util/oslib-posix.c

   1 /*
   2  * os-posix-lib.c
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  * Copyright (c) 2010 Red Hat, Inc.
   6  *
   7  * QEMU library functions on POSIX which are shared between QEMU and
   8  * the QEMU tools.
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26  * THE SOFTWARE.
  27  */
  28
  29 /* The following block of code temporarily renames the daemon() function so the
  30    compiler does not see the warning associated with it in stdlib.h on OSX */
  31 #ifdef __APPLE__
  32 #define daemon qemu_fake_daemon_function
  33 #include <stdlib.h>
  34 #undef daemon
  35 extern int daemon(int, int);
  36 #endif
  37
  38 #if defined(__linux__) && (defined(__x86_64__) || defined(__arm__))
  39    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
  40       Valgrind does not support alignments larger than 1 MiB,
  41       therefore we need special code which handles running on Valgrind. */
  42 #  define QEMU_VMALLOC_ALIGN (512 * 4096)
  43 #elif defined(__linux__) && defined(__s390x__)
  44    /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */
  45 #  define QEMU_VMALLOC_ALIGN (256 * 4096)
  46 #else
  47 #  define QEMU_VMALLOC_ALIGN getpagesize()
  48 #endif
  49
  50 #include "config-host.h"
  51 #include "sysemu/sysemu.h"
  52 #include "trace.h"
  53 #include "qemu/sockets.h"
  54 #include <sys/mman.h>
  55
  56 #ifdef CONFIG_LINUX
  57 #include <sys/syscall.h>
  58 #endif
  59
  60 int qemu_get_thread_id(void)
  61 {
  62 #if defined(__linux__)
  63     return syscall(SYS_gettid);
  64 #else
  65     return getpid();
  66 #endif
  67 }
  68
  69 int qemu_daemon(int nochdir, int noclose)
  70 {
  71     return daemon(nochdir, noclose);
  72 }
  73
  74 void *qemu_oom_check(void *ptr)
  75 {
  76     if (ptr == NULL) {
  77         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  78         abort();
  79     }
  80     return ptr;
  81 }
  82
  83 void *qemu_memalign(size_t alignment, size_t size)
  84 {
  85     void *ptr;
  86 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  87     int ret;
  88     ret = posix_memalign(&ptr, alignment, size);
  89     if (ret != 0) {
  90         fprintf(stderr, "Failed to allocate %zu B: %s\n",
  91                 size, strerror(ret));
  92         abort();
  93     }
  94 #elif defined(CONFIG_BSD)
  95     ptr = qemu_oom_check(valloc(size));
  96 #else
  97     ptr = qemu_oom_check(memalign(alignment, size));
  98 #endif
  99     trace_qemu_memalign(alignment, size, ptr);
 100     return ptr;
 101 }
 102
 103 /* alloc shared memory pages */
 104 void *qemu_vmalloc(size_t size)
 105 {
 106     size_t align = QEMU_VMALLOC_ALIGN;
 107     size_t total = size + align - getpagesize();
 108     void *ptr = mmap(0, total, PROT_READ | PROT_WRITE,
 109                      MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 110     size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr;
 111
 112     if (ptr == MAP_FAILED) {
 113         fprintf(stderr, "Failed to allocate %zu B: %s\n",
 114                 size, strerror(errno));
 115         abort();
 116     }
 117
 118     ptr += offset;
 119     total -= offset;
 120
 121     if (offset > 0) {
 122         munmap(ptr - offset, offset);
 123     }
 124     if (total > size) {
 125         munmap(ptr + size, total - size);
 126     }
 127
 128     trace_qemu_vmalloc(size, ptr);
 129     return ptr;
 130 }
 131
 132 void qemu_vfree(void *ptr)
 133 {
 134     trace_qemu_vfree(ptr);
 135     free(ptr);
 136 }
 137
 138 void qemu_set_block(int fd)
 139 {
 140     int f;
 141     f = fcntl(fd, F_GETFL);
 142     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 143 }
 144
 145 void qemu_set_nonblock(int fd)
 146 {
 147     int f;
 148     f = fcntl(fd, F_GETFL);
 149     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 150 }
 151
 152 void qemu_set_cloexec(int fd)
 153 {
 154     int f;
 155     f = fcntl(fd, F_GETFD);
 156     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 157 }
 158
 159 /*
 160  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 161  */
 162 int qemu_pipe(int pipefd[2])
 163 {
 164     int ret;
 165
 166 #ifdef CONFIG_PIPE2
 167     ret = pipe2(pipefd, O_CLOEXEC);
 168     if (ret != -1 || errno != ENOSYS) {
 169         return ret;
 170     }
 171 #endif
 172     ret = pipe(pipefd);
 173     if (ret == 0) {
 174         qemu_set_cloexec(pipefd[0]);
 175         qemu_set_cloexec(pipefd[1]);
 176     }
 177
 178     return ret;
 179 }
 180
 181 int qemu_utimens(const char *path, const struct timespec *times)
 182 {
 183     struct timeval tv[2], tv_now;
 184     struct stat st;
 185     int i;
 186 #ifdef CONFIG_UTIMENSAT
 187     int ret;
 188
 189     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 190     if (ret != -1 || errno != ENOSYS) {
 191         return ret;
 192     }
 193 #endif
 194     /* Fallback: use utimes() instead of utimensat() */
 195
 196     /* happy if special cases */
 197     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 198         return 0;
 199     }
 200     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 201         return utimes(path, NULL);
 202     }
 203
 204     /* prepare for hard cases */
 205     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 206         gettimeofday(&tv_now, NULL);
 207     }
 208     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 209         stat(path, &st);
 210     }
 211
 212     for (i = 0; i < 2; i++) {
 213         if (times[i].tv_nsec == UTIME_NOW) {
 214             tv[i].tv_sec = tv_now.tv_sec;
 215             tv[i].tv_usec = tv_now.tv_usec;
 216         } else if (times[i].tv_nsec == UTIME_OMIT) {
 217             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 218             tv[i].tv_usec = 0;
 219         } else {
 220             tv[i].tv_sec = times[i].tv_sec;
 221             tv[i].tv_usec = times[i].tv_nsec / 1000;
 222         }
 223     }
 224
 225     return utimes(path, &tv[0]);
 226 }