util_script.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。

    else if (!r->path_info || !*r->path_info) {
	apr_table_setn(e, "SCRIPT_NAME", r->uri);
    }
    else {
	int path_info_start = ap_find_path_info(r->uri, r->path_info);

	apr_table_setn(e, "SCRIPT_NAME",
		      apr_pstrndup(r->pool, r->uri, path_info_start));

	apr_table_setn(e, "PATH_INFO", r->path_info);
    }

    if (r->path_info && r->path_info[0]) {
	/*
	 * To get PATH_TRANSLATED, treat PATH_INFO as a URI path.
	 * Need to re-escape it for this, since the entire URI was
	 * un-escaped before we determined where the PATH_INFO began.
	 */
	request_rec *pa_req;

	pa_req = ap_sub_req_lookup_uri(ap_escape_uri(r->pool, r->path_info), r,
                                       NULL);

	if (pa_req->filename) {
	    char *pt = apr_pstrcat(r->pool, pa_req->filename, pa_req->path_info,
				  NULL);
#ifdef WIN32
	    /* We need to make this a real Windows path name */
	    apr_filepath_merge(&pt, "", pt, APR_FILEPATH_NATIVE, r->pool);
#endif
	    apr_table_setn(e, "PATH_TRANSLATED", pt);
	}
	ap_destroy_sub_req(pa_req);
    }
}


static int set_cookie_doo_doo(void *v, const char *key, const char *val)
{
    apr_table_addn(v, key, val);
    return 1;
}

AP_DECLARE(int) ap_scan_script_header_err_core(request_rec *r, char *buffer,
				       int (*getsfunc) (char *, int, void *),
				       void *getsfunc_data)
{
    char x[MAX_STRING_LEN];
    char *w, *l;
    int p;
    int cgi_status = HTTP_OK;
    apr_table_t *merge;
    apr_table_t *cookie_table;

    if (buffer) {
	*buffer = '\0';
    }
    w = buffer ? buffer : x;

    /* temporary place to hold headers to merge in later */
    merge = apr_table_make(r->pool, 10);

    /* The HTTP specification says that it is legal to merge duplicate
     * headers into one.  Some browsers that support Cookies don't like
     * merged headers and prefer that each Set-Cookie header is sent
     * separately.  Lets humour those browsers by not merging.
     * Oh what a pain it is.
     */
    cookie_table = apr_table_make(r->pool, 2);
    apr_table_do(set_cookie_doo_doo, cookie_table, r->err_headers_out, "Set-Cookie", NULL);

    while (1) {

	if ((*getsfunc) (w, MAX_STRING_LEN - 1, getsfunc_data) == 0) {
	    ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_TOCLIENT, 0, r,
			  "Premature end of script headers: %s", 
                          apr_filename_of_pathname(r->filename));
	    return HTTP_INTERNAL_SERVER_ERROR;
	}

	/* Delete terminal (CR?)LF */

	p = strlen(w);
	     /* Indeed, the host's '\n':
	        '\012' for UNIX; '\015' for MacOS; '\025' for OS/390
	         -- whatever the script generates.
	     */                                  
	if (p > 0 && w[p - 1] == '\n') {
	    if (p > 1 && w[p - 2] == CR) {
		w[p - 2] = '\0';
	    }
	    else {
		w[p - 1] = '\0';
	    }
	}

	/*
	 * If we've finished reading the headers, check to make sure any
	 * HTTP/1.1 conditions are met.  If so, we're done; normal processing
	 * will handle the script's output.  If not, just return the error.
	 * The appropriate thing to do would be to send the script process a
	 * SIGPIPE to let it know we're ignoring it, close the channel to the
	 * script process, and *then* return the failed-to-meet-condition
	 * error.  Otherwise we'd be waiting for the script to finish
	 * blithering before telling the client the output was no good.
	 * However, we don't have the information to do that, so we have to
	 * leave it to an upper layer.
	 */
	if (w[0] == '\0') {
	    int cond_status = OK;

	    if ((cgi_status == HTTP_OK) && (r->method_number == M_GET)) {
		cond_status = ap_meets_conditions(r);
	    }
	    apr_table_overlap(r->err_headers_out, merge,
		APR_OVERLAP_TABLES_MERGE);
	    if (!apr_is_empty_table(cookie_table)) {
		/* the cookies have already been copied to the cookie_table */
		apr_table_unset(r->err_headers_out, "Set-Cookie");
		r->err_headers_out = apr_table_overlay(r->pool,
		    r->err_headers_out, cookie_table);
	    }
	    return cond_status;
	}

