path: root/camel/providers/imap/camel-imap-command.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-imap-command.c: IMAP command sending/parsing routines */

/*
 *  Authors:
 *    Dan Winship <danw@helixcode.com>
 *    Jeffrey Stedfast <fejj@helixcode.com>
 *
 *  Copyright 2000 Helix Code, Inc. (www.helixcode.com)
 *
 *  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 2 of the License, 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., 59 Temple Street #330, Boston, MA 02111-1307, USA.
 *
 */


#include <config.h>

#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include "camel-imap-command.h"
#include "camel-imap-utils.h"
#include "camel-imap-folder.h"
#include "camel-imap-store.h"
#include <camel/camel-exception.h>

static char *imap_read_untagged (CamelImapStore *store, char *line,
                 CamelException *ex);
static CamelImapResponse *imap_read_response (CamelImapStore *store,
                          CamelException *ex);
static char *imap_command_strdup_vprintf (CamelImapStore *store,
                      const char *fmt, va_list ap);

/**
 * camel_imap_command: Send a command to a IMAP server and get a response
 * @store: the IMAP store
 * @folder: The folder to perform the operation in (or %NULL if not
 * relevant).
 * @ex: a CamelException
 * @fmt: an sort of printf-style format string, followed by arguments
 *
 * This function makes sure that @folder (if non-%NULL) is the
 * currently-selected folder on @store and then sends the IMAP command
 * specified by @fmt and the following arguments. It then reads the
 * server's response(s) and parses the final result.
 *
 * As a special case, if @fmt is %NULL, it will just select @folder
 * and return the response from doing so.
 * 
 * @fmt can include the following %-escapes ONLY:
 *  %s, %d, %%: as with printf
 *  %S: an IMAP "string" (quoted string or literal)
 *
 * %S strings will be passed as literals if the server supports LITERAL+
 * and quoted strings otherwise. (%S does not support strings that
 * contain newlines.)
 *
 * This function assumes you have an exclusive lock on the command
 * channel/stream.
 *
 * Return value: %NULL if an error occurred (in which case @ex will
 * be set). Otherwise, a CamelImapResponse describing the server's
 * response, which the caller must free with camel_imap_response_free().
 **/
CamelImapResponse *
camel_imap_command (CamelImapStore *store, CamelFolder *folder,
            CamelException *ex, const char *fmt, ...)
{
    gchar *cmdbuf;
    va_list ap;

    /* Check for current folder */
    if (folder && (!fmt || folder != store->current_folder)) {
        CamelImapResponse *response;

        store->current_folder = NULL;
        response = camel_imap_command (store, NULL, ex, "SELECT %S",
                           folder->full_name);
        if (!response)
            return NULL;
        store->current_folder = folder;

        camel_imap_folder_selected (folder, response, ex);
        if (!fmt)
            return response;

        camel_imap_response_free (response);
    }

    /* Send the command */
    va_start (ap, fmt);
    cmdbuf = imap_command_strdup_vprintf (store, fmt, ap);
    va_end (ap);

    camel_remote_store_send_string (CAMEL_REMOTE_STORE (store), ex,
                    "A%.5d %s\r\n", store->command++,
                    cmdbuf);
    g_free (cmdbuf);
    if (camel_exception_is_set (ex))
        return NULL;

    /* Read the response. */
    return imap_read_response (store, ex);
}

/**
 * camel_imap_command_continuation: Send more command data to the IMAP server
 * @store: the IMAP store
 * @ex: a CamelException
 * @cmdbuf: buffer containing the response/request data
 *
 * This method is for sending continuing responses to the IMAP server
 * after camel_imap_command returns a CAMEL_IMAP_PLUS response.
 * 
 * This function assumes you have an exclusive lock on the remote stream.
 *
 * Return value: as for camel_imap_command()
 **/
CamelImapResponse *
camel_imap_command_continuation (CamelImapStore *store, CamelException *ex,
                 const char *cmdbuf)
{
    if (camel_remote_store_send_string (CAMEL_REMOTE_STORE (store), ex,
                        "%s\r\n", cmdbuf) < 0)
        return NULL;

    return imap_read_response (store, ex);
}

/* Read the response to an IMAP command. */
static CamelImapResponse *
imap_read_response (CamelImapStore *store, CamelException *ex)
{
    CamelImapResponse *response;
    int number, exists = 0;
    GArray *expunged = NULL;
    char *respbuf, *retcode, *word, *p;

