msh: cleaning up for -Wwrite-strings part #2

1 files changed, 648 insertions, 675 deletions

diff --git a/shell/msh.c b/shell/msh.c
index b71066abc..d821dfd20 100644
--- a/shell/msh.c
+++ b/shell/msh.c
@@ -17,6 +17,8 @@
 #include <sys/times.h>
 #include "busybox.h"
 
+extern char **environ;
+
 
 /*#define MSHDEBUG 1*/
 
@@ -181,10 +183,7 @@ static const char *const T_CMD_NAMES[] = {
 
 /* PROTOTYPES */
 static int newfile(char *s);
-static char *findeq(char *cp);
 static char *cclass(char *p, int sub);
-static void initarea(void);
-extern int msh_main(int argc, char **argv);
 
 
 struct brkcon {
@@ -254,6 +253,13 @@ static int yynerrs;				/* yacc */
 static char line[LINELIM];
 static char *elinep;
 
+#if ENABLE_FEATURE_EDITING
+static char *current_prompt;
+static line_input_t *line_input_state;
+#endif
+
+static int areanum;                             /* current allocation area */
+
 
 /*
  * other functions
@@ -262,12 +268,9 @@ typedef int (*builtin_func_ptr)(struct op *);
 static builtin_func_ptr inbuilt(char *s);
 
 static char *rexecve(char *c, char **v, char **envp);
-static char *space(int n);
-static char *strsave(char *s, int a);
 static char *evalstr(char *cp, int f);
 static char *putn(int n);
 static char *unquote(char *as);
-static struct var *lookup(char *n);
 static int rlookup(char *n);
 static struct wdblock *glob(char *cp, struct wdblock *wb);
 static int my_getc(int ec);
@@ -291,16 +294,6 @@ static void runtrap(int i);
 static int gmatch(char *s, char *p);
 
 
-/*
- * error handling
- */
-static void leave(void);                /* abort shell (or fail in subshell) */
-static void fail(void);                 /* fail but return to process next command */
-static void warn(const char *s);
-static void sig(int i);                 /* default signal handler */
-
-
-
 /* -------- area stuff -------- */
 
 #define REGSIZE   sizeof(struct region)
@@ -318,7 +311,6 @@ struct region {
 };
 
 
-
 /* -------- grammar stuff -------- */
 typedef union {
         char *cp;
@@ -327,32 +319,32 @@ typedef union {
         struct op *o;
 } YYSTYPE;
 
-#define WORD    256
-#define LOGAND  257
-#define LOGOR   258
-#define BREAK   259
-#define IF              260
-#define THEN    261
-#define ELSE    262
-#define ELIF    263
-#define FI              264
-#define CASE    265
-#define ESAC    266
-#define FOR             267
-#define WHILE   268
-#define UNTIL   269
-#define DO              270
-#define DONE    271
-#define IN              272
+#define WORD    256
+#define LOGAND  257
+#define LOGOR   258
+#define BREAK   259
+#define IF      260
+#define THEN    261
+#define ELSE    262
+#define ELIF    263
+#define FI      264
+#define CASE    265
+#define ESAC    266
+#define FOR     267
+#define WHILE   268
+#define UNTIL   269
+#define DO      270
+#define DONE    271
+#define IN      272
 /* Added for "." file expansion */
-#define DOT             273
+#define DOT     273
 
 #define YYERRCODE 300
 
 /* flags to yylex */
-#define CONTIN  01                              /* skip new lines to complete command */
+#define CONTIN 01     /* skip new lines to complete command */
 
-#define SYNTAXERR       zzerr()
+#define SYNTAXERR zzerr()
 
 static struct op *pipeline(int cf);
 static struct op *andor(void);
@@ -400,16 +392,6 @@ struct var {
 #define GETCELL 04                              /* name & value space was got with getcell */
 
 static int yyparse(void);
-static struct var *lookup(char *n);
-static void setval(struct var *vp, char *val);
-static void nameval(struct var *vp, char *val, char *name);
-static void export(struct var *vp);
-static void ronly(struct var *vp);
-static int isassign(char *s);
-static int checkname(char *cp);
-static int assign(char *s, int cf);
-static void putvlist(int f, int out);
-static int eqname(char *n1, char *n2);
 
 static int execute(struct op *t, int *pin, int *pout, int act);
 
@@ -519,23 +501,6 @@ static struct wdblock *addword(char *wd, struct wdblock *wb);
 static struct wdblock *newword(int nw);
 static char **getwords(struct wdblock *wb);
 
-/* -------- area.h -------- */
-
-/*
- * storage allocation
- */
-static char *getcell(unsigned nbytes);
-static void garbage(void);
-static void setarea(char *cp, int a);
-static int getarea(char *cp);
-static void freearea(int a);
-static void freecell(char *cp);
-static int areanum;                             /* current allocation area */
-
-#define NEW(type)   (type *)getcell(sizeof(type))
-#define DELETE(obj)     freecell((char *)obj)
-
-
 /* -------- misc stuff -------- */
 
 static int forkexec(struct op *t, int *pin, int *pout, int act, char **wp);
@@ -674,9 +639,8 @@ static const struct builtincmd builtincmds[] = {
 static struct op *scantree(struct op *);
 static struct op *dowholefile(int, int);
 
-/* Globals */
-extern char **environ;                  /* environment pointer */
 
+/* Globals */
 static char **dolv;
 static int dolc;
 static int exstat;
@@ -773,219 +737,457 @@ void print_tree(struct op *head)
 #endif                                                  /* MSHDEBUG */
 
