Initial import

1 files changed, 1215 insertions, 0 deletions

diff --git a/common/smtppass.c b/common/smtppass.c
new file mode 100644
index 0000000..71e5a3f
--- /dev/null
+++ b/common/smtppass.c
@@ -0,0 +1,1215 @@
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <paths.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <signal.h>
+#include <errno.h>
+
+#include "usuals.h"
+#include "compat.h"
+#include "sock_any.h"
+#include "clamsmtpd.h"
+#include "util.h"
+
+/* -----------------------------------------------------------------------
+ * Structures
+ */
+
+typedef struct clamsmtp_thread
+{
+    pthread_t tid;      /* Written to by the main thread */
+    int fd;             /* The file descriptor or -1 */
+}
+clamsmtp_thread_t;
+
+#define LINE_TOO_LONG(ctx)      ((ctx)->linelen >= (LINE_LENGTH - 2))
+#define RETURN(x)               { ret = x; goto cleanup; }
+
+/* -----------------------------------------------------------------------
+ * Strings
+ */
+
+#define KL(s)               ((sizeof(s) - 1) / sizeof(char))
+
+#define SMTP_TOOLONG        "500 Line too long\r\n"
+#define SMTP_STARTBUSY      "554 Server Busy\r\n"
+#define SMTP_STARTFAILED    "554 Local Error\r\n"
+#define SMTP_DATAVIRUS      "550 Virus Detected; Content Rejected\r\n"
+#define SMTP_DATAINTERMED   "354 Start mail input; end with <CRLF>.<CRLF>\r\n"
+#define SMTP_FAILED         "451 Local Error\r\n"
+
+#define SMTP_DATA           "DATA\r\n"
+#define SMTP_DELIMS         "\r\n\t :"
+
+#define FROM_CMD            "MAIL FROM"
+#define TO_CMD              "RCPT TO"
+#define DATA_CMD            "DATA"
+#define RSET_CMD            "RSET"
+
+#define DATA_END_SIG        "\r\n.\r\n"
+
+#define DATA_RSP            "354"
+
+#define CLAM_OK             "OK"
+#define CLAM_ERROR          "ERROR"
+#define CLAM_FOUND          "FOUND"
+
+#define CONNECT_RSP         "PONG"
+#define CLAM_SCAN           "SCAN "
+
+#define CLAM_CONNECT        "SESSION\nPING\n"
+#define CLAM_DISCONNECT     "END\n"
+
+/* -----------------------------------------------------------------------
+ * Default Settings
+ */
+
+#define DEFAULT_SOCKET  "0.0.0.0:10025"
+#define DEFAULT_PORT    10025
+#define DEFAULT_CLAMAV  "/var/run/clamav/clamd"
+#define DEFAULT_MAXTHREADS  64
+#define DEFAULT_TIMEOUT	180
+#define DEFAULT_HEADER  "X-AV-Checked: ClamAV using ClamSMTP\r\n"
+
+
+/* -----------------------------------------------------------------------
+ * Globals
+ */
+
+int g_daemonized = 0;                     /* Currently running as a daemon */
+int g_debuglevel = LOG_ERR;               /* what gets logged to console */
+int g_maxthreads = DEFAULT_MAXTHREADS;    /* The maximum number of threads */
+struct timeval g_timeout = { DEFAULT_TIMEOUT, 0 };
+
+struct sockaddr_any g_outaddr;              /* The outgoing address */
+const char* g_outname = NULL;
+struct sockaddr_any g_clamaddr;             /* Address for connecting to clamd */
+const char* g_clamname = DEFAULT_CLAMAV;
+
+const char* g_header = DEFAULT_HEADER;      /* The header to add to email */
+const char* g_directory = _PATH_TMP;        /* The directory for temp files */
+unsigned int g_unique_id = 0x00001000;      /* For connection ids */
+
+/* For main loop and signal handlers */
+int g_quit = 0;
+
+/* The main mutex and condition variables */
+pthread_mutex_t g_mutex;
+pthread_mutexattr_t g_mutexattr;
+
+
+/* -----------------------------------------------------------------------
+ * Forward Declarations
+ */
+
+static usage();
+static void on_quit(int signal);
+static void write_pid(const char* pid);
+static void connection_loop(int sock);
+static void* thread_main(void* arg);
+static int smtp_passthru(clamsmtp_context_t* ctx);
+static int connect_clam(clamsmtp_context_t* ctx);
+static int disconnect_clam(clamsmtp_context_t* ctx);
+static void add_to_logline(char* logline, char* prefix, char* line);
