ftpd.c

功能强大的ftp服务器源代码

    syslog(crit, "(%s@%s) %s%s",
           ((loggedin != 0 && *account != 0) ? account : "?"),
           (*host != 0 ? host : "?"),
           urgency, line);
# ifdef SAVE_DESCRIPTORS
    closelog();
# endif
    va_end(va);
#endif
}

#ifndef NO_STANDALONE

/* this is taken from the code examples for Stevens' "Advanced
 * Programming in the Unix Environment. The code is publicly available
 * at ftp://ftp.uu.net/published/books/stevens.advprog.tar.Z */

static unsigned int open_max(void)
{
    long z;

    if ((z = (long) sysconf(_SC_OPEN_MAX)) < 0L) {
        perror("_SC_OPEN_MAX");
        _EXIT(EXIT_FAILURE);
    }
    return (unsigned int) z;
}

#endif

static void addreply_newline(const char * const str, const size_t size)
{
    struct reply *newline;
    
    if ((newline = (struct reply *) malloc(offsetof(struct reply, line) +
                                           size)) == NULL) {
        die_mem();
    }
    if (firstreply == NULL) {
        firstreply = newline;
    } else {
        lastreply->next = newline;
    }
    newline->next = NULL;
    lastreply = newline;
    memcpy(newline->line, str, size);    
}

void addreply_noformat(const int code, const char * const line)
{
    if (code != 0) {
        replycode = code;
    }
    addreply_newline(line, strlen(line) + (size_t) 1U);
}

void addreply(const int code, const char * const line, ...)
{
    register char *a;
    register char *b;
    va_list ap;
    int last;
    char buf[MAX_SERVER_REPLY_LEN];

    if (code != 0) {
        replycode = code;
    }
    va_start(ap, line);
    vsnprintf(buf, sizeof buf, line, ap);
    va_end(ap);
    last = 0;
    a = buf;
    for (;;) {
        b = strchr(a, '\n');
        if (b != NULL) {
            *b = 0;
        } else {
            b = a;
            while (*b != 0) {
                b++;
            }
            last++;
        }
        addreply_newline(a, (size_t) (b - a) + (size_t) 1U);
        if (last != 0) {
            break;
        }
        a = b + 1;
    }
}

void doreply(void)
{
    register struct reply *scannedentry;
    register struct reply *nextentry;
    
    if ((scannedentry = firstreply) == NULL) {
        return;
    }
    CORK_ON(1);
    do {
        nextentry = scannedentry->next;
#ifdef WITH_TLS
        if (tls_cnx != NULL) {
            char buf[MAX_SERVER_REPLY_LEN];
            
            snprintf(buf, sizeof buf, "%3d%c%s\r\n", replycode, 
                     nextentry == NULL ? ' ' : '-', scannedentry->line);
            SSL_write(tls_cnx, buf, strlen(buf));            
        } else
#endif
        {
            printf("%3d%c%s\r\n", replycode, nextentry == NULL ? ' ' : '-',
                   scannedentry->line);
        }
        if (logging > 1) {
            logfile(LOG_DEBUG, "%3d%c%s", replycode, 
                    nextentry == NULL ? ' ' : '-', scannedentry->line);
        }       
    } while ((scannedentry = nextentry) != NULL);
    fflush(stdout);    
    CORK_OFF(1);
    /* We don't free() after printf() because of Solaris stream bugs,
     * Thanks to Kenneth Stailey */
    scannedentry = firstreply;
    do {
        nextentry = scannedentry->next;
        free(scannedentry);
    } while ((scannedentry = nextentry) != NULL);
    firstreply = lastreply = NULL;
}

/* Check whether a file name is valid. Files names starting
 * with a dot are only allowed to root and to users
 * chroot()ed in their home directories -Jedi. */

static int checknamesanity(const char *name, int dot_ok)
{
    register const char *namepnt;

#ifdef PARANOID_FILE_NAMES
    const char *validchars =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefgihjklmnopqrstuvwxyz"
        "0123456789./-_";
#endif
    
    if (name == NULL || *name == 0) {
        return -1;
    }
    /* optimize . and .. */
    if (name[0] == '.' && (name[1] == 0 || (name[1] == '.' && name[2] == 0))) {
        return 0;
    }
    namepnt = name;
#ifdef PARANOID_FILE_NAMES
    /* we want to make sure we don't get any non-alphanumeric file name */
    if (strlen(namepnt) != strspn(namepnt, validchars)) {
        return -1;
    }
#endif
#ifdef QUOTAS
    if (hasquota() == 0 && strstr(namepnt, QUOTA_FILE) != NULL) {
        return -1;                     /* .ftpquota => *NO* */
    }
#endif
    if (strstr(namepnt, PUREFTPD_TMPFILE_PREFIX) != NULL) {
        return -1;
    }
    while (*namepnt != 0) {
        if (ISCTRLCODE(*namepnt) || *namepnt == '\\') {
            return -1;
        }
        if (dot_ok == 0) {
            if (*namepnt == '/') {
                namepnt++;
            } else if (namepnt != name) {
                namepnt++;
                continue;
            }
            if (namepnt[0] == 0) {     /* /$ */
                return 0;
            }
            if (namepnt[0] == '.') {   /* /. */
                if (namepnt[1] == 0) { /* /.$ => ok */
                    return 0;
                }
                if (namepnt[1] == '.') {   /* /.. */
                    if (namepnt[2] == 0) {   /* /..$ => ok */
                        return 0;
                    }
                    if (namepnt[2] != '/') {   /* /..[^/] => *NO* */
                        return -1;
                    }
                } else if (namepnt[1] != '/') {   /* /.[^/]/ => *NO* */
                    return -1;
                }
            }
            if (namepnt != name) {
                continue;
            }
        }
        namepnt++;
    }
    return 0;
}

