librempeg/libavformat/ftp.c

/*
 * Copyright (c) 2013 Lukasz Marek <lukasz.m.luki@gmail.com>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdlib.h>
#include "libavutil/avstring.h"
#include "libavutil/time.h"
#include "avformat.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
#include "url.h"
#include "libavutil/opt.h"

#define CONTROL_BUFFER_SIZE 1024
#define CREDENTIALS_BUFFER_SIZE 128

typedef enum {
    UNKNOWN,
    READY,
    DOWNLOADING,
    UPLOADING,
    DISCONNECTED
} FTPState;

typedef struct {
    const AVClass *class;
    URLContext *conn_control;                    /**< Control connection */
    int conn_control_block_flag;                 /**< Controls block/unblock mode of data connection */
    AVIOInterruptCB conn_control_interrupt_cb;   /**< Controls block/unblock mode of data connection */
    URLContext *conn_data;                       /**< Data connection, NULL when not connected */
    uint8_t control_buffer[CONTROL_BUFFER_SIZE]; /**< Control connection buffer */
    uint8_t *control_buf_ptr, *control_buf_end;
    int server_data_port;                        /**< Data connection port opened by server, -1 on error. */
    int server_control_port;                     /**< Control connection port, default is 21 */
    char hostname[512];                          /**< Server address. */
    char credencials[CREDENTIALS_BUFFER_SIZE];   /**< Authentication data */
    char path[MAX_URL_SIZE];                     /**< Path to resource on server. */
    int64_t filesize;                            /**< Size of file on server, -1 on error. */
    int64_t position;                            /**< Current position, calculated. */
    int rw_timeout;                              /**< Network timeout. */
    const char *anonymous_password;              /**< Password to be used for anonymous user. An email should be used. */
    int write_seekable;                          /**< Control seekability, 0 = disable, 1 = enable. */
    FTPState state;                              /**< State of data connection */
} FTPContext;

#define OFFSET(x) offsetof(FTPContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
    {"timeout", "set timeout of socket I/O operations", OFFSET(rw_timeout), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, D|E },
    {"ftp-write-seekable", "control seekability of connection during encoding", OFFSET(write_seekable), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
    {"ftp-anonymous-password", "password for anonymous login. E-mail address should be used.", OFFSET(anonymous_password), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },
    {NULL}
};

static const AVClass ftp_context_class = {
    .class_name     = "ftp",
    .item_name      = av_default_item_name,
    .option         = options,
    .version        = LIBAVUTIL_VERSION_INT,
};

static int ftp_conn_control_block_control(void *data)
{
    FTPContext *s = data;
    return s->conn_control_block_flag;
}

static int ftp_getc(FTPContext *s)
{
    int len;
    if (s->control_buf_ptr >= s->control_buf_end) {
        if (s->conn_control_block_flag)
            return AVERROR_EXIT;
        len = ffurl_read(s->conn_control, s->control_buffer, CONTROL_BUFFER_SIZE);
        if (len < 0) {
            return len;
        } else if (!len) {
            return -1;
        } else {
            s->control_buf_ptr = s->control_buffer;
            s->control_buf_end = s->control_buffer + len;
        }
    }
    return *s->control_buf_ptr++;
}

static int ftp_get_line(FTPContext *s, char *line, int line_size)
{
    int ch;
    char *q = line;
    int ori_block_flag = s->conn_control_block_flag;

    for (;;) {
        ch = ftp_getc(s);
        if (ch < 0) {
            s->conn_control_block_flag = ori_block_flag;
            return ch;
        }
        if (ch == '\n') {
            /* process line */
            if (q > line && q[-1] == '\r')
                q--;
            *q = '\0';

            s->conn_control_block_flag = ori_block_flag;
            return 0;
        } else {
            s->conn_control_block_flag = 0; /* line need to be finished */
            if ((q - line) < line_size - 1)
                *q++ = ch;
        }
    }
}

static int ftp_flush_control_input(FTPContext *s)
{
    char buf[CONTROL_BUFFER_SIZE];
    int err, ori_block_flag = s->conn_control_block_flag;

    s->conn_control_block_flag = 1;
    do {
        err = ftp_get_line(s, buf, sizeof(buf));
    } while (err > 0);

    s->conn_control_block_flag = ori_block_flag;

    if (err < 0 && err != AVERROR_EXIT)
        return err;

    return 0;
}

/*
 * This routine returns ftp server response code.
 * Server may send more than one response for a certain command, following priorities are used:
 *   - When pref_codes are set then pref_code is return if occurred. (expected result)
 *   - 0 is returned when no pref_codes or not occurred
 */
static int ftp_status(FTPContext *s, char **line, const int response_codes[])
{
    int err, i, result = 0, pref_code_found = 0, wait_count = 100;
    char buf[CONTROL_BUFFER_SIZE];