+static int avcheck_data(clamsmtp_context_t* ctx, char* logline);
+static int complete_data_transfer(clamsmtp_context_t* ctx, const char* tempname);
+static int transfer_to_file(clamsmtp_context_t* ctx, char* tempname);
+static int transfer_from_file(clamsmtp_context_t* ctx, const char* filename);
+static int clam_scan_file(clamsmtp_context_t* ctx, const char* tempname, char* logline);
+static int read_server_response(clamsmtp_context_t* ctx);
+static void read_junk(clamsmtp_context_t* ctx, int fd);
+static int read_line(clamsmtp_context_t* ctx, int* fd, int trim);
+static int write_data(clamsmtp_context_t* ctx, int* fd, unsigned char* buf);
+static int write_data_raw(clamsmtp_context_t* ctx, int* fd, unsigned char* buf, int len);
+
+
+int main(int argc, char* argv[])
+{
+    const char* listensock = DEFAULT_SOCKET;
+    clamsmtp_thread_t* threads = NULL;
+    struct sockaddr_any addr;
+    char* pidfile = NULL;
+    int daemonize = 1;
+    int sock;
+    int true = 1;
+    int ch = 0;
+    char* t;
+
+    /* Parse the arguments nicely */
+    while((ch = getopt(argc, argv, "c:d:D:h:l:m:p:t:")) != -1)
+    {
+        switch(ch)
+        {
+        /* Change the CLAM socket */
+        case 'c':
+            g_clamname = optarg;
+            break;
+
+		/*  Don't daemonize  */
+        case 'd':
+            daemonize = 0;
+            g_debuglevel = strtol(optarg, &t, 10);
+            if(*t || g_debuglevel > 4)
+                errx(1, "invalid debug log level");
+            g_debuglevel += LOG_ERR;
+            break;
+
+        /* The directory for the files */
+        case 'D':
+            g_directory = optarg;
+            break;
+
+        /* The header to add */
+        case 'h':
+            if(strlen(optarg) == 0)
+                g_header = NULL;
+            else
+                g_header = optarg;
+            break;
+
+        /* Change our listening port */
+        case 'l':
+            listensock = optarg;
+            break;
+
+        /* The maximum number of threads */
+        case 'm':
+            g_maxthreads = strtol(optarg, &t, 10);
+            if(*t || g_maxthreads <= 1 || g_maxthreads >= 1024)
+                  errx(1, "invalid max threads (must be between 1 and 1024");
+            break;
+
+        /* Write out a pid file */
+        case 'p':
+            pidfile = optarg;
+            break;
+
+        /* The timeout */
+		case 't':
+			g_timeout.tv_sec = strtol(optarg, &t, 10);
+			if(*t || g_timeout.tv_sec <= 0)
+				errx(1, "invalid timeout: %s", optarg);
+			break;
+
+        /* Usage information */
+        case '?':
+        default:
+            usage();
+            break;
+		}
+    }
+
+	argc -= optind;
+	argv += optind;
+
+    if(argc != 1)
+        usage();
+
+    g_outname = argv[0];
+
+    messagex(NULL, LOG_DEBUG, "starting up...");
+
+    /* Parse all the addresses */
+    if(sock_any_pton(listensock, &addr, DEFAULT_PORT) == -1)
+        errx(1, "invalid listen socket name or ip: %s", listensock);
+    if(sock_any_pton(g_outname, &g_outaddr, 25) == -1)
+        errx(1, "invalid connect socket name or ip: %s", g_outname);
+    if(sock_any_pton(g_clamname, &g_clamaddr, 0) == -1)
+        errx(1, "invalid clam socket name: %s", g_clamname);
+
+    /* Create the socket */
+    sock = socket(SANY_TYPE(addr), SOCK_STREAM, 0);
+    if(sock < 0)
+      err(1, "couldn't open socket");
+
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&true, sizeof(true));
+
+    /* Unlink the socket file if it exists */
+    if(SANY_TYPE(addr) == AF_UNIX)
+        unlink(listensock);
+
+    if(bind(sock, &SANY_ADDR(addr), SANY_LEN(addr)) != 0)
+      err(1, "couldn't bind to address: %s", listensock);
+
+    /* Let 5 connections queue up */
+    if(listen(sock, 5) != 0)
+      err(1, "couldn't listen on socket");
+
+    messagex(NULL, LOG_DEBUG, "created socket: %s", listensock);
