path: root/lib/libalpm/dload.c

/*
 *  download.c
 *
 *  Copyright (c) 2006-2011 Pacman Development Team <pacman-dev@archlinux.org>
 *  Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.org>
 *
 *  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, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>

#ifdef HAVE_LIBCURL
#include <curl/curl.h>
#endif

/* libalpm */
#include "dload.h"
#include "alpm_list.h"
#include "alpm.h"
#include "log.h"
#include "util.h"
#include "handle.h"

#ifdef HAVE_LIBCURL
static const char *get_filename(const char *url)
{
  char *filename = strrchr(url, '/');
  if(filename != NULL) {
    filename++;
  }
  return filename;
}

static char *get_fullpath(const char *path, const char *filename,
    const char *suffix)
{
  char *filepath;
  /* len = localpath len + filename len + suffix len + null */
  size_t len = strlen(path) + strlen(filename) + strlen(suffix) + 1;
  MALLOC(filepath, len, return NULL);
  snprintf(filepath, len, "%s%s%s", path, filename, suffix);

  return filepath;
}

static CURL *get_libcurl_handle(alpm_handle_t *handle)
{
  if(!handle->curl) {
    curl_global_init(CURL_GLOBAL_SSL);
    handle->curl = curl_easy_init();
  }
  return handle->curl;
}

enum {
  ABORT_SIGINT = 1,
  ABORT_OVER_MAXFILESIZE
};

static int dload_interrupted;
static void inthandler(int UNUSED signum)
{
  dload_interrupted = ABORT_SIGINT;
}

static int curl_progress(void *file, double dltotal, double dlnow,
    double UNUSED ultotal, double UNUSED ulnow)
{
  struct dload_payload *payload = (struct dload_payload *)file;
  off_t current_size, total_size;

  /* SIGINT sent, abort by alerting curl */
  if(dload_interrupted) {
    return 1;
  }

  current_size = payload->initial_size + (off_t)dlnow;

  /* is our filesize still under any set limit? */
  if(payload->max_size && current_size > payload->max_size) {
    dload_interrupted = ABORT_OVER_MAXFILESIZE;
    return 1;
  }

  /* none of what follows matters if the front end has no callback */
  if(payload->handle->dlcb == NULL) {
    return 0;
  }

  total_size = payload->initial_size + (off_t)dltotal;

  if(DOUBLE_EQ(dltotal, 0.0) || payload->prevprogress == total_size) {
    return 0;
  }

  /* initialize the progress bar here to avoid displaying it when
   * a repo is up to date and nothing gets downloaded */
  if(payload->prevprogress == 0) {
    payload->handle->dlcb(payload->remote_name, 0, (off_t)dltotal);
  }

  payload->handle->dlcb(payload->remote_name, current_size, total_size);

  payload->prevprogress = current_size;

  return 0;
}

static int curl_gethost(const char *url, char *buffer, size_t buf_len)
{
  size_t hostlen;
  char *p, *q;

  if(strncmp(url, "file://", 7) == 0) {
    p = _("disk");
    hostlen = strlen(p);
  } else {
    p = strstr(url, "//");
    if(!p) {
      return 1;
    }
    p += 2; /* jump over the found // */
    hostlen = strcspn(p, "/");

    /* there might be a user:pass@ on the URL. hide it. avoid using memrchr()
     * for portability concerns. */
    q = p + hostlen;
    while(--q > p) {
      if(*q == '@') {
        break;
      }
    }
    if(*q == '@' && p != q) {
      hostlen -= q - p + 1;
      p = q + 1;
    }
  }

  if(hostlen > buf_len - 1) {
    /* buffer overflow imminent */
    return 1;
  }
  memcpy(buffer, p, hostlen);
  buffer[hostlen] = '\0';

  return 0;
}

static int utimes_long(const char *path, long seconds)
{
  if(seconds != -1) {
    struct timeval tv[2];
    memset(&tv, 0, sizeof(tv));
    tv[0].tv_sec = tv[1].tv_sec = seconds;
    return utimes(path, tv);
  }
  return 0;
}

static size_t parse_headers(void *ptr, size_t size, size_t nmemb, void *user)
{
  size_t realsize = size * nmemb;
  const char *fptr, *endptr = NULL;
  const char * const cd_header = "Content-Disposition:";
  const char * const fn_key = "filename=";
  struct dload_payload *payload = (struct dload_payload *)user;

  if(_alpm_raw_ncmp(cd_header, ptr, strlen(cd_header)) == 0) {
    if((fptr = strstr(ptr, fn_key))) {
      fptr += strlen(fn_key);