 
-#if ENABLE_FEATURE_EDITING
-static char *current_prompt;
-#endif
+/* fail but return to process next command */
+static void fail(void)
+{
+        longjmp(failpt, 1);
+        /* NOTREACHED */
+}
+
+/* abort shell (or fail in subshell) */
+static void leave(void) ATTRIBUTE_NORETURN;
+static void leave(void)
+{
+        DBGPRINTF(("LEAVE: leave called!\n"));
+
+        if (execflg)
+                fail();
+        scraphere();
+        freehere(1);
+        runtrap(0);
+        _exit(exstat);
+        /* NOTREACHED */
+}
+
+static void warn(const char *s)
+{
+        if (*s) {
+                prs(s);
+                exstat = -1;
+        }
+        prs("\n");
+        if (flag['e'])
+                leave();
+}
+
+static void err(const char *s)
+{
+        warn(s);
+        if (flag['n'])
+                return;
+        if (!interactive)
+                leave();
+        if (e.errpt)
+                longjmp(e.errpt, 1);
+        closeall();
+        e.iop = e.iobase = iostack;
+}
+
+/* -------- area.c -------- */
 
-/* -------- sh.c -------- */
 /*
- * shell
+ * All memory between (char *)areabot and (char *)(areatop+1) is
+ * exclusively administered by the area management routines.
+ * It is assumed that sbrk() and brk() manipulate the high end.
  */
 
+#define sbrk(X) ({ \
+        void * __q = (void *)-1; \
+        if (brkaddr + (int)(X) < brktop) { \
+                __q = brkaddr; \
+                brkaddr += (int)(X); \
+        } \
+        __q; \
+})
 
-#if ENABLE_FEATURE_EDITING
-static line_input_t *line_input_state;
-#endif
+static void initarea(void)
+{
+        brkaddr = xmalloc(AREASIZE);
+        brktop = brkaddr + AREASIZE;
 
-int msh_main(int argc, char **argv)
+        while ((long) sbrk(0) & ALIGN)
+                sbrk(1);
+        areabot = (struct region *) sbrk(REGSIZE);
+
+        areabot->next = areabot;
+        areabot->area = BUSY;
+        areatop = areabot;
+        areanxt = areabot;
+}
+
+static char *getcell(unsigned nbytes)
 {
-        int f;
-        char *s;
-        int cflag;
-        char *name, **ap;
-        int (*iof) (struct ioarg *);
+        int nregio;
+        struct region *p, *q;
+        int i;
 
-#if ENABLE_FEATURE_EDITING
-        line_input_state = new_line_input_t(FOR_SHELL);
-#endif
+        if (nbytes == 0) {
+                puts("getcell(0)");
+                abort();
+        }
+        /* silly and defeats the algorithm */
+        /*
+         * round upwards and add administration area
+         */
+        nregio = (nbytes + (REGSIZE - 1)) / REGSIZE + 1;
+        p = areanxt;
+        for (;;) {
+                if (p->area > areanum) {
+                        /*
+                         * merge free cells
+                         */
+                        while ((q = p->next)->area > areanum && q != areanxt)
+                                p->next = q->next;
+                        /*
+                         * exit loop if cell big enough
+                         */
+                        if (q >= p + nregio)
+                                goto found;
+                }
+                p = p->next;
+                if (p == areanxt)
+                        break;
+        }
+        i = nregio >= GROWBY ? nregio : GROWBY;
+        p = (struct region *) sbrk(i * REGSIZE);
+        if (p == (struct region *) -1)
+                return NULL;
+        p--;
+        if (p != areatop) {
+                puts("not contig");
+                abort();                                /* allocated areas are contiguous */
+        }
+        q = p + i;
+        p->next = q;
+        p->area = FREE;
+        q->next = areabot;
+        q->area = BUSY;
+        areatop = q;
+ found:
+        /*
+         * we found a FREE area big enough, pointed to by 'p', and up to 'q'
+         */
+        areanxt = p + nregio;
+        if (areanxt < q) {
+                /*
+                 * split into requested area and rest
+                 */
+                if (areanxt + 1 > q) {
+                        puts("OOM");
+                        abort();                        /* insufficient space left for admin */
+                }
+                areanxt->next = q;
+                areanxt->area = FREE;
+                p->next = areanxt;
+        }
+        p->area = areanum;
+        return (char *) (p + 1);
+}
 
-        DBGPRINTF(("MSH_MAIN: argc %d, environ %p\n", argc, environ));
+static void freecell(char *cp)
+{
+        struct region *p;
 
-        initarea();
-        ap = environ;
-        if (ap != NULL) {
-                while (*ap)
-                        assign(*ap++, !COPYV);
-                for (ap = environ; *ap;)
-                        export(lookup(*ap++));
+        p = (struct region *) cp;
+        if (p != NULL) {
+                p--;
+                if (p < areanxt)
+                        areanxt = p;
+                p->area = FREE;
         }
-        closeall();
-        areanum = 1;
+}
+#define DELETE(obj) freecell((char *)obj)
 
-        shell = lookup("SHELL");
-        if (shell->value == null)
-                setval(shell, (char *)DEFAULT_SHELL);
-        export(shell);
+static void freearea(int a)
+{
+        struct region *p, *top;
 
-        homedir = lookup("HOME");
-        if (homedir->value == null)
-                setval(homedir, "/");
-        export(homedir);
+        top = areatop;
+        for (p = areabot; p != top; p = p->next)
+                if (p->area >= a)
+                        p->area = FREE;
+}
 