+
+    if(daemonize)
+    {
+        /* Fork a daemon nicely here */
+        if(daemon(0, 0) == -1)
+        {
+            message(NULL, LOG_ERR, "couldn't run as daemon");
+            exit(1);
+        }
+
+        messagex(NULL, LOG_DEBUG, "running as a daemon");
+        g_daemonized = 1;
+
+        /* Open the system log */
+        openlog("clamsmtp", 0, LOG_MAIL);
+    }
+
+    if(pidfile)
+        write_pid(pidfile);
+
+    /* Handle some signals */
+    signal(SIGPIPE, SIG_IGN);
+    signal(SIGHUP, SIG_IGN);
+    signal(SIGINT,  on_quit);
+    signal(SIGTERM, on_quit);
+
+    siginterrupt(SIGINT, 1);
+    siginterrupt(SIGTERM, 1);
+
+    messagex(NULL, LOG_DEBUG, "accepting connections");
+
+    connection_loop(sock);
+
+    messagex(NULL, LOG_DEBUG, "stopped");
+
+    return 0;
+}
+
+static void connection_loop(int sock)
+{
+    clamsmtp_thread_t* threads = NULL;
+    struct sockaddr_any addr;
+    int fd, i, x, r;
+
+    /* Create the thread buffers */
+    threads = (clamsmtp_thread_t*)calloc(g_maxthreads, sizeof(clamsmtp_thread_t));
+    if(!threads)
+        errx(1, "out of memory");
+
+    /* Create the main mutex and condition variable */
+    if(pthread_mutexattr_init(&g_mutexattr) != 0 ||
+       pthread_mutexattr_settype(&g_mutexattr, MUTEX_TYPE) ||
+       pthread_mutex_init(&g_mutex, &g_mutexattr) != 0)
+        errx(1, "threading problem. can't create mutex or condition var");
+
+    /* Now loop and accept the connections */
+    while(!g_quit)
+    {
+        fd = accept(sock, NULL, NULL);
+        if(fd == -1)
+        {
+            switch(errno)
+            {
+            case EINTR:
+            case EAGAIN:
+                break;
+
+            case ECONNABORTED:
+                message(NULL, LOG_ERR, "couldn't accept a connection");
+                break;
+
+            default:
+                message(NULL, LOG_ERR, "couldn't accept a connection");
+                g_quit = 1;
+                break;
+            };
+
+            if(g_quit)
+                break;
+
+            continue;
+        }
+
+        /* Look for thread and also clean up others */
+        for(i = 0; i < g_maxthreads; i++)
+        {
+            /* Find a thread to run or clean up old threads */
+            if(threads[i].tid != 0)
+            {
+                plock();
+                    x = threads[i].fd;
+                punlock();
+
+                if(x == -1)
+                {
+                    messagex(NULL, LOG_DEBUG, "cleaning up completed thread");
+                    pthread_join(threads[i].tid, NULL);
+                    threads[i].tid = 0;
+                }
+            }
+
+            /* Start a new thread if neccessary */
+            if(fd != -1 && threads[i].tid == 0)
+            {
+                threads[i].fd = fd;
+                r = pthread_create(&(threads[i].tid), NULL, thread_main,
+                                   (void*)(threads + i));
+                if(r != 0)
+                {
+                    errno = r;
+                    message(NULL, LOG_ERR, "couldn't create thread");
+                    g_quit = 1;
+                    break;
+                }
+
+                messagex(NULL, LOG_DEBUG, "created thread for connection");
+                fd = -1;
+                break;
+            }
+        }
+
+        /* Check to make sure we have a thread */
+        if(fd != -1)
+        {
+            messagex(NULL, LOG_ERR, "too many connections open (max %d)", g_maxthreads);
+
+            /* TODO: Respond with a too many connections message */
+            write_data(NULL, &fd, SMTP_STARTBUSY);
+            shutdown(fd, SHUT_RDWR);
+        }
+    }
+
+    messagex(NULL, LOG_INFO, "waiting for threads to quit");
+
+    /* Quit all threads here */
+    for(i = 0; i < g_maxthreads; i++)
+    {