      /* find the end of the field, which is either a semi-colon, or the end of
       * the data. As per curl_easy_setopt(3), we cannot count on headers being
       * null terminated, so we look for the closing \r\n */
      endptr = fptr + strcspn(fptr, ";\r\n") - 1;

      /* remove quotes */
      if(*fptr == '"' && *endptr == '"') {
        fptr++;
        endptr--;
      }

      STRNDUP(payload->content_disp_name, fptr, endptr - fptr + 1,
          RET_ERR(payload->handle, ALPM_ERR_MEMORY, realsize));
    }
  }

  return realsize;
}

static void curl_set_handle_opts(struct dload_payload *payload,
    CURL *curl, char *error_buffer)
{
  alpm_handle_t *handle = payload->handle;
  const char *useragent = getenv("HTTP_USER_AGENT");
  struct stat st;

  /* the curl_easy handle is initialized with the alpm handle, so we only need
   * to reset the handle's parameters for each time it's used. */
  curl_easy_reset(curl);
  curl_easy_setopt(curl, CURLOPT_URL, payload->fileurl);
  curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
  curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error_buffer);
  curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10L);
  curl_easy_setopt(curl, CURLOPT_FILETIME, 1L);
  curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0L);
  curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
  curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, curl_progress);
  curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, (void *)payload);
  curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 1024L);
  curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 10L);
  curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, parse_headers);
  curl_easy_setopt(curl, CURLOPT_WRITEHEADER, (void *)payload);
  curl_easy_setopt(curl, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);

  _alpm_log(handle, ALPM_LOG_DEBUG, "url: %s\n", payload->fileurl);

  if(payload->max_size) {
    _alpm_log(handle, ALPM_LOG_DEBUG, "maxsize: %jd\n",
        (intmax_t)payload->max_size);
    curl_easy_setopt(curl, CURLOPT_MAXFILESIZE_LARGE,
        (curl_off_t)payload->max_size);
  }

  if(useragent != NULL) {
    curl_easy_setopt(curl, CURLOPT_USERAGENT, useragent);
  }

  if(!payload->allow_resume && !payload->force && payload->destfile_name &&
      stat(payload->destfile_name, &st) == 0) {
    /* start from scratch, but only download if our local is out of date. */
    curl_easy_setopt(curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
    curl_easy_setopt(curl, CURLOPT_TIMEVALUE, (long)st.st_mtime);
    _alpm_log(handle, ALPM_LOG_DEBUG,
        "using time condition: %lu\n", (long)st.st_mtime);
  } else if(stat(payload->tempfile_name, &st) == 0 && payload->allow_resume) {
    /* a previous partial download exists, resume from end of file. */
    payload->tempfile_openmode = "ab";
    curl_easy_setopt(curl, CURLOPT_RESUME_FROM_LARGE, (curl_off_t)st.st_size);
    _alpm_log(handle, ALPM_LOG_DEBUG,
        "tempfile found, attempting continuation from %jd bytes\n",
        (intmax_t)st.st_size);
    payload->initial_size = st.st_size;
  }
}

static void mask_signal(int signal, void (*handler)(int),
    struct sigaction *origaction)
{
  struct sigaction newaction;

  newaction.sa_handler = handler;
  sigemptyset(&newaction.sa_mask);
  newaction.sa_flags = 0;

  sigaction(signal, NULL, origaction);
  sigaction(signal, &newaction, NULL);
}

static void unmask_signal(int signal, struct sigaction sa)
{
  sigaction(signal, &sa, NULL);
}

static FILE *create_tempfile(struct dload_payload *payload, const char *localpath)
{
  int fd;
  FILE *fp;
  char *randpath;
  size_t len;

