osdep.c

/*
 * QEMU low level functions
 *
 * Copyright (c) 2003 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

/* Needed early for CONFIG_BSD etc. */
#include "config-host.h"

#if defined(CONFIG_MADVISE) || defined(CONFIG_POSIX_MADVISE)
#include <sys/mman.h>
#endif

#ifdef CONFIG_SOLARIS
#include <sys/types.h>
#include <sys/statvfs.h>
/* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
   discussion about Solaris header problems */
extern int madvise(caddr_t, size_t, int);
#endif

#include "qemu-common.h"
#include "trace.h"
#include "sysemu.h"
#include "qemu_socket.h"

int qemu_madvise(void *addr, size_t len, int advice)
{
    if (advice == QEMU_MADV_INVALID) {
        errno = EINVAL;
        return -1;
    }
#if defined(CONFIG_MADVISE)
    return madvise(addr, len, advice);
#elif defined(CONFIG_POSIX_MADVISE)
    return posix_madvise(addr, len, advice);
#else
    errno = EINVAL;
    return -1;
#endif
}


/*
 * Opens a file with FD_CLOEXEC set
 */
int qemu_open(const char *name, int flags, ...)
{
    int ret;
    int mode = 0;

    if (flags & O_CREAT) {
        va_list ap;

        va_start(ap, flags);
        mode = va_arg(ap, int);
        va_end(ap);
    }

#ifdef O_CLOEXEC
    ret = open(name, flags | O_CLOEXEC, mode);
#else
    ret = open(name, flags, mode);
    if (ret >= 0) {
        qemu_set_cloexec(ret);
    }
#endif

    return ret;
}

/*
 * A variant of write(2) which handles partial write.
 *
 * Return the number of bytes transferred.
 * Set errno if fewer than `count' bytes are written.
 *
 * This function don't work with non-blocking fd's.
 * Any of the possibilities with non-bloking fd's is bad:
 *   - return a short write (then name is wrong)
 *   - busy wait adding (errno == EAGAIN) to the loop
 */
ssize_t qemu_write_full(int fd, const void *buf, size_t count)
{
    ssize_t ret = 0;
    ssize_t total = 0;

    while (count) {
        ret = write(fd, buf, count);
        if (ret < 0) {
            if (errno == EINTR)
                continue;
            break;
        }

        count -= ret;
        buf += ret;
        total += ret;
    }

    return total;
}

/*
 * Opens a socket with FD_CLOEXEC set
 */
int qemu_socket(int domain, int type, int protocol)
{
    int ret;

#ifdef SOCK_CLOEXEC
    ret = socket(domain, type | SOCK_CLOEXEC, protocol);
    if (ret != -1 || errno != EINVAL) {
        return ret;
    }
#endif
    ret = socket(domain, type, protocol);
    if (ret >= 0) {
        qemu_set_cloexec(ret);
    }

    return ret;
}

/*
 * Accept a connection and set FD_CLOEXEC
 */
int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
    int ret;

#ifdef CONFIG_ACCEPT4
    ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
    if (ret != -1 || errno != ENOSYS) {
        return ret;
    }
#endif
    ret = accept(s, addr, addrlen);
    if (ret >= 0) {
        qemu_set_cloexec(ret);
    }

    return ret;
}