path: root/lib/libalpm/dload.c

/*
 *  download.c
 *
 *  Copyright (c) 2002-2008 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>
#if defined(INTERNAL_DOWNLOAD)
#include <download.h> /* libdownload */
#endif

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

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

static char *get_destfile(const char *path, const char *filename) {
  char *destfile;
  /* len = localpath len + filename len + null */
  int len = strlen(path) + strlen(filename) + 1;
  CALLOC(destfile, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, NULL));
  snprintf(destfile, len, "%s%s", path, filename);

  return(destfile);
}

static char *get_tempfile(const char *path, const char *filename) {
  char *tempfile;
  /* len = localpath len + filename len + '.part' len + null */
  int len = strlen(path) + strlen(filename) + 6;
  CALLOC(tempfile, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, NULL));
  snprintf(tempfile, len, "%s%s.part", path, filename);

  return(tempfile);
}

#if defined(INTERNAL_DOWNLOAD)
/* Build a 'struct url' from an url. */
static struct url *url_for_string(const char *url)
{
  struct url *ret = NULL;
  ret = downloadParseURL(url);
  if(!ret) {
    _alpm_log(PM_LOG_ERROR, _("url '%s' is invalid\n"), url);
    RET_ERR(PM_ERR_SERVER_BAD_URL, NULL);
  }

  /* if no URL scheme specified, assume HTTP */
  if(strlen(ret->scheme) == 0) {
    _alpm_log(PM_LOG_WARNING, _("url scheme not specified, assuming HTTP\n"));
    strcpy(ret->scheme, SCHEME_HTTP);
  }
  /* add a user & password for anonymous FTP */
  if(strcmp(ret->scheme,SCHEME_FTP) == 0 && strlen(ret->user) == 0) {
    strcpy(ret->user, "anonymous");
    strcpy(ret->pwd, "libalpm@guest");
  }

  return(ret);
}

static int download_internal(const char *url, const char *localpath,
    time_t mtimeold, time_t *mtimenew) {
  FILE *dlf, *localf = NULL;
  struct url_stat ust;
  struct stat st;
  int chk_resume = 0;
  int dl_thisfile = 0;
  char *tempfile, *destfile, *filename;
  int ret = 0;
  struct url *fileurl = url_for_string(url);

  if(!fileurl) {
    return(-1);
  }

  filename = get_filename(url);
  if(!filename) {
    return(-1);
  }
  destfile = get_destfile(localpath, filename);
  tempfile = get_tempfile(localpath, filename);

  /* pass the raw filename for passing to the callback function */
  _alpm_log(PM_LOG_DEBUG, "using '%s' for download progress\n", filename);

  if(stat(tempfile, &st) == 0 && st.st_size > 0) {
    _alpm_log(PM_LOG_DEBUG, "existing file found, using it\n");
    fileurl->offset = (off_t)st.st_size;
    dl_thisfile = st.st_size;
    localf = fopen(tempfile, "ab");
    chk_resume = 1;
  } else {
    fileurl->offset = (off_t)0;
    dl_thisfile = 0;
  }

  /* libdownload does not reset the error code, reset it in
   * the case of previous errors */
  downloadLastErrCode = 0;

  /* 10s timeout - TODO make a config option */
  downloadTimeout = 10000;

  dlf = downloadXGet(fileurl, &ust, (handle->nopassiveftp ? "" : "p"));

  if(downloadLastErrCode != 0 || dlf == NULL) {
    const char *host = _("disk");
    if(strcmp(SCHEME_FILE, fileurl->scheme) != 0) {
      host = fileurl->host;
    }
    pm_errno = PM_ERR_LIBDOWNLOAD;
    _alpm_log(PM_LOG_ERROR, _("failed retrieving file '%s' from %s : %s\n"),
        filename, host, downloadLastErrString);
    ret = -1;
    goto cleanup;
  } else {
    _alpm_log(PM_LOG_DEBUG, "connected to %s successfully\n", fileurl->host);
  }

  if(ust.mtime && mtimeold && ust.mtime == mtimeold) {
    _alpm_log(PM_LOG_DEBUG, "mtimes are identical, skipping %s\n", filename);
    ret = 1;
    goto cleanup;
  }