  /* create a random filename, which is opened with O_EXCL */
  len = strlen(localpath) + 14 + 1;
  MALLOC(randpath, len, RET_ERR(payload->handle, ALPM_ERR_MEMORY, NULL));
  snprintf(randpath, len, "%salpmtmp.XXXXXX", localpath);
  if((fd = mkstemp(randpath)) == -1 ||
      !(fp = fdopen(fd, payload->tempfile_openmode))) {
    unlink(randpath);
    close(fd);
    _alpm_log(payload->handle, ALPM_LOG_ERROR,
        _("failed to create temporary file for download\n"));
    return NULL;
  }
  /* fp now points to our alpmtmp.XXXXXX */
  free(payload->tempfile_name);
  payload->tempfile_name = randpath;
  free(payload->remote_name);
  STRDUP(payload->remote_name, strrchr(randpath, '/') + 1,
      RET_ERR(payload->handle, ALPM_ERR_MEMORY, NULL));

  return fp;
}

/* RFC1123 states applications should support this length */
#define HOSTNAME_SIZE 256

static int curl_download_internal(struct dload_payload *payload,
    const char *localpath, char **final_file)
{
  int ret = -1;
  FILE *localf = NULL;
  char *effective_url;
  char hostname[HOSTNAME_SIZE];
  char error_buffer[CURL_ERROR_SIZE] = {0};
  struct stat st;
  long timecond, respcode = 0, remote_time = -1;
  double remote_size, bytes_dl;
  struct sigaction orig_sig_pipe, orig_sig_int;
  /* shortcut to our handle within the payload */
  alpm_handle_t *handle = payload->handle;
  CURL *curl = get_libcurl_handle(handle);
  handle->pm_errno = 0;

  payload->tempfile_openmode = "wb";
  if(!payload->remote_name) {
    payload->remote_name = strdup(get_filename(payload->fileurl));
  }
  if(!payload->remote_name || curl_gethost(payload->fileurl, hostname, sizeof(hostname)) != 0) {
    _alpm_log(handle, ALPM_LOG_ERROR, _("url '%s' is invalid\n"), payload->fileurl);
    RET_ERR(handle, ALPM_ERR_SERVER_BAD_URL, -1);
  }

  if(strlen(payload->remote_name) > 0 && strcmp(payload->remote_name, ".sig") != 0) {
    payload->destfile_name = get_fullpath(localpath, payload->remote_name, "");
    payload->tempfile_name = get_fullpath(localpath, payload->remote_name, ".part");
    if(!payload->destfile_name || !payload->tempfile_name) {
      goto cleanup;
    }
  } else {
    /* URL doesn't contain a filename, so make a tempfile. We can't support
     * resuming this kind of download; partial transfers will be destroyed */
    payload->unlink_on_fail = 1;

    localf = create_tempfile(payload, localpath);
    if(localf == NULL) {
      goto cleanup;
    }
  }

  curl_set_handle_opts(payload, curl, error_buffer);

  if(localf == NULL) {
    localf = fopen(payload->tempfile_name, payload->tempfile_openmode);
    if(localf == NULL) {
      goto cleanup;
    }
  }

  _alpm_log(handle, ALPM_LOG_DEBUG,
      "opened tempfile for download: %s (%s)\n", payload->tempfile_name,
      payload->tempfile_openmode);

  curl_easy_setopt(curl, CURLOPT_WRITEDATA, localf);

  /* ignore any SIGPIPE signals- these may occur if our FTP socket dies or
   * something along those lines. Store the old signal handler first. */
  mask_signal(SIGPIPE, SIG_IGN, &orig_sig_pipe);
  mask_signal(SIGINT, &inthandler, &orig_sig_int);

  /* perform transfer */
  payload->curlerr = curl_easy_perform(curl);

  /* disconnect relationships from the curl handle for things that might go out
   * of scope, but could still be touched on connection teardown.  This really
   * only applies to FTP transfers. See FS#26327 for an example. */
  curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
  curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, (char *)NULL);