+        /* Clean up quit threads */
+        if(threads[i].tid != 0)
+        {
+            if(threads[i].fd != -1)
+                shutdown(threads[i].fd, SHUT_RDWR);
+
+            pthread_join(threads[i].tid, NULL);
+        }
+    }
+
+    /* Close the mutex */
+    pthread_mutex_destroy(&g_mutex);
+    pthread_mutexattr_destroy(&g_mutexattr);
+}
+
+static void on_quit(int signal)
+{
+    g_quit = 1;
+
+    /* fprintf(stderr, "clamsmtpd: got signal to quit\n"); */
+}
+
+static int usage()
+{
+    fprintf(stderr, "clamsmtp [-c clamaddr] [-d debuglevel] [-D tmpdir] [-h header]"
+            "[-l listenaddr] [-m maxconn] [-p pidfile] [-t timeout] serveraddr\n");
+    return 2;
+}
+
+static void write_pid(const char* pidfile)
+{
+    FILE* f = fopen(pidfile, "w");
+    if(f == NULL)
+    {
+        message(NULL, LOG_ERR, "couldn't open pid file: %s", pidfile);
+    }
+    else
+    {
+        fprintf(f, "%d\n", (int)getpid());
+
+        if(ferror(f))
+            message(NULL, LOG_ERR, "couldn't write to pid file: %s", pidfile);
+
+        fclose(f);
+    }
+}
+
+static void* thread_main(void* arg)
+{
+    clamsmtp_thread_t* thread = (clamsmtp_thread_t*)arg;
+    char peername[MAXPATHLEN];
+    struct sockaddr_any addr;
+    clamsmtp_context_t ctx;
+    int r;
+
+    ASSERT(thread);
+
+    siginterrupt(SIGINT, 1);
+    siginterrupt(SIGTERM, 1);
+
+    memset(&ctx, 0, sizeof(ctx));
+
+    plock();
+        ctx.client = thread->fd;
+    punlock();
+
+    ctx.server = -1;
+    ctx.clam = -1;
+
+    ASSERT(ctx.client != -1);
+
+    /* Assign a unique id to the connection */
+    ctx.id = g_unique_id++;
+
+    /* Get the peer name */
+    if(getpeername(ctx.client, &SANY_ADDR(addr), &SANY_LEN(addr)) == -1 ||
+       sock_any_ntop(&addr, peername, MAXPATHLEN) == -1)
+        messagex(&ctx, LOG_WARNING, "couldn't get peer address");
+    else
+        messagex(&ctx, LOG_INFO, "accepted connection from: %s", peername);
+
+    /* call the processor */
+    r = smtp_passthru(&ctx);
+
+    /* Close the incoming connection if neccessary */
+    if(ctx.client != -1)
+        shutdown(ctx.client, SHUT_RDWR);
+
+    messagex(&ctx, LOG_INFO, "closed client connection");
+
+    /* mark this as done */
+    plock();
+        thread->fd = -1;
+    punlock();
+
+    return (void*)(r == 0 ? 0 : 1);
+}
+
+static int smtp_passthru(clamsmtp_context_t* ctx)
+{
+    char logline[LINE_LENGTH];
+    int processing = 0;
+    int r, ret = 0;
+	fd_set mask;
+
+    ASSERT(ctx->server == -1);
+
+    if((ctx->server = socket(SANY_TYPE(g_outaddr), SOCK_STREAM, 0)) < 0 ||
+        connect(ctx->server, &SANY_ADDR(g_outaddr), SANY_LEN(g_outaddr)) < 0)
+    {
+        message(ctx, LOG_ERR, "couldn't connect to %s", g_outname);
+        RETURN(-1);
+    }
+
+    messagex(ctx, LOG_DEBUG, "connected to server: %s", g_outname);
+
+    if(connect_clam(ctx) == -1)
+        RETURN(-1);
+
+    /* This changes the error code sent to the client when an
+     * error occurs. See cleanup below */
+    processing = 1;
+    logline[0] = 0;
+
+    for(;;)
+    {
+		FD_ZERO(&mask);
+
+    	FD_SET(ctx->client, &mask);
+    	FD_SET(ctx->server, &mask);
+
+		switch(select(FD_SETSIZE, &mask, NULL, NULL, &g_timeout))
+		{
+		case 0:
+			message(ctx, LOG_ERR, "network operation timed out");
+            RETURN(-1);
+		case -1:
+			message(ctx, LOG_ERR, "couldn't select on sockets");
+            RETURN(-1);
+		};
+
+        /* Client has data available, read a line and process */
+        if(FD_ISSET(ctx->client, &mask))
+        {
+            if(read_line(ctx, &(ctx->client), 0) == -1)
+                RETURN(-1);
+
+            /* Client disconnected, we're done */
+            if(ctx->linelen == 0)
+                RETURN(0);
+
+            /* We don't let clients send really long lines */
+            if(LINE_TOO_LONG(ctx))
+            {