  if(ust.mtime && mtimenew) {
    *mtimenew = ust.mtime;
  }

  if(chk_resume && fileurl->offset == 0) {
    _alpm_log(PM_LOG_WARNING, _("cannot resume download, starting over\n"));
    if(localf != NULL) {
      fclose(localf);
      localf = NULL;
    }
  }

  if(localf == NULL) {
    _alpm_rmrf(tempfile);
    fileurl->offset = (off_t)0;
    dl_thisfile = 0;
    localf = fopen(tempfile, "wb");
    if(localf == NULL) { /* still null? */
      _alpm_log(PM_LOG_ERROR, _("cannot write to file '%s'\n"), tempfile);
      ret = -1;
      goto cleanup;
    }
  }

  /* Progress 0 - initialize */
  if(handle->dlcb) {
    handle->dlcb(filename, 0, ust.size);
  }

  int nread = 0;
  char buffer[PM_DLBUF_LEN];
  while((nread = fread(buffer, 1, PM_DLBUF_LEN, dlf)) > 0) {
    if(ferror(dlf)) {
      pm_errno = PM_ERR_LIBDOWNLOAD;
      _alpm_log(PM_LOG_ERROR, _("error downloading '%s': %s\n"),
          filename, downloadLastErrString);
      ret = -1;
      goto cleanup;
    }

    int nwritten = 0;
    while(nwritten < nread) {
      nwritten += fwrite(buffer, 1, (nread - nwritten), localf);
      if(ferror(localf)) {
        _alpm_log(PM_LOG_ERROR, _("error writing to file '%s': %s\n"),
            destfile, strerror(errno));
        ret = -1;
        goto cleanup;
      }
    }
    dl_thisfile += nread;

    if(handle->dlcb) {
      handle->dlcb(filename, dl_thisfile, ust.size);
    }
  }
  /* probably safer to close the file descriptors now before renaming the file,
   * for example to make sure the buffers are flushed.
   */
  fclose(localf);
  localf = NULL;
  fclose(dlf);
  dlf = NULL;

  rename(tempfile, destfile);
  ret = 0;

cleanup:
  FREE(tempfile);
  FREE(destfile);
  if(localf != NULL) {
    fclose(localf);
  }
  if(dlf != NULL) {
    fclose(dlf);
  }
  downloadFreeURL(fileurl);
  return(ret);
}
#endif

static int download_external(const char *url, const char *localpath,
    time_t mtimeold, time_t *mtimenew) {
  int ret = 0;
  int retval;
  int usepart = 0;
  char *ptr1, *ptr2;
  char origCmd[PATH_MAX];
  char parsedCmd[PATH_MAX] = "";
  char cwd[PATH_MAX];
  char *destfile, *tempfile, *filename;

  if(!handle->xfercommand) {
    RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
  }

  filename = get_filename(url);
  if(!filename) {
    RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
  }
  destfile = get_destfile(localpath, filename);
  tempfile = get_tempfile(localpath, filename);

  /* replace all occurrences of %o with fn.part */
  strncpy(origCmd, handle->xfercommand, sizeof(origCmd));
  ptr1 = origCmd;
  while((ptr2 = strstr(ptr1, "%o"))) {
    usepart = 1;
    ptr2[0] = '\0';
    strcat(parsedCmd, ptr1);
    strcat(parsedCmd, tempfile);
    ptr1 = ptr2 + 2;
  }
  strcat(parsedCmd, ptr1);
  /* replace all occurrences of %u with the download URL */
  strncpy(origCmd, parsedCmd, sizeof(origCmd));
  parsedCmd[0] = '\0';
  ptr1 = origCmd;
  while((ptr2 = strstr(ptr1, "%u"))) {
    ptr2[0] = '\0';
    strcat(parsedCmd, ptr1);
    strcat(parsedCmd, url);
    ptr1 = ptr2 + 2;
  }
  strcat(parsedCmd, ptr1);
  /* cwd to the download directory */
  getcwd(cwd, PATH_MAX);
  if(chdir(localpath)) {
    _alpm_log(PM_LOG_WARNING, _("could not chdir to %s\n"), localpath);
    pm_errno = PM_ERR_EXTERNAL_DOWNLOAD;
    ret = -1;
    goto cleanup;
  }
  /* execute the parsed command via /bin/sh -c */
  _alpm_log(PM_LOG_DEBUG, "running command: %s\n", parsedCmd);
  retval = system(parsedCmd);

