isc/win32/file.c

	file.c revision ec5347e2c775f027573ce5648b910361aa926c01
/*
 * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000-2002  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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 1.30 2007/06/18 23:47:49 tbox Exp $ */

#include <config.h>

#undef rename
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <io.h>
#include <process.h>

#include <sys/stat.h>
#include <fcntl.h>
#include <sys/utime.h>

#include <isc/file.h>
#include <isc/result.h>
#include <isc/time.h>
#include <isc/util.h>
#include <isc/stat.h>

#include "errno2result.h"

/*
 * Emulate UNIX mkstemp, which returns an open FD to the new file
 *
 */
static int
gettemp(char *path, int *doopen) {
    char *start, *trv;
    struct stat sbuf;
    int pid;

    trv = strrchr(path, 'X');
    trv++;
    pid = getpid();
    /* extra X's get set to 0's */
    while (*--trv == 'X') {
        *trv = (pid % 10) + '0';
        pid /= 10;
    }
    /*
     * check the target directory; if you have six X's and it
     * doesn't exist this runs for a *very* long time.
     */
    for (start = trv + 1;; --trv) {
        if (trv <= path)
            break;
        if (*trv == '\\') {
            *trv = '\0';
            if (stat(path, &sbuf))
                return (0);
            if (!S_ISDIR(sbuf.st_mode)) {
                errno = ENOTDIR;
                return (0);
            }
            *trv = '\\';
            break;
        }
    }

    for (;;) {
        if (doopen) {
            if ((*doopen =
                open(path, O_CREAT|O_EXCL|O_RDWR,
                 _S_IREAD | _S_IWRITE)) >= 0)
                return (1);
            if (errno != EEXIST)
                return (0);
        } else if (stat(path, &sbuf))
            return (errno == ENOENT ? 1 : 0);

        /* tricky little algorithm for backward compatibility */
        for (trv = start;;) {
            if (!*trv)
                return (0);
            if (*trv == 'z')
                *trv++ = 'a';
            else {
                if (isdigit(*trv))
                    *trv = 'a';
                else
                    ++*trv;
                break;
            }
        }
    }
    /*NOTREACHED*/
}

static int
mkstemp(char *path) {
    int fd;

    return (gettemp(path, &fd) ? fd : -1);
}

/*
 * 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);
}

/*
 * isc_file_safemovefile is needed to be defined here to ensure that
 * any file with the new name is renamed to a backup name and then the
 * rename is done. If all goes well then the backup can be deleted,
 * otherwise it gets renamed back.
 */

int
isc_file_safemovefile(const char *oldname, const char *newname) {
    BOOL filestatus;
    char buf[512];
    struct stat sbuf;
    BOOL exists = FALSE;
    int tmpfd;

    /*
     * Make sure we have something to do
     */
    if (stat(oldname, &sbuf) != 0) {
        errno = ENOENT;
        return (-1);
    }

    /*
     * Rename to a backup the new file if it still exists
     */
    if (stat(newname, &sbuf) == 0) {
        exists = TRUE;
        strcpy(buf, newname);
        strcat(buf, ".XXXXX");
        tmpfd = mkstemp(buf);
        if (tmpfd > 0)
            _close(tmpfd);
        DeleteFile(buf);
        _chmod(newname, _S_IREAD | _S_IWRITE);

        filestatus = MoveFile(newname, buf);
    }
    /* Now rename the file to the new name
     */
    _chmod(oldname, _S_IREAD | _S_IWRITE);

    filestatus = MoveFile(oldname, newname);
    if (filestatus == 0) {
        /*
         * Try to rename the backup back to the original name
         * if the backup got created
         */
        if (exists == TRUE) {
            filestatus = MoveFile(buf, newname);
            if (filestatus == 0)
                errno = EACCES;
        }
        return (-1);
    }

    /*
     * Delete the backup file if it got created
     */
    if (exists == TRUE)
        filestatus = DeleteFile(buf);
    return (0);
}

isc_result_t
isc_file_getmodtime(const char *file, isc_time_t *time) {
    int fh;

