cmd/csh/sh.exec.c

/*
 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*  Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley Software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include "sh.h"
#include <dirent.h>
#include <string.h>
#include "sh.tconst.h"


/*
 * C shell
 */

/*
 * System level search and execute of a command.
 * We look in each directory for the specified command name.
 * If the name contains a '/' then we execute only the full path name.
 * If there is no search path then we execute only full path names.
 */

/*
 * As we search for the command we note the first non-trivial error
 * message for presentation to the user.  This allows us often
 * to show that a file has the wrong mode/no access when the file
 * is not in the last component of the search path, so we must
 * go on after first detecting the error.
 */
char *exerr;            /* Execution error message */

void    pexerr(void);
void    texec(struct command *, tchar *, tchar **);
void    xechoit(tchar **);
void    dohash(char []);

static void tconvert(struct command *, tchar *, tchar **);


extern DIR *opendir_(tchar *);

void
doexec(struct command *t)
{
    tchar *sav;
    tchar *dp, **pv, **av;
    struct varent *v;
    bool slash;
    int hashval, hashval1, i;
    tchar *blk[2];
#ifdef TRACE
    tprintf("TRACE- doexec()\n");
#endif

    /*
     * Glob the command name.  If this does anything, then we
     * will execute the command only relative to ".".  One special
     * case: if there is no PATH, then we execute only commands
     * which start with '/'.
     */
    dp = globone(t->t_dcom[0]);
    sav = t->t_dcom[0];
    exerr = 0; t->t_dcom[0] = dp;
    setname(dp);
    xfree(sav);
    v = adrof(S_path /* "path" */);
    if (v == 0 && dp[0] != '/') {
        pexerr();
    }
    slash = gflag;

    /*
     * Glob the argument list, if necessary.
     * Otherwise trim off the quote bits.
     */
    gflag = 0; av = &t->t_dcom[1];
    tglob(av);
    if (gflag) {
        av = glob(av);
        if (av == 0)
            error("No match");
    }
    blk[0] = t->t_dcom[0];
    blk[1] = 0;
    av = blkspl(blk, av);
#ifdef VFORK
    Vav = av;
#endif
    trim(av);
    slash |= any('/', av[0]);

    xechoit(av);        /* Echo command if -x */
    /*
     * Since all internal file descriptors are set to close on exec,
     * we don't need to close them explicitly here.  Just reorient
     * ourselves for error messages.
     */
    SHIN = 0; SHOUT = 1; SHDIAG = 2; OLDSTD = 0;

    /*
     * We must do this AFTER any possible forking (like `foo`
     * in glob) so that this shell can still do subprocesses.
     */
    (void) sigsetmask(0);

    /*
     * If no path, no words in path, or a / in the filename
     * then restrict the command search.
     */
    if (v == 0 || v->vec[0] == 0 || slash)
        pv = justabs;
    else
        pv = v->vec;
    /* / command name for postpending */
    sav = strspl(S_SLASH /* "/" */, *av);
#ifdef VFORK
    Vsav = sav;
#endif
    if (havhash)
        hashval = hashname(*av);
    i = 0;
#ifdef VFORK
    hits++;
#endif
    do {
        if (!slash && pv[0][0] == '/' && havhash) {
            hashval1 = hash(hashval, i);
            if (!bit(xhash, hashval1))
                goto cont;
        }

        /* don't make ./xxx */
        if (pv[0][0] == 0 || eq(pv[0], S_DOT /* "." */)) {
            texec(t, *av, av);
        } else {
            dp = strspl(*pv, sav);
#ifdef VFORK
            Vdp = dp;
#endif
            texec(t, dp, av);
#ifdef VFORK
            Vdp = 0;
#endif
            xfree(dp);
        }
#ifdef VFORK
        misses++;
#endif
cont:
        pv++;
        i++;
    } while (*pv);
#ifdef VFORK
    hits--;
#endif
#ifdef VFORK
    Vsav = 0;
    Vav = 0;
#endif
    xfree(sav);
    xfree((char *)av);
    pexerr();
}

void
pexerr(void)
{

#ifdef TRACE
    tprintf("TRACE- pexerr()\n");
#endif
    /* Couldn't find the damn thing */
    if (exerr)
        bferr(exerr);
    bferr("Command not found");
}

/*
 * Execute command f, arg list t.
 * Record error message if not found.
 * Also do shell scripts here.
 */
void
texec(struct command *cmd, tchar *f, tchar **t)
{
    struct  varent *v;
    tchar   **vp;
    tchar       *lastsh[2];

#ifdef TRACE
    tprintf("TRACE- texec()\n");
#endif
    /* convert cfname and cargs from tchar to char */
    tconvert(cmd, f, t);

    execv(cmd->cfname, cmd->cargs);

    /*
     * exec returned, free up allocations from above
     * tconvert(), zero cfname and cargs to prevent
     * duplicate free() in freesyn()
     */
    xfree(cmd->cfname);
    chr_blkfree(cmd->cargs);
    cmd->cfname = (char *)0;
    cmd->cargs = (char **)0;

    switch (errno) {
    case ENOEXEC:
        /* check that this is not a binary file */
        {
            int ff = open_(f, 0);
            tchar ch[MB_LEN_MAX];

            if (ff != -1 && read_(ff, ch, 1) == 1 &&
                !isprint(ch[0]) && !isspace(ch[0])) {
                printf("Cannot execute binary file.\n");
                Perror(f);
                (void) close(ff);
                unsetfd(ff);
                return;
            }
            (void) close(ff);
            unsetfd(ff);
        }
        /*
         * If there is an alias for shell, then
         * put the words of the alias in front of the
         * argument list replacing the command name.
         * Note no interpretation of the words at this point.
         */
        v = adrof1(S_shell /* "shell" */, &aliases);
        if (v == 0) {
#ifdef OTHERSH
            int ff = open_(f, 0);
            tchar ch[MB_LEN_MAX];
#endif