  if(retval == -1) {
    _alpm_log(PM_LOG_WARNING, _("running XferCommand: fork failed!\n"));
    pm_errno = PM_ERR_EXTERNAL_DOWNLOAD;
    ret = -1;
  } else if(retval != 0) {
    /* download failed */
    _alpm_log(PM_LOG_DEBUG, "XferCommand command returned non-zero status "
        "code (%d)\n", retval);
    ret = -1;
  } else {
    /* download was successful */
    if(usepart) {
      rename(tempfile, destfile);
    }
    ret = 0;
  }

cleanup:
  chdir(cwd);
  if(ret == -1) {
    /* hack to let an user the time to cancel a download */
    sleep(2);
  }
  FREE(destfile);
  FREE(tempfile);

  return(ret);
}

static int download(const char *url, const char *localpath,
    time_t mtimeold, time_t *mtimenew) {
  int ret;
  const char *proto = "file://";
  int len = strlen(proto);
  if(strncmp(url, proto, len) == 0) {
    /* we can simply grab an absolute path from the file:// url by starting
     * our path at the char following the proto (the root '/')
     */
    const char *sourcefile = url + len;
    const char *filename = get_filename(url);
    char *destfile = get_destfile(localpath, filename);

    ret = _alpm_copyfile(sourcefile, destfile);
    FREE(destfile);
    /* copyfile returns 1 on failure, we want to return -1 on failure */
    return(ret ? -1 : 0);
  }

  /* We have a few things to take into account here.
   * 1. If we have both internal/external available, choose based on
   * whether xfercommand is populated.
   * 2. If we only have external available, we should first check
   * if a command was provided before we drop into download_external.
   */
  if(handle->xfercommand == NULL) {
#if defined(INTERNAL_DOWNLOAD)
    ret = download_internal(url, localpath, mtimeold, mtimenew);
#else
    RET_ERR(PM_ERR_EXTERNAL_DOWNLOAD, -1);
#endif
  } else {
    ret = download_external(url, localpath, mtimeold, mtimenew);
  }
  return(ret);
}

/*
 * Download a single file
 *   - if mtimeold is non-NULL, then only download the file if it's different
 *     than mtimeold.
 *   - if *mtimenew is non-NULL, it will be filled with the mtime of the remote
 *     file.
 *
 * RETURN:  0 for successful download
 *          1 if the mtimes are identical
 *         -1 on error
 */
int _alpm_download_single_file(const char *filename,
    alpm_list_t *servers, const char *localpath,
    time_t mtimeold, time_t *mtimenew)
{
  alpm_list_t *i;
  int ret = -1;

  for(i = servers; i; i = i->next) {
    const char *server = i->data;
    char *fileurl = NULL;
    int len;

    /* print server + filename into a buffer */
    len = strlen(server) + strlen(filename) + 2;
    CALLOC(fileurl, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, -1));
    snprintf(fileurl, len, "%s/%s", server, filename);

    ret = download(fileurl, localpath, mtimeold, mtimenew);
    FREE(fileurl);
    if(ret != -1) {
      break;
    }
  }

  return(ret);
}

int _alpm_download_files(alpm_list_t *files,
    alpm_list_t *servers, const char *localpath)
{
  int ret = 0;
  alpm_list_t *lp;

  for(lp = files; lp; lp = lp->next) {
    char *filename = lp->data;
    if(_alpm_download_single_file(filename, servers,
          localpath, 0, NULL) == -1) {
      ret++;
    }
  }

  return(ret);
}

/** Fetch a remote pkg.
 * @param url URL of the package to download
 * @return the downloaded filepath on success, NULL on error
 * @addtogroup alpm_misc
 */
char SYMEXPORT *alpm_fetch_pkgurl(const char *url)
{
  char *filename, *filepath;
  const char *cachedir;
  int ret;

  ALPM_LOG_FUNC;

  filename = get_filename(url);

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

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

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

/* vim: set ts=2 sw=2 noet: */