/*
 * file - determine type of file
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <a.out.h>
#include <errno.h>
#include <string.h>

int in;
int i  = 0;
char buf[BUFSIZ];
char *troff[] = {   /* new troff intermediate lang */
    "x","T","res","init","font","202","V0","p1",0};
char *fort[] = {
    "function","subroutine","common","dimension","block","integer",
    "real","data","double",0};
char *asc[] = {
    "sys","mov","tst","clr","jmp",0};
char *c[] = {
    "int","char","float","double","struct","extern",0};
char *as[] = {
    "globl","byte","align","text","data","comm",0};
char *sh[] = {
    "fi", "elif", "esac", "done", "export",
    "readonly", "trap", "PATH", "HOME", 0 };
char *csh[] = {
    "alias", "breaksw", "endsw", "foreach", "limit",  "onintr",
    "repeat", "setenv", "source", "path", "home", 0 };
int ifile;

main(argc, argv)
char **argv;
{
    register FILE *fl;
    register char *p;
    char ap[MAXPATHLEN + 1];

    if (argc < 2) {
        fprintf(stderr, "usage: %s file ...\n", argv[0]);
        exit(3);
    }

    if (argc>1 && argv[1][0]=='-' && argv[1][1]=='f') {
        if ((fl = fopen(argv[2], "r")) == NULL) {
            perror(argv[2]);
            exit(2);
        }
        while ((p = fgets(ap, sizeof ap, fl)) != NULL) {
            int l = strlen(p);
            if (l>0)
                p[l-1] = '\0';
            printf("%s: ", p);
            type(p);
            if (ifile>=0)
                close(ifile);
        }
        exit(1);
    }
    while(argc > 1) {
        printf("%s: ", argv[1]);
        type(argv[1]);
        fflush(stdout);
        argc--;
        argv++;
        if (ifile >= 0)
            close(ifile);
    }
    exit(0);
}

type(file)
char *file;
{
    register int j;
    int nl;
    char ch;
    struct stat mbuf;
    char slink[MAXPATHLEN + 1];

    ifile = -1;
    if (lstat(file, &mbuf) < 0) {
        printf("%s\n", strerror(errno));
        return;
    }
    switch (mbuf.st_mode & S_IFMT) {

    case S_IFLNK:
        printf("symbolic link");
        j = readlink(file, slink, sizeof slink - 1);
        if (j >= 0) {
            slink[j] = '\0';
            printf(" to %s", slink);
        }
        printf("\n");
        return;

    case S_IFDIR:
        if (mbuf.st_mode & S_ISVTX)
            printf("append-only ");
        printf("directory\n");
        return;

    case S_IFCHR:
    case S_IFBLK:
        printf("%s special (%d/%d)\n",
            (mbuf.st_mode&S_IFMT) == S_IFCHR ? "character" : "block",
             major(mbuf.st_rdev), minor(mbuf.st_rdev));
        return;

    case S_IFSOCK:
        printf("socket\n");
        return;
    }

    ifile = open(file, 0);
    if(ifile < 0) {
        printf("%s\n", strerror(errno));
        return;
    }
    in = read(ifile, buf, BUFSIZ);
    if(in == 0){
        printf("empty\n");
        return;
    }
    switch(*(int *)buf) {

    case 0413:
        printf("demand paged ");

    case 0410:
        printf("pure ");
        goto exec;

    case 0411:
        printf("separate ");
        goto exec;

    case 0407:
exec:
        if (mbuf.st_mode & S_ISUID)
            printf("set-uid ");
        if (mbuf.st_mode & S_ISGID)
            printf("set-gid ");
        if (mbuf.st_mode & S_ISVTX)
            printf("sticky ");
        printf("executable");
        if(((int *)buf)[4] != 0)
            printf(" not stripped");
        if (((int *)buf)[1] == 0 && ((int *)buf)[2] != 0 &&
            ((int *)buf)[3] == 0)
            printf(" (likely vax)");
        printf("\n");
        return;

    case 0177555:
        printf("very old archive\n");
        return;

    case 0177545:
        printf("old archive\n");
        return;

