root/luci/trunk/contrib/package/uhttpd/src/uhttpd.c @ 5901

/*
 * uhttpd - Tiny single-threaded httpd - Main component
 *
 *   Copyright (C) 2010 Jo-Philipp Wich <xm@subsignal.org>
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#define _XOPEN_SOURCE 500   /* crypt() */

#include "uhttpd.h"
#include "uhttpd-utils.h"
#include "uhttpd-file.h"

#ifdef HAVE_CGI
#include "uhttpd-cgi.h"
#endif

#ifdef HAVE_LUA
#include "uhttpd-lua.h"
#endif

#ifdef HAVE_TLS
#include "uhttpd-tls.h"
#endif


static int run = 1;

static void uh_sigterm(int sig)
{
    run = 0;
}

static void uh_config_parse(const char *path)
{
    FILE *c;
    char line[512];
    char *user = NULL;
    char *pass = NULL;
    char *eol  = NULL;

    if( (c = fopen(path ? path : "/etc/httpd.conf", "r")) != NULL )
    {
        memset(line, 0, sizeof(line));

        while( fgets(line, sizeof(line) - 1, c) )
        {
            if( (line[0] == '/') && (strchr(line, ':') != NULL) )
            {
                if( !(user = strchr(line, ':')) || (*user++ = 0) ||
                    !(pass = strchr(user, ':')) || (*pass++ = 0) ||
                    !(eol = strchr(pass, '\n')) || (*eol++  = 0) )
                        continue;

                if( !uh_auth_add(line, user, pass) )
                {
                    fprintf(stderr,
                        "Can not manage more than %i basic auth realms, "
                        "will skip the rest\n", UH_LIMIT_AUTHREALMS
                    );

                    break;
                } 
            }
        }

        fclose(c);
    }
}

static int uh_socket_bind(
    fd_set *serv_fds, int *max_fd, const char *host, const char *port,
    struct addrinfo *hints, int do_tls, struct config *conf
) {
    int sock = -1;
    int yes = 1;
    int status;
    int bound = 0;

    struct listener *l = NULL;
    struct addrinfo *addrs = NULL, *p = NULL;

    if( (status = getaddrinfo(host, port, hints, &addrs)) != 0 )
    {
        fprintf(stderr, "getaddrinfo(): %s\n", gai_strerror(status));
    }

    /* try to bind a new socket to each found address */
    for( p = addrs; p; p = p->ai_next )
    {
        /* get the socket */
        if( (sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1 )
        {
            perror("socket()");
            goto error;
        }

        /* "address already in use" */
        if( setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) == -1 )
        {
            perror("setsockopt()");
            goto error;
        }

        /* required to get parallel v4 + v6 working */
        if( p->ai_family == AF_INET6 )
        {
            if( setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes)) == -1 )
            {
                perror("setsockopt()");
                goto error;
            }
        }

        /* bind */
        if( bind(sock, p->ai_addr, p->ai_addrlen) == -1 )
        {
            perror("bind()");
            goto error;
        }

        /* listen */
        if( listen(sock, UH_LIMIT_CLIENTS) == -1 )
        {
            perror("listen()");
            goto error;
        }

        /* add listener to global list */
        if( ! (l = uh_listener_add(sock, conf)) )
        {
            fprintf(stderr,
                "uh_listener_add(): Can not create more than "
                "%i listen sockets\n", UH_LIMIT_LISTENERS
            );

            goto error;
        }

#ifdef HAVE_TLS
        /* init TLS */
        l->tls = do_tls ? conf->tls : NULL;
#endif

        /* add socket to server fd set */
        FD_SET(sock, serv_fds);
        *max_fd = max(*max_fd, sock);

        bound++;
        continue;

        error:
        if( sock > 0 )
            close(sock);
    }

    freeaddrinfo(addrs);

    return bound;
}

static struct http_request * uh_http_header_parse(struct client *cl, char *buffer, int buflen)
{
    char *method  = &buffer[0];
    char *path    = NULL;
    char *version = NULL;

    char *headers = NULL;
    char *hdrname = NULL;
    char *hdrdata = NULL;

    int i;
    int hdrcount = 0;

    static struct http_request req;

    memset(&req, 0, sizeof(req));