static void do_ipv6_port(char *p, char delim)
{
    char *deb;    
    struct sockaddr_storage a;

    deb = p;
    while (*p && strchr("0123456789abcdefABCDEF:", *p) != NULL) {
        p++;
    }
    if (*p != delim || atoi(p + 1) == 0) {
        nope:
        (void) close(datafd);
        datafd = -1;
        addreply_noformat(501, MSG_SYNTAX_ERROR_IP);
        return;
    }
    *p++ = 0;
    if (generic_aton(deb, &a) != 0) {
        goto nope;
    }
    doport2(a, (unsigned int) atoi(p));
}

#ifndef MINIMAL
void doesta(void)
{
    struct sockaddr_storage dataconn;    
    socklen_t socksize;    
    char hbuf[NI_MAXHOST];
    char pbuf[NI_MAXSERV];
    
    if (passive != 0 || datafd == -1) {
	addreply_noformat(520, MSG_ACTIVE_DISABLED);
	return;
    }
    if (xferfd == -1) {
	opendata();
	if (xferfd == -1) {
	    addreply_noformat(425, MSG_CANT_CREATE_DATA_SOCKET);
	    return;
	}
    }
    socksize = (socklen_t) sizeof dataconn;
    if (getsockname(xferfd, (struct sockaddr *) &dataconn, &socksize) < 0 ||
	getnameinfo((struct sockaddr *) &dataconn, STORAGE_LEN(dataconn),
		    hbuf, sizeof hbuf, pbuf, sizeof pbuf,
		    NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
	addreply_noformat(425, MSG_GETSOCKNAME_DATA);
	closedata();
	return;
    }
    addreply(225, "Connected from (|%c|%s|%s|)",
	     STORAGE_FAMILY(dataconn) == AF_INET6 ? '2' : '1', hbuf, pbuf);
}

void doestp(void)
{
    struct sockaddr_storage dataconn;
    socklen_t socksize;        
    char hbuf[NI_MAXHOST];
    char pbuf[NI_MAXSERV];
    
    if (passive == 0 || datafd == -1) {
	addreply_noformat(520, MSG_CANT_PASSIVE);
	return;
    }
    if (xferfd == -1) {
	opendata();
	if (xferfd == -1) {
	    addreply_noformat(425, MSG_CANT_CREATE_DATA_SOCKET);
	    return;
	}
    }
    socksize = (socklen_t) sizeof dataconn;
    if (getpeername(xferfd, (struct sockaddr *) &dataconn, &socksize) < 0 ||
	getnameinfo((struct sockaddr *) &dataconn, STORAGE_LEN(dataconn),
		    hbuf, sizeof hbuf, pbuf, sizeof pbuf,
		    NI_NUMERICHOST | NI_NUMERICSERV) != 0) {
	addreply_noformat(425, MSG_GETSOCKNAME_DATA);
	closedata();
	return;
    }
    addreply(225, "Connected to (|%c|%s|%s|)",
	     STORAGE_FAMILY(dataconn) == AF_INET6 ? '2' : '1', hbuf, pbuf);
}
#endif

void doeprt(char *p)
{
    char delim;
    int family;

    delim = *p++;
    family = atoi(p);
    while (isdigit((unsigned char) *p)) {
        p++;
    }
    if (*p == delim) {
        p++;
    } else {
        addreply_noformat(501, MSG_SYNTAX_ERROR_IP);
        return;
    }
    if (family == 2 && v6ready) {
        do_ipv6_port(p, delim);
        return;
    }
    if (family != 1) {
        if (v6ready) {
            addreply_noformat(522, MSG_ONLY_IPV4V6);
        } else {
            addreply_noformat(522, MSG_ONLY_IPV4);
        }
        return;
    }