    case 070707:
        printf("cpio data\n");
        return;
    }

    if (buf[0] == '#' && buf[1] == '!' && shellscript(buf+2, &mbuf))
        return;
    if (buf[0] == '\037' && buf[1] == '\235') {
        if (buf[2]&0x80)
            printf("block ");
        printf("compressed %d bit code data\n", buf[2]&0x1f);
        return;
    }
    if(strncmp(buf, "!<arch>\n__.SYMDEF", 17) == 0 ) {
        printf("archive random library\n");
        return;
    }
    if (strncmp(buf, "!<arch>\n", 8)==0) {
        printf("archive\n");
        return;
    }
    if (mbuf.st_size % 512 == 0) {  /* it may be a PRESS file */
        lseek(ifile, -512L, 2); /* last block */
        if (read(ifile, buf, BUFSIZ) > 0 && *(short *)buf == 12138) {
            printf("PRESS file\n");
            return;
        }
    }
    i = 0;
    if(ccom() == 0)goto notc;
    while(buf[i] == '#'){
        j = i;
        while(buf[i++] != '\n'){
            if(i - j > 255){
                printf("data\n");
                return;
            }
            if(i >= in)goto notc;
        }
        if(ccom() == 0)goto notc;
    }
check:
    if(lookup(c) == 1){
        while((ch = buf[i++]) != ';' && ch != '{')if(i >= in)goto notc;
        printf("c program text");
        goto outa;
    }
    nl = 0;
    while(buf[i] != '('){
        if(buf[i] <= 0)
            goto notas;
        if(buf[i] == ';'){
            i++;
            goto check;
        }
        if(buf[i++] == '\n')
            if(nl++ > 6)goto notc;
        if(i >= in)goto notc;
    }
    while(buf[i] != ')'){
        if(buf[i++] == '\n')
            if(nl++ > 6)goto notc;
        if(i >= in)goto notc;
    }
    while(buf[i] != '{'){
        if(buf[i++] == '\n')
            if(nl++ > 6)goto notc;
        if(i >= in)goto notc;
    }
    printf("c program text");
    goto outa;
notc:
    i = 0;
    while(buf[i] == 'c' || buf[i] == '#'){
        while(buf[i++] != '\n')if(i >= in)goto notfort;
    }
    if(lookup(fort) == 1){
        printf("fortran program text");
        goto outa;
    }
notfort:
    i=0;
    if(ascom() == 0)goto notas;
    j = i-1;
    if(buf[i] == '.'){
        i++;
        if(lookup(as) == 1){
            printf("assembler program text");
            goto outa;
        }
        else if(buf[j] == '\n' && isalpha(buf[j+2])){
            printf("roff, nroff, or eqn input text");
            goto outa;
        }
    }
    while(lookup(asc) == 0){
        if(ascom() == 0)goto notas;
        while(buf[i] != '\n' && buf[i++] != ':')
            if(i >= in)goto notas;
        while(buf[i] == '\n' || buf[i] == ' ' || buf[i] == '\t')if(i++ >= in)goto notas;
        j = i-1;
        if(buf[i] == '.'){
            i++;
            if(lookup(as) == 1){
                printf("assembler program text");
                goto outa;
            }
            else if(buf[j] == '\n' && isalpha(buf[j+2])){
                printf("roff, nroff, or eqn input text");
                goto outa;
            }
        }
    }
    printf("assembler program text");
    goto outa;
notas:
    for(i=0; i < in; i++)if(buf[i]&0200){
        if (buf[0]=='\100' && buf[1]=='\357')
            printf("troff (CAT) output\n");
        else
            printf("data\n");
        return;
    }
    if (mbuf.st_mode&((S_IEXEC)|(S_IEXEC>>3)|(S_IEXEC>>6))) {
        if (mbuf.st_mode & S_ISUID)
            printf("set-uid ");
        if (mbuf.st_mode & S_ISGID)
            printf("set-gid ");
        if (mbuf.st_mode & S_ISVTX)
            printf("sticky ");
        if (shell(buf, in, sh))
            printf("shell script");
        else if (shell(buf, in, csh))
            printf("c-shell script");
        else
            printf("commands text");
    } else if (troffint(buf, in))
        printf("troff intermediate output text");
    else if (shell(buf, in, sh))
        printf("shell commands");
    else if (shell(buf, in, csh))
        printf("c-shell commands");
    else if (english(buf, in))
        printf("English text");
    else
        printf("ascii text");
outa:
    while(i < in)
        if((buf[i++]&0377) > 127){
            printf(" with garbage\n");
            return;
        }
    /* if next few lines in then read whole file looking for nulls ...
        while((in = read(ifile,buf,BUFSIZ)) > 0)
            for(i = 0; i < in; i++)
                if((buf[i]&0377) > 127){
                    printf(" with garbage\n");
                    return;
                }
        /*.... */
    printf("\n");
}

