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 double prevprogress; /* last download amount */
#endif

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

#ifdef HAVE_LIBCURL
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;
  CALLOC(filepath, len, sizeof(char), return NULL);
  snprintf(filepath, len, "%s%s%s", path, filename, suffix);

  return filepath;
}

#define check_stop() if(dload_interrupted) { ret = -1; goto cleanup; }
enum sighandlers { OLD = 0, NEW = 1 };

static int dload_interrupted;
static void inthandler(int UNUSED signum)
{
  dload_interrupted = 1;
}

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

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

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

  current_size = dlfile->initial_size + dlnow;
  total_size = dlfile->initial_size + dltotal;

  if(DOUBLE_EQ(dltotal, 0) || DOUBLE_EQ(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(DOUBLE_EQ(prevprogress, 0)) {
    dlfile->handle->dlcb(dlfile->filename, 0, (long)dltotal);
  }

  dlfile->handle->dlcb(dlfile->filename, (long)current_size, (long)total_size);

  prevprogress = current_size;

  return 0;
}

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

  if(strncmp(url, "file://", 7) == 0) {
    strcpy(buffer, _("disk"));
  } else {
    p = strstr(url, "//");
    if(!p) {
      return 1;
    }
    p += 2; /* jump over the found // */
    hostlen = strcspn(p, "/");
    if(hostlen > 255) {
      /* buffer overflow imminent */
      return 1;
    }
    snprintf(buffer, hostlen + 1, "%s", p);
  }

  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 int curl_download_internal(alpm_handle_t *handle,
    const char *url, const char *localpath,
    int force, int allow_resume, int errors_ok)
{
  int ret = -1;
  FILE *localf = NULL;
  const char *useragent;
  const char *open_mode = "wb";
  char *destfile, *tempfile;
  /* RFC1123 states applications should support this length */
  char hostname[256];
  char error_buffer[CURL_ERROR_SIZE];
  struct stat st;
  long timecond, remote_time;
  double remote_size, bytes_dl;
  struct sigaction sig_pipe[2], sig_int[2];
  struct fileinfo dlfile;

  dlfile.handle = handle;
  dlfile.initial_size = 0.0;
  dlfile.filename = get_filename(url);
  if(!dlfile.filename || curl_gethost(url, hostname) != 0) {
    _alpm_log(handle, PM_LOG_ERROR, _("url '%s' is invalid\n"), url);
    RET_ERR(handle, PM_ERR_SERVER_BAD_URL, -1);
  }

  destfile = get_fullpath(localpath, dlfile.filename, "");
  tempfile = get_fullpath(localpath, dlfile.filename, ".part");
  if(!destfile || !tempfile) {
    goto cleanup;
  }

  error_buffer[0] = '\0';

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

  useragent = getenv("HTTP_USER_AGENT");
  if(useragent != NULL) {
    curl_easy_setopt(handle->curl, CURLOPT_USERAGENT, useragent);
  }

  if(!allow_resume && !force && stat(destfile, &st) == 0) {
    /* start from scratch, but only download if our local is out of date. */
    curl_easy_setopt(handle->curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
    curl_easy_setopt(handle->curl, CURLOPT_TIMEVALUE, (long)st.st_mtime);
  } else if(stat(tempfile, &st) == 0 && allow_resume) {
    /* a previous partial download exists, resume from end of file. */
    open_mode = "ab";
    curl_easy_setopt(handle->curl, CURLOPT_RESUME_FROM, (long)st.st_size);
    _alpm_log(handle, PM_LOG_DEBUG, "tempfile found, attempting continuation");
    dlfile.initial_size = (double)st.st_size;
  }

  localf = fopen(tempfile, open_mode);
  if(localf == NULL) {
    goto cleanup;
  }

  curl_easy_setopt(handle->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. */
  sig_pipe[NEW].sa_handler = SIG_IGN;
  sigemptyset(&sig_pipe[NEW].sa_mask);
  sig_pipe[NEW].sa_flags = 0;
  sigaction(SIGPIPE, NULL, &sig_pipe[OLD]);
  sigaction(SIGPIPE, &sig_pipe[NEW], NULL);

  dload_interrupted = 0;
  sig_int[NEW].sa_handler = &inthandler;
  sigemptyset(&sig_int[NEW].sa_mask);
  sig_int[NEW].sa_flags = 0;
  sigaction(SIGINT, NULL, &sig_int[OLD]);
  sigaction(SIGINT, &sig_int[NEW], NULL);