    /* Set blocking mode */
    s->conn_control_block_flag = 0;
    for (;;) {
        if ((err = ftp_get_line(s, buf, sizeof(buf))) < 0) {
            if (err == AVERROR_EXIT) {
                if (!pref_code_found && wait_count--) {
                    av_usleep(10000);
                    continue;
                }
            }
            return result;
        }

        /* first code received. Now get all lines in non blocking mode */
        s->conn_control_block_flag = 1;

        av_log(s, AV_LOG_DEBUG, "%s\n", buf);

        if (!pref_code_found) {
            if (strlen(buf) < 3)
                continue;

            err = 0;
            for (i = 0; i < 3; ++i) {
                if (buf[i] < '0' || buf[i] > '9')
                    continue;
                err *= 10;
                err += buf[i] - '0';
            }

            for (i = 0; response_codes[i]; ++i) {
                if (err == response_codes[i]) {
                    pref_code_found = 1;
                    result = err;
                    if (line)
                        *line = av_strdup(buf);
                    break;
                }
            }
        }
    }
    return result;
}

static int ftp_send_command(FTPContext *s, const char *command,
                            const int response_codes[], char **response)
{
    int err;

    /* Flush control connection input to get rid of non relevant responses if any */
    if ((err = ftp_flush_control_input(s)) < 0)
        return err;

    /* send command in blocking mode */
    s->conn_control_block_flag = 0;
    if ((err = ffurl_write(s->conn_control, command, strlen(command))) < 0)
        return err;

    /* return status */
    return ftp_status(s, response, response_codes);
}

static int ftp_auth(FTPContext *s)
{
    const char *user = NULL, *pass = NULL;
    char *end = NULL, buf[CONTROL_BUFFER_SIZE], credencials[CREDENTIALS_BUFFER_SIZE];
    int err;
    const int user_codes[] = {331, 230, 0};
    const int pass_codes[] = {230, 0};

    /* Authentication may be repeated, original string has to be saved */
    av_strlcpy(credencials, s->credencials, sizeof(credencials));

    user = av_strtok(credencials, ":", &end);
    pass = av_strtok(end, ":", &end);

    if (!user) {
        user = "anonymous";
        pass = s->anonymous_password ? s->anonymous_password : "nopassword";
    }

    snprintf(buf, sizeof(buf), "USER %s\r\n", user);
    err = ftp_send_command(s, buf, user_codes, NULL);
    if (err == 331) {
        if (pass) {
            snprintf(buf, sizeof(buf), "PASS %s\r\n", pass);
            err = ftp_send_command(s, buf, pass_codes, NULL);
        } else
            return AVERROR(EACCES);
    }
    if (!err)
        return AVERROR(EACCES);

    return 0;
}

static int ftp_passive_mode(FTPContext *s)
{
    char *res = NULL, *start, *end;
    int i;
    const char *command = "PASV\r\n";
    const int pasv_codes[] = {227, 0};

    if (!ftp_send_command(s, command, pasv_codes, &res))
        goto fail;

    start = NULL;
    for (i = 0; i < strlen(res); ++i) {
        if (res[i] == '(') {
            start = res + i + 1;
        } else if (res[i] == ')') {
            end = res + i;
            break;
        }
    }
    if (!start || !end)
        goto fail;

    *end  = '\0';
    /* skip ip */
    if (!av_strtok(start, ",", &end)) goto fail;
    if (!av_strtok(end, ",", &end)) goto fail;
    if (!av_strtok(end, ",", &end)) goto fail;
    if (!av_strtok(end, ",", &end)) goto fail;

