common/bltins/test.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1982-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * test expression
 * [ expression ]
 *
 *   David Korn
 *   AT&T Labs
 *
 */


#include    "defs.h"
#include    <error.h>
#include    <ls.h>
#include    "io.h"
#include    "terminal.h"
#include    "test.h"
#include    "builtins.h"
#include    "FEATURE/externs"
#include    "FEATURE/poll"
#include    <tmx.h>

#if !_lib_setregid
#   undef _lib_setreuid
#endif /* _lib_setregid */

#ifdef S_ISSOCK
#   if _pipe_socketpair
#       if _socketpair_shutdown_mode
#           define isapipe(f,p) (test_stat(f,p)>=0&&S_ISFIFO((p)->st_mode)||S_ISSOCK((p)->st_mode)&&(p)->st_ino&&((p)->st_mode&(S_IRUSR|S_IWUSR))!=(S_IRUSR|S_IWUSR))
#       else
#           define isapipe(f,p) (test_stat(f,p)>=0&&S_ISFIFO((p)->st_mode)||S_ISSOCK((p)->st_mode)&&(p)->st_ino)
#       endif
#   else
#       define isapipe(f,p) (test_stat(f,p)>=0&&S_ISFIFO((p)->st_mode)||S_ISSOCK((p)->st_mode)&&(p)->st_ino)
#   endif
#   define isasock(f,p) (test_stat(f,p)>=0&&S_ISSOCK((p)->st_mode))
#else
#   define isapipe(f,p) (test_stat(f,p)>=0&&S_ISFIFO((p)->st_mode))
#   define isasock(f,p) (0)
#endif

#define permission(a,f)     (sh_access(a,f)==0)
static time_t   test_time(const char*, const char*);
static int  test_stat(const char*, struct stat*);
static int  test_mode(const char*);

/* single char string compare */
#define c_eq(a,c)   (*a==c && *(a+1)==0)
/* two character string compare */
#define c2_eq(a,c1,c2)  (*a==c1 && *(a+1)==c2 && *(a+2)==0)

struct test
{
        Shell_t *sh;
        int     ap;
        int     ac;
        char    **av;
};

static char *nxtarg(struct test*,int);
static int expr(struct test*,int);
static int e3(struct test*);

static int test_strmatch(const char *str, const char *pat)
{
    int match[2*(MATCH_MAX+1)],n;
    register int c, m=0;
    register const char *cp=pat;
    while(c = *cp++)
    {
        if(c=='(')
            m++;
        if(c=='\\' && *cp)
            cp++;
    }
    if(m)
        m++;
    else
        match[0] = 0;
    if(m >  elementsof(match)/2)
        m = elementsof(match)/2;
    n = strgrpmatch(str, pat, match, m, STR_MAXIMAL|STR_LEFT|STR_RIGHT);
    if(m==0 && n==1)
        match[1] = strlen(str);
    if(n)
        sh_setmatch(str, -1, n, match);
    return(n);
}

int b_test(int argc, char *argv[],void *extra)
{
    struct test tdata;
    register char *cp = argv[0];
    register int not;
    tdata.sh = ((Shbltin_t*)extra)->shp;
    tdata.av = argv;
    tdata.ap = 1;
    if(c_eq(cp,'['))
    {
        cp = argv[--argc];
        if(!c_eq(cp, ']'))
            errormsg(SH_DICT,ERROR_exit(2),e_missing,"']'");
    }
    if(argc <= 1)
        return(1);
    cp = argv[1];
    if(c_eq(cp,'(') && argc<=6 && c_eq(argv[argc-1],')'))
    {
        /* special case  ( binop ) to conform with standard */
        if(!(argc==4  && (not=sh_lookup(cp=argv[2],shtab_testops))))
        {
            cp =  (++argv)[1];
            argc -= 2;
        }
    }
    not = c_eq(cp,'!');
    /* posix portion for test */
    switch(argc)
    {
        case 5:
            if(!not)
                break;
            argv++;
            /* fall through */
        case 4:
        {
            register int op = sh_lookup(cp=argv[2],shtab_testops);
            if(op&TEST_BINOP)
                break;
            if(!op)
            {
                if(argc==5)
                    break;
                if(not && cp[0]=='-' && cp[2]==0)
                    return(test_unop(cp[1],argv[3])!=0);
                else if(argv[1][0]=='-' && argv[1][2]==0)
                    return(!test_unop(argv[1][1],cp));
                errormsg(SH_DICT,ERROR_exit(2),e_badop,cp);
            }
            return(test_binop(op,argv[1],argv[3])^(argc!=5));
        }
        case 3:
            if(not)
                return(*argv[2]!=0);
            if(cp[0] != '-' || cp[2] || cp[1]=='?')
            {
                if(cp[0]=='-' && (cp[1]=='-' || cp[1]=='?') &&
                    strcmp(argv[2],"--")==0)
                {
                    char *av[3];
                    av[0] = argv[0];
                    av[1] = argv[1];
                    av[2] = 0;
                    optget(av,sh_opttest);
                    errormsg(SH_DICT,ERROR_usage(2), "%s",opt_info.arg);
                    return(2);
                }
                break;
            }
            return(!test_unop(cp[1],argv[2]));
        case 2:
            return(*cp==0);
    }
    tdata.ac = argc;
    return(!expr(&tdata,0));
}

