isc/unix/file.c

	file.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2000-2002, 2004, 2005, 2007, 2009, 2011-2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/*
 * Portions Copyright (c) 1987, 1993
 *      The Regents of the University of California.  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.
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <time.h>       /* Required for utimes on some platforms. */
#include <unistd.h>     /* Required for mkstemp on NetBSD. */


#include <sys/stat.h>
#include <sys/time.h>

#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif

#include <isc/dir.h>
#include <isc/file.h>
#include <isc/log.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/random.h>
#include <isc/sha2.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/util.h>

#include "errno2result.h"

/*
 * XXXDCL As the API for accessing file statistics undoubtedly gets expanded,
 * it might be good to provide a mechanism that allows for the results
 * of a previous stat() to be used again without having to do another stat,
 * such as perl's mechanism of using "_" in place of a file name to indicate
 * that the results of the last stat should be used.  But then you get into
 * annoying MP issues.   BTW, Win32 has stat().
 */
static isc_result_t
file_stats(const char *file, struct stat *stats) {
    isc_result_t result = ISC_R_SUCCESS;

    REQUIRE(file != NULL);
    REQUIRE(stats != NULL);

    if (stat(file, stats) != 0)
        result = isc__errno2result(errno);

    return (result);
}

static isc_result_t
fd_stats(int fd, struct stat *stats) {
    isc_result_t result = ISC_R_SUCCESS;

    REQUIRE(stats != NULL);

    if (fstat(fd, stats) != 0)
        result = isc__errno2result(errno);

    return (result);
}

isc_result_t
isc_file_getsizefd(int fd, off_t *size) {
    isc_result_t result;
    struct stat stats;

    REQUIRE(size != NULL);

    result = fd_stats(fd, &stats);

    if (result == ISC_R_SUCCESS)
        *size = stats.st_size;

    return (result);
}

isc_result_t
isc_file_mode(const char *file, mode_t *modep) {
    isc_result_t result;
    struct stat stats;

    REQUIRE(modep != NULL);

    result = file_stats(file, &stats);
    if (result == ISC_R_SUCCESS)
        *modep = (stats.st_mode & 07777);

    return (result);
}

isc_result_t
isc_file_getmodtime(const char *file, isc_time_t *modtime) {
    isc_result_t result;
    struct stat stats;

    REQUIRE(file != NULL);
    REQUIRE(modtime != NULL);

    result = file_stats(file, &stats);

    if (result == ISC_R_SUCCESS)
#ifdef ISC_PLATFORM_HAVESTATNSEC
        isc_time_set(modtime, stats.st_mtime, stats.st_mtim.tv_nsec);
#else
        isc_time_set(modtime, stats.st_mtime, 0);
#endif

    return (result);
}

isc_result_t
isc_file_getsize(const char *file, off_t *size) {
    isc_result_t result;
    struct stat stats;

    REQUIRE(file != NULL);
    REQUIRE(size != NULL);

    result = file_stats(file, &stats);

    if (result == ISC_R_SUCCESS)
        *size = stats.st_size;

    return (result);
}

isc_result_t
isc_file_settime(const char *file, isc_time_t *when) {
    struct timeval times[2];

    REQUIRE(file != NULL && when != NULL);

    /*
     * tv_sec is at least a 32 bit quantity on all platforms we're
     * dealing with, but it is signed on most (all?) of them,
     * so we need to make sure the high bit isn't set.  This unfortunately
     * loses when either:
     *   * tv_sec becomes a signed 64 bit integer but long is 32 bits
     *  and isc_time_seconds > LONG_MAX, or
     *   * isc_time_seconds is changed to be > 32 bits but long is 32 bits
     *      and isc_time_seconds has at least 33 significant bits.
     */
    times[0].tv_sec = times[1].tv_sec = (long)isc_time_seconds(when);