    /* terminate initial header line */
    if( (headers = strfind(buffer, buflen, "\r\n", 2)) != NULL )
    {
        buffer[buflen-1] = 0;

        *headers++ = 0;
        *headers++ = 0;

        /* find request path */
        if( (path = strchr(buffer, ' ')) != NULL )
            *path++ = 0;

        /* find http version */
        if( (path != NULL) && ((version = strchr(path, ' ')) != NULL) )
            *version++ = 0;


        /* check method */
        if( strcmp(method, "GET") && strcmp(method, "HEAD") && strcmp(method, "POST") )
        {
            /* invalid method */
            uh_http_response(cl, 405, "Method Not Allowed");
            return NULL;
        }
        else
        {
            switch(method[0])
            {
                case 'G':
                    req.method = UH_HTTP_MSG_GET;
                    break;

                case 'H':
                    req.method = UH_HTTP_MSG_HEAD;
                    break;

                case 'P':
                    req.method = UH_HTTP_MSG_POST;
                    break;
            }
        }

        /* check path */
        if( !path || !strlen(path) )
        {
            /* malformed request */
            uh_http_response(cl, 400, "Bad Request");
            return NULL;
        }
        else
        {
            req.url = path;
        }

        /* check version */
        if( strcmp(version, "HTTP/0.9") && strcmp(version, "HTTP/1.0") && strcmp(version, "HTTP/1.1") )
        {
            /* unsupported version */
            uh_http_response(cl, 400, "Bad Request");
            return NULL;
        }
        else
        {
            req.version = strtof(&version[5], NULL);
        }


        /* process header fields */
        for( i = (int)(headers - buffer); i < buflen; i++ )
        {
            /* found eol and have name + value, push out header tuple */
            if( hdrname && hdrdata && (buffer[i] == '\r' || buffer[i] == '\n') )
            {
                buffer[i] = 0;

                /* store */
                if( (hdrcount + 1) < array_size(req.headers) )
                {
                    req.headers[hdrcount++] = hdrname;
                    req.headers[hdrcount++] = hdrdata;

                    hdrname = hdrdata = NULL;
                }

                /* too large */
                else
                {
                    uh_http_response(cl, 413, "Request Entity Too Large");
                    return NULL;
                }
            }

            /* have name but no value and found a colon, start of value */
            else if( hdrname && !hdrdata && ((i+2) < buflen) &&
                (buffer[i] == ':') && (buffer[i+1] == ' ')
            ) {
                buffer[i] = 0;
                hdrdata = &buffer[i+2];
            }

            /* have no name and found [A-Z], start of name */
            else if( !hdrname && isalpha(buffer[i]) && isupper(buffer[i]) )
            {
                hdrname = &buffer[i];
            }
        }

        /* valid enough */
        return &req;
    }

    /* Malformed request */
    uh_http_response(cl, 400, "Bad Request");
    return NULL;
}


static struct http_request * uh_http_header_recv(struct client *cl)
{
    static char buffer[UH_LIMIT_MSGHEAD];
    char *bufptr = &buffer[0];
    char *idxptr = NULL;

    struct timeval timeout;

    fd_set reader;

    ssize_t blen = sizeof(buffer)-1;
    ssize_t rlen = 0;


    memset(buffer, 0, sizeof(buffer));

    while( blen > 0 )
    {
        FD_ZERO(&reader);
        FD_SET(cl->socket, &reader);

        /* fail after 0.1s */
        timeout.tv_sec  = 0;
        timeout.tv_usec = 100000;

        /* check whether fd is readable */
        if( select(cl->socket + 1, &reader, NULL, NULL, &timeout) > 0 )
        {
            /* receive data */
            rlen = uh_tcp_peek(cl, bufptr, blen);

            if( rlen > 0 )
            {
                if( (idxptr = strfind(buffer, sizeof(buffer), "\r\n\r\n", 4)) )
                {
                    blen -= uh_tcp_recv(cl, bufptr, (int)(idxptr - bufptr) + 4);

