mod_mime_magic.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

    /*
     * try tests in /etc/magic (or surrogate magic file)
     */
    if (softmagic(r, buf, nb) == 1)
        return OK;

    /*
     * try known keywords, check for ascii-ness too.
     */
    if (ascmagic(r, buf, nb) == 1)
        return OK;

    /*
     * abandon hope, all ye who remain here
     */
    return DECLINED;
}

#define    EATAB {while (apr_isspace(*l))  ++l;}

/*
 * apprentice - load configuration from the magic file r
 *  API request record
 */
static int apprentice(server_rec *s, apr_pool_t *p)
{
    apr_file_t *f = NULL;
    apr_status_t result;
    char line[BUFSIZ + 1];
    int errs = 0;
    int lineno;
#if MIME_MAGIC_DEBUG
    int rule = 0;
    struct magic *m, *prevm;
#endif
    magic_server_config_rec *conf = (magic_server_config_rec *)
                    ap_get_module_config(s->module_config, &mime_magic_module);
    const char *fname = ap_server_root_relative(p, conf->magicfile);

    if (!fname) {
        ap_log_error(APLOG_MARK, APLOG_ERR, APR_EBADPATH, s,
                     MODNAME ": Invalid magic file path %s", conf->magicfile);
        return -1;
    }
    if ((result = apr_file_open(&f, fname, APR_READ | APR_BUFFERED,
                                APR_OS_DEFAULT, p)) != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_ERR, result, s,
                     MODNAME ": can't read magic file %s", fname);
        return -1;
    }

    /* set up the magic list (empty) */
    conf->magic = conf->last = NULL;

    /* parse it */
    for (lineno = 1; apr_file_gets(line, BUFSIZ, f) == APR_SUCCESS; lineno++) {
        int ws_offset;
        char *last = line + strlen(line) - 1; /* guaranteed that len >= 1 since an
                                               * "empty" line contains a '\n'
                                               */

        /* delete newline and any other trailing whitespace */
        while (last >= line
               && apr_isspace(*last)) {
            *last = '\0';
            --last;
        }

        /* skip leading whitespace */
        ws_offset = 0;
        while (line[ws_offset] && apr_isspace(line[ws_offset])) {
            ws_offset++;
        }

        /* skip blank lines */
        if (line[ws_offset] == 0) {
            continue;
        }

        /* comment, do not parse */
        if (line[ws_offset] == '#')
            continue;

#if MIME_MAGIC_DEBUG
        /* if we get here, we're going to use it so count it */
        rule++;
#endif

        /* parse it */
        if (parse(s, p, line + ws_offset, lineno) != 0)
            ++errs;
    }

    (void) apr_file_close(f);

#if MIME_MAGIC_DEBUG
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice conf=%x file=%s m=%s m->next=%s last=%s",
                conf,
                conf->magicfile ? conf->magicfile : "NULL",
                conf->magic ? "set" : "NULL",
                (conf->magic && conf->magic->next) ? "set" : "NULL",
                conf->last ? "set" : "NULL");
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice read %d lines, %d rules, %d errors",
                lineno, rule, errs);
#endif

#if MIME_MAGIC_DEBUG
    prevm = 0;
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                MODNAME ": apprentice test");
    for (m = conf->magic; m; m = m->next) {
        if (apr_isprint((((unsigned long) m) >> 24) & 255) &&
            apr_isprint((((unsigned long) m) >> 16) & 255) &&
            apr_isprint((((unsigned long) m) >> 8) & 255) &&
            apr_isprint(((unsigned long) m) & 255)) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
                        MODNAME ": apprentice: POINTER CLOBBERED! "
                        "m=\"%c%c%c%c\" line=%d",
                        (((unsigned long) m) >> 24) & 255,
                        (((unsigned long) m) >> 16) & 255,
                        (((unsigned long) m) >> 8) & 255,
                        ((unsigned long) m) & 255,
                        prevm ? prevm->lineno : -1);
            break;
        }
        prevm = m;
    }
#endif