/*
 * evaluate a test expression.
 * flag is 0 on outer level
 * flag is 1 when in parenthesis
 * flag is 2 when evaluating -a
 */
static int expr(struct test *tp,register int flag)
{
    register int r;
    register char *p;
    r = e3(tp);
    while(tp->ap < tp->ac)
    {
        p = nxtarg(tp,0);
        /* check for -o and -a */
        if(flag && c_eq(p,')'))
        {
            tp->ap--;
            break;
        }
        if(*p=='-' && *(p+2)==0)
        {
            if(*++p == 'o')
            {
                if(flag==2)
                {
                    tp->ap--;
                    break;
                }
                r |= expr(tp,3);
                continue;
            }
            else if(*p == 'a')
            {
                r &= expr(tp,2);
                continue;
            }
        }
        if(flag==0)
            break;
        errormsg(SH_DICT,ERROR_exit(2),e_badsyntax);
    }
    return(r);
}

static char *nxtarg(struct test *tp,int mt)
{
    if(tp->ap >= tp->ac)
    {
        if(mt)
        {
            tp->ap++;
            return(0);
        }
        errormsg(SH_DICT,ERROR_exit(2),e_argument);
    }
    return(tp->av[tp->ap++]);
}


static int e3(struct test *tp)
{
    register char *arg, *cp;
    register int op;
    char *binop;
    arg=nxtarg(tp,0);
    if(arg && c_eq(arg, '!'))
        return(!e3(tp));
    if(c_eq(arg, '('))
    {
        op = expr(tp,1);
        cp = nxtarg(tp,0);
        if(!cp || !c_eq(cp, ')'))
            errormsg(SH_DICT,ERROR_exit(2),e_missing,"')'");
        return(op);
    }
    cp = nxtarg(tp,1);
    if(cp!=0 && (c_eq(cp,'=') || c2_eq(cp,'!','=')))
        goto skip;
    if(c2_eq(arg,'-','t'))
    {
        if(cp)
        {
            op = strtol(cp,&binop, 10);
            return(*binop?0:tty_check(op));
        }
        else
        {
        /* test -t with no arguments */
            tp->ap--;
            return(tty_check(1));
        }
    }
    if(*arg=='-' && arg[2]==0)
    {
        op = arg[1];
        if(!cp)
        {
            /* for backward compatibility with new flags */
            if(op==0 || !strchr(test_opchars+10,op))
                return(1);
            errormsg(SH_DICT,ERROR_exit(2),e_argument);
        }
        if(strchr(test_opchars,op))
            return(test_unop(op,cp));
    }
    if(!cp)
    {
        tp->ap--;
        return(*arg!=0);
    }
skip:
    op = sh_lookup(binop=cp,shtab_testops);
    if(!(op&TEST_BINOP))
        cp = nxtarg(tp,0);
    if(!op)
        errormsg(SH_DICT,ERROR_exit(2),e_badop,binop);
    if(op==TEST_AND || op==TEST_OR)
        tp->ap--;
    return(test_binop(op,arg,cp));
}

int test_unop(register int op,register const char *arg)
{
    struct stat statb;
    int f;
    switch(op)
    {
        case 'r':
        return(permission(arg, R_OK));
        case 'w':
        return(permission(arg, W_OK));
        case 'x':
        return(permission(arg, X_OK));
        case 'V':
#if SHOPT_FS_3D
        {
        register int offset = staktell();
        if(stat(arg,&statb)<0 || !S_ISREG(statb.st_mode))
            return(0);
        /* add trailing / */
        stakputs(arg);
        stakputc('/');
        stakputc(0);
        arg = (const char*)stakptr(offset);
        stakseek(offset);
        /* FALL THRU */
        }
#else
        return(0);
#endif /* SHOPT_FS_3D */
        case 'd':
        return(test_stat(arg,&statb)>=0 && S_ISDIR(statb.st_mode));
        case 'c':
        return(test_stat(arg,&statb)>=0 && S_ISCHR(statb.st_mode));
        case 'b':
        return(test_stat(arg,&statb)>=0 && S_ISBLK(statb.st_mode));
        case 'f':
        return(test_stat(arg,&statb)>=0 && S_ISREG(statb.st_mode));
        case 'u':
        return(test_mode(arg)&S_ISUID);
        case 'g':
        return(test_mode(arg)&S_ISGID);
        case 'k':
#ifdef S_ISVTX
        return(test_mode(arg)&S_ISVTX);
#else
        return(0);
#endif /* S_ISVTX */
#if SHOPT_TEST_L
        case 'l':
#endif
        case 'L':
        case 'h': /* undocumented, and hopefully will disappear */
        if(*arg==0 || arg[strlen(arg)-1]=='/' || lstat(arg,&statb)<0)
            return(0);
        return(S_ISLNK(statb.st_mode));