    /* Read first line */
    if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store),
                      &respbuf, ex) < 0)
        return NULL;

    response = g_new0 (CamelImapResponse, 1);
    response->untagged = g_ptr_array_new ();

    /* Check for untagged data */
    while (!strncmp (respbuf, "* ", 2)) {
        /* Read the rest of the response if it is multi-line. */
        respbuf = imap_read_untagged (store, respbuf, ex);
        if (camel_exception_is_set (ex))
            break;

        /* If it starts with a number, we might deal with
         * it ourselves.
         */
        word = imap_next_word (respbuf);
        number = strtoul (word, &p, 10);
        if (p != word && store->current_folder) {
            word = imap_next_word (p);
            if (!g_strcasecmp (word, "EXISTS")) {
                exists = number;
                g_free (respbuf);
                goto next;
            } else if (!g_strcasecmp (word, "EXPUNGE")) {
                if (!expunged) {
                    expunged = g_array_new (FALSE, FALSE,
                                sizeof (int));
                }
                g_array_append_val (expunged, number);
                g_free (respbuf);
                goto next;
            }
        } else {
            if (!g_strncasecmp (word, "BYE", 3)) {
                /* connection was lost, no more data to fetch */
                store->connected = FALSE;
                g_free (respbuf);
                respbuf = NULL;
                break;
            }
        }

        g_ptr_array_add (response->untagged, respbuf);
    next:
        if (camel_remote_store_recv_line (
            CAMEL_REMOTE_STORE (store), &respbuf, ex) < 0)
            break;
    }

    /* Update the summary */
    if (store->current_folder && (exists > 0 || expunged)) {
        camel_imap_folder_changed (store->current_folder, exists,
                       expunged, NULL);
    }
    if (expunged)
        g_array_free (expunged, TRUE);

    if (!respbuf || camel_exception_is_set (ex)) {
        camel_imap_response_free (response);
        return NULL;
    }

    response->status = respbuf;

    /* Check for OK or continuation response. */
    if (!strncmp (respbuf, "+ ", 2))
        return response;
    retcode = imap_next_word (respbuf);
    if (!strncmp (retcode, "OK", 2))
        return response;

    /* We should never get BAD, or anything else but +, OK, or NO
     * for that matter.
     */
    if (strncmp (retcode, "NO", 2) != 0) {
        g_warning ("Unexpected response from IMAP server: %s",
               respbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      _("Unexpected response from IMAP "
                    "server: %s"), respbuf);
        camel_imap_response_free (response);
        return NULL;
    }

    retcode = imap_next_word (retcode);
    camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                  _("IMAP command failed: %s"),
                  retcode ? retcode : _("Unknown error"));
    camel_imap_response_free (response);
    return NULL;
}

/* Given a line that is the start of an untagged response, read and
 * return the complete response, which may include an arbitrary number
 * of literals.
 */
static char *
imap_read_untagged (CamelImapStore *store, char *line, CamelException *ex)
{
    int fulllen, length, ldigits, nread, i;
    GPtrArray *data;
    GString *str;
    char *end, *p, *s, *d;

    p = strrchr (line, '{');
    if (!p)
        return line;

    data = g_ptr_array_new ();
    fulllen = 0;

    while (1) {
        str = g_string_new (line);
        g_free (line);
        fulllen += str->len;
        g_ptr_array_add (data, str);

        p = strrchr (str->str, '{');
        if (!p)
            break;

        length = strtoul (p + 1, &end, 10);
        if (*end != '}' || *(end + 1) || end == p + 1)
            break;
        ldigits = end - (p + 1);