    /*
     * Here is the real check for the high bit being set.
     */
    if ((times[0].tv_sec &
         (1ULL << (sizeof(times[0].tv_sec) * CHAR_BIT - 1))) != 0)
        return (ISC_R_RANGE);

    /*
     * isc_time_nanoseconds guarantees a value that divided by 1000 will
     * fit into the minimum possible size tv_usec field.  Unfortunately,
     * we don't know what that type is so can't cast directly ... but
     * we can at least cast to signed so the IRIX compiler shuts up.
     */
    times[0].tv_usec = times[1].tv_usec =
        (isc_int32_t)(isc_time_nanoseconds(when) / 1000);

    if (utimes(file, times) < 0)
        return (isc__errno2result(errno));

    return (ISC_R_SUCCESS);
}

#undef TEMPLATE
#define TEMPLATE "tmp-XXXXXXXXXX" /*%< 14 characters. */

isc_result_t
isc_file_mktemplate(const char *path, char *buf, size_t buflen) {
    return (isc_file_template(path, TEMPLATE, buf, buflen));
}

isc_result_t
isc_file_template(const char *path, const char *templet, char *buf,
          size_t buflen)
{
    const char *s;

    REQUIRE(path != NULL);
    REQUIRE(templet != NULL);
    REQUIRE(buf != NULL);

    s = strrchr(templet, '/');
    if (s != NULL)
        templet = s + 1;

    s = strrchr(path, '/');

    if (s != NULL) {
        if ((s - path + 1 + strlen(templet) + 1) > buflen)
            return (ISC_R_NOSPACE);

        strncpy(buf, path, s - path + 1);
        buf[s - path + 1] = '\0';
        strcat(buf, templet);
    } else {
        if ((strlen(templet) + 1) > buflen)
            return (ISC_R_NOSPACE);

        strcpy(buf, templet);
    }

    return (ISC_R_SUCCESS);
}

static const char alphnum[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

isc_result_t
isc_file_renameunique(const char *file, char *templet) {
    char *x;
    char *cp;

    REQUIRE(file != NULL);
    REQUIRE(templet != NULL);

    cp = templet;
    while (*cp != '\0')
        cp++;
    if (cp == templet)
        return (ISC_R_FAILURE);

    x = cp--;
    while (cp >= templet && *cp == 'X') {
        isc_uint32_t which;

        isc_random_get(&which);
        *cp = alphnum[which % (sizeof(alphnum) - 1)];
        x = cp--;
    }
    while (link(file, templet) == -1) {
        if (errno != EEXIST)
            return (isc__errno2result(errno));
        for (cp = x;;) {
            const char *t;
            if (*cp == '\0')
                return (ISC_R_FAILURE);
            t = strchr(alphnum, *cp);
            if (t == NULL || *++t == '\0')
                *cp++ = alphnum[0];
            else {
                *cp = *t;
                break;
            }
        }
    }
    if (unlink(file) < 0)
        if (errno != ENOENT)
            return (isc__errno2result(errno));
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_openunique(char *templet, FILE **fp) {
    int mode = S_IWUSR|S_IRUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
    return (isc_file_openuniquemode(templet, mode, fp));
}

isc_result_t
isc_file_openuniqueprivate(char *templet, FILE **fp) {
    int mode = S_IWUSR|S_IRUSR;
    return (isc_file_openuniquemode(templet, mode, fp));
}

isc_result_t
isc_file_openuniquemode(char *templet, int mode, FILE **fp) {
    int fd;
    FILE *f;
    isc_result_t result = ISC_R_SUCCESS;
    char *x;
    char *cp;