    /* parse port number */
    start = av_strtok(end, ",", &end);
    if (!start) goto fail;
    s->server_data_port = atoi(start) * 256;
    start = av_strtok(end, ",", &end);
    if (!start) goto fail;
    s->server_data_port += atoi(start);
    av_dlog(s, "Server data port: %d\n", s->server_data_port);

    av_free(res);
    return 0;

  fail:
    av_free(res);
    s->server_data_port = -1;
    return AVERROR(EIO);
}

static int ftp_current_dir(FTPContext *s)
{
    char *res = NULL, *start = NULL, *end = NULL;
    int i;
    const char *command = "PWD\r\n";
    const int pwd_codes[] = {257, 0};

    if (!ftp_send_command(s, command, pwd_codes, &res))
        goto fail;

    for (i = 0; res[i]; ++i) {
        if (res[i] == '"') {
            if (!start) {
                start = res + i + 1;
                continue;
            }
            end = res + i;
            break;
        }
    }

    if (!end)
        goto fail;

    if (end > res && end[-1] == '/') {
        end[-1] = '\0';
    } else
        *end = '\0';
    av_strlcpy(s->path, start, sizeof(s->path));

    av_free(res);
    return 0;

  fail:
    av_free(res);
    return AVERROR(EIO);
}

static int ftp_file_size(FTPContext *s)
{
    char command[CONTROL_BUFFER_SIZE];
    char *res = NULL;
    const int size_codes[] = {213, 0};

    snprintf(command, sizeof(command), "SIZE %s\r\n", s->path);
    if (ftp_send_command(s, command, size_codes, &res)) {
        s->filesize = strtoll(&res[4], NULL, 10);
    } else {
        s->filesize = -1;
        av_free(res);
        return AVERROR(EIO);
    }

    av_free(res);
    return 0;
}

static int ftp_retrieve(FTPContext *s)
{
    char command[CONTROL_BUFFER_SIZE];
    const int retr_codes[] = {150, 0};

    snprintf(command, sizeof(command), "RETR %s\r\n", s->path);
    if (!ftp_send_command(s, command, retr_codes, NULL))
        return AVERROR(EIO);

    s->state = DOWNLOADING;

    return 0;
}

static int ftp_store(FTPContext *s)
{
    char command[CONTROL_BUFFER_SIZE];
    const int stor_codes[] = {150, 0};

    snprintf(command, sizeof(command), "STOR %s\r\n", s->path);
    if (!ftp_send_command(s, command, stor_codes, NULL))
        return AVERROR(EIO);

    s->state = UPLOADING;

    return 0;
}

static int ftp_type(FTPContext *s)
{
    const char *command = "TYPE I\r\n";
    const int type_codes[] = {200, 0};

    if (!ftp_send_command(s, command, type_codes, NULL))
        return AVERROR(EIO);

    return 0;
}

static int ftp_abort(FTPContext *s)
{
    int err;
    const char *command = "ABOR\r\n";
    const int abor_codes[] = {225, 226, 0};

    if ((err = ftp_flush_control_input(s)) < 0)
        return err;

    if (s->state == DOWNLOADING) {
        s->conn_control_block_flag = 0;
        if ((err = ffurl_write(s->conn_control, command, strlen(command))) < 0)
            return err;
    }
    ffurl_closep(&s->conn_data);
    s->state = DISCONNECTED;

    if (!ftp_status(s, NULL, abor_codes))
        return AVERROR(EIO);

    return 0;
}

static int ftp_restart(FTPContext *s, int64_t pos)
{
    char command[CONTROL_BUFFER_SIZE];
    const int rest_codes[] = {350, 0};

    snprintf(command, sizeof(command), "REST %"PRId64"\r\n", pos);
    if (!ftp_send_command(s, command, rest_codes, NULL))
        return AVERROR(EIO);

    return 0;
}

static int ftp_connect_control_connection(URLContext *h)
{
    char buf[CONTROL_BUFFER_SIZE], opts_format[20];
    int err;
    AVDictionary *opts = NULL;
    FTPContext *s = h->priv_data;
    const int connect_codes[] = {220, 0};

    s->conn_control_block_flag = 0;

    if (!s->conn_control) {
        ff_url_join(buf, sizeof(buf), "tcp", NULL,
                    s->hostname, s->server_control_port, NULL);
        if (s->rw_timeout != -1) {
            snprintf(opts_format, sizeof(opts_format), "%d", s->rw_timeout);
            av_dict_set(&opts, "timeout", opts_format, 0);
        } /* if option is not given, don't pass it and let tcp use its own default */
        err = ffurl_open(&s->conn_control, buf, AVIO_FLAG_READ_WRITE,
                         &s->conn_control_interrupt_cb, &opts);
        av_dict_free(&opts);
        if (err < 0) {
            av_dlog(h, "Cannot open control connection, error %d\n", err);
            return err;
        }

