download.c

/*-
 * Copyright (c) 2009-2013 Juan Romero Pardines
 * Copyright (c) 2000-2004 Dag-Erling Coïdan Smørgrav
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in this position and unchanged.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * From FreeBSD fetch(8):
 * $FreeBSD: src/usr.bin/fetch/fetch.c,v 1.84.2.1 2009/08/03 08:13:06 kensmith Exp $
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
 
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
 
#include <openssl/sha.h>
 
#include "xbps_api_impl.h"
#include "fetch.h"
#include "compat.h"
 
/**
 * @file lib/download.c
 * @brief Download routines
 * @defgroup download Download functions
 *
 * XBPS download related functions, frontend for NetBSD's libfetch.
 */
static const char *
print_time(time_t *t)
{
        struct tm tm;
        static char buf[255];
 
        gmtime_r(t, &tm);
        strftime(buf, sizeof(buf), "%d %b %Y %H:%M", &tm);
        return buf;
}
 
void HIDDEN
xbps_fetch_set_cache_connection(int global, int per_host)
{
        if (global == 0)
                global = XBPS_FETCH_CACHECONN;
        if (per_host == 0)
                per_host = XBPS_FETCH_CACHECONN_HOST;
 
        fetchConnectionCacheInit(global, per_host);
}
 
void HIDDEN
xbps_fetch_unset_cache_connection(void)
{
        fetchConnectionCacheClose();
}
 
const char *
xbps_fetch_error_string(void)
{
        if (fetchLastErrCode == 0 || fetchLastErrCode == FETCH_OK)
                return NULL;
 
        return fetchLastErrString;
}
 
int
xbps_fetch_file_dest_sha256(struct xbps_handle *xhp, const char *uri, const char *filename, const char *flags, unsigned char *digest, size_t digestlen)
{
        struct stat st, st_tmpfile, *stp;
        struct url *url = NULL;
        struct url_stat url_st;
        struct fetchIO *fio = NULL;
        struct timespec ts[2];
        off_t bytes_dload = 0;
        ssize_t bytes_read = 0, bytes_written = 0;
        char buf[4096], *tempfile = NULL;
        char fetch_flags[8];
        int fd = -1, rv = 0;
        bool refetch = false, restart = false;
        SHA256_CTX sha256;
 
        assert(xhp);
        assert(uri);
 
        if (digest != NULL) {
                assert(digestlen >= XBPS_SHA256_DIGEST_SIZE);
                if (digestlen < XBPS_SHA256_DIGEST_SIZE) {
                        errno = ENOBUFS;
                        return -1;
                }
                SHA256_Init(&sha256);
        }
 
        /* Extern vars declared in libfetch */
        fetchLastErrCode = 0;
 
        if (!filename || (url = fetchParseURL(uri)) == NULL)
                return -1;
 
        memset(&fetch_flags, 0, sizeof(fetch_flags));
        if (flags != NULL)
                xbps_strlcpy(fetch_flags, flags, 7);
 
        tempfile = xbps_xasprintf("%s.part", filename);
        /*
         * Check if we have to resume a transfer.
         */
        memset(&st_tmpfile, 0, sizeof(st_tmpfile));
        if (stat(tempfile, &st_tmpfile) == 0) {
                if (st_tmpfile.st_size > 0)
                        restart = true;
        } else {
                if (errno != ENOENT) {
                        rv = -1;
                        goto fetch_file_out;
                }
        }
        /*
         * Check if we have to refetch a transfer.
         */
        memset(&st, 0, sizeof(st));
        if (stat(filename, &st) == 0) {
                refetch = true;
                url->last_modified = st.st_mtime;
                xbps_strlcat(fetch_flags, "i", sizeof(fetch_flags));
        } else {
                if (errno != ENOENT) {
                        rv = -1;
                        goto fetch_file_out;
                }
        }
        if (refetch && !restart) {
                /* fetch the whole file, filename available */
                stp = &st;
        } else {
                /* resume transfer, partial file found */
                stp = &st_tmpfile;
                url->offset = stp->st_size;
        }
        /*
         * Issue a GET request.
         */
        fio = fetchXGet(url, &url_st, fetch_flags);
 
        /* debug stuff */
        xbps_dbg_printf("st.st_size: %zd\n", (ssize_t)stp->st_size);
        xbps_dbg_printf("st.st_atime: %s\n", print_time(&stp->st_atime));
        xbps_dbg_printf("st.st_mtime: %s\n", print_time(&stp->st_mtime));
        xbps_dbg_printf("url_stat.size: %zd\n", (ssize_t)url_st.size);
        xbps_dbg_printf("url_stat.atime: %s\n", print_time(&url_st.atime));
        xbps_dbg_printf("url_stat.mtime: %s\n", print_time(&url_st.mtime));
 