                    /* header read complete ... */
                    return uh_http_header_parse(cl, buffer, sizeof(buffer) - blen - 1);
                }
                else
                {
                    rlen = uh_tcp_recv(cl, bufptr, rlen);
                    blen -= rlen;
                    bufptr += rlen;
                }
            }
            else
            {
                /* invalid request (unexpected eof/timeout) */
                uh_http_response(cl, 408, "Request Timeout");
                return NULL;
            }
        }
        else
        {
            /* invalid request (unexpected eof/timeout) */
            uh_http_response(cl, 408, "Request Timeout");
            return NULL;
        }
    }

    /* request entity too large */
    uh_http_response(cl, 413, "Request Entity Too Large");
    return NULL;
}

static int uh_path_match(const char *prefix, const char *url)
{
    if( (strstr(url, prefix) == url) &&
        ((prefix[strlen(prefix)-1] == '/') ||
         (strlen(url) == strlen(prefix))   ||
         (url[strlen(prefix)] == '/'))
    ) {
        return 1;
    }

    return 0;
}


int main (int argc, char **argv)
{
#ifdef HAVE_LUA
    /* Lua runtime */
    lua_State *L = NULL;
#endif

    /* master file descriptor list */
    fd_set used_fds, serv_fds, read_fds;

    /* working structs */
    struct addrinfo hints;
    struct http_request *req;
    struct path_info *pin;
    struct client *cl;
    struct sigaction sa;
    struct config conf;

    /* maximum file descriptor number */
    int new_fd, cur_fd, max_fd = 0;

    int tls = 0;
    int keys = 0;
    int bound = 0;
    int nofork = 0;

    /* args */
    char opt;
    char bind[128];
    char *port = NULL;

    /* clear the master and temp sets */
    FD_ZERO(&used_fds);
    FD_ZERO(&serv_fds);
    FD_ZERO(&read_fds);

    /* handle SIGPIPE, SIGCHILD */
    sa.sa_handler = SIG_IGN;
    sigaction(SIGPIPE, &sa, NULL);
    sigaction(SIGCHLD, &sa, NULL);

    sa.sa_handler = uh_sigterm;
    sigaction(SIGINT,  &sa, NULL);
    sigaction(SIGTERM, &sa, NULL);

    /* prepare addrinfo hints */
    memset(&hints, 0, sizeof(hints));
    hints.ai_family   = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags    = AI_PASSIVE;

    /* parse args */
    memset(&conf, 0, sizeof(conf));
    memset(bind, 0, sizeof(bind));

#ifdef HAVE_TLS
    /* init SSL context */
    if( ! (conf.tls = uh_tls_ctx_init()) )
    {
        fprintf(stderr, "Failed to initalize SSL context\n");
        exit(1);
    }
#endif

    while( (opt = getopt(argc, argv, "fC:K:p:s:h:c:l:L:d:r:m:x:")) > 0 )
    {
        switch(opt)
        {
            /* [addr:]port */
            case 'p':
            case 's':
                if( (port = strrchr(optarg, ':')) != NULL )
                {
                    if( (optarg[0] == '[') && (port > optarg) && (port[-1] == ']') )
                        memcpy(bind, optarg + 1,
                            min(sizeof(bind), (int)(port - optarg) - 2));
                    else
                        memcpy(bind, optarg,
                            min(sizeof(bind), (int)(port - optarg)));

                    port++;
                }
                else
                {
                    port = optarg;
                }

                if( opt == 's' )
                    tls = 1;

                /* bind sockets */
                bound += uh_socket_bind(
                    &serv_fds, &max_fd, bind[0] ? bind : NULL, port,
                    &hints, tls, &conf
                );

                break;

#ifdef HAVE_TLS
            /* certificate */
            case 'C':
                if( SSL_CTX_use_certificate_file(conf.tls, optarg, SSL_FILETYPE_ASN1) < 1 )
                {
                    fprintf(stderr, "Invalid certificate file given\n");
                    exit(1);
                }

                keys++;
                break;

