell_common.h"
+
+#if IFS_BROKEN
+const char defifsvar[] ALIGN1 = "IFS= \t\n";
+#else
+const char defifs[] ALIGN1 = " \t\n";
+#endif
diff --git a/shell/shell_common.h b/shell/shell_common.h
new file mode 100644
index 000000000..a9e9a2239
--- /dev/null
+++ b/shell/shell_common.h
@@ -0,0 +1,35 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Adapted from ash applet code
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Copyright (c) 1989, 1991, 1993, 1994
+ *      The Regents of the University of California.  All rights reserved.
+ *
+ * Copyright (c) 1997-2005 Herbert Xu <herbert@gondor.apana.org.au>
+ * was re-ported from NetBSD and debianized.
+ *
+ * Copyright (c) 2010 Denys Vlasenko
+ * Split from ash.c
+ *
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ */
+#ifndef SHELL_COMMON_H
+#define SHELL_COMMON_H 1
+
+PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
+
+#define IFS_BROKEN 1
+
+#if IFS_BROKEN
+extern const char defifsvar[]; /* "IFS= \t\n" */
+#define defifs (defifsvar + 4)
+#else
+extern const char defifs[]; /* " \t\n" */
+#endif
+
+POP_SAVED_FUNCTION_VISIBILITY
+
+#endif