mod_rewrite.c

Apache HTTP Server 是一个功能强大的灵活的与HTTP/1.1相兼容的web服务器.这里给出的是Apache HTTP服务器的源码。

    sconf->rewriteloglevel = atoi(a1);

    return NULL;
}

static const char *cmd_rewritemap(cmd_parms *cmd, void *dconf, const char *a1,
                                  const char *a2)
{
    rewrite_server_conf *sconf;
    rewritemap_entry *newmap;
    apr_finfo_t st;

    sconf = ap_get_module_config(cmd->server->module_config, &rewrite_module);

    newmap = apr_array_push(sconf->rewritemaps);

    newmap->name = a1;
    newmap->func = NULL;
    if (strncmp(a2, "txt:", 4) == 0) {
        newmap->type      = MAPTYPE_TXT;
        newmap->datafile  = a2+4;
        newmap->checkfile = a2+4;
        newmap->cachename = apr_psprintf(cmd->pool, "%pp:%s",
                                         (void *)cmd->server, a1);
    }
    else if (strncmp(a2, "rnd:", 4) == 0) {
        newmap->type      = MAPTYPE_RND;
        newmap->datafile  = a2+4;
        newmap->checkfile = a2+4;
        newmap->cachename = apr_psprintf(cmd->pool, "%pp:%s",
                                         (void *)cmd->server, a1);
    }
    else if (strncmp(a2, "dbm", 3) == 0) {
        const char *ignored_fname;
        int bad = 0;
        apr_status_t rv;

        newmap->type = MAPTYPE_DBM;
        newmap->cachename = apr_psprintf(cmd->pool, "%pp:%s",
                                         (void *)cmd->server, a1);

        if (a2[3] == ':') {
            newmap->dbmtype    = "default";
            newmap->datafile   = a2+4;
        }
        else if (a2[3] == '=') {
            const char *colon = ap_strchr_c(a2 + 4, ':');

            if (colon) {
                newmap->dbmtype = apr_pstrndup(cmd->pool, a2 + 4,
                                               colon - (a2 + 3) - 1);
                newmap->datafile = colon + 1;
            }
            else {
                ++bad;
            }
        }
        else {
            ++bad;
        }

        if (bad) {
            return apr_pstrcat(cmd->pool, "RewriteMap: bad map:",
                               a2, NULL);
        }

        rv = apr_dbm_get_usednames_ex(cmd->pool, newmap->dbmtype,
                                      newmap->datafile, &newmap->checkfile,
                                      &ignored_fname);
        if (rv != APR_SUCCESS) {
            return apr_pstrcat(cmd->pool, "RewriteMap: dbm type ",
                               newmap->dbmtype, " is invalid", NULL);
        }
    }
    else if (strncmp(a2, "prg:", 4) == 0) {
        newmap->type      = MAPTYPE_PRG;
        apr_tokenize_to_argv(a2 + 4, &newmap->argv, cmd->pool);
        newmap->datafile  = NULL;
        newmap->checkfile = newmap->argv[0];
        newmap->cachename = NULL;

    }
    else if (strncmp(a2, "int:", 4) == 0) {
        newmap->type      = MAPTYPE_INT;
        newmap->datafile  = NULL;
        newmap->checkfile = NULL;
        newmap->cachename = NULL;
        newmap->func      = (char *(*)(request_rec *,char *))
                            apr_hash_get(mapfunc_hash, a2+4, strlen(a2+4));
        if ((sconf->state == ENGINE_ENABLED) && (newmap->func == NULL)) {
            return apr_pstrcat(cmd->pool, "RewriteMap: internal map not found:",
                               a2+4, NULL);
        }
    }
    else {
        newmap->type      = MAPTYPE_TXT;
        newmap->datafile  = a2;
        newmap->checkfile = a2;
        newmap->cachename = apr_psprintf(cmd->pool, "%pp:%s",
                                         (void *)cmd->server, a1);
    }
    newmap->fpin  = NULL;
    newmap->fpout = NULL;

    if (newmap->checkfile && (sconf->state == ENGINE_ENABLED)
        && (apr_stat(&st, newmap->checkfile, APR_FINFO_MIN,
                     cmd->pool) != APR_SUCCESS)) {
        return apr_pstrcat(cmd->pool,
                           "RewriteMap: file for map ", newmap->name,
                           " not found:", newmap->checkfile, NULL);
    }

    return NULL;
}

static const char *cmd_rewritelock(cmd_parms *cmd, void *dconf, const char *a1)
{
    const char *error;

    if ((error = ap_check_cmd_context(cmd, GLOBAL_ONLY)) != NULL)
        return error;