  /* was it a success? */
  switch(payload->curlerr) {
    case CURLE_OK:
      /* get http/ftp response code */
      curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &respcode);
      if(respcode >= 400) {
        payload->unlink_on_fail = 1;
        goto cleanup;
      }
      break;
    case CURLE_ABORTED_BY_CALLBACK:
      /* handle the interrupt accordingly */
      if(dload_interrupted == ABORT_OVER_MAXFILESIZE) {
        payload->curlerr = CURLE_FILESIZE_EXCEEDED;
        handle->pm_errno = ALPM_ERR_LIBCURL;
        /* the hardcoded 'size exceeded' message is same as libcurl's normal */
        _alpm_log(handle, ALPM_LOG_ERROR,
            _("failed retrieving file '%s' from %s : %s\n"),
            payload->remote_name, hostname, "Maximum file size exceeded");
      }
      goto cleanup;
    default:
      /* delete zero length downloads */
      if(stat(payload->tempfile_name, &st) == 0 && st.st_size == 0) {
        payload->unlink_on_fail = 1;
      }
      if(!payload->errors_ok) {
        handle->pm_errno = ALPM_ERR_LIBCURL;
        _alpm_log(handle, ALPM_LOG_ERROR,
            _("failed retrieving file '%s' from %s : %s\n"),
            payload->remote_name, hostname, error_buffer);
      } else {
        _alpm_log(handle, ALPM_LOG_DEBUG,
            "failed retrieving file '%s' from %s : %s\n",
            payload->remote_name, hostname, error_buffer);
      }
      goto cleanup;
  }

  /* retrieve info about the state of the transfer */
  curl_easy_getinfo(curl, CURLINFO_FILETIME, &remote_time);
  curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &remote_size);
  curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &bytes_dl);
  curl_easy_getinfo(curl, CURLINFO_CONDITION_UNMET, &timecond);
  curl_easy_getinfo(curl, CURLINFO_EFFECTIVE_URL, &effective_url);

  /* time condition was met and we didn't download anything. we need to
   * clean up the 0 byte .part file that's left behind. */
  if(timecond == 1 && DOUBLE_EQ(bytes_dl, 0)) {
    _alpm_log(handle, ALPM_LOG_DEBUG, "file met time condition\n");
    ret = 1;
    unlink(payload->tempfile_name);
    goto cleanup;
  }

  /* remote_size isn't necessarily the full size of the file, just what the
   * server reported as remaining to download. compare it to what curl reported
   * as actually being transferred during curl_easy_perform() */
  if(!DOUBLE_EQ(remote_size, -1) && !DOUBLE_EQ(bytes_dl, -1) &&
      !DOUBLE_EQ(bytes_dl, remote_size)) {
    handle->pm_errno = ALPM_ERR_RETRIEVE;
    _alpm_log(handle, ALPM_LOG_ERROR, _("%s appears to be truncated: %jd/%jd bytes\n"),
        payload->remote_name, (intmax_t)bytes_dl, (intmax_t)remote_size);
    goto cleanup;
  }

  if(payload->content_disp_name) {
    /* content-disposition header has a better name for our file */
    free(payload->destfile_name);
    payload->destfile_name = get_fullpath(localpath, payload->content_disp_name, "");
  } else {
    const char *effective_filename = strrchr(effective_url, '/');
    if(effective_filename && strlen(effective_filename) > 2) {
      effective_filename++;

      /* if destfile was never set, we wrote to a tempfile. even if destfile is
       * set, we may have followed some redirects and the effective url may
       * have a better suggestion as to what to name our file. in either case,
       * refactor destfile to this newly derived name. */
      if(!payload->destfile_name || strcmp(effective_filename,
            strrchr(payload->destfile_name, '/') + 1) != 0) {
        free(payload->destfile_name);
        payload->destfile_name = get_fullpath(localpath, effective_filename, "");
      }
    }
  }

  ret = 0;

cleanup:
  if(localf != NULL) {
    fclose(localf);
    utimes_long(payload->tempfile_name, remote_time);
  }

  if(ret == 0) {
    const char *realname = payload->tempfile_name;
    if(payload->destfile_name) {
      realname = payload->destfile_name;
      if(rename(payload->tempfile_name, payload->destfile_name)) {
        _alpm_log(handle, ALPM_LOG_ERROR, _("could not rename %s to %s (%s)\n"),
            payload->tempfile_name, payload->destfile_name, strerror(errno));
        ret = -1;
      }
    }
    if(ret != -1 && final_file) {
      STRDUP(*final_file, strrchr(realname, '/') + 1,
          RET_ERR(handle, ALPM_ERR_MEMORY, -1));
    }
  }

  if((ret == -1 || dload_interrupted) && payload->unlink_on_fail &&
      payload->tempfile_name) {
    unlink(payload->tempfile_name);
  }