        case 'C':
#ifdef S_ISCTG
        return(test_stat(arg,&statb)>=0 && S_ISCTG(statb.st_mode));
#else
        return(0);
#endif  /* S_ISCTG */
        case 'H':
#ifdef S_ISCDF
        {
        register int offset = staktell();
        if(test_stat(arg,&statb)>=0 && S_ISCDF(statb.st_mode))
            return(1);
        stakputs(arg);
        stakputc('+');
        stakputc(0);
        arg = (const char*)stakptr(offset);
        stakseek(offset);
        return(test_stat(arg,&statb)>=0 && S_ISCDF(statb.st_mode));
        }
#else
        return(0);
#endif  /* S_ISCDF */

        case 'S':
        return(isasock(arg,&statb));
        case 'N':
        return(test_stat(arg,&statb)>=0 && tmxgetmtime(&statb) > tmxgetatime(&statb));
        case 'p':
        return(isapipe(arg,&statb));
        case 'n':
        return(*arg != 0);
        case 'z':
        return(*arg == 0);
        case 's':
        sfsync(sfstdout);
        case 'O':
        case 'G':
        if(*arg==0 || test_stat(arg,&statb)<0)
            return(0);
        if(op=='s')
            return(statb.st_size>0);
        else if(op=='O')
            return(statb.st_uid==sh.userid);
        return(statb.st_gid==sh.groupid);
        case 'a':
        case 'e':
        return(permission(arg, F_OK));
        case 'o':
        f=1;
        if(*arg=='?')
            return(sh_lookopt(arg+1,&f)>0);
        op = sh_lookopt(arg,&f);
        return(op && (f==(sh_isoption(op)!=0)));
        case 't':
        {
        char *last;
        op = strtol(arg,&last, 10);
        return(*last?0:tty_check(op));
        }
        case 'v':
        case 'R':
        {
        Namval_t *np;
        Namarr_t *ap;
        int isref;
        if(!(np = nv_open(arg,sh.var_tree,NV_VARNAME|NV_NOFAIL|NV_NOADD|NV_NOREF)))
            return(0);
        isref = nv_isref(np);
        if(op=='R')
            return(isref);
        if(isref)
        {
            if(np->nvalue.cp)
                np = nv_refnode(np);
            else
                return(0);

        }
        if(ap = nv_arrayptr(np))
            return(nv_arrayisset(np,ap));
        return(!nv_isnull(np) || nv_isattr(np,NV_INTEGER));
        }
        default:
        {
        static char a[3] = "-?";
        a[1]= op;
        errormsg(SH_DICT,ERROR_exit(2),e_badop,a);
        /* NOTREACHED  */
        return(0);
        }
    }
}

int test_binop(register int op,const char *left,const char *right)
{
    register double lnum,rnum;
    if(op&TEST_ARITH)
    {
        while(*left=='0')
            left++;
        while(*right=='0')
            right++;
        lnum = sh_arith(left);
        rnum = sh_arith(right);
    }
    switch(op)
    {
        /* op must be one of the following values */
        case TEST_AND:
        case TEST_OR:
            return(*left!=0);
        case TEST_PEQ:
            return(test_strmatch(left, right));
        case TEST_PNE:
            return(!test_strmatch(left, right));
        case TEST_SGT:
            return(strcoll(left, right)>0);
        case TEST_SLT:
            return(strcoll(left, right)<0);
        case TEST_SEQ:
            return(strcmp(left, right)==0);
        case TEST_SNE:
            return(strcmp(left, right)!=0);
        case TEST_EF:
            return(test_inode(left,right));
        case TEST_NT:
            return(test_time(left,right)>0);
        case TEST_OT:
            return(test_time(left,right)<0);
        case TEST_EQ:
            return(lnum==rnum);
        case TEST_NE:
            return(lnum!=rnum);
        case TEST_GT:
            return(lnum>rnum);
        case TEST_LT:
            return(lnum<rnum);
        case TEST_GE:
            return(lnum>=rnum);
        case TEST_LE:
            return(lnum<=rnum);
    }
    /* NOTREACHED */
    return(0);
}

