/*
 * RCONFIG/SERVER.C
 *
 * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "defs.h"

static void server_connection(int fd);
static void service_packet_loop(int fd);
static void server_chld_exit(int signo);
static int nconnects;

void
doServer(void)
{
    tag_t tag;

    /*
     * Listen on one or more UDP and TCP addresses, fork for each one.
     */
    signal(SIGCHLD, SIG_IGN);
    for (tag = AddrBase; tag; tag = tag->next) {
        struct sockaddr_in sain;
        const char *host;
        int lfd;
        int fd;
        int on = 1;

        bzero(&sain, sizeof(sain));
        if (tag->name == NULL) {
            sain.sin_addr.s_addr = INADDR_ANY;
            host = "<any>";
        } else {
            if (inet_aton(tag->name, &sain.sin_addr) == 0) {
                struct hostent *hp;
                if ((hp = gethostbyname2(tag->name, AF_INET)) == NULL) {
                    fprintf(stderr, "Unable to resolve %s\n", tag->name);
                    exit(1);
                }
                bcopy(hp->h_addr_list[0], &sain.sin_addr, hp->h_length);
                host = strdup(hp->h_name);
                endhostent();
            } else {
                host = strdup(tag->name);
            }
        }
        sain.sin_port = htons(257);
        sain.sin_len = sizeof(sain);
        sain.sin_family = AF_INET;
        fflush(stdout);
        if (fork() == 0) {
            if ((lfd = socket(AF_INET, SOCK_STREAM, PF_UNSPEC)) < 0) {
                fprintf(stderr, "%s: socket: %s\n", host, strerror(errno));
                exit(1);
            }
            setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
            if (bind(lfd, (void *)&sain, sizeof(sain)) < 0) {
                fprintf(stderr, "%s: bind: %s\n", host, strerror(errno));
                exit(1);
            }
            if (listen(lfd, 20) < 0) {
                fprintf(stderr, "%s: listen: %s\n", host, strerror(errno));
                exit(1);
            }
            signal(SIGCHLD, server_chld_exit);
            for (;;) {
                socklen_t slen = sizeof(sain);
                fd = accept(lfd, (void *)&sain, &slen);
                if (fd < 0) {
                    if (errno != EINTR)
                        break;
                    continue;
                }
                ++nconnects; /* XXX sigblock/sigsetmask */
                if (fork() == 0) {
                    close(lfd);
                    server_connection(fd);
                    exit(0);
                }
                close(fd);
            }
            exit(0);
        }
        if (fork() == 0) {
            if ((lfd = socket(AF_INET, SOCK_DGRAM, PF_UNSPEC)) < 0) {
                fprintf(stderr, "%s: socket: %s\n", host, strerror(errno));
                exit(1);
            }
            if (bind(lfd, (void *)&sain, sizeof(sain)) < 0) {
                fprintf(stderr, "%s: bind: %s\n", host, strerror(errno));
                exit(1);
            }
            service_packet_loop(lfd);
            exit(1);
        }
    }
    while (wait(NULL) > 0 || errno != EINTR)
        ;
}

static
void
server_chld_exit(int signo __unused)
{
    while (wait3(NULL, WNOHANG, NULL) > 0)
        --nconnects;
}

static
void
server_connection(int fd)
{
    FILE *fi;
    FILE *fo;
    char buf[256];
    char *scan;
    const char *cmd;
    const char *name;

    fi = fdopen(fd, "r");
    fo = fdopen(dup(fd), "w");

    if (gethostname(buf, sizeof(buf)) == 0) {
        fprintf(fo, "108 HELLO SERVER=%s\r\n", buf);
    } else {
        fprintf(fo, "108 HELLO\r\n");
    }
    fflush(fo);