-        setval(lookup("$"), putn(getpid()));
+static void setarea(char *cp, int a)
+{
+        struct region *p;
 
-        path = lookup("PATH");
-        if (path->value == null) {
-                if (geteuid() == 0)
-                        setval(path, "/sbin:/bin:/usr/sbin:/usr/bin");
-                else
-                        setval(path, "/bin:/usr/bin");
-        }
-        export(path);
+        p = (struct region *) cp;
+        if (p != NULL)
+                (p - 1)->area = a;
+}
 
-        ifs = lookup("IFS");
-        if (ifs->value == null)
-                setval(ifs, " \t\n");
+static int getarea(char *cp)
+{
+        return ((struct region *) cp - 1)->area;
+}
 
-#ifdef MSHDEBUG
-        mshdbg_var = lookup("MSHDEBUG");
-        if (mshdbg_var->value == null)
-                setval(mshdbg_var, "0");
-#endif
+static void garbage(void)
+{
+        struct region *p, *q, *top;
 
-        prompt = lookup("PS1");
-#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-        if (prompt->value == null)
-#endif
-                setval(prompt, DEFAULT_USER_PROMPT);
-        if (geteuid() == 0) {
-                setval(prompt, DEFAULT_ROOT_PROMPT);
-                prompt->status &= ~EXPORT;
+        top = areatop;
+        for (p = areabot; p != top; p = p->next) {
+                if (p->area > areanum) {
+                        while ((q = p->next)->area > areanum)
+                                p->next = q->next;
+                        areanxt = p;
+                }
+        }
+#ifdef SHRINKBY
+        if (areatop >= q + SHRINKBY && q->area > areanum) {
+                brk((char *) (q + 1));
+                q->next = areabot;
+                q->area = BUSY;
+                areatop = q;
         }
-        cprompt = lookup("PS2");
-#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
-        if (cprompt->value == null)
 #endif
-                setval(cprompt, "> ");
+}
 
-        iof = filechar;
-        cflag = 0;
-        name = *argv++;
-        if (--argc >= 1) {
-                if (argv[0][0] == '-' && argv[0][1] != '\0') {
-                        for (s = argv[0] + 1; *s; s++)
-                                switch (*s) {
-                                case 'c':
-                                        prompt->status &= ~EXPORT;
-                                        cprompt->status &= ~EXPORT;
-                                        setval(prompt, "");
-                                        setval(cprompt, "");
-                                        cflag = 1;
-                                        if (--argc > 0)
-                                                PUSHIO(aword, *++argv, iof = nlchar);
-                                        break;
+static char *space(int n)
+{
+        char *cp;
 
-                                case 'q':
-                                        qflag = SIG_DFL;
-                                        break;
+        cp = getcell(n);
+        if (cp == '\0')
+                err("out of string space");
+        return cp;
+}
 
-                                case 's':
-                                        /* standard input */
-                                        break;
+static char *strsave(const char *s, int a)
+{
+        char *cp;
 
-                                case 't':
-                                        prompt->status &= ~EXPORT;
-                                        setval(prompt, "");
-                                        iof = linechar;
-                                        break;
+        cp = space(strlen(s) + 1);
+        if (cp != NULL) {
+                setarea(cp, a);
+                strcpy(cp, s);
+                return cp;
+        }
+        return "";
+}
 
-                                case 'i':
-                                        interactive++;
-                                default:
-                                        if (*s >= 'a' && *s <= 'z')
-                                                flag[(int) *s]++;
-                                }
-                } else {
-                        argv--;
-                        argc++;
-                }
+/* -------- var.c -------- */
 
-                if (iof == filechar && --argc > 0) {
-                        setval(prompt, "");
-                        setval(cprompt, "");
-                        prompt->status &= ~EXPORT;
-                        cprompt->status &= ~EXPORT;
+static int eqname(const char *n1, const char *n2)
+{
+        for (; *n1 != '=' && *n1 != '\0'; n1++)
+                if (*n2++ != *n1)
+                        return 0;
+        return *n2 == '\0' || *n2 == '=';
+}
 
-/* Shell is non-interactive, activate printf-based debug */
-#ifdef MSHDEBUG
-                        mshdbg = (int) (((char) (mshdbg_var->value[0])) - '0');
-                        if (mshdbg < 0)
-                                mshdbg = 0;
-#endif
-                        DBGPRINTF(("MSH_MAIN: calling newfile()\n"));
+static char *findeq(const char *cp)
+{
+        while (*cp != '\0' && *cp != '=')
+                cp++;
+        return cp;
+}
 
-                        name = *++argv;
-                        if (newfile(name))
-                                exit(1);                /* Exit on error */
-                }
+/*
+ * Find the given name in the dictionary
+ * and return its value.  If the name was
+ * not previously there, enter it now and
+ * return a null value.
+ */
+static struct var *lookup(const char *n)
+{
+        struct var *vp;
+        char *cp;
+        int c;
+        static struct var dummy;
+
+        if (isdigit(*n)) {
+                dummy.name = n;
+                for (c = 0; isdigit(*n) && c < 1000; n++)
+                        c = c * 10 + *n - '0';
+                dummy.status = RONLY;
+                dummy.value = (c <= dolc ? dolv[c] : null);
+                return &dummy;
+        }
+        for (vp = vlist; vp; vp = vp->next)
+                if (eqname(vp->name, n))
+                        return vp;
+        cp = findeq(n);
+        vp = (struct var *) space(sizeof(*vp));
+        if (vp == 0 || (vp->name = space((int) (cp - n) + 2)) == 0) {
+                dummy.name = dummy.value = "";
+                return &dummy;
         }
+        for (cp = vp->name; (*cp = *n++) && *cp != '='; cp++);
+        if (*cp == '\0')
+                *cp = '=';
+        *++cp = '\0';
+        setarea((char *) vp, 0);
+        setarea((char *) vp->name, 0);
+        vp->value = null;
+        vp->next = vlist;
+        vp->status = GETCELL;
+        vlist = vp;
+        return vp;
+}
 