    /* fixup the path, especially for rewritelock_remove() */
    lockname = ap_server_root_relative(cmd->pool, a1);

    if (!lockname) {
        return apr_pstrcat(cmd->pool, "Invalid RewriteLock path ", a1);
    }

    return NULL;
}

static const char *cmd_rewritebase(cmd_parms *cmd, void *in_dconf,
                                   const char *a1)
{
    rewrite_perdir_conf *dconf = in_dconf;

    if (cmd->path == NULL || dconf == NULL) {
        return "RewriteBase: only valid in per-directory config files";
    }
    if (a1[0] == '\0') {
        return "RewriteBase: empty URL not allowed";
    }
    if (a1[0] != '/') {
        return "RewriteBase: argument is not a valid URL";
    }

    dconf->baseurl = a1;

    return NULL;
}

static const char *cmd_rewritecond(cmd_parms *cmd, void *in_dconf,
                                   const char *in_str)
{
    rewrite_perdir_conf *dconf = in_dconf;
    char *str = apr_pstrdup(cmd->pool, in_str);
    rewrite_server_conf *sconf;
    rewritecond_entry *newcond;
    regex_t *regexp;
    char *a1;
    char *a2;
    char *a3;
    char *cp;
    const char *err;
    int rc;

    sconf = ap_get_module_config(cmd->server->module_config, &rewrite_module);

    /*  make a new entry in the internal temporary rewrite rule list */
    if (cmd->path == NULL) {   /* is server command */
        newcond = apr_array_push(sconf->rewriteconds);
    }
    else {                     /* is per-directory command */
        newcond = apr_array_push(dconf->rewriteconds);
    }

    /*  parse the argument line ourself */
    if (parseargline(str, &a1, &a2, &a3)) {
        return apr_pstrcat(cmd->pool, "RewriteCond: bad argument line '", str,
                           "'", NULL);
    }

    /*  arg1: the input string */
    newcond->input = apr_pstrdup(cmd->pool, a1);

    /* arg3: optional flags field
       (this have to be first parsed, because we need to
        know if the regex should be compiled with ICASE!) */
    newcond->flags = CONDFLAG_NONE;
    if (a3 != NULL) {
        if ((err = cmd_rewritecond_parseflagfield(cmd->pool, newcond,
                                                  a3)) != NULL) {
            return err;
        }
    }

    /*  arg2: the pattern
        try to compile the regexp to test if is ok */
    cp = a2;
    if (cp[0] == '!') {
        newcond->flags |= CONDFLAG_NOTMATCH;
        cp++;
    }

    /* now be careful: Under the POSIX regex library
       we can compile the pattern for case insensitive matching,
       under the old V8 library we have to do it self via a hack */
    if (newcond->flags & CONDFLAG_NOCASE) {
        rc = ((regexp = ap_pregcomp(cmd->pool, cp, REG_EXTENDED|REG_ICASE))
              == NULL);
    }
    else {
        rc = ((regexp = ap_pregcomp(cmd->pool, cp, REG_EXTENDED)) == NULL);
    }
    if (rc) {
        return apr_pstrcat(cmd->pool,
                           "RewriteCond: cannot compile regular expression '",
                           a2, "'", NULL);
    }

    newcond->pattern = apr_pstrdup(cmd->pool, cp);
    newcond->regexp  = regexp;

    return NULL;
}

static const char *cmd_rewritecond_parseflagfield(apr_pool_t *p,
                                                  rewritecond_entry *cfg,
                                                  char *str)
{
    char *cp;
    char *cp1;
    char *cp2;
    char *cp3;
    char *key;
    char *val;
    const char *err;

    if (str[0] != '[' || str[strlen(str)-1] != ']') {
        return "RewriteCond: bad flag delimiters";
    }

    cp = str+1;
    str[strlen(str)-1] = ','; /* for simpler parsing */
    for ( ; *cp != '\0'; ) {
        /* skip whitespaces */
        for ( ; (*cp == ' ' || *cp == '\t') && *cp != '\0'; cp++)
            ;
        if (*cp == '\0') {
            break;
        }
        cp1 = cp;
        if ((cp2 = strchr(cp, ',')) != NULL) {
            cp = cp2+1;
            for ( ; (*(cp2-1) == ' ' || *(cp2-1) == '\t'); cp2--)
                ;
            *cp2 = '\0';
            if ((cp3 = strchr(cp1, '=')) != NULL) {
                *cp3 = '\0';
                key = cp1;
                val = cp3+1;
            }
            else {
                key = cp1;
                val = "";
            }
            if ((err = cmd_rewritecond_setflag(p, cfg, key, val)) != NULL) {
                return err;
            }
        }
        else {
            break;
        }
    }