    while (fgets(buf, sizeof(buf), fi) != NULL) {
        scan = buf;
        cmd = parse_str(&scan, PAS_ALPHA);
        if (cmd == NULL) {
            fprintf(fo, "502 Illegal Command String\r\n");
        } else if (strcasecmp(cmd, "VAR") == 0) {
            fprintf(fo, "100 OK\r\n");
        } else if (strcasecmp(cmd, "TAG") == 0) {
            if ((name = parse_str(&scan, PAS_ALPHA|PAS_SYMBOL|PAS_NUMERIC))
                    == NULL) {
                fprintf(fo, "401 Illegal Tag\r\n");
            } else {
                char *path = NULL;
                FILE *fp;
                asprintf(&path, "%s/%s.sh", TagDir, name);
                if ((fp = fopen(path, "r")) == NULL) {
                    fprintf(fo, "402 '%s' Not Found\r\n", name);
                } else {
                    size_t bytes;
                    size_t n;
                    int error = 0;

                    fseek(fp, 0L, 2);
                    bytes = (size_t)ftell(fp);
                    fseek(fp, 0L, 0);
                    fprintf(fo, "201 SIZE=%d\r\n", (int)bytes);
                    while (bytes > 0) {
                        n = (bytes > sizeof(buf)) ? sizeof(buf) : bytes;
                        n = fread(buf, 1, n, fp);
                        if (n <= 0) {
                            error = 1;
                            break;
                        }
                        if (fwrite(buf, 1, n, fo) != n) {
                            error = 1;
                            break;
                        }
                        bytes -= n;
                    }
                    fclose(fp);
                    if (bytes > 0 && ferror(fo) == 0) {
                        bzero(buf, sizeof(buf));
                        while (bytes > 0) {
                            n = (bytes > sizeof(buf)) ? sizeof(buf) : bytes;
                            if (fwrite(buf, 1, n, fo) != n)
                                break;
                            bytes -= n;
                        }
                    }
                    fprintf(fo, "202 ERROR=%d\r\n", error);
                }
                free(path);
            }
        } else if (strcasecmp(cmd, "IDLE") == 0) {
            if ((name = parse_str(&scan, PAS_ANY)) == NULL) {
                fprintf(fo, "401 Illegal String\r\n");
            } else {
                fprintf(fo, "109 %s\r\n", name);
            }
        } else if (strcasecmp(cmd, "QUIT") == 0) {
            fprintf(fo, "409 Bye!\r\n");
            break;
        } else {
            fprintf(fo, "501 Unknown Command\r\n");
        }
        fflush(fo);
    }
    fclose(fi);
    fclose(fo);
}

/*
 * UDP packet loop.  For now just handle one request per packet.  Note that
 * since the protocol is designed to be used in a broadcast environment,
 * we only respond when we have something to contribute.
 */
static
void
service_packet_loop(int fd)
{
    struct sockaddr_in sain;
    char ibuf[256+1];
    char obuf[256+1];
    socklen_t sain_len;
    int n;
    char *scan;
    const char *cmd;
    const char *name;

    for (;;) {
        sain_len = sizeof(sain);
        n = recvfrom(fd, ibuf, sizeof(ibuf) - 1, 0, (void *)&sain, &sain_len);
        if (n < 0) {
            if (errno == EINTR)
                continue;
            break;
        }
        ibuf[n] = 0;
        n = 0;
        scan = ibuf;
        cmd = parse_str(&scan, PAS_ALPHA);
        if (cmd == NULL) {
            ;
        } else if (strcasecmp(cmd, "TAG") == 0) {
            if ((name = parse_str(&scan, PAS_ALPHA|PAS_SYMBOL|PAS_NUMERIC))
                    != NULL) {
                char *path = NULL;
                struct stat st;
                asprintf(&path, "%s/%s.sh", TagDir, name);
                if (stat(path, &st) == 0) {
                    snprintf(obuf, sizeof(obuf), "101 TAG=%s\r\n", name);
                    n = strlen(obuf);
                }
                free(path);
            }
        }
        if (n)
            sendto(fd, obuf, n, 0, (void *)&sain, sain_len);
    }
}