-        setdash();
+/*
+ * if name is not NULL, it must be
+ * a prefix of the space `val',
+ * and end with `='.
+ * this is all so that exporting
+ * values is reasonably painless.
+ */
+static void nameval(struct var *vp, const char *val, const char *name)
+{
+        const char *cp;
+        char *xp;
+        int fl;
 
-        /* This won't be true if PUSHIO has been called, say from newfile() above */
-        if (e.iop < iostack) {
-                PUSHIO(afile, 0, iof);
-                if (isatty(0) && isatty(1) && !cflag) {
-                        interactive++;
-#if !ENABLE_FEATURE_SH_EXTRA_QUIET
-#ifdef MSHDEBUG
-                        printf("\n\n%s Built-in shell (msh with debug)\n", BB_BANNER);
-#else
-                        printf("\n\n%s Built-in shell (msh)\n", BB_BANNER);
-#endif
-                        printf("Enter 'help' for a list of built-in commands.\n\n");
-#endif
-                }
+        if (vp->status & RONLY) {
+                xp = vp->name;
+                while (*xp && *xp != '=')
+                        putc(*xp++, stderr);
+                err(" is read-only");
+                return;
         }
-
-        signal(SIGQUIT, qflag);
-        if (name && name[0] == '-') {
-                interactive++;
-                f = open(".profile", 0);
-                if (f >= 0)
-                        next(remap(f));
-                f = open("/etc/profile", 0);
-                if (f >= 0)
-                        next(remap(f));
+        fl = 0;
+        if (name == NULL) {
+                xp = space(strlen(vp->name) + strlen(val) + 2);
+                if (xp == NULL)
+                        return;
+                /* make string: name=value */
+                setarea(xp, 0);
+                name = xp;
+                cp = vp->name;
+                while ((*xp = *cp++) != '\0' && *xp != '=')
+                        xp++;
+                *xp++ = '=';
+                strcpy(xp, val);
+                val = xp;
+                fl = GETCELL;
         }
-        if (interactive)
-                signal(SIGTERM, sig);
+        if (vp->status & GETCELL)
+                freecell(vp->name);             /* form new string `name=value' */
+        vp->name = name;
+        vp->value = val;
+        vp->status |= fl;
+}
 
-        if (signal(SIGINT, SIG_IGN) != SIG_IGN)
-                signal(SIGINT, onintr);
-        dolv = argv;
-        dolc = argc;
-        dolv[0] = name;
-        if (dolc > 1) {
-                for (ap = ++argv; --argc > 0;) {
-                        *ap = *argv++;
-                        if (assign(*ap, !COPYV)) {
-                                dolc--;                 /* keyword */
-                        } else {
-                                ap++;
-                        }
+/*
+ * give variable at `vp' the value `val'.
+ */
+static void setval(struct var *vp, const char *val)
+{
+        nameval(vp, val, NULL);
+}
+
+static void export(struct var *vp)
+{
+        vp->status |= EXPORT;
+}
+
+static void ronly(struct var *vp)
+{
+        if (isalpha(vp->name[0]) || vp->name[0] == '_') /* not an internal symbol */
+                vp->status |= RONLY;
+}
+
+static int isassign(const char *s)
+{
+        unsigned char c;
+        DBGPRINTF7(("ISASSIGN: enter, s=%s\n", s));
+
+        /* no isalpha() - we shouldn't use locale */
+        c = *s;
+        if (c != '_'
+         && (unsigned)((c|0x20) - 'a') > 25 /* not letter */
+        ) {
+                return 0;
+        }
+        while (1) {
+                c = *++s;
+                if (c == '\0')
+                        return 0;
+                if (c == '=')
+                        return 1;
+                c |= 0x20; /* lowercase letters, doesn't affect numbers */
+                if (c != '_'
+                 && (unsigned)(c - '0') > 9  /* not number */
+                 && (unsigned)(c - 'a') > 25 /* not letter */
+                ) {
+                        return 0;
                 }
         }
-        setval(lookup("#"), putn((--dolc < 0) ? (dolc = 0) : dolc));
+}
 
-        DBGPRINTF(("MSH_MAIN: begin FOR loop, interactive %d, e.iop %p, iostack %p\n", interactive, e.iop, iostack));
+static int assign(const char *s, int cf)
+{
+        char *cp;
+        struct var *vp;
 