        /* consume all messages from server */
        if (!ftp_status(s, NULL, connect_codes)) {
            av_log(h, AV_LOG_ERROR, "FTP server not ready for new users\n");
            err = AVERROR(EACCES);
            return err;
        }

        if ((err = ftp_auth(s)) < 0) {
            av_log(h, AV_LOG_ERROR, "FTP authentication failed\n");
            return err;
        }

        if ((err = ftp_type(s)) < 0) {
            av_dlog(h, "Set content type failed\n");
            return err;
        }
    }
    return 0;
}

static int ftp_connect_data_connection(URLContext *h)
{
    int err;
    char buf[CONTROL_BUFFER_SIZE], opts_format[20];
    AVDictionary *opts = NULL;
    FTPContext *s = h->priv_data;

    if (!s->conn_data) {
        /* Enter passive mode */
        if ((err = ftp_passive_mode(s)) < 0) {
            av_dlog(h, "Set passive mode failed\n");
            return err;
        }
        /* Open data connection */
        ff_url_join(buf, sizeof(buf), "tcp", NULL, s->hostname, s->server_data_port, NULL);
        if (s->rw_timeout != -1) {
            snprintf(opts_format, sizeof(opts_format), "%d", s->rw_timeout);
            av_dict_set(&opts, "timeout", opts_format, 0);
        } /* if option is not given, don't pass it and let tcp use its own default */
        err = ffurl_open(&s->conn_data, buf, AVIO_FLAG_READ_WRITE,
                         &h->interrupt_callback, &opts);
        av_dict_free(&opts);
        if (err < 0)
            return err;
    }
    s->state = READY;
    s->position = 0;
    return 0;
}

static int ftp_open(URLContext *h, const char *url, int flags)
{
    char proto[10], path[MAX_URL_SIZE];
    int err;
    FTPContext *s = h->priv_data;

    av_dlog(h, "ftp protocol open\n");

    s->state = DISCONNECTED;
    s->filesize = -1;
    s->conn_control_interrupt_cb.opaque = s;
    s->conn_control_interrupt_cb.callback = ftp_conn_control_block_control;

    av_url_split(proto, sizeof(proto),
                 s->credencials, sizeof(s->credencials),
                 s->hostname, sizeof(s->hostname),
                 &s->server_control_port,
                 path, sizeof(path),
                 url);

    if (s->server_control_port < 0 || s->server_control_port > 65535)
        s->server_control_port = 21;

    if ((err = ftp_connect_control_connection(h)) < 0)
        goto fail;

    if ((err = ftp_current_dir(s)) < 0)
        goto fail;
    av_strlcat(s->path, path, sizeof(s->path));

    if (ftp_file_size(s) < 0 && flags & AVIO_FLAG_READ)
        h->is_streamed = 1;
    if (s->write_seekable != 1 && flags & AVIO_FLAG_WRITE)
        h->is_streamed = 1;

    if ((err = ftp_connect_data_connection(h)) < 0)
        goto fail;

    return 0;
  fail:
    av_log(h, AV_LOG_ERROR, "FTP open failed\n");
    ffurl_closep(&s->conn_control);
    ffurl_closep(&s->conn_data);
    return err;
}

static int64_t ftp_seek(URLContext *h, int64_t pos, int whence)
{
    FTPContext *s = h->priv_data;
    int err;
    int64_t new_pos;

    av_dlog(h, "ftp protocol seek %"PRId64" %d\n", pos, whence);

    switch(whence) {
    case AVSEEK_SIZE:
        return s->filesize;
    case SEEK_SET:
        new_pos = pos;
        break;
    case SEEK_CUR:
        new_pos = s->position + pos;
        break;
    case SEEK_END:
        if (s->filesize < 0)
            return AVERROR(EIO);
        new_pos = s->filesize + pos;
        break;
    default:
        return AVERROR(EINVAL);
    }

