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 "qemu_socket.h"
  50
  51 int qemu_madvise(void *addr, size_t len, int advice)
  52 {
  53     if (advice == QEMU_MADV_INVALID) {
  54         errno = EINVAL;
  55         return -1;
  56     }
  57 #if defined(CONFIG_MADVISE)
  58     return madvise(addr, len, advice);
  59 #elif defined(CONFIG_POSIX_MADVISE)
  60     return posix_madvise(addr, len, advice);
  61 #else
  62     errno = EINVAL;
  63     return -1;
  64 #endif
  65 }
  66
  67
  68 /*
  69  * Opens a file with FD_CLOEXEC set
  70  */
  71 int qemu_open(const char *name, int flags, ...)
  72 {
  73     int ret;
  74     int mode = 0;
  75
  76     if (flags & O_CREAT) {
  77         va_list ap;
  78
  79         va_start(ap, flags);
  80         mode = va_arg(ap, int);
  81         va_end(ap);
  82     }
  83
  84 #ifdef O_CLOEXEC
  85     ret = open(name, flags | O_CLOEXEC, mode);
  86 #else
  87     ret = open(name, flags, mode);
  88     if (ret >= 0) {
  89         qemu_set_cloexec(ret);
  90     }
  91 #endif
  92
  93     return ret;
  94 }
  95
  96 /*
  97  * A variant of write(2) which handles partial write.
  98  *
  99  * Return the number of bytes transferred.
 100  * Set errno if fewer than `count' bytes are written.
 101  *
 102  * This function don't work with non-blocking fd's.
 103  * Any of the possibilities with non-bloking fd's is bad:
 104  *   - return a short write (then name is wrong)
 105  *   - busy wait adding (errno == EAGAIN) to the loop
 106  */
 107 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 108 {
 109     ssize_t ret = 0;
 110     ssize_t total = 0;
 111
 112     while (count) {
 113         ret = write(fd, buf, count);
 114         if (ret < 0) {
 115             if (errno == EINTR)
 116                 continue;
 117             break;
 118         }
 119
 120         count -= ret;
 121         buf += ret;
 122         total += ret;
 123     }
 124
 125     return total;
 126 }
 127
 128 /*
 129  * Opens a socket with FD_CLOEXEC set
 130  */
 131 int qemu_socket(int domain, int type, int protocol)
 132 {
 133     int ret;
 134
 135 #ifdef SOCK_CLOEXEC
 136     ret = socket(domain, type | SOCK_CLOEXEC, protocol);
 137     if (ret != -1 || errno != EINVAL) {
 138         return ret;
 139     }
 140 #endif
 141     ret = socket(domain, type, protocol);
 142     if (ret >= 0) {
 143         qemu_set_cloexec(ret);
 144     }
 145
 146     return ret;
 147 }
 148
 149 /*
 150  * Accept a connection and set FD_CLOEXEC
 151  */
 152 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
 153 {
 154     int ret;
 155
 156 #ifdef CONFIG_ACCEPT4
 157     ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
 158     if (ret != -1 || errno != ENOSYS) {
 159         return ret;
 160     }
 161 #endif
 162     ret = accept(s, addr, addrlen);
 163     if (ret >= 0) {
 164         qemu_set_cloexec(ret);
 165     }
 166
 167     return ret;
 168 }