-        for (;;) {
-                if (interactive && e.iop <= iostack) {
-#if ENABLE_FEATURE_EDITING
-                        current_prompt = prompt->value;
-#else
-                        prs(prompt->value);
-#endif
+        DBGPRINTF7(("ASSIGN: enter, s=%s, cf=%d\n", s, cf));
+
+        if (!isalpha(*s) && *s != '_')
+                return 0;
+        for (cp = s; *cp != '='; cp++)
+                if (*cp == '\0' || (!isalnum(*cp) && *cp != '_'))
+                        return 0;
+        vp = lookup(s);
+        nameval(vp, ++cp, cf == COPYV ? NULL : s);
+        if (cf != COPYV)
+                vp->status &= ~GETCELL;
+        return 1;
+}
+
+static int checkname(char *cp)
+{
+        DBGPRINTF7(("CHECKNAME: enter, cp=%s\n", cp));
+
+        if (!isalpha(*cp++) && *(cp - 1) != '_')
+                return 0;
+        while (*cp)
+                if (!isalnum(*cp++) && *(cp - 1) != '_')
+                        return 0;
+        return 1;
+}
+
+static void putvlist(int f, int out)
+{
+        struct var *vp;
+
+        for (vp = vlist; vp; vp = vp->next)
+                if (vp->status & f && (isalpha(*vp->name) || *vp->name == '_')) {
+                        if (vp->status & EXPORT)
+                                write(out, "export ", 7);
+                        if (vp->status & RONLY)
+                                write(out, "readonly ", 9);
+                        write(out, vp->name, (int) (findeq(vp->name) - vp->name));
+                        write(out, "\n", 1);
                 }
-                onecommand();
-                /* Ensure that getenv("PATH") stays current */
-                setenv("PATH", path->value, 1);
-        }
+}
 
-        DBGPRINTF(("MSH_MAIN: returning.\n"));
+
+/*
+ * trap handling
+ */
+static void sig(int i)
+{
+        trapset = i;
+        signal(i, sig);
 }
 
+static void runtrap(int i)
+{
+        char *trapstr;
+
+        trapstr = trap[i];
+        if (trapstr == NULL)
+                return;
+
+        if (i == 0)
+                trap[i] = NULL;
+
+        RUN(aword, trapstr, nlchar);
+}
+
+
 static void setdash(void)
 {
         char *cp;
@@ -1083,7 +1285,6 @@ static void onecommand(void)
         setjmp(failpt);         /* Bruce Evans' fix */
         failpt = m1;
         if (setjmp(failpt) || yyparse() || intr) {
-
                 DBGPRINTF(("ONECOMMAND: this is not good.\n"));
 
                 while (e.oenv)
@@ -1119,49 +1320,6 @@ static void onecommand(void)
         }
 }
 
-static void fail(void)
-{
-        longjmp(failpt, 1);
-        /* NOTREACHED */
-}
-
-static void leave(void)
-{
-        DBGPRINTF(("LEAVE: leave called!\n"));
-
-        if (execflg)
-                fail();
-        scraphere();
-        freehere(1);
-        runtrap(0);
-        _exit(exstat);
-        /* NOTREACHED */
-}
-
-static void warn(const char *s)
-{
-        if (*s) {
-                prs(s);
-                exstat = -1;
-        }
-        prs("\n");
-        if (flag['e'])
-                leave();
-}
-
-static void err(const char *s)
-{
-        warn(s);
-        if (flag['n'])
-                return;
-        if (!interactive)
-                leave();
-        if (e.errpt)
-                longjmp(e.errpt, 1);
-        closeall();
-        e.iop = e.iobase = iostack;
-}
-
 static int newenv(int f)
 {
         struct env *ep;
@@ -1251,232 +1409,6 @@ static void onintr(int s)					/* ANSI C requires a parameter */
         }
 }
 