            vp = lastsh;
            vp[0] = adrof(S_shell /* "shell" */) ?
                value(S_shell /* "shell" */) :
                S_SHELLPATH /* SHELLPATH */;
            vp[1] =  (tchar *) NULL;
#ifdef OTHERSH
            if (ff != -1 && read_(ff, ch, 1) == 1 && ch[0] != '#')
                vp[0] = S_OTHERSH /* OTHERSH */;
            (void) close(ff);
            unsetfd(ff);
#endif
        } else
            vp = v->vec;
        t[0] = f;
        t = blkspl(vp, t);      /* Splice up the new arglst */
        f = *t;

        tconvert(cmd, f, t);        /* convert tchar to char */

        /*
         * now done with tchar arg list t,
         * free the space calloc'd by above blkspl()
         */
        xfree((char *)t);

        execv(cmd->cfname, cmd->cargs); /* exec the command */

        /* exec returned, same free'ing as above */
        xfree(cmd->cfname);
        chr_blkfree(cmd->cargs);
        cmd->cfname = (char *)0;
        cmd->cargs = (char **)0;

        /* The sky is falling, the sky is falling! */

    case ENOMEM:
        Perror(f);

    case ENOENT:
        break;

    default:
        if (exerr == 0) {
            exerr = strerror(errno);
            setname(f);
        }
    }
}


static void
tconvert(struct command *cmd, tchar *fname, tchar **list)
{
    char **rc;
    int len;

    cmd->cfname = tstostr(NULL, fname);

    len = blklen(list);
    rc = cmd->cargs = (char **)
        xcalloc((uint_t)(len + 1), sizeof (char **));
    while (len--)
        *rc++ = tstostr(NULL, *list++);
    *rc = NULL;
}


/*ARGSUSED*/
void
execash(tchar **t, struct command *kp)
{
#ifdef TRACE
    tprintf("TRACE- execash()\n");
#endif

    rechist();
    (void) signal(SIGINT, parintr);
    (void) signal(SIGQUIT, parintr);
    (void) signal(SIGTERM, parterm);    /* if doexec loses, screw */
    lshift(kp->t_dcom, 1);
    exiterr++;
    doexec(kp);
    /*NOTREACHED*/
}

void
xechoit(tchar **t)
{
#ifdef TRACE
    tprintf("TRACE- xechoit()\n");
#endif

    if (adrof(S_echo /* "echo" */)) {
        flush();
        haderr = 1;
        blkpr(t), Putchar('\n');
        haderr = 0;
    }
}

/*
 * This routine called when user enters "rehash".
 * Both the path and cdpath caching arrays will
 * be rehashed, via calling dohash.  If either
 * variable is not set with a value, then dohash
 * just exits.
 */
void
dorehash(void)
{
    dohash(xhash);
    dohash(xhash2);
}

/*
 * Fill up caching arrays for path and cdpath
 */
void
dohash(char cachearray[])
{
    struct stat stb;
    DIR *dirp;
    struct dirent *dp;
    int cnt;
    int i = 0;
    struct varent *v;
    tchar **pv;
    int hashval;
    tchar curdir_[MAXNAMLEN+1];

#ifdef TRACE
    tprintf("TRACE- dohash()\n");
#endif
    /* Caching $path */
    if (cachearray == xhash) {
        havhash = 1;
        v = adrof(S_path /* "path" */);
    } else {    /* Caching $cdpath */
        havhash2 = 1;
        v = adrof(S_cdpath /* "cdpath" */);
    }

    for (cnt = 0; cnt < (HSHSIZ / 8); cnt++)
        cachearray[cnt] = 0;
    if (v == 0)
        return;
    for (pv = v->vec; *pv; pv++, i++) {
        if (pv[0][0] != '/')
            continue;
        dirp = opendir_(*pv);
        if (dirp == NULL)
            continue;
        if (fstat(dirp->dd_fd, &stb) < 0 || !isdir(stb)) {
            unsetfd(dirp->dd_fd);
            closedir_(dirp);
            continue;
        }
        while ((dp = readdir(dirp)) != NULL) {
            if (dp->d_ino == 0)
                continue;
            if (dp->d_name[0] == '.' &&
                (dp->d_name[1] == '\0' ||
                dp->d_name[1] == '.' && dp->d_name[2] == '\0'))
                continue;
            hashval = hash(hashname(strtots(curdir_, dp->d_name)),
                i);
            bis(cachearray, hashval);
        }
        unsetfd(dirp->dd_fd);
        closedir_(dirp);
    }
}

void
dounhash(void)
{

#ifdef TRACE
    tprintf("TRACE- dounhash()\n");
#endif
    havhash = 0;
    havhash2 = 0;
}

#ifdef VFORK
void
hashstat(void)
{
#ifdef TRACE
    tprintf("TRACE- hashstat_()\n");
#endif

    if (hits+misses)
        printf("%d hits, %d misses, %d%%\n",
            hits, misses, 100 * hits / (hits + misses));
}
#endif

/*
 * Hash a command name.
 */
int
hashname(tchar *cp)
{
    long h = 0;

#ifdef TRACE
    tprintf("TRACE- hashname()\n");
#endif
    while (*cp)
        h = hash(h, *cp++);
    return ((int)h);
}