    {
        unsigned int a1, a2, a3, a4, port = 0U;
        /* there should be dot-decimal ip as rfc2428 states,
         * but troll used for some reason "comma-decimal" notation
         * so I decided to leave it */
        if ((sscanf(p, "%u,%u,%u,%u", &a1, &a2, &a3, &a4) != 4 &&
             sscanf(p, "%u.%u.%u.%u", &a1, &a2, &a3, &a4) != 4) ||
            a1 > 255U || a2 > 255U || a3 > 255U || a4 > 255U ||
            (a1 | a2 | a3 | a4) == 0U) {
            addreply_noformat(501, MSG_SYNTAX_ERROR_IP);
            return;
        }
        while (*p && strchr("0123456789.,", *p)) {
            p++;
        }
        if (*p == delim) {
            port = (unsigned int) atoi(++p);
            while (*p && isdigit((unsigned char) *p)) {
                p++;
            }
        }
        if (*p != delim || port > 65535U || port <= 0U) {
            addreply_noformat(501, MSG_SYNTAX_ERROR_IP);
            return;
        } else {
            struct sockaddr_storage a;

            memset(&a, 0, sizeof a);
            STORAGE_FAMILY(a) = AF_INET;
            STORAGE_SIN_ADDR(a) =
                htonl((a1 << 24) | (a2 << 16) | (a3 << 8) | a4);
            SET_STORAGE_LEN(a, sizeof(struct sockaddr_in));
            doport2(a, port);
        }
    }
}

void stripctrl(char * const buf, size_t len)
{
    if (len <= (size_t) 0U) {
        return;
    }
    do {
        len--;
        if (ISCTRLCODE(buf[len]) &&
            buf[len] != 0 && buf[len] != '\n') {
            buf[len] = '_';
        }
    } while (len != (size_t) 0U);
}

#ifndef MINIMAL

/*
 * small help routine to display a banner
 * type = 0 reads .banner/welcome.msg
 * type = 1 reads .message (after cd'ing into a directory)
 */
void dobanner(const int type)
{
    char buffer[512];    
    FILE *msg;
    size_t buflen;
    unsigned int nblines = BANNER_MAXLINES;    
    
    switch (type) {
    case 0:
	if ((msg = fopen(".banner", "r")) == NULL
# ifdef WITH_WELCOME_MSG
	    && (msg = fopen("welcome.msg", "r")) == NULL
# endif
	    ) {
	    return;
	}
	break;
    case 1:
	if ((msg = fopen(".message", "r")) == NULL) {
	    return;
	}
	break;
    default:
	return;
    }	
    
    while (fgets(buffer, sizeof buffer, msg) != NULL && nblines > 0U) {
	nblines--;	    
	if ((buflen = strlen(buffer)) > (size_t) 0U) {
	    buflen--;
	    while (buffer[buflen] == '\n' || buffer[buflen] == '\r') {
		buffer[buflen] = 0;
		if (buflen == (size_t) 0U) {
		    break;
		}
		buflen--;
	    }
	    stripctrl(buffer, buflen);
	}
	addreply_noformat(0, buffer);
    }
    (void) fclose(msg);
}

#endif

#ifndef MINIMAL

int modernformat(const char *file,
                 char *target, size_t target_size)
{
    const char *ft;
    struct tm *t;
    struct stat st;
    int ret = 0;

    if (stat(file, &st) != 0 ||
        !(t = gmtime((time_t *) &st.st_mtime))) {
        return -1;
    }
    if (S_ISREG(st.st_mode)) {
        ft = "file";
    } else if (S_ISDIR(st.st_mode)) {
        ret = 1;
        ft = "dir";
        if (*file == '.') {
            if (file[1] == '.' && file[2] == 0) {
                ft = "pdir";
            } else if (file[1] == 0) {
                ft = "cdir";
            }
        } else if (*file == '/' && file[1] == 0) {
            ft = "pdir";
        }
    } else {
        ft = "unknown";
    }
    if (guest != 0) {
        if (SNCHECK(snprintf(target, target_size,
                             "type=%s;siz%c=%llu;modify=%04d%02d%02d%02d%02d%02d;UNIX.mode=0%o;unique=%xg%llx; %s",
                             ft,
                             ret ? 'd' : 'e',
                             (unsigned long long) st.st_size,
                             t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
                             t->tm_hour, t->tm_min, t->tm_sec,
                             (unsigned int) st.st_mode & 07777,
                             (unsigned int) st.st_dev,
                             (unsigned long long) st.st_ino,
                             file), target_size)) {
            _EXIT(EXIT_FAILURE);
        }
    } else {
        if (SNCHECK(snprintf(target, target_size,
                             "type=%s;siz%c=%llu;modify=%04d%02d%02d%02d%02d%02d;UNIX.mode=0%o;UNIX.uid=%lld;UNIX.gid=%lld;unique=%xg%llx; %s",
                             ft,
                             ret ? 'd' : 'e',
                             (unsigned long long) st.st_size,
                             t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
                             t->tm_hour, t->tm_min, t->tm_sec,
                             (unsigned int) st.st_mode & 07777,
                             (unsigned long long) st.st_uid,
                             (unsigned long long) st.st_gid,
                             (unsigned int) st.st_dev,
                             (unsigned long long) st.st_ino,
                             file), target_size)) {
            _EXIT(EXIT_FAILURE);
        }
    }
    return ret;
}