-static char *space(int n)
-{
-        char *cp;
-
-        cp = getcell(n);
-        if (cp == '\0')
-                err("out of string space");
-        return cp;
-}
-
-static char *strsave(char *s, int a)
-{
-        char *cp;
-
-        cp = space(strlen(s) + 1);
-        if (cp != NULL) {
-                setarea(cp, a);
-                strcpy(cp, s);
-                return cp;
-        }
-        return "";
-}
-
-/*
- * trap handling
- */
-static void sig(int i)
-{
-        trapset = i;
-        signal(i, sig);
-}
-
-static void runtrap(int i)
-{
-        char *trapstr;
-
-        trapstr = trap[i];
-        if (trapstr == NULL)
-                return;
-
-        if (i == 0)
-                trap[i] = NULL;
-
-        RUN(aword, trapstr, nlchar);
-}
-
-/* -------- var.c -------- */
-
-/*
- * Find the given name in the dictionary
- * and return its value.  If the name was
- * not previously there, enter it now and
- * return a null value.
- */
-static struct var *lookup(char *n)
-{
-        struct var *vp;
-        char *cp;
-        int c;
-        static struct var dummy;
-
-        if (isdigit(*n)) {
-                dummy.name = n;
-                for (c = 0; isdigit(*n) && c < 1000; n++)
-                        c = c * 10 + *n - '0';
-                dummy.status = RONLY;
-                dummy.value = c <= dolc ? dolv[c] : null;
-                return &dummy;
-        }
-        for (vp = vlist; vp; vp = vp->next)
-                if (eqname(vp->name, n))
-                        return vp;
-        cp = findeq(n);
-        vp = (struct var *) space(sizeof(*vp));
-        if (vp == 0 || (vp->name = space((int) (cp - n) + 2)) == 0) {
-                dummy.name = dummy.value = "";
-                return &dummy;
-        }
-        for (cp = vp->name; (*cp = *n++) && *cp != '='; cp++);
-        if (*cp == 0)
-                *cp = '=';
-        *++cp = '\0';
-        setarea((char *) vp, 0);
-        setarea((char *) vp->name, 0);
-        vp->value = null;
-        vp->next = vlist;
-        vp->status = GETCELL;
-        vlist = vp;
-        return vp;
-}
-
-/*
- * give variable at `vp' the value `val'.
- */
-static void setval(struct var *vp, char *val)
-{
-        nameval(vp, val, (char *) NULL);
-}
-
-/*
- * if name is not NULL, it must be
- * a prefix of the space `val',
- * and end with `='.
- * this is all so that exporting
- * values is reasonably painless.
- */
-static void nameval(struct var *vp, char *val, char *name)
-{
-        char *cp, *xp;
-        char *nv;
-        int fl;
-
-        if (vp->status & RONLY) {
-                for (xp = vp->name; *xp && *xp != '=';)
-                        putc(*xp++, stderr);
-                err(" is read-only");
-                return;
-        }
-        fl = 0;
-        if (name == NULL) {
-                xp = space(strlen(vp->name) + strlen(val) + 2);
-                if (xp == NULL)
-                        return;
-                /* make string:  name=value */
-                setarea((char *) xp, 0);
-                name = xp;
-                for (cp = vp->name; (*xp = *cp++) && *xp != '='; xp++);
-                if (*xp++ == '\0')
-                        xp[-1] = '=';
-                nv = xp;
-                for (cp = val; (*xp++ = *cp++) != '\0';);
-                val = nv;
-                fl = GETCELL;
-        }
-        if (vp->status & GETCELL)
-                freecell(vp->name);             /* form new string `name=value' */
-        vp->name = name;
-        vp->value = val;
-        vp->status |= fl;
-}
-
-static void export(struct var *vp)
-{
-        vp->status |= EXPORT;
-}
-
-static void ronly(struct var *vp)
-{
-        if (isalpha(vp->name[0]) || vp->name[0] == '_') /* not an internal symbol */
-                vp->status |= RONLY;
-}
-
-static int isassign(char *s)
-{
-        DBGPRINTF7(("ISASSIGN: enter, s=%s\n", s));
-
-        if (!isalpha((int) *s) && *s != '_')
-                return 0;
-        for (; *s != '='; s++)
-                if (*s == '\0' || (!isalnum(*s) && *s != '_'))
-                        return 0;
-
-        return 1;
-}
-
-static int assign(char *s, int cf)
-{
-        char *cp;
-        struct var *vp;
-
-        DBGPRINTF7(("ASSIGN: enter, s=%s, cf=%d\n", s, cf));
-
-        if (!isalpha(*s) && *s != '_')
-                return 0;
-        for (cp = s; *cp != '='; cp++)
-                if (*cp == '\0' || (!isalnum(*cp) && *cp != '_'))
-                        return 0;
-        vp = lookup(s);
-        nameval(vp, ++cp, cf == COPYV ? (char *) NULL : s);
-        if (cf != COPYV)
-                vp->status &= ~GETCELL;
-        return 1;
-}
-
-static int checkname(char *cp)
-{
-        DBGPRINTF7(("CHECKNAME: enter, cp=%s\n", cp));
-
-        if (!isalpha(*cp++) && *(cp - 1) != '_')
-                return 0;
-        while (*cp)
-                if (!isalnum(*cp++) && *(cp - 1) != '_')
-                        return 0;
-        return 1;
-}
-
-static void putvlist(int f, int out)
-{
-        struct var *vp;
-
-        for (vp = vlist; vp; vp = vp->next)
-                if (vp->status & f && (isalpha(*vp->name) || *vp->name == '_')) {
-                        if (vp->status & EXPORT)
-                                write(out, "export ", 7);
-                        if (vp->status & RONLY)
-                                write(out, "readonly ", 9);
-                        write(out, vp->name, (int) (findeq(vp->name) - vp->name));
-                        write(out, "\n", 1);
-                }
-}
-
-static int eqname(char *n1, char *n2)
-{
-        for (; *n1 != '=' && *n1 != '\0'; n1++)
-                if (*n2++ != *n1)
-                        return 0;
-        return *n2 == '\0' || *n2 == '=';
-}
-
-static char *findeq(char *cp)
-{
-        while (*cp != '\0' && *cp != '=')
-                cp++;
-        return cp;
-}
-
 /* -------- gmatch.c -------- */
 /*
  * int gmatch(string, pattern)
@@ -1550,165 +1482,6 @@ static char *cclass(char *p, int sub)
 }
 