	/* if we see a bogus header don't ignore it. Shout and scream */

#if APR_CHARSET_EBCDIC
	    /* Chances are that we received an ASCII header text instead of
	     * the expected EBCDIC header lines. Try to auto-detect:
	     */
	if (!(l = strchr(w, ':'))) {
	    int maybeASCII = 0, maybeEBCDIC = 0;
	    unsigned char *cp, native;
            apr_size_t inbytes_left, outbytes_left;

	    for (cp = w; *cp != '\0'; ++cp) {
                native = apr_xlate_conv_byte(ap_hdrs_from_ascii, *cp);
		if (apr_isprint(*cp) && !apr_isprint(native))
		    ++maybeEBCDIC;
		if (!apr_isprint(*cp) && apr_isprint(native))
		    ++maybeASCII;
            }
	    if (maybeASCII > maybeEBCDIC) {
		ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
                             "CGI Interface Error: Script headers apparently ASCII: (CGI = %s)",
                             r->filename);
                inbytes_left = outbytes_left = cp - w;
                apr_xlate_conv_buffer(ap_hdrs_from_ascii,
                                      w, &inbytes_left, w, &outbytes_left);
	    }
	}
#endif /*APR_CHARSET_EBCDIC*/
	if (!(l = strchr(w, ':'))) {
	    char malformed[(sizeof MALFORMED_MESSAGE) + 1
			   + MALFORMED_HEADER_LENGTH_TO_SHOW];

	    strcpy(malformed, MALFORMED_MESSAGE);
	    strncat(malformed, w, MALFORMED_HEADER_LENGTH_TO_SHOW);

	    if (!buffer) {
		/* Soak up all the script output - may save an outright kill */
	        while ((*getsfunc) (w, MAX_STRING_LEN - 1, getsfunc_data)) {
		    continue;
		}
	    }

	    ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_TOCLIENT, 0, r,
			  "%s: %s", malformed, 
                          apr_filename_of_pathname(r->filename));
	    return HTTP_INTERNAL_SERVER_ERROR;
	}

	*l++ = '\0';
	while (*l && apr_isspace(*l)) {
	    ++l;
	}

	if (!strcasecmp(w, "Content-type")) {
	    char *tmp;

	    /* Nuke trailing whitespace */

	    char *endp = l + strlen(l) - 1;
	    while (endp > l && apr_isspace(*endp)) {
		*endp-- = '\0';
	    }

	    tmp = apr_pstrdup(r->pool, l);
	    ap_content_type_tolower(tmp);
	    ap_set_content_type(r, tmp);
	}
	/*
	 * If the script returned a specific status, that's what
	 * we'll use - otherwise we assume 200 OK.
	 */
	else if (!strcasecmp(w, "Status")) {
	    r->status = cgi_status = atoi(l);
	    r->status_line = apr_pstrdup(r->pool, l);
	}
	else if (!strcasecmp(w, "Location")) {
	    apr_table_set(r->headers_out, w, l);
	}
	else if (!strcasecmp(w, "Content-Length")) {
	    apr_table_set(r->headers_out, w, l);
	}
        else if (!strcasecmp(w, "Content-Range")) {
            apr_table_set(r->headers_out, w, l);
        }
	else if (!strcasecmp(w, "Transfer-Encoding")) {
	    apr_table_set(r->headers_out, w, l);
	}
	/*
	 * If the script gave us a Last-Modified header, we can't just
	 * pass it on blindly because of restrictions on future values.
	 */
	else if (!strcasecmp(w, "Last-Modified")) {
	    ap_update_mtime(r, apr_date_parse_http(l));
	    ap_set_last_modified(r);
	}
	else if (!strcasecmp(w, "Set-Cookie")) {
	    apr_table_add(cookie_table, w, l);
	}
	else {
	    apr_table_add(merge, w, l);
	}
    }

    return OK;
}

static int getsfunc_FILE(char *buf, int len, void *f)
{
    return apr_file_gets(buf, len, (apr_file_t *) f) == APR_SUCCESS;
}