+                if(write_data(ctx, &(ctx->server), SMTP_TOOLONG) == -1)
+                    RETURN(-1);
+            }
+
+            else
+            {
+                if(is_first_word(ctx->line, DATA_CMD, KL(DATA_CMD)))
+                {
+                    /* Send back the intermediate response to the client */
+                    if(write_data(ctx, &(ctx->client), SMTP_DATAINTERMED) == -1)
+                        RETURN(-1);
+
+                    /*
+                     * Now go into avcheck mode. This also handles the eventual
+                     * sending of the data to the server, making the av check
+                     * transparent
+                     */
+                    if(avcheck_data(ctx, logline) == -1)
+                        RETURN(-1);
+
+                    /* Print the log out for this email */
+                    messagex(ctx, LOG_INFO, "%s", logline);
+
+                    /* Reset log line */
+                    logline[0] = 0;
+                }
+
+                /* All other commands just get passed through to server */
+                else
+                {
+
+                    /* Append recipients to log line */
+                    if((r = check_first_word(ctx->line, FROM_CMD, KL(FROM_CMD), SMTP_DELIMS)) > 0)
+                        add_to_logline(logline, "from=", ctx->line + r);
+
+                    /* Append sender to log line */
+                    else if((r = check_first_word(ctx->line, TO_CMD, KL(TO_CMD), SMTP_DELIMS)) > 0)
+                        add_to_logline(logline, "to=", ctx->line + r);
+
+                    /* Reset log line */
+                    else if(is_first_word(ctx->line, RSET_CMD, KL(RSET_CMD)))
+                        logline[0] = 0;
+
+                    if(write_data(ctx, &(ctx->server), ctx->line) == -1)
+                        RETURN(-1);
+                }
+            }
+
+            continue;
+        }
+
+        /* Server has data available, read a line and forward */
+        if(FD_ISSET(ctx->server, &mask))
+        {
+            if(read_line(ctx, &(ctx->server), 0) == -1)
+                RETURN(-1);
+
+            if(ctx->linelen == 0)
+                RETURN(0);
+
+            if(LINE_TOO_LONG(ctx))
+                messagex(ctx, LOG_WARNING, "SMTP response line too long. discarded extra");
+
+            if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+                RETURN(-1);
+
+            continue;
+        }
+    }
+
+cleanup:
+
+    disconnect_clam(ctx);
+
+    if(ret == -1 && ctx->client != -1)
+    {
+       write_data(ctx, &(ctx->client),
+                processing ? SMTP_FAILED : SMTP_STARTFAILED);
+    }
+
+    if(ctx->server != -1)
+    {
+        shutdown(ctx->server, SHUT_RDWR);
+        messagex(ctx, LOG_DEBUG, "closed server connection");
+    }
+
+    return ret;
+}
+
+static void add_to_logline(char* logline, char* prefix, char* line)
+{
+    int l = strlen(logline);
+    char* t = logline;
+
+    /* Simple optimization */
+    logline += l;
+    l = LINE_LENGTH - l;
+
+    ASSERT(l >= 0);
+
+    if(t[0] != 0)
+        strlcat(logline, ", ", l);
+
+    strlcat(logline, prefix, l);
+
+    /* Skip initial white space */
+    while(*line && isspace(*line))
+        *line++;
+
+    strlcat(logline, line, l);
+    t = logline + strlen(logline);
+
+    /* Skip later white space */
+    while(t > logline && isspace(*(t - 1)))
+        *(--t) = 0;
+}
+
+static int connect_clam(clamsmtp_context_t* ctx)
+{
+    int r, len = -1;
+    int ret = 0;
+
+    ASSERT(ctx);
+    ASSERT(ctx->clam == -1);
+
+    if((ctx->clam = socket(SANY_TYPE(g_clamaddr), SOCK_STREAM, 0)) < 0 ||
+       connect(ctx->clam, &SANY_ADDR(g_clamaddr), SANY_LEN(g_clamaddr)) < 0)
+    {
+        message(ctx, LOG_ERR, "couldn't connect to clamd at %s", g_clamname);
+        RETURN(-1);
+    }
+