 
-/* -------- area.c -------- */
-
-/*
- * All memory between (char *)areabot and (char *)(areatop+1) is
- * exclusively administered by the area management routines.
- * It is assumed that sbrk() and brk() manipulate the high end.
- */
-
-#define sbrk(X) ({ \
-        void * __q = (void *)-1; \
-        if (brkaddr + (int)(X) < brktop) { \
-                __q = brkaddr; \
-                brkaddr += (int)(X); \
-        } \
-        __q; \
-})
-
-static void initarea(void)
-{
-        brkaddr = xmalloc(AREASIZE);
-        brktop = brkaddr + AREASIZE;
-
-        while ((long) sbrk(0) & ALIGN)
-                sbrk(1);
-        areabot = (struct region *) sbrk(REGSIZE);
-
-        areabot->next = areabot;
-        areabot->area = BUSY;
-        areatop = areabot;
-        areanxt = areabot;
-}
-
-char *getcell(unsigned nbytes)
-{
-        int nregio;
-        struct region *p, *q;
-        int i;
-
-        if (nbytes == 0) {
-                puts("getcell(0)");
-                abort();
-        }
-        /* silly and defeats the algorithm */
-        /*
-         * round upwards and add administration area
-         */
-        nregio = (nbytes + (REGSIZE - 1)) / REGSIZE + 1;
-        for (p = areanxt;;) {
-                if (p->area > areanum) {
-                        /*
-                         * merge free cells
-                         */
-                        while ((q = p->next)->area > areanum && q != areanxt)
-                                p->next = q->next;
-                        /*
-                         * exit loop if cell big enough
-                         */
-                        if (q >= p + nregio)
-                                goto found;
-                }
-                p = p->next;
-                if (p == areanxt)
-                        break;
-        }
-        i = nregio >= GROWBY ? nregio : GROWBY;
-        p = (struct region *) sbrk(i * REGSIZE);
-        if (p == (struct region *) -1)
-                return NULL;
-        p--;
-        if (p != areatop) {
-                puts("not contig");
-                abort();                                /* allocated areas are contiguous */
-        }
-        q = p + i;
-        p->next = q;
-        p->area = FREE;
-        q->next = areabot;
-        q->area = BUSY;
-        areatop = q;
- found:
-        /*
-         * we found a FREE area big enough, pointed to by 'p', and up to 'q'
-         */
-        areanxt = p + nregio;
-        if (areanxt < q) {
-                /*
-                 * split into requested area and rest
-                 */
-                if (areanxt + 1 > q) {
-                        puts("OOM");
-                        abort();                        /* insufficient space left for admin */
-                }
-                areanxt->next = q;
-                areanxt->area = FREE;
-                p->next = areanxt;
-        }
-        p->area = areanum;
-        return (char *) (p + 1);
-}
-
-static void freecell(char *cp)
-{
-        struct region *p;
-
-        p = (struct region *) cp;
-        if (p != NULL) {
-                p--;
-                if (p < areanxt)
-                        areanxt = p;
-                p->area = FREE;
-        }
-}
-
-static void freearea(int a)
-{
-        struct region *p, *top;
-
-        top = areatop;
-        for (p = areabot; p != top; p = p->next)
-                if (p->area >= a)
-                        p->area = FREE;
-}
-
-static void setarea(char *cp, int a)
-{
-        struct region *p;
-
-        p = (struct region *) cp;
-        if (p != NULL)
-                (p - 1)->area = a;
-}
-
-int getarea(char *cp)
-{
-        return ((struct region *) cp - 1)->area;
-}
-
-static void garbage(void)
-{
-        struct region *p, *q, *top;
-
-        top = areatop;
-        for (p = areabot; p != top; p = p->next) {
-                if (p->area > areanum) {
-                        while ((q = p->next)->area > areanum)
-                                p->next = q->next;
-                        areanxt = p;
-                }
-        }
-#ifdef SHRINKBY
-        if (areatop >= q + SHRINKBY && q->area > areanum) {
-                brk((char *) (q + 1));
-                q->next = areabot;
-                q->area = BUSY;
-                areatop = q;
-        }
-#endif
-}
-
 /* -------- csyn.c -------- */
 /*
  * shell: syntax (C version)
@@ -2591,9 +2364,7 @@ static int execute(struct op *t, int *pin, int *pout, int act)
                 break;
 
         case TCOM:
-                {
-                        rv = forkexec(t, pin, pout, act, wp);
-                }
+                rv = forkexec(t, pin, pout, act, wp);
                 break;
 
         case TPIPE:
@@ -2846,8 +2617,7 @@ forkexec(struct op *t, int *pin, int *pout, int act, char **wp)
                         return -1;
                 }
 
-                if (newpid > 0) {               /* Parent */
-
+                if (newpid > 0) {  /* Parent */
                         /* Restore values */
                         pin = hpin;
                         pout = hpout;
@@ -2856,12 +2626,10 @@ forkexec(struct op *t, int *pin, int *pout, int act, char **wp)
                         intr = hintr;
                         brklist = hbrklist;
                         execflg = hexecflg;
-
 /* moved up
                         if (i == -1)
                                 return rv;
 */
-
                         if (pin != NULL)
                                 closepipe(pin);
 
@@ -3566,12 +3334,12 @@ static int dotrap(struct op *t)
                         } else
                                 setsig(n, SIG_IGN);
                 } else {
-                        if (interactive)
+                        if (interactive) {
                                 if (n == SIGINT)
                                         setsig(n, onintr);
                                 else
                                         setsig(n, n == SIGQUIT ? SIG_IGN : SIG_DFL);
-                        else
+                        } else
                                 setsig(n, SIG_DFL);
                 }
         }
@@ -5311,6 +5079,211 @@ static void freehere(int area)
 }
 