        if (fio == NULL) {
                if (fetchLastErrCode == FETCH_UNCHANGED) {
                        /* Last-Modified matched */
                        goto fetch_file_out;
                } else if (fetchLastErrCode == FETCH_PROTO && url_st.size == stp->st_size) {
                        /* 413, requested offset == length */
                        goto rename_file;
                }
                rv = -1;
                goto fetch_file_out;
        }
        if (url_st.size == -1) {
                xbps_dbg_printf("Remote file size is unknown, resume "
                     "not possible...\n");
                restart = false;
        } else if (stp->st_size > url_st.size) {
                /*
                 * Remove local file if bigger than remote, and refetch the
                 * whole shit again.
                 */
                xbps_dbg_printf("Local file %s is greater than remote, "
                    "removing local file and refetching...\n", filename);
                (void)remove(tempfile);
                restart = false;
        }
        xbps_dbg_printf("url->scheme: %s\n", url->scheme);
        xbps_dbg_printf("url->host: %s\n", url->host);
        xbps_dbg_printf("url->port: %d\n", url->port);
        xbps_dbg_printf("url->doc: %s\n", url->doc);
        xbps_dbg_printf("url->offset: %zd\n", (ssize_t)url->offset);
        xbps_dbg_printf("url->length: %zu\n", url->length);
        xbps_dbg_printf("url->last_modified: %s\n",
            print_time(&url->last_modified));
        /*
         * If restarting, open the file for appending otherwise create it.
         */
        if (restart)
                fd = open(tempfile, O_RDWR|O_CLOEXEC);
        else
                fd = open(tempfile, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC, 0644);
 
        if (fd == -1) {
                rv = -1;
                goto fetch_file_out;
        }
 
        /*
         * If restarting and digest was requested, read the current data
         * and feed into sha256 hash.
         */
        if (restart) {
                if (digest) {
                        while ((bytes_read = read(fd, buf, sizeof(buf))) > 0) {
                                SHA256_Update(&sha256, buf, bytes_read);
                        }
                        if (bytes_read == -1) {
                                xbps_dbg_printf("IO error while reading %s: %s\n",
                                        tempfile, strerror(errno));
                                errno = EIO;
                                rv = -1;
                                goto fetch_file_out;
                        }
                }
                lseek(fd, 0, SEEK_END);
        }
 
        /*
         * Initialize data for the fetch progress function callback
         * and let the user know that the transfer is going to start
         * immediately.
         */
        xbps_set_cb_fetch(xhp, url_st.size, url->offset, url->offset,
            filename, true, false, false);
        /*
         * Start fetching requested file.
         */
        while ((bytes_read = fetchIO_read(fio, buf, sizeof(buf))) > 0) {
                if (digest)
                        SHA256_Update(&sha256, buf, bytes_read);
                bytes_written = write(fd, buf, (size_t)bytes_read);
                if (bytes_written != bytes_read) {
                        xbps_dbg_printf("Couldn't write to %s!\n", tempfile);
                        rv = -1;
                        goto fetch_file_out;
                }
                bytes_dload += bytes_read;
                /*
                 * Let the fetch progress callback know that
                 * we are sucking more bytes from it.
                 */
                xbps_set_cb_fetch(xhp, url_st.size, url->offset,
                    url->offset + bytes_dload,
                    filename, false, true, false);
        }
        if (bytes_read == -1) {
                xbps_dbg_printf("IO error while fetching %s: %s\n",
                    filename, fetchLastErrString);
                errno = EIO;
                rv = -1;
                goto fetch_file_out;
        } else if (url_st.size > 0 && ((bytes_dload + url->offset) != url_st.size)) {
                xbps_dbg_printf("file %s is truncated\n", filename);
                errno = EIO;
                rv = -1;
                goto fetch_file_out;
        }
 
        /*
         * Let the fetch progress callback know that the file
         * has been fetched.
         */
        xbps_set_cb_fetch(xhp, url_st.size, url->offset, bytes_dload,
            filename, false, false, true);
 
        /*
         * Update mtime in local file to match remote file if transfer
         * was successful.
         */
        ts[0].tv_sec = url_st.atime ? url_st.atime : url_st.mtime;
        ts[1].tv_sec = url_st.mtime;
        ts[0].tv_nsec = ts[1].tv_nsec = 0;
        if (futimens(fd, ts) == -1) {
                rv = -1;
                goto fetch_file_out;
        }
        (void)close(fd);
        fd = -1;
 
rename_file:
        /* File downloaded successfully, rename to destfile */
        if (rename(tempfile, filename) == -1) {
                xbps_dbg_printf("failed to rename %s to %s: %s",
                    tempfile, filename, strerror(errno));
                rv = -1;
                goto fetch_file_out;
        }
        rv = 1;
 
        if (digest)
                SHA256_Final(digest, &sha256);
 
fetch_file_out:
        if (fio != NULL)
                fetchIO_close(fio);
        if (fd != -1)
                (void)close(fd);
        if (url != NULL)
                fetchFreeURL(url);
 
        free(tempfile);
 
        return rv;
}
 
int
xbps_fetch_file_dest(struct xbps_handle *xhp, const char *uri,
                const char *filename, const char *flags)
{
        return xbps_fetch_file_dest_sha256(xhp, uri, filename, flags, NULL, 0);
}
 
int
xbps_fetch_file_sha256(struct xbps_handle *xhp, const char *uri,
                const char *flags, unsigned char *digest, size_t digestlen)
{
        const char *filename;
        /*
         * Get the filename specified in URI argument.
         */
        if ((filename = strrchr(uri, '/')) == NULL)
                return -1;
 
        filename++;
        return xbps_fetch_file_dest_sha256(xhp, uri, filename, flags,
            digest, digestlen);
}
 
int
xbps_fetch_file(struct xbps_handle *xhp, const char *uri, const char *flags)
{
        return xbps_fetch_file_sha256(xhp, uri, flags, NULL, 0);
}