get.c

用于移植到嵌入式linux系统的boa http服务器

/*
 *  Boa, an http server
 *  Copyright (C) 1995 Paul Phillips <[e-mail]>
 *  Copyright (C) 1996,99 Larry Doolittle <[e-mail]>
 *  Copyright (C) 1996-2002 Jon Nelson <[e-mail]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 1, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/* $Id: get.c,v 1.76.2.35 2005/02/22 14:11:29 jnelson Exp $*/

#include "boa.h"
#include "access.h"

#define STR(s) __STR(s)
#define __STR(s) #s


/* I think that permanent redirections (301) are supposed
 * to be absolute URIs, but they can be troublesome.
 * change to 1 to allow much simpler redirections.
 */
/* #define ALLOW_LOCAL_REDIRECT */

/* local prototypes */
static int get_cachedir_file(request * req, struct stat *statbuf);
static int index_directory(request * req, char *dest_filename);

/*
 * Name: init_get
 * Description: Initializes a non-script GET or HEAD request.
 *
 * Return values:
 *   0: finished or error, request will be freed
 *   1: successfully initialized, added to ready queue
 */

int init_get(request * req)
{
    int data_fd, saved_errno;
    struct stat statbuf;
    volatile unsigned int bytes_free;

    data_fd = open(req->pathname, O_RDONLY);
    saved_errno = errno;        /* might not get used */

#ifdef GUNZIP
    if (data_fd == -1 && errno == ENOENT) {
        /* cannot open */
        /* it's either a gunzipped file or a directory */
        char gzip_pathname[MAX_PATH_LENGTH];
        unsigned int len;

        len = strlen(req->pathname);

        if (len + 4 > sizeof(gzip_pathname)) {
            log_error_doc(req);
            fprintf(stderr, "Pathname + .gz too long! (%s)\n", req->pathname);
            send_r_bad_request(req);
            return 0;
        }

        memcpy(gzip_pathname, req->pathname, len);
        memcpy(gzip_pathname + len, ".gz", 3);
        gzip_pathname[len + 3] = '\0';
        data_fd = open(gzip_pathname, O_RDONLY);
        if (data_fd != -1) {
            close(data_fd);

            req->response_status = R_REQUEST_OK;
            if (req->pathname)
                free(req->pathname);
            req->pathname = strdup(gzip_pathname);
            if (!req->pathname) {
                boa_perror(req, "strdup req->pathname for gzipped filename " __FILE__ ":" STR(__LINE__));
                return 0;
            }
            if (req->http_version != HTTP09) {
                req_write(req, http_ver_string(req->http_version));
                req_write(req, " 200 OK-GUNZIP" CRLF);
                print_http_headers(req);
                print_content_type(req);
                print_last_modified(req);
                req_write(req, CRLF);
                req_flush(req);
            }
            if (req->method == M_HEAD)
                return 0;

            return init_cgi(req);
        }
    }
#endif

    if (data_fd == -1) {
        log_error_doc(req);
        errno = saved_errno;
        perror("document open");

        if (saved_errno == ENOENT)
            send_r_not_found(req);
        else if (saved_errno == EACCES)
            send_r_forbidden(req);
        else
            send_r_bad_request(req);
        return 0;
    }

#ifdef ACCESS_CONTROL
    if (!access_allow(req->pathname)) {
      send_r_forbidden(req);
      return 0;
    }
#endif

    fstat(data_fd, &statbuf);

    if (S_ISDIR(statbuf.st_mode)) { /* directory */
        close(data_fd);         /* close dir */

        if (req->pathname[strlen(req->pathname) - 1] != '/') {
            char buffer[3 * MAX_PATH_LENGTH + 128];
            unsigned int len;

#ifdef ALLOW_LOCAL_REDIRECT
            len = strlen(req->request_uri);
            if (len + 2 > sizeof(buffer)) {
                send_r_error(req);
                return 0;
            }
            memcpy(buffer, req->request_uri, len);
            buffer[len] = '/';
            buffer[len+1] = '\0';
#else
            char *host = server_name;
            unsigned int l2;
            char *port = NULL;
            const char *prefix = "http://";
            static unsigned int l3 = 0;
            static unsigned int l4 = 0;

            if (l4 == 0) {
                l4 = strlen(prefix);
            }
            len = strlen(req->request_uri);
            if (!port && server_port != 80) {
                port = strdup(simple_itoa(server_port));
                if (port == NULL) {
                    errno = ENOMEM;
                    boa_perror(req, "Unable to perform simple_itoa conversion on server port!");
                    return 0;
                }
                l3 = strlen(port);
            }
            /* l3 and l4 are done */

            if (req->host) {
                /* only shows up in vhost mode */
                /* what about the port? (in vhost_mode?) */
                /* we don't currently report ports that differ
                 * from out "bound" (listening) port, so we don't care
                 */
                host = req->host;
            }
            l2 = strlen(host);