            /* key */
            case 'K':
                if( SSL_CTX_use_PrivateKey_file(conf.tls, optarg, SSL_FILETYPE_ASN1) < 1 )
                {
                    fprintf(stderr, "Invalid private key file given\n");
                    exit(1);
                }

                keys++;
                break;
#endif

            /* docroot */
            case 'h':
                if( ! realpath(optarg, conf.docroot) )
                {
                    fprintf(stderr, "Invalid directory %s: %s\n", optarg, strerror(errno));
                    exit(1);
                }
                break;

#ifdef HAVE_CGI
            /* cgi prefix */
            case 'x':
                conf.cgi_prefix = optarg;
                break;
#endif

#ifdef HAVE_LUA
            /* lua prefix */
            case 'l':
                conf.lua_prefix = optarg;
                break;

            /* lua handler */
            case 'L':
                conf.lua_handler = optarg;
                break;
#endif

            /* no fork */
            case 'f':
                nofork = 1;
                break;

            /* urldecode */
            case 'd':
                if( (port = malloc(strlen(optarg)+1)) != NULL )
                {
                    memset(port, 0, strlen(optarg)+1);
                    uh_urldecode(port, strlen(optarg), optarg, strlen(optarg));
                    printf("%s", port);
                    free(port);
                    exit(0);
                }
                break;

            /* basic auth realm */
            case 'r':
                conf.realm = optarg;
                break;

            /* md5 crypt */
            case 'm':
                printf("%s\n", crypt(optarg, "$1$"));
                exit(0);
                break;

            /* config file */
            case 'c':
                conf.file = optarg;
                break;

            default:
                fprintf(stderr,
                    "Usage: %s -p [addr:]port [-h docroot]\n"
                    "   -f              Do not fork to background\n"
                    "   -c file         Configuration file, default is '/etc/httpd.conf'\n"
                    "   -p [addr:]port  Bind to specified address and port, multiple allowed\n"
#ifdef HAVE_TLS
                    "   -s [addr:]port  Like -p but provide HTTPS on this port\n"
                    "   -C file         ASN.1 server certificate file\n"
                    "   -K file         ASN.1 server private key file\n"
#endif
                    "   -h directory    Specify the document root, default is '.'\n"
#ifdef HAVE_LUA
                    "   -l string       URL prefix for Lua handler, default is '/lua'\n"
                    "   -L file         Lua handler script, omit to disable Lua\n"
#endif
#ifdef HAVE_CGI
                    "   -x string       URL prefix for CGI handler, default is '/cgi-bin'\n"
#endif
                    "   -d string       URL decode given string\n"
                    "   -r string       Specify basic auth realm\n"
                    "   -m string       MD5 crypt given string\n"
                    "\n", argv[0]
                );

                exit(1);
        }
    }

#ifdef HAVE_TLS
    if( (tls == 1) && (keys < 2) )
    {
        fprintf(stderr, "Missing private key or certificate file\n");
        exit(1);
    }
#endif

    if( bound < 1 )
    {
        fprintf(stderr, "No sockets bound, unable to continue\n");
        exit(1);
    }

    /* default docroot */
    if( !conf.docroot[0] && !realpath(".", conf.docroot) )
    {
        fprintf(stderr, "Can not determine default document root: %s\n",
            strerror(errno));
        exit(1);
    }

    /* default realm */
    if( ! conf.realm )
        conf.realm = "Protected Area";

    /* config file */
    uh_config_parse(conf.file);

#ifdef HAVE_CGI
    /* default cgi prefix */
    if( ! conf.cgi_prefix )
        conf.cgi_prefix = "/cgi-bin";
#endif

#ifdef HAVE_LUA
    /* init Lua runtime if handler is specified */
    if( conf.lua_handler )
    {
        /* default lua prefix */
        if( ! conf.lua_prefix )
            conf.lua_prefix = "/lua";