    return NULL;
}

static const char *cmd_rewritecond_setflag(apr_pool_t *p,
                                           rewritecond_entry *cfg,
                                           char *key, char *val)
{
    if (   strcasecmp(key, "nocase") == 0
        || strcasecmp(key, "NC") == 0    ) {
        cfg->flags |= CONDFLAG_NOCASE;
    }
    else if (   strcasecmp(key, "ornext") == 0
             || strcasecmp(key, "OR") == 0    ) {
        cfg->flags |= CONDFLAG_ORNEXT;
    }
    else {
        return apr_pstrcat(p, "RewriteCond: unknown flag '", key, "'", NULL);
    }
    return NULL;
}

static const char *cmd_rewriterule(cmd_parms *cmd, void *in_dconf,
                                   const char *in_str)
{
    rewrite_perdir_conf *dconf = in_dconf;
    char *str = apr_pstrdup(cmd->pool, in_str);
    rewrite_server_conf *sconf;
    rewriterule_entry *newrule;
    regex_t *regexp;
    char *a1;
    char *a2;
    char *a3;
    char *cp;
    const char *err;
    int mode;

    sconf = ap_get_module_config(cmd->server->module_config, &rewrite_module);

    /*  make a new entry in the internal rewrite rule list */
    if (cmd->path == NULL) {   /* is server command */
        newrule = apr_array_push(sconf->rewriterules);
    }
    else {                     /* is per-directory command */
        newrule = apr_array_push(dconf->rewriterules);
    }

    /*  parse the argument line ourself */
    if (parseargline(str, &a1, &a2, &a3)) {
        return apr_pstrcat(cmd->pool, "RewriteRule: bad argument line '", str,
                           "'", NULL);
    }

    /* arg3: optional flags field */
    newrule->forced_mimetype     = NULL;
    newrule->forced_responsecode = HTTP_MOVED_TEMPORARILY;
    newrule->flags  = RULEFLAG_NONE;
    newrule->env[0] = NULL;
    newrule->cookie[0] = NULL;
    newrule->skip   = 0;
    if (a3 != NULL) {
        if ((err = cmd_rewriterule_parseflagfield(cmd->pool, newrule,
                                                  a3)) != NULL) {
            return err;
        }
    }

    /*  arg1: the pattern
     *  try to compile the regexp to test if is ok
     */
    cp = a1;
    if (cp[0] == '!') {
        newrule->flags |= RULEFLAG_NOTMATCH;
        cp++;
    }
    mode = REG_EXTENDED;
    if (newrule->flags & RULEFLAG_NOCASE) {
        mode |= REG_ICASE;
    }
    if ((regexp = ap_pregcomp(cmd->pool, cp, mode)) == NULL) {
        return apr_pstrcat(cmd->pool,
                           "RewriteRule: cannot compile regular expression '",
                           a1, "'", NULL);
    }
    newrule->pattern = apr_pstrdup(cmd->pool, cp);
    newrule->regexp  = regexp;

    /*  arg2: the output string
     *  replace the $<N> by \<n> which is needed by the currently
     *  used Regular Expression library
     *
     * TODO: Is this still required for PCRE?  If not, does it *work* with PCRE?
     */
    newrule->output = apr_pstrdup(cmd->pool, a2);

    /* now, if the server or per-dir config holds an
     * array of RewriteCond entries, we take it for us
     * and clear the array
     */
    if (cmd->path == NULL) {  /* is server command */
        newrule->rewriteconds   = sconf->rewriteconds;
        sconf->rewriteconds = apr_array_make(cmd->pool, 2,
                                            sizeof(rewritecond_entry));
    }
    else {                    /* is per-directory command */
        newrule->rewriteconds   = dconf->rewriteconds;
        dconf->rewriteconds = apr_array_make(cmd->pool, 2,
                                            sizeof(rewritecond_entry));
    }

    return NULL;
}

static const char *cmd_rewriterule_parseflagfield(apr_pool_t *p,
                                                  rewriterule_entry *cfg,
                                                  char *str)
{
    char *cp;
    char *cp1;
    char *cp2;