+    read_junk(ctx, ctx->clam);
+
+    /* Send a session and a check header to ClamAV */
+
+    if(write_data(ctx, &(ctx->clam), "SESSION\n") == -1)
+        RETURN(-1);
+
+    read_junk(ctx, ctx->clam);
+/*
+    if(write_data(ctx, &(ctx->clam), "PING\n") == -1 ||
+       read_line(ctx, &(ctx->clam), 1) == -1)
+        RETURN(-1);
+
+    if(strcmp(ctx->line, CONNECT_RESPONSE) != 0)
+    {
+        message(ctx, LOG_ERR, "clamd sent an unexpected response: %s", ctx->line);
+        RETURN(-1);
+    }
+*/
+    messagex(ctx, LOG_DEBUG, "connected to clamd: %s", g_clamname);
+
+cleanup:
+
+    if(ret < 0)
+    {
+        if(ctx->clam != -1)
+        {
+            shutdown(ctx->clam, SHUT_RDWR);
+            ctx->clam == -1;
+        }
+    }
+
+    return ret;
+}
+
+static int disconnect_clam(clamsmtp_context_t* ctx)
+{
+    if(ctx->clam == -1)
+        return 0;
+
+    if(write_data(ctx, &(ctx->clam), CLAM_DISCONNECT) != -1)
+        read_junk(ctx, ctx->clam);
+
+    messagex(ctx, LOG_DEBUG, "disconnected from clamd");
+    shutdown(ctx->clam, SHUT_RDWR);
+    ctx->clam = -1;
+    return 0;
+}
+
+static int clam_scan_file(clamsmtp_context_t* ctx, const char* tempname, char* logline)
+{
+    int len;
+
+    ASSERT(LINE_LENGTH < MAXPATHLEN + 32);
+
+    strcpy(ctx->line, CLAM_SCAN);
+    strcat(ctx->line, tempname);
+    strcat(ctx->line, "\n");
+
+    if(write_data(ctx, &(ctx->clam), ctx->line) == -1)
+        return -1;
+
+    len = read_line(ctx, &(ctx->clam), 1);
+    if(len == 0)
+    {
+        messagex(ctx, LOG_ERR, "clamd disconnected unexpectedly");
+        return -1;
+    }
+
+    if(is_last_word(ctx->line, CLAM_OK, KL(CLAM_OK)))
+    {
+        add_to_logline(logline, "status=", "CLEAN");
+        messagex(ctx, LOG_DEBUG, "no virus");
+        return 0;
+    }
+
+    if(is_last_word(ctx->line, CLAM_FOUND, KL(CLAM_FOUND)))
+    {
+        len = strlen(tempname);
+
+        if(ctx->linelen > len)
+            add_to_logline(logline, "status=VIRUS:", ctx->line + len + 1);
+        else
+            add_to_logline(logline, "status=", "VIRUS");
+
+        messagex(ctx, LOG_DEBUG, "found virus");
+        return 1;
+    }
+
+    if(is_last_word(ctx->line, CLAM_ERROR, KL(CLAM_ERROR)))
+    {
+        messagex(ctx, LOG_ERR, "clamav error: %s", ctx->line);
+        return -1;
+    }
+
+    messagex(ctx, LOG_ERR, "unexepected response from clamd: %s", ctx->line);
+    return -1;
+}
+
+static int avcheck_data(clamsmtp_context_t* ctx, char* logline)
+{
+    /*
+     * Note that most failures are non fatal in this function.
+     * We only return -1 for data connection errors and the like,
+     * For most others we actually send a response back to the
+     * client letting them know what happened and let the SMTP
+     * connection continue.
+     */
+
+    char buf[MAXPATHLEN];
+    int havefile = 0;
+    int r, ret = 0;
+
+    strlcpy(buf, g_directory, MAXPATHLEN);
+    strlcat(buf, "/clamsmtp.XXXXXX", MAXPATHLEN);
+
+    /* transfer_to_file deletes the temp file on failure */
+    if((r = transfer_to_file(ctx, buf)) > 0)
+    {
+        havefile = 1;
+        r = clam_scan_file(ctx, buf, logline);
+    }
+
+    switch(r)
+    {
+
+    /*
+     * There was an error tell the client. We haven't notified
+     * the server about any of this yet
+     */
+    case -1:
+        if(write_data(ctx, &(ctx->client), SMTP_FAILED))
+            RETURN(-1);
+        break;
+
+    /*
+     * No virus was found. Now we initiate a connection to the server
+     * and transfer the file to it.
+     */
+    case 0:
+        if(complete_data_transfer(ctx, buf) == -1)
+            RETURN(-1);
+        break;
+
+    /*
+     * A virus was found, just send back a simple message to the client.
+     * The server doesn't know data was ever sent, and the client can
+     * choose to reset the connection to reuse it if it wants.