  /* restore the old signal handlers */
  unmask_signal(SIGINT, orig_sig_int);
  unmask_signal(SIGPIPE, orig_sig_pipe);
  /* if we were interrupted, trip the old handler */
  if(dload_interrupted) {
    raise(SIGINT);
  }

  return ret;
}
#endif

/** Download a file given by a URL to a local directory.
 * Does not overwrite an existing file if the download fails.
 * @param payload the payload context
 * @param localpath the directory to save the file in
 * @param final_file the real name of the downloaded file (may be NULL)
 * @return 0 on success, -1 on error (pm_errno is set accordingly if errors_ok == 0)
 */
int _alpm_download(struct dload_payload *payload, const char *localpath,
    char **final_file)
{
  alpm_handle_t *handle = payload->handle;

  if(handle->fetchcb == NULL) {
#ifdef HAVE_LIBCURL
    return curl_download_internal(payload, localpath, final_file);
#else
    RET_ERR(handle, ALPM_ERR_EXTERNAL_DOWNLOAD, -1);
#endif
  } else {
    int ret = handle->fetchcb(payload->fileurl, localpath, payload->force);
    if(ret == -1 && !payload->errors_ok) {
      RET_ERR(handle, ALPM_ERR_EXTERNAL_DOWNLOAD, -1);
    }
    return ret;
  }
}

/** Fetch a remote pkg. */
char SYMEXPORT *alpm_fetch_pkgurl(alpm_handle_t *handle, const char *url)
{
  char *filepath;
  const char *cachedir;
  char *final_file = NULL;
  struct dload_payload payload;
  int ret;

  CHECK_HANDLE(handle, return NULL);
  ASSERT(url, RET_ERR(handle, ALPM_ERR_WRONG_ARGS, NULL));

  /* find a valid cache dir to download to */
  cachedir = _alpm_filecache_setup(handle);

  memset(&payload, 0, sizeof(struct dload_payload));
  payload.handle = handle;
  STRDUP(payload.fileurl, url, RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
  payload.allow_resume = 1;

  /* download the file */
  ret = _alpm_download(&payload, cachedir, &final_file);
  _alpm_dload_payload_reset(&payload);
  if(ret == -1) {
    _alpm_log(handle, ALPM_LOG_WARNING, _("failed to download %s\n"), url);
    free(final_file);
    return NULL;
  }
  _alpm_log(handle, ALPM_LOG_DEBUG, "successfully downloaded %s\n", url);

  /* attempt to download the signature */
  if(ret == 0 && (handle->siglevel & ALPM_SIG_PACKAGE)) {
    char *sig_final_file = NULL;
    size_t len;

    len = strlen(url) + 5;
    MALLOC(payload.fileurl, len, RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
    snprintf(payload.fileurl, len, "%s.sig", url);
    payload.handle = handle;
    payload.force = 1;
    payload.errors_ok = (handle->siglevel & ALPM_SIG_PACKAGE_OPTIONAL);

    ret = _alpm_download(&payload, cachedir, &sig_final_file);
    if(ret == -1 && !payload.errors_ok) {
      _alpm_log(handle, ALPM_LOG_WARNING,
          _("failed to download %s\n"), payload.fileurl);
      /* Warn now, but don't return NULL. We will fail later during package
       * load time. */
    } else if(ret == 0) {
      _alpm_log(handle, ALPM_LOG_DEBUG,
          "successfully downloaded %s\n", payload.fileurl);
    }
    FREE(sig_final_file);
    _alpm_dload_payload_reset(&payload);
  }

  /* we should be able to find the file the second time around */
  filepath = _alpm_filecache_find(handle, final_file);
  free(final_file);

  return filepath;
}

void _alpm_dload_payload_reset(struct dload_payload *payload)
{
  ASSERT(payload, return);

  FREE(payload->remote_name);
  FREE(payload->tempfile_name);
  FREE(payload->destfile_name);
  FREE(payload->content_disp_name);
  FREE(payload->fileurl);
}

/* vim: set ts=2 sw=2 noet: */