 
+/* -------- sh.c -------- */
+/*
+ * shell
+ */
+
+int msh_main(int argc, char **argv)
+{
+        int f;
+        char *s;
+        int cflag;
+        char *name, **ap;
+        int (*iof) (struct ioarg *);
+
+#if ENABLE_FEATURE_EDITING
+        line_input_state = new_line_input_t(FOR_SHELL);
+#endif
+
+        DBGPRINTF(("MSH_MAIN: argc %d, environ %p\n", argc, environ));
+
+        initarea();
+        ap = environ;
+        if (ap != NULL) {
+                while (*ap)
+                        assign(*ap++, !COPYV);
+                for (ap = environ; *ap;)
+                        export(lookup(*ap++));
+        }
+        closeall();
+        areanum = 1;
+
+        shell = lookup("SHELL");
+        if (shell->value == null)
+                setval(shell, (char *)DEFAULT_SHELL);
+        export(shell);
+
+        homedir = lookup("HOME");
+        if (homedir->value == null)
+                setval(homedir, "/");
+        export(homedir);
+
+        setval(lookup("$"), putn(getpid()));
+
+        path = lookup("PATH");
+        if (path->value == null) {
+                if (geteuid() == 0)
+                        setval(path, "/sbin:/bin:/usr/sbin:/usr/bin");
+                else
+                        setval(path, "/bin:/usr/bin");
+        }
+        export(path);
+
+        ifs = lookup("IFS");
+        if (ifs->value == null)
+                setval(ifs, " \t\n");
+
+#ifdef MSHDEBUG
+        mshdbg_var = lookup("MSHDEBUG");
+        if (mshdbg_var->value == null)
+                setval(mshdbg_var, "0");
+#endif
+
+        prompt = lookup("PS1");
+#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
+        if (prompt->value == null)
+#endif
+                setval(prompt, DEFAULT_USER_PROMPT);
+        if (geteuid() == 0) {
+                setval(prompt, DEFAULT_ROOT_PROMPT);
+                prompt->status &= ~EXPORT;
+        }
+        cprompt = lookup("PS2");
+#if ENABLE_FEATURE_EDITING_FANCY_PROMPT
+        if (cprompt->value == null)
+#endif
+                setval(cprompt, "> ");
+
+        iof = filechar;
+        cflag = 0;
+        name = *argv++;
+        if (--argc >= 1) {
+                if (argv[0][0] == '-' && argv[0][1] != '\0') {
+                        for (s = argv[0] + 1; *s; s++)
+                                switch (*s) {
+                                case 'c':
+                                        prompt->status &= ~EXPORT;
+                                        cprompt->status &= ~EXPORT;
+                                        setval(prompt, "");
+                                        setval(cprompt, "");
+                                        cflag = 1;
+                                        if (--argc > 0)
+                                                PUSHIO(aword, *++argv, iof = nlchar);
+                                        break;
+
+                                case 'q':
+                                        qflag = SIG_DFL;
+                                        break;
+
+                                case 's':
+                                        /* standard input */
+                                        break;
+
+                                case 't':
+                                        prompt->status &= ~EXPORT;
+                                        setval(prompt, "");
+                                        iof = linechar;
+                                        break;
+
+                                case 'i':
+                                        interactive++;
+                                default:
+                                        if (*s >= 'a' && *s <= 'z')
+                                                flag[(int) *s]++;
+                                }
+                } else {
+                        argv--;
+                        argc++;
+                }
+
+                if (iof == filechar && --argc > 0) {
+                        setval(prompt, "");
+                        setval(cprompt, "");
+                        prompt->status &= ~EXPORT;
+                        cprompt->status &= ~EXPORT;
+
+/* Shell is non-interactive, activate printf-based debug */
+#ifdef MSHDEBUG
+                        mshdbg = (int) (((char) (mshdbg_var->value[0])) - '0');
+                        if (mshdbg < 0)
+                                mshdbg = 0;
+#endif
+                        DBGPRINTF(("MSH_MAIN: calling newfile()\n"));
+
+                        name = *++argv;
+                        if (newfile(name))
+                                exit(1);                /* Exit on error */
+                }
+        }
+
+        setdash();
+
+        /* This won't be true if PUSHIO has been called, say from newfile() above */
+        if (e.iop < iostack) {
+                PUSHIO(afile, 0, iof);
+                if (isatty(0) && isatty(1) && !cflag) {
+                        interactive++;
+#if !ENABLE_FEATURE_SH_EXTRA_QUIET
+#ifdef MSHDEBUG
+                        printf("\n\n%s Built-in shell (msh with debug)\n", BB_BANNER);
+#else
+                        printf("\n\n%s Built-in shell (msh)\n", BB_BANNER);
+#endif
+                        printf("Enter 'help' for a list of built-in commands.\n\n");
+#endif
+                }
+        }
+
+        signal(SIGQUIT, qflag);
+        if (name && name[0] == '-') {
+                interactive++;
+                f = open(".profile", 0);
+                if (f >= 0)
+                        next(remap(f));
+                f = open("/etc/profile", 0);
+                if (f >= 0)
+                        next(remap(f));
+        }
+        if (interactive)
+                signal(SIGTERM, sig);
+
+        if (signal(SIGINT, SIG_IGN) != SIG_IGN)
+                signal(SIGINT, onintr);
+        dolv = argv;
+        dolc = argc;
+        dolv[0] = name;
+        if (dolc > 1) {
+                for (ap = ++argv; --argc > 0;) {
+                        *ap = *argv++;
+                        if (assign(*ap, !COPYV)) {
+                                dolc--;                 /* keyword */
+                        } else {
+                                ap++;
+                        }
+                }
+        }
+        setval(lookup("#"), putn((--dolc < 0) ? (dolc = 0) : dolc));
+
+        DBGPRINTF(("MSH_MAIN: begin FOR loop, interactive %d, e.iop %p, iostack %p\n", interactive, e.iop, iostack));
+
+        for (;;) {
+                if (interactive && e.iop <= iostack) {
+#if ENABLE_FEATURE_EDITING
+                        current_prompt = prompt->value;
+#else
+                        prs(prompt->value);
+#endif
+                }
+                onecommand();
+                /* Ensure that getenv("PATH") stays current */
+                setenv("PATH", path->value, 1);
+        }
+
+        DBGPRINTF(("MSH_MAIN: returning.\n"));
+}
+
+
 /*
  * Copyright (c) 1987,1997, Prentice Hall
  * All rights reserved.