    REQUIRE(templet != NULL);
    REQUIRE(fp != NULL && *fp == NULL);

    cp = templet;
    while (*cp != '\0')
        cp++;
    if (cp == templet)
        return (ISC_R_FAILURE);

    x = cp--;
    while (cp >= templet && *cp == 'X') {
        isc_uint32_t which;

        isc_random_get(&which);
        *cp = alphnum[which % (sizeof(alphnum) - 1)];
        x = cp--;
    }


    while ((fd = open(templet, O_RDWR|O_CREAT|O_EXCL, mode)) == -1) {
        if (errno != EEXIST)
            return (isc__errno2result(errno));
        for (cp = x;;) {
            char *t;
            if (*cp == '\0')
                return (ISC_R_FAILURE);
            t = strchr(alphnum, *cp);
            if (t == NULL || *++t == '\0')
                *cp++ = alphnum[0];
            else {
                *cp = *t;
                break;
            }
        }
    }
    f = fdopen(fd, "w+");
    if (f == NULL) {
        result = isc__errno2result(errno);
        if (remove(templet) < 0) {
            isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
                      ISC_LOGMODULE_FILE, ISC_LOG_ERROR,
                      "remove '%s': failed", templet);
        }
        (void)close(fd);
    } else
        *fp = f;

    return (result);
}

isc_result_t
isc_file_bopenunique(char *templet, FILE **fp) {
    int mode = S_IWUSR|S_IRUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
    return (isc_file_openuniquemode(templet, mode, fp));
}

isc_result_t
isc_file_bopenuniqueprivate(char *templet, FILE **fp) {
    int mode = S_IWUSR|S_IRUSR;
    return (isc_file_openuniquemode(templet, mode, fp));
}

isc_result_t
isc_file_bopenuniquemode(char *templet, int mode, FILE **fp) {
    return (isc_file_openuniquemode(templet, mode, fp));
}

isc_result_t
isc_file_remove(const char *filename) {
    int r;

    REQUIRE(filename != NULL);

    r = unlink(filename);
    if (r == 0)
        return (ISC_R_SUCCESS);
    else
        return (isc__errno2result(errno));
}

isc_result_t
isc_file_rename(const char *oldname, const char *newname) {
    int r;

    REQUIRE(oldname != NULL);
    REQUIRE(newname != NULL);

    r = rename(oldname, newname);
    if (r == 0)
        return (ISC_R_SUCCESS);
    else
        return (isc__errno2result(errno));
}

isc_boolean_t
isc_file_exists(const char *pathname) {
    struct stat stats;

    REQUIRE(pathname != NULL);

    return (ISC_TF(file_stats(pathname, &stats) == ISC_R_SUCCESS));
}

isc_result_t
isc_file_isplainfile(const char *filename) {
    /*
     * This function returns success if filename is a plain file.
     */
    struct stat filestat;
    memset(&filestat,0,sizeof(struct stat));

    if ((stat(filename, &filestat)) == -1)
        return(isc__errno2result(errno));

    if(! S_ISREG(filestat.st_mode))
        return(ISC_R_INVALIDFILE);

    return(ISC_R_SUCCESS);
}

isc_result_t
isc_file_isplainfilefd(int fd) {
    /*
     * This function returns success if filename is a plain file.
     */
    struct stat filestat;
    memset(&filestat,0,sizeof(struct stat));

    if ((fstat(fd, &filestat)) == -1)
        return(isc__errno2result(errno));

    if(! S_ISREG(filestat.st_mode))
        return(ISC_R_INVALIDFILE);

    return(ISC_R_SUCCESS);
}

isc_result_t
isc_file_isdirectory(const char *filename) {
    /*
     * This function returns success if filename exists and is a
     * directory.
     */
    struct stat filestat;
    memset(&filestat,0,sizeof(struct stat));

    if ((stat(filename, &filestat)) == -1)
        return(isc__errno2result(errno));

    if(! S_ISDIR(filestat.st_mode))
        return(ISC_R_INVALIDFILE);

    return(ISC_R_SUCCESS);
}


isc_boolean_t
isc_file_isabsolute(const char *filename) {
    REQUIRE(filename != NULL);
    return (ISC_TF(filename[0] == '/'));
}

isc_boolean_t
isc_file_iscurrentdir(const char *filename) {
    REQUIRE(filename != NULL);
    return (ISC_TF(filename[0] == '.' && filename[1] == '\0'));
}

isc_boolean_t
isc_file_ischdiridempotent(const char *filename) {
    REQUIRE(filename != NULL);
    if (isc_file_isabsolute(filename))
        return (ISC_TRUE);
    if (isc_file_iscurrentdir(filename))
        return (ISC_TRUE);
    return (ISC_FALSE);
}

const char *
isc_file_basename(const char *filename) {
    const char *s;