  /* Progress 0 - initialize */
  prevprogress = 0;

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

  /* was it a success? */
  if(handle->curlerr == CURLE_ABORTED_BY_CALLBACK) {
    goto cleanup;
  } else if(handle->curlerr != CURLE_OK) {
    if(!errors_ok) {
      handle->pm_errno = PM_ERR_LIBCURL;
      _alpm_log(handle, PM_LOG_ERROR, _("failed retrieving file '%s' from %s : %s\n"),
          dlfile.filename, hostname, error_buffer);
    } else {
      _alpm_log(handle, PM_LOG_DEBUG, "failed retrieving file '%s' from %s : %s\n",
          dlfile.filename, hostname, error_buffer);
    }
    unlink(tempfile);
    goto cleanup;
  }

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

  /* 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)) {
    ret = 1;
    unlink(tempfile);
    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 = PM_ERR_RETRIEVE;
    _alpm_log(handle, PM_LOG_ERROR, _("%s appears to be truncated: %jd/%jd bytes\n"),
        dlfile.filename, (intmax_t)bytes_dl, (intmax_t)remote_size);
    goto cleanup;
  }

  ret = 0;

cleanup:
  if(localf != NULL) {
    fclose(localf);
    utimes_long(tempfile, remote_time);
  }

  if(ret == 0) {
    rename(tempfile, destfile);
  }

  FREE(tempfile);
  FREE(destfile);

  /* restore the old signal handlers */
  sigaction(SIGINT, &sig_int[OLD], NULL);
  sigaction(SIGPIPE, &sig_pipe[OLD], NULL);
  /* 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 handle the context handle
 * @param url the file's URL
 * @param localpath the directory to save the file in
 * @param force force download even if there is an up-to-date local copy
 * @param allow_resume allow a partial download to be resumed
 * @param errors_ok do not log errors (but still return them)
 * @return 0 on success, -1 on error (pm_errno is set accordingly if errors_ok == 0)
 */
int _alpm_download(alpm_handle_t *handle, const char *url, const char *localpath,
    int force, int allow_resume, int errors_ok)
{
  if(handle->fetchcb == NULL) {
#ifdef HAVE_LIBCURL
    return curl_download_internal(handle, url, localpath,
        force, allow_resume, errors_ok);
#else
    RET_ERR(handle, PM_ERR_EXTERNAL_DOWNLOAD, -1);
#endif
  } else {
    int ret = handle->fetchcb(url, localpath, force);
    if(ret == -1 && !errors_ok) {
      RET_ERR(handle, PM_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 *filename, *cachedir;
  int ret;

  CHECK_HANDLE(handle, return NULL);

  filename = get_filename(url);

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

  /* download the file */
  ret = _alpm_download(handle, url, cachedir, 0, 1, 0);
  if(ret == -1) {
    _alpm_log(handle, PM_LOG_WARNING, _("failed to download %s\n"), url);
    return NULL;
  }
  _alpm_log(handle, PM_LOG_DEBUG, "successfully downloaded %s\n", url);

  /* attempt to download the signature */
  if(ret == 0 && (handle->sigverify == PM_PGP_VERIFY_ALWAYS ||
        handle->sigverify == PM_PGP_VERIFY_OPTIONAL)) {
    char *sig_url;
    size_t len;
    int errors_ok = (handle->sigverify == PM_PGP_VERIFY_OPTIONAL);

    len = strlen(url) + 5;
    CALLOC(sig_url, len, sizeof(char), RET_ERR(handle, PM_ERR_MEMORY, NULL));
    snprintf(sig_url, len, "%s.sig", url);

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

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

/* vim: set ts=2 sw=2 noet: */