    return (errs ? -1 : 0);
}

/*
 * extend the sign bit if the comparison is to be signed
 */
static unsigned long signextend(server_rec *s, struct magic *m, unsigned long v)
{
    if (!(m->flag & UNSIGNED))
        switch (m->type) {
            /*
             * Do not remove the casts below.  They are vital. When later
             * compared with the data, the sign extension must have happened.
             */
        case BYTE:
            v = (char) v;
            break;
        case SHORT:
        case BESHORT:
        case LESHORT:
            v = (short) v;
            break;
        case DATE:
        case BEDATE:
        case LEDATE:
        case LONG:
        case BELONG:
        case LELONG:
            v = (long) v;
            break;
        case STRING:
            break;
        default:
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
                        MODNAME ": can't happen: m->type=%d", m->type);
            return -1;
        }
    return v;
}

/*
 * parse one line from magic file, put into magic[index++] if valid
 */
static int parse(server_rec *serv, apr_pool_t *p, char *l, int lineno)
{
    struct magic *m;
    char *t, *s;
    magic_server_config_rec *conf = (magic_server_config_rec *)
                    ap_get_module_config(serv->module_config, &mime_magic_module);

    /* allocate magic structure entry */
    m = (struct magic *) apr_pcalloc(p, sizeof(struct magic));

    /* append to linked list */
    m->next = NULL;
    if (!conf->magic || !conf->last) {
        conf->magic = conf->last = m;
    }
    else {
        conf->last->next = m;
        conf->last = m;
    }

    /* set values in magic structure */
    m->flag = 0;
    m->cont_level = 0;
    m->lineno = lineno;

    while (*l == '>') {
        ++l;  /* step over */
        m->cont_level++;
    }

    if (m->cont_level != 0 && *l == '(') {
        ++l;  /* step over */
        m->flag |= INDIR;
    }

    /* get offset, then skip over it */
    m->offset = (int) strtol(l, &t, 0);
    if (l == t) {
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                    MODNAME ": offset %s invalid", l);
    }
    l = t;

    if (m->flag & INDIR) {
        m->in.type = LONG;
        m->in.offset = 0;
        /*
         * read [.lbs][+-]nnnnn)
         */
        if (*l == '.') {
            switch (*++l) {
            case 'l':
                m->in.type = LONG;
                break;
            case 's':
                m->in.type = SHORT;
                break;
            case 'b':
                m->in.type = BYTE;
                break;
            default:
                ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": indirect offset type %c invalid", *l);
                break;
            }
            l++;
        }
        s = l;
        if (*l == '+' || *l == '-')
            l++;
        if (apr_isdigit((unsigned char) *l)) {
            m->in.offset = strtol(l, &t, 0);
            if (*s == '-')
                m->in.offset = -m->in.offset;
        }
        else
            t = l;
        if (*t++ != ')') {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": missing ')' in indirect offset");
        }
        l = t;
    }


    while (apr_isdigit((unsigned char) *l))
        ++l;
    EATAB;

#define NBYTE           4
#define NSHORT          5
#define NLONG           4
#define NSTRING         6
#define NDATE           4
#define NBESHORT        7
#define NBELONG         6
#define NBEDATE         6
#define NLESHORT        7
#define NLELONG         6
#define NLEDATE         6