    REQUIRE(filename != NULL);

    s = strrchr(filename, '/');
    if (s == NULL)
        return (filename);

    return (s + 1);
}

isc_result_t
isc_file_progname(const char *filename, char *buf, size_t buflen) {
    const char *base;
    size_t len;

    REQUIRE(filename != NULL);
    REQUIRE(buf != NULL);

    base = isc_file_basename(filename);
    len = strlen(base) + 1;

    if (len > buflen)
        return (ISC_R_NOSPACE);
    memmove(buf, base, len);

    return (ISC_R_SUCCESS);
}

/*
 * Put the absolute name of the current directory into 'dirname', which is
 * a buffer of at least 'length' characters.  End the string with the
 * appropriate path separator, such that the final product could be
 * concatenated with a relative pathname to make a valid pathname string.
 */
static isc_result_t
dir_current(char *dirname, size_t length) {
    char *cwd;
    isc_result_t result = ISC_R_SUCCESS;

    REQUIRE(dirname != NULL);
    REQUIRE(length > 0U);

    cwd = getcwd(dirname, length);

    if (cwd == NULL) {
        if (errno == ERANGE)
            result = ISC_R_NOSPACE;
        else
            result = isc__errno2result(errno);
    } else {
        if (strlen(dirname) + 1 == length)
            result = ISC_R_NOSPACE;
        else if (dirname[1] != '\0')
            strcat(dirname, "/");
    }

    return (result);
}

isc_result_t
isc_file_absolutepath(const char *filename, char *path, size_t pathlen) {
    isc_result_t result;
    result = dir_current(path, pathlen);
    if (result != ISC_R_SUCCESS)
        return (result);
    if (strlen(path) + strlen(filename) + 1 > pathlen)
        return (ISC_R_NOSPACE);
    strcat(path, filename);
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_truncate(const char *filename, isc_offset_t size) {
    isc_result_t result = ISC_R_SUCCESS;

    if (truncate(filename, size) < 0)
        result = isc__errno2result(errno);
    return (result);
}

isc_result_t
isc_file_safecreate(const char *filename, FILE **fp) {
    isc_result_t result;
    int flags;
    struct stat sb;
    FILE *f;
    int fd;

    REQUIRE(filename != NULL);
    REQUIRE(fp != NULL && *fp == NULL);

    result = file_stats(filename, &sb);
    if (result == ISC_R_SUCCESS) {
        if ((sb.st_mode & S_IFREG) == 0)
            return (ISC_R_INVALIDFILE);
        flags = O_WRONLY | O_TRUNC;
    } else if (result == ISC_R_FILENOTFOUND) {
        flags = O_WRONLY | O_CREAT | O_EXCL;
    } else
        return (result);

    fd = open(filename, flags, S_IRUSR | S_IWUSR);
    if (fd == -1)
        return (isc__errno2result(errno));

    f = fdopen(fd, "w");
    if (f == NULL) {
        result = isc__errno2result(errno);
        close(fd);
        return (result);
    }