        L = uh_lua_init(conf.lua_handler);
    }
#endif

    /* fork (if not disabled) */
    if( ! nofork )
    {
        switch( fork() )
        {
            case -1:
                perror("fork()");
                exit(1);

            case 0:
                /* daemon setup */
                if( chdir("/") )
                    perror("chdir()");

                if( (cur_fd = open("/dev/null", O_WRONLY)) > -1 )
                    dup2(cur_fd, 0);

                if( (cur_fd = open("/dev/null", O_RDONLY)) > -1 )
                    dup2(cur_fd, 1);

                if( (cur_fd = open("/dev/null", O_RDONLY)) > -1 )
                    dup2(cur_fd, 2);

                break;

            default:
                exit(0);
        }
    }

    /* backup server descriptor set */
    used_fds = serv_fds;

    /* loop */
    while(run)
    {
        /* create a working copy of the used fd set */
        read_fds = used_fds;

        /* sleep until socket activity */
        if( select(max_fd + 1, &read_fds, NULL, NULL, NULL) == -1 )
        {
            perror("select()");
            exit(1);
        }

        /* run through the existing connections looking for data to be read */
        for( cur_fd = 0; cur_fd <= max_fd; cur_fd++ )
        {
            /* is a socket managed by us */
            if( FD_ISSET(cur_fd, &read_fds) )
            {
                /* is one of our listen sockets */
                if( FD_ISSET(cur_fd, &serv_fds) )
                {
                    /* handle new connections */
                    if( (new_fd = accept(cur_fd, NULL, 0)) != -1 )
                    {
                        /* add to global client list */
                        if( (cl = uh_client_add(new_fd, uh_listener_lookup(cur_fd))) != NULL )
                        {
#ifdef HAVE_TLS
                            /* setup client tls context */
                            uh_tls_client_accept(cl);
#endif

                            /* add client socket to global fdset */
                            FD_SET(new_fd, &used_fds);
                            max_fd = max(max_fd, new_fd);
                        }

                        /* insufficient resources */
                        else
                        {
                            fprintf(stderr,
                                "uh_client_add(): Can not manage more than "
                                "%i client sockets, connection dropped\n",
                                UH_LIMIT_CLIENTS
                            );

                            close(new_fd);
                        }
                    }
                }

                /* is a client socket */
                else
                {
                    if( ! (cl = uh_client_lookup(cur_fd)) )
                    {
                        /* this should not happen! */
                        fprintf(stderr,
                            "uh_client_lookup(): No entry for fd %i!\n",
                            cur_fd);

                        goto cleanup;
                    }

                    /* parse message header */
                    if( (req = uh_http_header_recv(cl)) != NULL )
                    {
#ifdef HAVE_LUA
                        /* Lua request? */
                        if( L && uh_path_match(conf.lua_prefix, req->url) )
                        {
                            uh_lua_request(cl, req, L);
                        }
                        else
#endif
                        /* dispatch request */
                        if( (pin = uh_path_lookup(cl, req->url)) != NULL )
                        {
                            /* auth ok? */
                            if( uh_auth_check(cl, req, pin) )
                            {
#ifdef HAVE_CGI
                                if( uh_path_match(conf.cgi_prefix, pin->name) )
                                {
                                    uh_cgi_request(cl, req, pin);
                                }
                                else
#endif
                                {
                                    uh_file_request(cl, req, pin);
                                }
                            }
                        }

                        /* 404 */
                        else
                        {
                            uh_http_sendhf(cl, 404, "Not Found",
                                "No such file or directory");
                        }
                    }

                    /* 400 */
                    else
                    {
                        uh_http_sendhf(cl, 400, "Bad Request",
                            "Malformed request received");
                    }

#ifdef HAVE_TLS
                    /* free client tls context */
                    uh_tls_client_close(cl);
#endif

                    cleanup:

                    /* close client socket */
                    close(cur_fd);
                    FD_CLR(cur_fd, &used_fds);

                    /* remove from global client list */
                    uh_client_remove(cur_fd);
                }
            }
        }
    }

#ifdef HAVE_LUA
    /* destroy the Lua state */
    if( L != NULL )
        lua_close(L);
#endif

    return 0;
}