+     */
+    case 1:
+        if(write_data(ctx, &(ctx->client), SMTP_DATAVIRUS) == -1)
+            RETURN(-1);
+        break;
+
+    default:
+        ASSERT(0 && "Invalid clam_scan_file return value");
+        break;
+    };
+
+cleanup:
+    if(havefile)
+    {
+        messagex(ctx, LOG_DEBUG, "deleting temporary file: %s", buf);
+        unlink(buf);
+    }
+
+    return ret;
+}
+
+static int complete_data_transfer(clamsmtp_context_t* ctx, const char* tempname)
+{
+    ASSERT(ctx);
+    ASSERT(tempname);
+
+    /* Ask the server for permission to send data */
+    if(write_data(ctx, &(ctx->server), SMTP_DATA) == -1)
+        return -1;
+
+    if(read_server_response(ctx) == -1)
+        return -1;
+
+    /* If server returns an error then tell the client */
+    if(!is_first_word(ctx->line, DATA_RSP, KL(DATA_RSP)))
+    {
+        if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+            return -1;
+
+        messagex(ctx, LOG_DEBUG, "server refused data transfer");
+
+        return 0;
+    }
+
+    /* Now pull up the file and send it to the server */
+    if(transfer_from_file(ctx, tempname) == -1)
+    {
+        /* Tell the client it went wrong */
+        write_data(ctx, &(ctx->client), SMTP_FAILED);
+        return -1;
+    }
+
+    /* Okay read the response from the server and echo it to the client */
+    if(read_server_response(ctx) == -1)
+        return -1;
+
+    if(write_data(ctx, &(ctx->client), ctx->line) == -1)
+        return -1;
+
+    return 0;
+}
+
+static int transfer_to_file(clamsmtp_context_t* ctx, char* tempname)
+{
+    /* If there aren't any lines in the message and just an
+       end signature then start at the dot. */
+    const char* topsig = strchr(DATA_END_SIG, '.');
+    const char* cursig = topsig;
+    FILE* tfile = NULL;
+    int tfd = -1;
+    int ret = 0;
+    char ch;
+    int count = 0;
+
+    ASSERT(topsig != NULL);
+
+    if((tfd = mkstemp(tempname)) == -1 ||
+       (tfile = fdopen(tfd, "w")) == NULL)
+    {
+        message(ctx, LOG_ERR, "couldn't open temp file");
+        RETURN(-1);
+    }
+
+    messagex(ctx, LOG_DEBUG, "created temporary file: %s", tempname);
+
+    for(;;)
+    {
+        switch(read(ctx->client, &ch, 1))
+        {
+        case 0:
+            messagex(ctx, LOG_ERR, "unexpected end of data from client");
+            RETURN(-1);
+
+        case -1:
+            message(ctx, LOG_ERR, "error reading from client");
+            RETURN(-1);
+        };
+
+        if((char)ch != *cursig)
+        {
+            /* Write out the part of the sig we kept back */
+            if(cursig != topsig)
+            {
+                /* We check errors on this later */
+                fwrite(topsig, 1, cursig - topsig, tfile);
+                count += (cursig - topsig);
+            }
+
+            /* We've seen at least one char not in the sig */
+            cursig = topsig = DATA_END_SIG;
+        }
+
+        /* The sig may have been reset above so check again */
+        if((char)ch == *cursig)
+        {
+            cursig++;
+
+            if(!*cursig)
+            {
+                /* We found end of data */
+                break;
+            }
+        }
+
+        else
+        {
+            fputc(ch, tfile);
+            count++;
+        }
+    }
+
+    if(ferror(tfile))
+    {
+        message(ctx, LOG_ERR, "error writing to temp file: %s", tempname);
+        RETURN(-1);
+    }
+
+    ret = count;
+    messagex(ctx, LOG_DEBUG, "wrote %d bytes to temp file", count);
+
+cleanup:
+
+    if(tfile)
+       fclose(tfile);
+
+    if(tfd != -1)
+    {
+        /* Only close this if not opened as a stream */
+        if(tfile == NULL)
+            close(tfd);
+
+        if(ret == -1)
+        {
+            messagex(ctx, LOG_DEBUG, "discarding temporary file");
+            unlink(tempname);
+        }
+    }
+
+    return ret;
+}
+
+static int transfer_from_file(clamsmtp_context_t* ctx, const char* filename)
+{
+    FILE* file = NULL;
+    const char* t;
+    const char* e;
+    int header = 0;
+    int ret = 0;
+    int len, r;
+
+    file = fopen(filename, "r");
+    if(file == NULL)
+    {
+        message(ctx, LOG_ERR, "couldn't open temporary file: %s", filename);
+        RETURN(-1);
+    }
+
+    messagex(ctx, LOG_DEBUG, "opened temporary file: %s", filename);
+
+    while(fgets(ctx->line, LINE_LENGTH, file) != NULL)
+    {
+        if(g_header && !header)
+        {
+            /*
+             * The first blank line we see means the headers are done.
+             * At this point we add in our virus checked header.
