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