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 <termios.h> 51 #include <unistd.h> 52 53 #include <glib/gprintf.h> 54 55 #include "config-host.h" 56 #include "sysemu/sysemu.h" 57 #include "trace.h" 58 #include "qemu/sockets.h" 59 #include <sys/mman.h> 60 #include <libgen.h> 61 62 #ifdef CONFIG_LINUX 63 #include <sys/syscall.h> 64 #endif 65 66 #ifdef __FreeBSD__ 67 #include <sys/sysctl.h> 68 #endif 69 70 int qemu_get_thread_id(void) 71 { 72 #if defined(__linux__) 73 return syscall(SYS_gettid); 74 #else 75 return getpid(); 76 #endif 77 } 78 79 int qemu_daemon(int nochdir, int noclose) 80 { 81 return daemon(nochdir, noclose); 82 } 83 84 void *qemu_oom_check(void *ptr) 85 { 86 if (ptr == NULL) { 87 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 88 abort(); 89 } 90 return ptr; 91 } 92 93 void *qemu_memalign(size_t alignment, size_t size) 94 { 95 void *ptr; 96 97 if (alignment < sizeof(void*)) { 98 alignment = sizeof(void*); 99 } 100 101 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 102 int ret; 103 ret = posix_memalign(&ptr, alignment, size); 104 if (ret != 0) { 105 fprintf(stderr, "Failed to allocate %zu B: %s\n", 106 size, strerror(ret)); 107 abort(); 108 } 109 #elif defined(CONFIG_BSD) 110 ptr = qemu_oom_check(valloc(size)); 111 #else 112 ptr = qemu_oom_check(memalign(alignment, size)); 113 #endif 114 trace_qemu_memalign(alignment, size, ptr); 115 return ptr; 116 } 117 118 /* alloc shared memory pages */ 119 void *qemu_anon_ram_alloc(size_t size) 120 { 121 size_t align = QEMU_VMALLOC_ALIGN; 122 size_t total = size + align - getpagesize(); 123 void *ptr = mmap(0, total, PROT_READ | PROT_WRITE, 124 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 125 size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; 126 127 if (ptr == MAP_FAILED) { 128 return NULL; 129 } 130 131 ptr += offset; 132 total -= offset; 133 134 if (offset > 0) { 135 munmap(ptr - offset, offset); 136 } 137 if (total > size) { 138 munmap(ptr + size, total - size); 139 } 140 141 trace_qemu_anon_ram_alloc(size, ptr); 142 return ptr; 143 } 144 145 void qemu_vfree(void *ptr) 146 { 147 trace_qemu_vfree(ptr); 148 free(ptr); 149 } 150 151 void qemu_anon_ram_free(void *ptr, size_t size) 152 { 153 trace_qemu_anon_ram_free(ptr, size); 154 if (ptr) { 155 munmap(ptr, size); 156 } 157 } 158 159 void qemu_set_block(int fd) 160 { 161 int f; 162 f = fcntl(fd, F_GETFL); 163 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 164 } 165 166 void qemu_set_nonblock(int fd) 167 { 168 int f; 169 f = fcntl(fd, F_GETFL); 170 fcntl(fd, F_SETFL, f | O_NONBLOCK); 171 } 172 173 int socket_set_fast_reuse(int fd) 174 { 175 int val = 1, ret; 176 177 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 178 (const char *)&val, sizeof(val)); 179 180 assert(ret == 0); 181 182 return ret; 183 } 184 185 void qemu_set_cloexec(int fd) 186 { 187 int f; 188 f = fcntl(fd, F_GETFD); 189 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 190 } 191 192 /* 193 * Creates a pipe with FD_CLOEXEC set on both file descriptors 194 */ 195 int qemu_pipe(int pipefd[2]) 196 { 197 int ret; 198 199 #ifdef CONFIG_PIPE2 200 ret = pipe2(pipefd, O_CLOEXEC); 201 if (ret != -1 || errno != ENOSYS) { 202 return ret; 203 } 204 #endif 205 ret = pipe(pipefd); 206 if (ret == 0) { 207 qemu_set_cloexec(pipefd[0]); 208 qemu_set_cloexec(pipefd[1]); 209 } 210 211 return ret; 212 } 213 214 int qemu_utimens(const char *path, const struct timespec *times) 215 { 216 struct timeval tv[2], tv_now; 217 struct stat st; 218 int i; 219 #ifdef CONFIG_UTIMENSAT 220 int ret; 221 222 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 223 if (ret != -1 || errno != ENOSYS) { 224 return ret; 225 } 226 #endif 227 /* Fallback: use utimes() instead of utimensat() */ 228 229 /* happy if special cases */ 230 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 231 return 0; 232 } 233 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 234 return utimes(path, NULL); 235 } 236 237 /* prepare for hard cases */ 238 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 239 gettimeofday(&tv_now, NULL); 240 } 241 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 242 stat(path, &st); 243 } 244 245 for (i = 0; i < 2; i++) { 246 if (times[i].tv_nsec == UTIME_NOW) { 247 tv[i].tv_sec = tv_now.tv_sec; 248 tv[i].tv_usec = tv_now.tv_usec; 249 } else if (times[i].tv_nsec == UTIME_OMIT) { 250 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 251 tv[i].tv_usec = 0; 252 } else { 253 tv[i].tv_sec = times[i].tv_sec; 254 tv[i].tv_usec = times[i].tv_nsec / 1000; 255 } 256 } 257 258 return utimes(path, &tv[0]); 259 } 260 261 char * 262 qemu_get_local_state_pathname(const char *relative_pathname) 263 { 264 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 265 relative_pathname); 266 } 267 268 void qemu_set_tty_echo(int fd, bool echo) 269 { 270 struct termios tty; 271 272 tcgetattr(fd, &tty); 273 274 if (echo) { 275 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 276 } else { 277 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 278 } 279 280 tcsetattr(fd, TCSANOW, &tty); 281 } 282 283 static char exec_dir[PATH_MAX]; 284 285 void qemu_init_exec_dir(const char *argv0) 286 { 287 char *dir; 288 char *p = NULL; 289 char buf[PATH_MAX]; 290 291 assert(!exec_dir[0]); 292 293 #if defined(__linux__) 294 { 295 int len; 296 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 297 if (len > 0) { 298 buf[len] = 0; 299 p = buf; 300 } 301 } 302 #elif defined(__FreeBSD__) 303 { 304 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 305 size_t len = sizeof(buf) - 1; 306 307 *buf = '\0'; 308 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 309 *buf) { 310 buf[sizeof(buf) - 1] = '\0'; 311 p = buf; 312 } 313 } 314 #endif 315 /* If we don't have any way of figuring out the actual executable 316 location then try argv[0]. */ 317 if (!p) { 318 if (!argv0) { 319 return; 320 } 321 p = realpath(argv0, buf); 322 if (!p) { 323 return; 324 } 325 } 326 dir = dirname(p); 327 328 pstrcpy(exec_dir, sizeof(exec_dir), dir); 329 } 330 331 char *qemu_get_exec_dir(void) 332 { 333 return g_strdup(exec_dir); 334 } 335