    *fp = f;
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_splitpath(isc_mem_t *mctx, const char *path, char **dirname,
           char const **basename)
{
    char *dir;
    const char *file, *slash;

    if (path == NULL)
        return (ISC_R_INVALIDFILE);

    slash = strrchr(path, '/');

    if (slash == path) {
        file = ++slash;
        dir = isc_mem_strdup(mctx, "/");
    } else if (slash != NULL) {
        file = ++slash;
        dir = isc_mem_allocate(mctx, slash - path);
        if (dir != NULL)
            strlcpy(dir, path, slash - path);
    } else {
        file = path;
        dir = isc_mem_strdup(mctx, ".");
    }

    if (dir == NULL)
        return (ISC_R_NOMEMORY);

    if (*file == '\0') {
        isc_mem_free(mctx, dir);
        return (ISC_R_INVALIDFILE);
    }

    *dirname = dir;
    *basename = file;

    return (ISC_R_SUCCESS);
}

void *
isc_file_mmap(void *addr, size_t len, int prot,
          int flags, int fd, off_t offset)
{
#ifdef HAVE_MMAP
    return (mmap(addr, len, prot, flags, fd, offset));
#else
    void *buf;
    ssize_t ret;
    off_t end;

    UNUSED(addr);
    UNUSED(prot);
    UNUSED(flags);

    end = lseek(fd, 0, SEEK_END);
    lseek(fd, offset, SEEK_SET);
    if (end - offset < (off_t) len)
        len = end - offset;

    buf = malloc(len);
    if (buf == NULL)
        return (NULL);

    ret = read(fd, buf, len);
    if (ret != (ssize_t) len) {
        free(buf);
        buf = NULL;
    }

    return (buf);
#endif
}

int
isc_file_munmap(void *addr, size_t len) {
#ifdef HAVE_MMAP
    return (munmap(addr, len));
#else
    UNUSED(len);

    free(addr);
    return (0);
#endif
}

#define DISALLOW "\\/ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#ifndef PATH_MAX
#define PATH_MAX 1024
#endif

isc_result_t
isc_file_sanitize(const char *dir, const char *base, const char *ext,
          char *path, size_t length)
{
    char buf[PATH_MAX], hash[PATH_MAX];
    size_t l = 0;

    REQUIRE(base != NULL);
    REQUIRE(path != NULL);

    l = strlen(base) + 1;

    /*
     * allow room for a full sha256 hash (64 chars
     * plus null terminator)
     */
    if (l < 65U)
        l = 65;

    if (dir != NULL)
        l += strlen(dir) + 1;
    if (ext != NULL)
        l += strlen(ext) + 1;

    if (l > length || l > (unsigned)PATH_MAX)
        return (ISC_R_NOSPACE);

    /* Check whether the full-length SHA256 hash filename exists */
    isc_sha256_data((const void *) base, strlen(base), hash);
    snprintf(buf, sizeof(buf), "%s%s%s%s%s",
        dir != NULL ? dir : "", dir != NULL ? "/" : "",
        hash, ext != NULL ? "." : "", ext != NULL ? ext : "");
    if (isc_file_exists(buf)) {
        strlcpy(path, buf, length);
        return (ISC_R_SUCCESS);
    }

    /* Check for a truncated SHA256 hash filename */
    hash[16] = '\0';
    snprintf(buf, sizeof(buf), "%s%s%s%s%s",
        dir != NULL ? dir : "", dir != NULL ? "/" : "",
        hash, ext != NULL ? "." : "", ext != NULL ? ext : "");
    if (isc_file_exists(buf)) {
        strlcpy(path, buf, length);
        return (ISC_R_SUCCESS);
    }

    /*
     * If neither hash filename already exists, then we'll use
     * the original base name if it has no disallowed characters,
     * or the truncated hash name if it does.
     */
    if (strpbrk(base, DISALLOW) != NULL) {
        strlcpy(path, buf, length);
        return (ISC_R_SUCCESS);
    }

    snprintf(buf, sizeof(buf), "%s%s%s%s%s",
        dir != NULL ? dir : "", dir != NULL ? "/" : "",
        base, ext != NULL ? "." : "", ext != NULL ? ext : "");
    strlcpy(path, buf, length);
    return (ISC_R_SUCCESS);
}