        /* Read the literal */
        str = g_string_sized_new (length + 2);
        str->str[0] = '\n';
        nread = camel_stream_read (CAMEL_REMOTE_STORE (store)->istream,
                       str->str + 1, length);
        if (nread == -1) {
            if (errno == EINTR)
                camel_exception_set(ex, CAMEL_EXCEPTION_USER_CANCEL, _("Operation cancelled"));
            else
                camel_exception_set(ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE, strerror(errno));
            camel_service_disconnect (CAMEL_SERVICE (store), FALSE, NULL);
            goto lose;
        }
        if (nread < length) {
            camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                          _("Server response ended too soon."));
            camel_service_disconnect (CAMEL_SERVICE (store),
                          FALSE, NULL);
            goto lose;
        }
        str->str[length + 1] = '\0';

        /* Fix up the literal, turning CRLFs into LF. Also, if
         * we find any embedded NULs, strip them. This is
         * dubious, but:
         *   - The IMAP grammar says you can't have NULs here
         *     anyway, so this will not affect our behavior
         *     against any completely correct server.
         *   - WU-imapd 12.264 (at least) will cheerily pass
         *     NULs along if they are embedded in the message
         *   - The only cause of embedded NULs we've seen is an
         *     Evolution base64-encoder bug that sometimes
         *     inserts a NUL into the last line when it
         *     shouldn't.
         */

        s = d = str->str + 1;
        end = str->str + 1 + length;
        while (s < end) {
            while (s < end && *s == '\0') {
                s++;
                length--;
            }
            if (*s == '\r' && *(s + 1) == '\n') {
                s++;
                length--;
            }
            *d++ = *s++;
        }
        *d = '\0';
        str->len = length + 1;

        /* p points to the "{" in the line that starts the
         * literal. The length of the CR-less response must be
         * less than or equal to the length of the response
         * with CRs, therefore overwriting the old value with
         * the new value cannot cause an overrun. However, we
         * don't want it to be shorter either, because then the
         * GString's length would be off...
         */
        sprintf (p, "{%0*d}", ldigits, length);

        fulllen += str->len;
        g_ptr_array_add (data, str);

        /* Read the next line. */
        if (camel_remote_store_recv_line (CAMEL_REMOTE_STORE (store),
                          &line, ex) < 0)
            goto lose;
    }

    /* Now reassemble the data. */
    p = line = g_malloc (fulllen + 1);
    for (i = 0; i < data->len; i++) {
        str = data->pdata[i];
        memcpy (p, str->str, str->len);
        p += str->len;
        g_string_free (str, TRUE);
    }
    *p = '\0';
    g_ptr_array_free (data, TRUE);
    return line;

 lose:
    for (i = 0; i < data->len; i++)
        g_string_free (data->pdata[i], TRUE);
    g_ptr_array_free (data, TRUE);
    return NULL;
}


/**
 * camel_imap_response_free:
 * response: a CamelImapResponse:
 *
 * Frees all of the data in @response.
 **/
void
camel_imap_response_free (CamelImapResponse *response)
{
    int i;

    if (!response)
        return;
    for (i = 0; i < response->untagged->len; i++)
        g_free (response->untagged->pdata[i]);
    g_ptr_array_free (response->untagged, TRUE);
    g_free (response->status);
    g_free (response);
}

/**
 * camel_imap_response_extract:
 * @response: the response data returned from camel_imap_command
 * @type: the response type to extract
 * @ex: a CamelException
 *
 * This checks that @response contains a single untagged response of
 * type @type and returns just that response data. If @response
 * doesn't contain the right information, the function will set @ex and
 * return %NULL. Either way, @response will be freed.
 *
 * Return value: the desired response string, which the caller must free.
 **/
char *
camel_imap_response_extract (CamelImapResponse *response, const char *type,
                 CamelException *ex)
{
    int len = strlen (type), i;
    char *resp;

