isc/unix/file.c

	file.c revision 9c3531d72aeaad6c5f01efe6a1c82023e1379e4d
/*
 * Copyright (C) 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: file.c,v 1.17 2000/06/22 21:58:35 tale Exp $ */

#include <config.h>

#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>            /* Required for mkstemp on NetBSD. */

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

#include <isc/file.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;

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

    return (result);
}

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

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

    result = file_stats(file, &stats);

    if (result == ISC_R_SUCCESS)
        /*
         * XXXDCL some operating systems provide nanoseconds, too,
         * such as BSD/OS via st_mtimespec.
         */
        isc_time_set(time, stats.st_mtime, 0);

    return (result);
}

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

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

    /*
     * Solaris 5.6 gives this warning about the left shift:
     *  warning: integer overflow detected: op "<<"
     * if the U(nsigned) qualifier is not on the 1.
     */
    if ((times[0].tv_sec &
         (1U << (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(time) / 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) {
    char *s;

    REQUIRE(buf != NULL);

    s = strrchr(path, '/');

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

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

        strcpy(buf, TEMPLATE);
    }

    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_openunique(char *templet, FILE **fp) {
    int fd;
    FILE *f;
    isc_result_t result = ISC_R_SUCCESS;

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

    /*
     * Win32 does not have mkstemp.
     */
    fd = mkstemp(templet);

    if (fd == -1)
        result = isc__errno2result(errno);
    if (result == ISC_R_SUCCESS) {
        f = fdopen(fd, "w+");
        if (f == NULL) {
            result = isc__errno2result(errno);
            (void)remove(templet);
            (void)close(fd);

        } else
            *fp = f;
    }

    return (result);
}

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

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