            if (server_port != 80) {
                if (l4 + l2 + 1 + l3 + len + 1 > sizeof(buffer)) {
                    errno = ENOMEM;
                    boa_perror(req, "buffer not large enough for directory redirect");
                    return 0;
                }
                memcpy(buffer, prefix, l4);
                memcpy(buffer + l4, host, l2);
                buffer[l4 + l2] = ':';
                memcpy(buffer + l4 + l2 + 1, port, l3);
                memcpy(buffer + l4 + l2 + 1 + l3, req->request_uri, len);
                buffer[l4 + l2 + 1 + l3 + len] = '/';
                buffer[l4 + l2 + 1 + l3 + len + 1] = '\0';
            } else {
                if (l4 + l2 + len + 1 > sizeof(buffer)) {
                    errno = ENOMEM;
                    boa_perror(req, "buffer not large enough for directory redirect");
                    return 0;
                }
                memcpy(buffer, prefix, l4);
                memcpy(buffer + l4, host, l2);
                memcpy(buffer + l4 + l2, req->request_uri, len);
                buffer[l4 + l2 + len] = '/';
                buffer[l4 + l2 + len + 1] = '\0';
            }
#endif /* ALLOW LOCAL REDIRECT */
            send_r_moved_perm(req, buffer);
            return 0;
        }
        data_fd = get_dir(req, &statbuf); /* updates statbuf */

        if (data_fd < 0)      /* couldn't do it */
            return 0;           /* errors reported by get_dir */
        else if (data_fd == 0 || data_fd == 1)
            return data_fd;
        /* else, data_fd contains the fd of the file... */
    }

    if (!S_ISREG(statbuf.st_mode)) { /* regular file */
        log_error_doc(req);
        fprintf(stderr, "Resulting file is not a regular file.\n");
        send_r_bad_request(req);
        close(data_fd);
        return 0;
    }

    /* If-UnModified-Since asks
     *  is the file newer than date located in time_cval
     *  yes -> return 412
     *   no -> return 200
     *
     * If-Modified-Since asks
     *  is the file date less than or same as the date located in time_cval
     *  yes -> return 304
     *  no  -> return 200
     *
     * If-Unmodified-Since overrides If-Modified-Since
     */

    /*
    if (req->headers[H_IF_UNMODIFIED_SINCE] &&
        modified_since(&(statbuf.st_mtime),
                       req->headers[H_IF_UNMODIFIED_SINCE])) {
        send_r_precondition_failed(req);
        return 0;
    } else
    */
    if (req->if_modified_since &&
        !modified_since(&(statbuf.st_mtime), req->if_modified_since)) {
        send_r_not_modified(req);
        close(data_fd);
        return 0;
    }

    req->filesize = statbuf.st_size;
    req->last_modified = statbuf.st_mtime;

    /* ignore if-range without range */
    if (req->header_ifrange && !req->ranges)
        req->header_ifrange = NULL;

    /* we don't support it yet */
    req->header_ifrange = NULL;

    /* parse ranges now */
    /* we have to wait until req->filesize exists to fix them up */
    /* fixup handles handles communicating with the client */
    /* ranges_fixup logs as appropriate, and sends
     * send_r_invalid_range on error.
     */

    if (req->filesize == 0) {
        if (req->http_version < HTTP11) {
            send_r_request_ok(req);
            close(data_fd);
            return 0;
        }
        send_r_no_content(req);
        close(data_fd);
        return 0;
    }

    if (req->ranges && !ranges_fixup(req)) {
        close(data_fd);
        return 0;
    }

    /* if no range has been set, use default range */
#if 0
    DEBUG(DEBUG_RANGE) {
        log_error_time();
        fprintf(stderr, "if-range: %s\time_cval: %d\tmtime: %d\n",
                req->header_ifrange, req->time_cval, statbuf->st_mtime);
    }
#endif

    /*
     If the entity tag given in the If-Range header matches the current
     entity tag for the entity, then the server should provide the
     specified sub-range of the entity using a 206 (Partial content)
     response.

     If the entity tag does not match, then the server should
     return the entire entity using a 200 (OK) response.
     */
    /* IF we have range data *and* no if-range or if-range matches... */

#ifdef MAX_FILE_MMAP
    if (req->filesize > MAX_FILE_MMAP) {
        req->data_fd = data_fd;
        req->status = IOSHUFFLE;
    } else
#endif
    {
        /* NOTE: I (Jon Nelson) tried performing a read(2)
         * into the output buffer provided the file data would
         * fit, before mmapping, and if successful, writing that
         * and stopping there -- all to avoid the cost
         * of a mmap.  Oddly, it was *slower* in benchmarks.
         */
        req->mmap_entry_var = find_mmap(data_fd, &statbuf);
        if (req->mmap_entry_var == NULL) {
            req->data_fd = data_fd;
            req->status = IOSHUFFLE;
        } else {
            req->data_mem = req->mmap_entry_var->mmap;
            close(data_fd);             /* close data file */
        }
    }

    if (!req->ranges) {
        req->ranges = range_pool_pop();
        req->ranges->start = 0;
        req->ranges->stop = -1;
        if (!ranges_fixup(req)) {
            return 0;
        }
        send_r_request_ok(req);
    } else {
        /* FIXME: support if-range header here, by the following logic:
         * if !req->header_ifrange || st_mtime > header_ifrange,
         *   send_r_partial_content
         * else
         *   reset-ranges, etc...
         */
        if (!req->header_ifrange) {
            send_r_partial_content(req);
        } else {
            /* either no if-range or the if-range does not match */
            ranges_reset(req);
            req->ranges = range_pool_pop();
            req->ranges->start = 0;
            req->ranges->stop = -1;
            if (!ranges_fixup(req)) {
                return 0;
            }
            send_r_request_ok(req);
        }
    }

    if (req->method == M_HEAD) {
        return complete_response(req);
    }

    bytes_free = 0;
    if (req->data_mem) {
        /* things can really go tilt if req->buffer_end > BUFFER_SIZE,
         * but basically that can't happen
         */

        /* We lose statbuf here, so make sure response has been sent */
        bytes_free = BUFFER_SIZE - req->buffer_end;