    for (i = 0; i < response->untagged->len; i++) {
        resp = response->untagged->pdata[i];
        /* Skip "* ", and initial sequence number, if present */
        strtoul (resp + 2, &resp, 10);
        if (*resp == ' ')
            resp = imap_next_word (resp);

        if (!g_strncasecmp (resp, type, len))
            break;
        
        g_free (response->untagged->pdata[i]);
    }

    if (i < response->untagged->len) {
        resp = response->untagged->pdata[i];
        for (i++; i < response->untagged->len; i++)
            g_free (response->untagged->pdata[i]);
    } else {
        resp = NULL;
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      _("IMAP server response did not contain "
                    "%s information"), type);
    }

    g_ptr_array_free (response->untagged, TRUE);
    g_free (response->status);
    g_free (response);
    return resp;
}

/**
 * camel_imap_response_extract_continuation:
 * @response: the response data returned from camel_imap_command
 * @ex: a CamelException
 *
 * This checks that @response contains a continuation response, and
 * returns just that data. If @response doesn't contain a continuation
 * response, the function will set @ex and return %NULL. Either way,
 * @response will be freed.
 *
 * Return value: the desired response string, which the caller must free.
 **/
char *
camel_imap_response_extract_continuation (CamelImapResponse *response,
                      CamelException *ex)
{
    char *status;

    if (response->status && !strncmp (response->status, "+ ", 2)) {
        status = response->status;
        response->status = NULL;
        camel_imap_response_free (response);
        return status;
    }

    camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                  _("Unexpected OK response from IMAP server: %s"),
                  response->status);
    camel_imap_response_free (response);
    return NULL;
}


static char *
imap_command_strdup_vprintf (CamelImapStore *store, const char *fmt,
                 va_list ap)
{
    GPtrArray *args;
    const char *p, *start;
    char *out, *op, *string;
    int num, len, i;

    args = g_ptr_array_new ();

    /* Determine the length of the data */
    len = strlen (fmt);
    p = start = fmt;
    while (*p) {
        p = strchr (start, '%');
        if (!p)
            break;

        switch (*++p) {
        case 'd':
            num = va_arg (ap, int);
            g_ptr_array_add (args, GINT_TO_POINTER (num));
            start = p + 1;
            len += 10;
            break;

        case 's':
            string = va_arg (ap, char *);
            g_ptr_array_add (args, string);
            start = p + 1;
            len += strlen (string);
            break;

        case 'S':
            string = va_arg (ap, char *);
            g_ptr_array_add (args, string);
            if (store->capabilities & IMAP_CAPABILITY_LITERALPLUS)
                len += strlen (string) + 15;
            else
                len += strlen (string) * 2;
            start = p + 1;
            break;

        case '%':
            start = p;
            break;

        default:
            g_warning ("camel-imap-command is not printf. I don't "
                   "know what '%%%c' means.", *p);
            start = *p ? p + 1 : p;
            break;
        }
    }

    /* Now write out the string */
    op = out = g_malloc (len + 1);
    p = start = fmt;
    i = 0;
    while (*p) {
        p = strchr (start, '%');
        if (!p) {
            strcpy (op, start);
            break;
        } else {
            strncpy (op, start, p - start);
            op += p - start;
        }

        switch (*++p) {
        case 'd':
            num = GPOINTER_TO_INT (args->pdata[i++]);
            op += sprintf (op, "%d", num);
            break;

        case 's':
            string = args->pdata[i++];
            op += sprintf (op, "%s", string);
            break;

        case 'S':
            string = args->pdata[i++];
            if (store->capabilities & IMAP_CAPABILITY_LITERALPLUS) {
                op += sprintf (op, "{%d+}\r\n%s",
                           strlen (string), string);
            } else {
                char *quoted = imap_quote_string (string);
                op += sprintf (op, "%s", quoted);
                g_free (quoted);
            }
            break;

        default:
            *op++ = '%';
            *op++ = *p;
        }

        start = *p ? p + 1 : p;
    }

    return out;
}