AP_DECLARE(int) ap_scan_script_header_err(request_rec *r, apr_file_t *f,
					  char *buffer)
{
    return ap_scan_script_header_err_core(r, buffer, getsfunc_FILE, f);
}

static int getsfunc_BRIGADE(char *buf, int len, void *arg)
{
    apr_bucket_brigade *bb = (apr_bucket_brigade *)arg;
    const char *dst_end = buf + len - 1; /* leave room for terminating null */
    char *dst = buf;
    apr_bucket *e = APR_BRIGADE_FIRST(bb);
    apr_status_t rv;
    int done = 0;

    while ((dst < dst_end) && !done && !APR_BUCKET_IS_EOS(e)) {
        const char *bucket_data;
        apr_size_t bucket_data_len;
        const char *src;
        const char *src_end;
        apr_bucket * next;

        rv = apr_bucket_read(e, &bucket_data, &bucket_data_len,
                             APR_BLOCK_READ);
        if (!APR_STATUS_IS_SUCCESS(rv) || (bucket_data_len == 0)) {
            return 0;
        }
        src = bucket_data;
        src_end = bucket_data + bucket_data_len;
        while ((src < src_end) && (dst < dst_end) && !done) {
            if (*src == '\n') {
                done = 1;
            }
            else if (*src != '\r') {
                *dst++ = *src;
            }
            src++;
        }

        if (src < src_end) {
            apr_bucket_split(e, src - bucket_data);
        }
        next = APR_BUCKET_NEXT(e);
        APR_BUCKET_REMOVE(e);
        apr_bucket_destroy(e);
        e = next;
    }
    *dst = 0;
    return 1;
}

AP_DECLARE(int) ap_scan_script_header_err_brigade(request_rec *r,
                                                  apr_bucket_brigade *bb,
                                                  char *buffer)
{
    return ap_scan_script_header_err_core(r, buffer, getsfunc_BRIGADE, bb);
}

struct vastrs {
    va_list args;
    int arg;
    const char *curpos;
};

static int getsfunc_STRING(char *w, int len, void *pvastrs)
{
    struct vastrs *strs = (struct vastrs*) pvastrs;
    const char *p;
    int t;
    
    if (!strs->curpos || !*strs->curpos) 
        return 0;
    p = ap_strchr_c(strs->curpos, '\n');
    if (p)
        ++p;
    else
        p = ap_strchr_c(strs->curpos, '\0');
    t = p - strs->curpos;
    if (t > len)
        t = len;
    strncpy (w, strs->curpos, t);
    w[t] = '\0';
    if (!strs->curpos[t]) {
        ++strs->arg;
        strs->curpos = va_arg(strs->args, const char *);
    }
    else
        strs->curpos += t;
    return t;    
}

/* ap_scan_script_header_err_strs() accepts additional const char* args...
 * each is treated as one or more header lines, and the first non-header
 * character is returned to **arg, **data.  (The first optional arg is
 * counted as 0.)
 */
AP_DECLARE_NONSTD(int) ap_scan_script_header_err_strs(request_rec *r, 
                                                      char *buffer, 
                                                      const char **termch,
                                                      int *termarg, ...)
{
    struct vastrs strs;
    int res;

    va_start(strs.args, termarg);
    strs.arg = 0;
    strs.curpos = va_arg(strs.args, char*);
    res = ap_scan_script_header_err_core(r, buffer, getsfunc_STRING, (void *) &strs);
    if (termch)
        *termch = strs.curpos;
    if (termarg)
        *termarg = strs.arg;
    va_end(strs.args);
    return res;
}