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

    if ((fh = open(file, _O_RDONLY | _O_BINARY)) < 0)
        return (isc__errno2result(errno));

    if (!GetFileTime((HANDLE) _get_osfhandle(fh),
             NULL,
             NULL,
             &time->absolute))
    {
        close(fh);
                errno = EINVAL;
                return (isc__errno2result(errno));
        }
    close(fh);
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_settime(const char *file, isc_time_t *time) {
    int fh;

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

    if ((fh = open(file, _O_RDWR | _O_BINARY)) < 0)
        return (isc__errno2result(errno));

        /*
     * Set the date via the filedate system call and return.  Failing
         * this call implies the new file times are not supported by the
         * underlying file system.
         */
    if (!SetFileTime((HANDLE) _get_osfhandle(fh),
             NULL,
             &time->absolute,
             &time->absolute))
    {
        close(fh);
                errno = EINVAL;
                return (isc__errno2result(errno));
        }

    close(fh);
        return (ISC_R_SUCCESS);

}

#undef TEMPLATE
#define TEMPLATE "XXXXXXXXXX.tmp" /* 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) {
    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);
}

isc_result_t
isc_file_renameunique(const char *file, char *templet) {
    int fd = -1;
    int res = 0;
    isc_result_t result = ISC_R_SUCCESS;

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

    fd = mkstemp(templet);
    if (fd == -1)
        result = isc__errno2result(errno);
    else
        close(fd);

    if (result == ISC_R_SUCCESS) {
        res = isc_file_safemovefile(file, templet);
        if (res != 0) {
            result = isc__errno2result(errno);
            (void)unlink(templet);
        }
    }
    return (result);
}

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. Using emulation above.
     */
    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;

    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 = isc_file_safemovefile(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_boolean_t
isc_file_isabsolute(const char *filename) {
    REQUIRE(filename != NULL);
    /*
     * Look for c:\path\... style, c:/path/... or \\computer\shar\path...
     * the UNC style file specs
     */
    if ((filename[0] == '\\') && (filename[1] == '\\'))
        return (ISC_TRUE);
    if (isalpha(filename[0]) && filename[1] == ':' && filename[2] == '\\')
        return (ISC_TRUE);
    if (isalpha(filename[0]) && filename[1] == ':' && filename[2] == '/')
        return (ISC_TRUE);
    return (ISC_FALSE);
}

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 (filename[0] == '\\')
        return (ISC_TRUE);
    if (filename[0] == '/')
        return (ISC_TRUE);
    if (isc_file_iscurrentdir(filename))
        return (ISC_TRUE);
    return (ISC_FALSE);
}

const char *
isc_file_basename(const char *filename) {
    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 *progname, size_t namelen) {
    const char *s;
    char *p;
    size_t len;

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

    /*
     * Strip the path from the name
     */
    s = isc_file_basename(filename);
    if (s == NULL) {
        return (ISC_R_NOSPACE);
    }

    /*
     * Strip any and all suffixes
     */
    p = strchr(s, '.');
    if (p == NULL) {
        if (namelen <= strlen(s))
            return (ISC_R_NOSPACE);

        strcpy(progname, s);
        return (ISC_R_SUCCESS);
    }

    /*
     * Copy the result to the buffer
     */
    len = p - s;
    if (len >= namelen)
        return (ISC_R_NOSPACE);

    strncpy(progname, s, len);
    progname[len] = '\0';
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_absolutepath(const char *filename, char *path, size_t pathlen) {
    char *ptrname;
    DWORD retval;

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

    retval = GetFullPathName(filename, pathlen, path, &ptrname);

    /* Something went wrong in getting the path */
    if (retval == 0)
        return (ISC_R_NOTFOUND);
    /* Caller needs to provide a larger buffer to contain the string */
    if (retval >= pathlen)
        return (ISC_R_NOSPACE);
    return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_truncate(const char *filename, isc_offset_t size) {
    int fh;

    REQUIRE(filename != NULL && size >= 0);

    if ((fh = open(filename, _O_RDWR | _O_BINARY)) < 0)
        return (isc__errno2result(errno));

    if(_chsize(fh, size) != 0) {
        close(fh);
        return (isc__errno2result(errno));
    }
    close(fh);

    return (ISC_R_SUCCESS);
}