+             */
+            if(is_blank_line(ctx->line))
+            {
+                if(write_data_raw(ctx, &(ctx->server), g_header, strlen(g_header)) == -1)
+                    RETURN(-1);
+            }
+
+            header = 1;
+        }
+
+        if(write_data_raw(ctx, &(ctx->server), ctx->line, strlen(ctx->line)) == -1)
+            RETURN(-1);
+    }
+
+    if(ferror(file))
+    {
+        message(ctx, LOG_ERR, "error reading temporary file: %s", filename);
+        RETURN(-1);
+    }
+
+    if(write_data(ctx, &(ctx->server), DATA_END_SIG) == -1)
+        RETURN(-1);
+
+    messagex(ctx, LOG_DEBUG, "sent email data");
+
+cleanup:
+
+    if(file != NULL)
+        fclose(file);
+
+    return ret;
+}
+
+static int read_server_response(clamsmtp_context_t* ctx)
+{
+    /* Read response line from the server */
+    if(read_line(ctx, &(ctx->server), 0) == -1)
+        return -1;
+
+    if(ctx->linelen == 0)
+    {
+        messagex(ctx, LOG_ERR, "server disconnected unexpectedly");
+
+        /* Tell the client it went wrong */
+        write_data(ctx, &(ctx->client), SMTP_FAILED);
+        return 0;
+    }
+
+    if(LINE_TOO_LONG(ctx))
+        messagex(ctx, LOG_WARNING, "SMTP response line too long. discarded extra");
+
+    return 0;
+}
+
+static void read_junk(clamsmtp_context_t* ctx, int fd)
+{
+    char buf[16];
+    const char* t;
+    int said = 0;
+    int l;
+
+    if(fd == -1)
+        return;
+
+    /* Make it non blocking */
+    fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
+
+    for(;;)
+    {
+        l = read(fd, buf, sizeof(buf) - 1);
+        if(l <= 0)
+            break;
+
+        buf[l] = 0;
+        t = buf;
+
+        while(*t && isspace(*t))
+            t++;
+
+        if(!said && *t)
+        {
+            messagex(ctx, LOG_WARNING, "received junk data from daemon");
+            said = 1;
+        }
+    }
+
+    fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
+}
+
+static int read_line(clamsmtp_context_t* ctx, int* fd, int trim)
+{
+    int l;
+    char* t;
+    const char* e;
+
+    if(*fd == -1)
+    {
+        messagex(ctx, LOG_WARNING, "tried to read from a closed connection");
+        return 0;
+    }
+
+    ctx->line[0] = 0;
+    e = ctx->line + (LINE_LENGTH - 1);
+
+    for(t = ctx->line; t < e; ++t)
+    {
+        l = read(*fd, (void*)t, sizeof(char));
+
+        /* We got a character */
+        if(l == 1)
+        {
+            /* End of line */
+            if(*t == '\n')
+            {
+                ++t;
+                break;
+            }
+
+            /* We skip spaces at the beginning if trimming */
+            if(trim && t == ctx->line && isspace(*t))
+                continue;
+        }
+
+        /* If it's the end of file then return that */
+        else if(l == 0)
+        {
+            /* Put in an extra line if there was anything */
+            if(t > ctx->line && !trim)
+            {
+                *t = '\n';
+                ++t;
+            }
+
+            break;
+        }
+
+        /* Transient errors */
+        else if(l == -1 && errno == EAGAIN)
+            continue;
+
+        /* Fatal errors */
+        else if(l == -1)
+        {
+            message(ctx, LOG_ERR, "couldn't read data");
+            return -1;
+        }
+    }
+
+    *t = 0;
+
+    if(trim)
+    {
+        while(t > ctx->line && isspace(*(t - 1)))
+        {
+            --t;
+            *t = 0;
+        }
+    }
+
+    ctx->linelen = t - ctx->line;
+    log_fd_data(ctx, ctx->line, fd, 1);
+
+    return ctx->linelen;
+}
+
+static int write_data_raw(clamsmtp_context_t* ctx, int* fd, unsigned char* buf, int len)
+{
+    int r;
+
+    while(len > 0)
+    {
+        r = write(*fd, buf, len);
+
+        if(r > 0)
+        {
+            buf += r;
+            len -= r;
+        }
+
+        else if(r == -1)
+        {
+            if(errno == EAGAIN)
+                continue;
+
+            if(errno == EPIPE)
+            {
+                shutdown(*fd, SHUT_RDWR);
+                *fd = -1;
+            }
+
+            message(ctx, LOG_ERR, "couldn't write data to socket");
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int write_data(clamsmtp_context_t* ctx, int* fd, unsigned char* buf)
+{
+    int len = strlen(buf);
+
+    if(*fd == -1)
+    {
+        message(ctx, LOG_ERR, "connection closed. can't write data.");
+        return -1;
+    }
+
+    log_fd_data(ctx, buf, fd, 0);
+    return write_data_raw(ctx, fd, buf, len);
+}