/*
 * returns the modification time of f1 - modification time of f2
 */

static time_t test_time(const char *file1,const char *file2)
{
    Time_t t1, t2;
    struct stat statb1,statb2;
    int r=test_stat(file2,&statb2);
    if(test_stat(file1,&statb1)<0)
        return(r<0?0:-1);
    if(r<0)
        return(1);
    t1 = tmxgetmtime(&statb1);
    t2 = tmxgetmtime(&statb2);
    if (t1 > t2)
        return(1);
    if (t1 < t2)
        return(-1);
    return(0);
}

/*
 * return true if inode of two files are the same
 */

int test_inode(const char *file1,const char *file2)
{
    struct stat stat1,stat2;
    if(test_stat(file1,&stat1)>=0  && test_stat(file2,&stat2)>=0)
        if(stat1.st_dev == stat2.st_dev && stat1.st_ino == stat2.st_ino)
            return(1);
    return(0);
}


/*
 * This version of access checks against effective uid/gid
 * The static buffer statb is shared with test_mode.
 */

int sh_access(register const char *name, register int mode)
{
    struct stat statb;
    if(*name==0)
        return(-1);
    if(strmatch(name,(char*)e_devfdNN))
        return(sh_ioaccess((int)strtol(name+8, (char**)0, 10),mode));
    /* can't use access function for execute permission with root */
    if(mode==X_OK && sh.euserid==0)
        goto skip;
    if(sh.userid==sh.euserid && sh.groupid==sh.egroupid)
        return(access(name,mode));
#ifdef _lib_setreuid
    /* swap the real uid to effective, check access then restore */
    /* first swap real and effective gid, if different */
    if(sh.groupid==sh.euserid || setregid(sh.egroupid,sh.groupid)==0)
    {
        /* next swap real and effective uid, if needed */
        if(sh.userid==sh.euserid || setreuid(sh.euserid,sh.userid)==0)
        {
            mode = access(name,mode);
            /* restore ids */
            if(sh.userid!=sh.euserid)
                setreuid(sh.userid,sh.euserid);
            if(sh.groupid!=sh.egroupid)
                setregid(sh.groupid,sh.egroupid);
            return(mode);
        }
        else if(sh.groupid!=sh.egroupid)
            setregid(sh.groupid,sh.egroupid);
    }
#endif /* _lib_setreuid */
skip:
    if(test_stat(name, &statb) == 0)
    {
        if(mode == F_OK)
            return(mode);
        else if(sh.euserid == 0)
        {
            if(!S_ISREG(statb.st_mode) || mode!=X_OK)
                return(0);
                /* root needs execute permission for someone */
            mode = (S_IXUSR|S_IXGRP|S_IXOTH);
        }
        else if(sh.euserid == statb.st_uid)
            mode <<= 6;
        else if(sh.egroupid == statb.st_gid)
            mode <<= 3;
#ifdef _lib_getgroups
        /* on some systems you can be in several groups */
        else
        {
            static int maxgroups;
            gid_t *groups;
            register int n;
            if(maxgroups==0)
            {
                /* first time */
                if((maxgroups=getgroups(0,(gid_t*)0)) <= 0)
                {
                    /* pre-POSIX system */
                    maxgroups=NGROUPS_MAX;
                }
            }
            groups = (gid_t*)stakalloc((maxgroups+1)*sizeof(gid_t));
            n = getgroups(maxgroups,groups);
            while(--n >= 0)
            {
                if(groups[n] == statb.st_gid)
                {
                    mode <<= 3;
                    break;
                }
            }
        }
#   endif /* _lib_getgroups */
        if(statb.st_mode & mode)
            return(0);
    }
    return(-1);
}

/*
 * Return the mode bits of file <file>
 * If <file> is null, then the previous stat buffer is used.
 * The mode bits are zero if the file doesn't exist.
 */

static int test_mode(register const char *file)
{
    struct stat statb;
    if(file && (*file==0 || test_stat(file,&statb)<0))
        return(0);
    return(statb.st_mode);
}

/*
 * do an fstat() for /dev/fd/n, otherwise stat()
 */
static int test_stat(const char *name,struct stat *buff)
{
    if(*name==0)
    {
        errno = ENOENT;
        return(-1);
    }
    if(strmatch(name,(char*)e_devfdNN))
        return(fstat((int)strtol(name+8, (char**)0, 10),buff));
    else
        return(stat(name,buff));
}