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 #ifdef _WIN32
  48 #include <windows.h>
  49 #elif defined(CONFIG_BSD)
  50 #include <stdlib.h>
  51 #else
  52 #include <malloc.h>
  53 #endif
  54
  55 #include "qemu-common.h"
  56 #include "trace.h"
  57 #include "sysemu.h"
  58 #include "qemu_socket.h"
  59
  60 int qemu_madvise(void *addr, size_t len, int advice)
  61 {
  62     if (advice == QEMU_MADV_INVALID) {
  63         errno = EINVAL;
  64         return -1;
  65     }
  66 #if defined(CONFIG_MADVISE)
  67     return madvise(addr, len, advice);
  68 #elif defined(CONFIG_POSIX_MADVISE)
  69     return posix_madvise(addr, len, advice);
  70 #else
  71     errno = EINVAL;
  72     return -1;
  73 #endif
  74 }
  75
  76 int qemu_create_pidfile(const char *filename)
  77 {
  78     char buffer[128];
  79     int len;
  80 #ifndef _WIN32
  81     int fd;
  82
  83     fd = qemu_open(filename, O_RDWR | O_CREAT, 0600);
  84     if (fd == -1)
  85         return -1;
  86
  87     if (lockf(fd, F_TLOCK, 0) == -1)
  88         return -1;
  89
  90     len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid());
  91     if (write(fd, buffer, len) != len)
  92         return -1;
  93 #else
  94     HANDLE file;
  95     OVERLAPPED overlap;
  96     BOOL ret;
  97     memset(&overlap, 0, sizeof(overlap));
  98
  99     file = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL,
 100                       OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 101
 102     if (file == INVALID_HANDLE_VALUE)
 103       return -1;
 104
 105     len = snprintf(buffer, sizeof(buffer), "%ld\n", (long)getpid());
 106     ret = WriteFileEx(file, (LPCVOID)buffer, (DWORD)len,
 107                       &overlap, NULL);
 108     if (ret == 0)
 109       return -1;
 110 #endif
 111     return 0;
 112 }
 113
 114
 115 /*
 116  * Opens a file with FD_CLOEXEC set
 117  */
 118 int qemu_open(const char *name, int flags, ...)
 119 {
 120     int ret;
 121     int mode = 0;
 122
 123     if (flags & O_CREAT) {
 124         va_list ap;
 125
 126         va_start(ap, flags);
 127         mode = va_arg(ap, int);
 128         va_end(ap);
 129     }
 130
 131 #ifdef O_CLOEXEC
 132     ret = open(name, flags | O_CLOEXEC, mode);
 133 #else
 134     ret = open(name, flags, mode);
 135     if (ret >= 0) {
 136         qemu_set_cloexec(ret);
 137     }
 138 #endif
 139
 140     return ret;
 141 }
 142
 143 /*
 144  * A variant of write(2) which handles partial write.
 145  *
 146  * Return the number of bytes transferred.
 147  * Set errno if fewer than `count' bytes are written.
 148  *
 149  * This function don't work with non-blocking fd's.
 150  * Any of the possibilities with non-bloking fd's is bad:
 151  *   - return a short write (then name is wrong)
 152  *   - busy wait adding (errno == EAGAIN) to the loop
 153  */
 154 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 155 {
 156     ssize_t ret = 0;
 157     ssize_t total = 0;
 158
 159     while (count) {
 160         ret = write(fd, buf, count);
 161         if (ret < 0) {
 162             if (errno == EINTR)
 163                 continue;
 164             break;
 165         }
 166
 167         count -= ret;
 168         buf += ret;
 169         total += ret;
 170     }
 171
 172     return total;
 173 }
 174
 175 /*
 176  * Opens a socket with FD_CLOEXEC set
 177  */
 178 int qemu_socket(int domain, int type, int protocol)
 179 {
 180     int ret;
 181
 182 #ifdef SOCK_CLOEXEC
 183     ret = socket(domain, type | SOCK_CLOEXEC, protocol);
 184     if (ret != -1 || errno != EINVAL) {
 185         return ret;
 186     }
 187 #endif
 188     ret = socket(domain, type, protocol);
 189     if (ret >= 0) {
 190         qemu_set_cloexec(ret);
 191     }
 192
 193     return ret;
 194 }
 195
 196 /*
 197  * Accept a connection and set FD_CLOEXEC
 198  */
 199 int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
 200 {
 201     int ret;
 202
 203 #ifdef CONFIG_ACCEPT4
 204     ret = accept4(s, addr, addrlen, SOCK_CLOEXEC);
 205     if (ret != -1 || errno != ENOSYS) {
 206         return ret;
 207     }
 208 #endif
 209     ret = accept(s, addr, addrlen);
 210     if (ret >= 0) {
 211         qemu_set_cloexec(ret);
 212     }
 213
 214     return ret;
 215 }