    if  (h->is_streamed)
        return AVERROR(EIO);

    if (new_pos < 0 || (s->filesize >= 0 && new_pos > s->filesize))
        return AVERROR(EINVAL);

    if (new_pos != s->position) {
        /* close existing data connection */
        if (s->state != READY) {
            if (s->conn_data) {
                /* abort existing transfer */
                if ((err = ftp_abort(s)) < 0)
                    return err;
            }
            /* open new data connection */
            if ((err = ftp_connect_data_connection(h)) < 0)
                return err;
        }

        if ((err = ftp_restart(s, new_pos)) < 0)
            return err;

        s->position = new_pos;
    }
    return new_pos;
}

static int ftp_read(URLContext *h, unsigned char *buf, int size)
{
    FTPContext *s = h->priv_data;
    int read, err, retry_done = 0;

    av_dlog(h, "ftp protocol read %d bytes\n", size);
  retry:
    if (s->state == READY) {
        ftp_retrieve(s);
    }
    if (s->conn_data && s->state == DOWNLOADING) {
        read = ffurl_read(s->conn_data, buf, size);
        if (read >= 0) {
            s->position += read;
            if (s->position >= s->filesize) {
                if (ftp_abort(s) < 0)
                    return AVERROR(EIO);
            }
        }
        if (!read && s->position < s->filesize && !h->is_streamed) {
            /* Server closed connection. Probably due to inactivity */
            /* TODO: Consider retry before reconnect */
            int64_t pos = s->position;
            av_log(h, AV_LOG_INFO, "Reconnect to FTP server.\n");
            ffurl_closep(&s->conn_control);
            ffurl_closep(&s->conn_data);
            s->position = 0;
            s->state = DISCONNECTED;
            if ((err = ftp_connect_control_connection(h)) < 0) {
                av_log(h, AV_LOG_ERROR, "Reconnect failed\n");
                return err;
            }
            if ((err = ftp_seek(h, pos, SEEK_SET)) < 0) {
                av_dlog(h, "Seek failed after reconnect\n");
                return err;
            }
            if (!retry_done) {
                retry_done = 1;
                goto retry;
            }
        }
        return read;
    }

    av_log(h, AV_LOG_DEBUG, "FTP read failed\n");
    return AVERROR(EIO);
}

static int ftp_write(URLContext *h, const unsigned char *buf, int size)
{
    FTPContext *s = h->priv_data;
    int written;

    av_dlog(h, "ftp protocol write %d bytes\n", size);

    if (s->state == READY) {
        ftp_store(s);
    }
    if (s->conn_data && s->state == UPLOADING) {
        written = ffurl_write(s->conn_data, buf, size);
        if (written > 0) {
            s->position += written;
            s->filesize = FFMAX(s->filesize, s->position);
        }
        return written;
    }

    av_log(h, AV_LOG_ERROR, "FTP write failed\n");
    return AVERROR(EIO);
}

static int ftp_close(URLContext *h)
{
    FTPContext *s = h->priv_data;

    av_dlog(h, "ftp protocol close\n");

    ffurl_closep(&s->conn_control);
    ffurl_closep(&s->conn_data);

    return 0;
}

static int ftp_get_file_handle(URLContext *h)
{
    FTPContext *s = h->priv_data;

    av_dlog(h, "ftp protocol get_file_handle\n");

    if (s->conn_data)
        return ffurl_get_file_handle(s->conn_data);

    return AVERROR(EIO);
}

static int ftp_shutdown(URLContext *h, int flags)
{
    FTPContext *s = h->priv_data;

    av_dlog(h, "ftp protocol shutdown\n");

    if (s->conn_data)
        return ffurl_shutdown(s->conn_data, flags);

    return AVERROR(EIO);
}

URLProtocol ff_ftp_protocol = {
    .name                = "ftp",
    .url_open            = ftp_open,
    .url_read            = ftp_read,
    .url_write           = ftp_write,
    .url_seek            = ftp_seek,
    .url_close           = ftp_close,
    .url_get_file_handle = ftp_get_file_handle,
    .url_shutdown        = ftp_shutdown,
    .priv_data_size      = sizeof(FTPContext),
    .priv_data_class     = &ftp_context_class,
    .flags               = URL_PROTOCOL_FLAG_NETWORK,
};