troffint(bp, n)
char *bp;
int n;
{
    int k;

    i = 0;
    for (k = 0; k < 6; k++) {
        if (lookup(troff) == 0)
            return(0);
        if (lookup(troff) == 0)
            return(0);
        while (i < n && buf[i] != '\n')
            i++;
        if (i++ >= n)
            return(0);
    }
    return(1);
}

lookup(tab)
char *tab[];
{
    char r;
    int k,j,l;
    while(buf[i] == ' ' || buf[i] == '\t' || buf[i] == '\n')i++;
    for(j=0; tab[j] != 0; j++){
        l=0;
        for(k=i; ((r=tab[j][l++]) == buf[k] && r != '\0');k++);
        if(r == '\0')
            if(buf[k] == ' ' || buf[k] == '\n' || buf[k] == '\t'
                || buf[k] == '{' || buf[k] == '/'){
                i=k;
                return(1);
            }
    }
    return(0);
}

ccom()
{
    char cc;
    while((cc = buf[i]) == ' ' || cc == '\t' || cc == '\n')if(i++ >= in)return(0);
    if(buf[i] == '/' && buf[i+1] == '*'){
        i += 2;
        while(buf[i] != '*' || buf[i+1] != '/'){
            if(buf[i] == '\\')i += 2;
            else i++;
            if(i >= in)return(0);
        }
        if((i += 2) >= in)return(0);
    }
    if(buf[i] == '\n')if(ccom() == 0)return(0);
    return(1);
}

ascom()
{
    while(buf[i] == '/'){
        i++;
        while(buf[i++] != '\n')if(i >= in)return(0);
        while(buf[i] == '\n')if(i++ >= in)return(0);
    }
    return(1);
}

english (bp, n)
char *bp;
{
#define NASC 128
    int ct[NASC], j, vow, freq, rare;
    int badpun = 0, punct = 0;
    if (n<50) return(0); /* no point in statistics on squibs */
    for(j=0; j<NASC; j++)
        ct[j]=0;
    for(j=0; j<n; j++)
    {
        if (bp[j]<NASC)
            ct[bp[j]|040]++;
        switch (bp[j])
        {
        case '.':
        case ',':
        case ')':
        case '%':
        case ';':
        case ':':
        case '?':
            punct++;
            if ( j < n-1 &&
                bp[j+1] != ' ' &&
                bp[j+1] != '\n')
                badpun++;
        }
    }
    if (badpun*5 > punct)
        return(0);
    vow = ct['a'] + ct['e'] + ct['i'] + ct['o'] + ct['u'];
    freq = ct['e'] + ct['t'] + ct['a'] + ct['i'] + ct['o'] + ct['n'];
    rare = ct['v'] + ct['j'] + ct['k'] + ct['q'] + ct['x'] + ct['z'];
    if (2*ct[';'] > ct['e']) return(0);
    if ( (ct['>']+ct['<']+ct['/'])>ct['e']) return(0); /* shell file test */
    return (vow*5 >= n-ct[' '] && freq >= 10*rare);
}

shellscript(buf, sb)
    char buf[];
    struct stat *sb;
{
    register char *tp;
    char *cp, *xp, *index();

    cp = index(buf, '\n');
    if (cp == 0 || cp - buf > in)
        return (0);
    for (tp = buf; tp != cp && isspace(*tp); tp++)
        if (!isascii(*tp))
            return (0);
    for (xp = tp; tp != cp && !isspace(*tp); tp++)
        if (!isascii(*tp))
            return (0);
    if (tp == xp)
        return (0);
    if (sb->st_mode & S_ISUID)
        printf("set-uid ");
    if (sb->st_mode & S_ISGID)
        printf("set-gid ");
    if (strncmp(xp, "/bin/sh", tp-xp) == 0)
        xp = "shell";
    else if (strncmp(xp, "/bin/csh", tp-xp) == 0)
        xp = "c-shell";
    else
        *tp = '\0';
    printf("executable %s script\n", xp);
    return (1);
}

shell(bp, n, tab)
    char *bp;
    int n;
    char *tab[];
{

    i = 0;
    do {
        if (buf[i] == '#' || buf[i] == ':')
            while (i < n && buf[i] != '\n')
                i++;
        if (++i >= n)
            break;
        if (lookup(tab) == 1)
            return (1);
    } while (i < n);
    return (0);
}
