osdep.c

   1 /*
   2  * QEMU low level functions
   3  *
   4  * Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <stdarg.h>
  27 #include <string.h>
  28 #include <errno.h>
  29 #include <unistd.h>
  30 #include <fcntl.h>
  31
  32 /* Needed early for CONFIG_BSD etc. */
  33 #include "config-host.h"
  34
  35 #if defined(CONFIG_MADVISE) || defined(CONFIG_POSIX_MADVISE)
  36 #include <sys/mman.h>
  37 #endif
  38
  39 #ifdef CONFIG_SOLARIS
  40 #include <sys/types.h>
  41 #include <sys/statvfs.h>
  42 /* See MySQL bug #7156 (http://bugs.mysql.com/bug.php?id=7156) for
  43    discussion about Solaris header problems */
  44 extern int madvise(caddr_t, size_t, int);
  45 #endif
  46
  47 #include "qemu-common.h"
  48 #include "trace.h"
  49 #include "sysemu.h"
  50 #include "qemu_socket.h"
  51
  52 int qemu_madvise(void *addr, size_t len, int advice)
  53 {
  54     if (advice == QEMU_MADV_INVALID) {
  55         errno = EINVAL;
  56         return -1;
  57     }
  58 #if defined(CONFIG_MADVISE)
  59     return madvise(addr, len, advice);
  60 #elif defined(CONFIG_POSIX_MADVISE)
  61     return posix_madvise(addr, len, advice);
  62 #else
  63     errno = EINVAL;
  64     return -1;
  65 #endif
  66 }
  67
  68
  69 /*
  70  * Opens a file with FD_CLOEXEC set
  71  */
  72 int qemu_open(const char *name, int flags, ...)
  73 {
  74     int ret;
  75     int mode = 0;
  76
  77     if (flags & O_CREAT) {
  78         va_list ap;
  79
  80         va_start(ap, flags);
  81         mode = va_arg(ap, int);
  82         va_end(ap);
  83     }
  84
  85 #ifdef O_CLOEXEC
  86     ret = open(name, flags | O_CLOEXEC, mode);
  87 #else
  88     ret = open(name, flags, mode);
  89     if (ret >= 0) {
  90         qemu_set_cloexec(ret);
  91     }
  92 #endif
  93
  94     return ret;
  95 }
  96
  97 /*
  98  * A variant of write(2) which handles partial write.
  99  *
 100  * Return the number of bytes transferred.
 101  * Set errno if fewer than `count' bytes are written.
 102  *
 103  * This function don't work with non-blocking fd's.
 104  * Any of the possibilities with non-bloking fd's is bad:
 105  *   - return a short write (then name is wrong)
 106  *   - busy wait adding (errno == EAGAIN) to the loop
 107  */
 108 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 109 {
 110     ssize_t ret = 0;
 111     ssize_t total = 0;
 112
 113     while (count) {
 114         ret = write(fd, buf, count);
 115         if (ret < 0) {
 116             if (errno == EINTR)
 117                 continue;
 118             break;
 119         }
 120
 121         count -= ret;
 122         buf += ret;
 123         total += ret;
 124     }
 125
 126     return total;
 127 }
 128
 129 /*
 130  * Opens a socket with FD_CLOEXEC set
 131  */
 132 int qemu_socket(int domain, int type, int protocol)
 133 {
 134     int ret;
 135
 136 #ifdef SOCK_CLOEXEC
 137     ret = socket(domain, type | SOCK_CLOEXEC, protocol);
 138     if (ret != -1 || errno != EINVAL) {
 139         return ret;
 140     }
 141 #endif
 142     ret = socket(domain, type, protocol);
 143     if (ret >= 0) {
 144         qemu_set_cloexec(ret);
 145     }
 146
 147     return ret;
 148 }
 149
 150 /*
 151  * Accept a connection and set FD_CLOEXEC
 152  */
 153 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
 154 {
 155     int ret;
 156
 157 #ifdef CONFIG_ACCEPT4
 158     ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
 159     if (ret != -1 || errno != ENOSYS) {
 160         return ret;
 161     }
 162 #endif
 163     ret = accept(s, addr, addrlen);
 164     if (ret >= 0) {
 165         qemu_set_cloexec(ret);
 166     }
 167
 168     return ret;
 169 }