    if (*l == 'u') {
        ++l;
        m->flag |= UNSIGNED;
    }

    /* get type, skip it */
    if (strncmp(l, "byte", NBYTE) == 0) {
        m->type = BYTE;
        l += NBYTE;
    }
    else if (strncmp(l, "short", NSHORT) == 0) {
        m->type = SHORT;
        l += NSHORT;
    }
    else if (strncmp(l, "long", NLONG) == 0) {
        m->type = LONG;
        l += NLONG;
    }
    else if (strncmp(l, "string", NSTRING) == 0) {
        m->type = STRING;
        l += NSTRING;
    }
    else if (strncmp(l, "date", NDATE) == 0) {
        m->type = DATE;
        l += NDATE;
    }
    else if (strncmp(l, "beshort", NBESHORT) == 0) {
        m->type = BESHORT;
        l += NBESHORT;
    }
    else if (strncmp(l, "belong", NBELONG) == 0) {
        m->type = BELONG;
        l += NBELONG;
    }
    else if (strncmp(l, "bedate", NBEDATE) == 0) {
        m->type = BEDATE;
        l += NBEDATE;
    }
    else if (strncmp(l, "leshort", NLESHORT) == 0) {
        m->type = LESHORT;
        l += NLESHORT;
    }
    else if (strncmp(l, "lelong", NLELONG) == 0) {
        m->type = LELONG;
        l += NLELONG;
    }
    else if (strncmp(l, "ledate", NLEDATE) == 0) {
        m->type = LEDATE;
        l += NLEDATE;
    }
    else {
        ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                    MODNAME ": type %s invalid", l);
        return -1;
    }
    /* New-style anding: "0 byte&0x80 =0x80 dynamically linked" */
    if (*l == '&') {
        ++l;
        m->mask = signextend(serv, m, strtol(l, &l, 0));
    }
    else
        m->mask = ~0L;
    EATAB;

    switch (*l) {
    case '>':
    case '<':
        /* Old-style anding: "0 byte &0x80 dynamically linked" */
    case '&':
    case '^':
    case '=':
        m->reln = *l;
        ++l;
        break;
    case '!':
        if (m->type != STRING) {
            m->reln = *l;
            ++l;
            break;
        }
        /* FALL THROUGH */
    default:
        if (*l == 'x' && apr_isspace(l[1])) {
            m->reln = *l;
            ++l;
            goto GetDesc;  /* Bill The Cat */
        }
        m->reln = '=';
        break;
    }
    EATAB;

    if (getvalue(serv, m, &l))
        return -1;
    /*
     * now get last part - the description
     */
  GetDesc:
    EATAB;
    if (l[0] == '\b') {
        ++l;
        m->nospflag = 1;
    }
    else if ((l[0] == '\\') && (l[1] == 'b')) {
        ++l;
        ++l;
        m->nospflag = 1;
    }
    else
        m->nospflag = 0;
    strncpy(m->desc, l, sizeof(m->desc) - 1);
    m->desc[sizeof(m->desc) - 1] = '\0';

#if MIME_MAGIC_DEBUG
    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, serv,
                MODNAME ": parse line=%d m=%x next=%x cont=%d desc=%s",
                lineno, m, m->next, m->cont_level, m->desc);
#endif /* MIME_MAGIC_DEBUG */

    return 0;
}

/*
 * Read a numeric value from a pointer, into the value union of a magic
 * pointer, according to the magic type.  Update the string pointer to point
 * just after the number read.  Return 0 for success, non-zero for failure.
 */
static int getvalue(server_rec *s, struct magic *m, char **p)
{
    int slen;

    if (m->type == STRING) {
        *p = getstr(s, *p, m->value.s, sizeof(m->value.s), &slen);
        m->vallen = slen;
    }
    else if (m->reln != 'x')
        m->value.l = signextend(s, m, strtol(*p, p, 0));
    return 0;
}

/*
 * Convert a string containing C character escapes.  Stop at an unescaped
 * space or tab. Copy the converted version to "p", returning its length in
 * *slen. Return updated scan pointer as function result.
 */
static char *getstr(server_rec *serv, register char *s, register char *p,
                    int plen, int *slen)
{
    char *origs = s, *origp = p;
    char *pmax = p + plen - 1;
    register int c;
    register int val;

    while ((c = *s++) != '\0') {
        if (apr_isspace(c))
            break;
        if (p >= pmax) {
            ap_log_error(APLOG_MARK, APLOG_ERR, 0, serv,
                        MODNAME ": string too long: %s", origs);
            break;
        }
        if (c == '\\') {
            switch (c = *s++) {

            case '\0':
                goto out;

            default:
                *p++ = (char) c;
                break;