diff options
Diffstat (limited to 'qemu/util/oslib-posix.c')
| -rw-r--r-- | qemu/util/oslib-posix.c | 133 |
1 files changed, 81 insertions, 52 deletions
diff --git a/qemu/util/oslib-posix.c b/qemu/util/oslib-posix.c index 3ae4987b6..6cc4b8f00 100644 --- a/qemu/util/oslib-posix.c +++ b/qemu/util/oslib-posix.c @@ -26,16 +26,8 @@ * THE SOFTWARE. */ -/* The following block of code temporarily renames the daemon() function so the - compiler does not see the warning associated with it in stdlib.h on OSX */ -#ifdef __APPLE__ -#define daemon qemu_fake_daemon_function -#include <stdlib.h> -#undef daemon -extern int daemon(int, int); -#endif - -#if defined(__linux__) && (defined(__x86_64__) || defined(__arm__)) +#if defined(__linux__) && \ + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) /* Use 2 MiB alignment so transparent hugepages can be used by KVM. Valgrind does not support alignments larger than 1 MiB, therefore we need special code which handles running on Valgrind. */ @@ -46,32 +38,32 @@ extern int daemon(int, int); #else # define QEMU_VMALLOC_ALIGN getpagesize() #endif -#define HUGETLBFS_MAGIC 0x958458f6 +#include "qemu/osdep.h" #include <termios.h> -#include <unistd.h> #include <termios.h> #include <glib/gprintf.h> -#include "config-host.h" #include "sysemu/sysemu.h" #include "trace.h" +#include "qapi/error.h" #include "qemu/sockets.h" #include <sys/mman.h> #include <libgen.h> -#include <setjmp.h> #include <sys/signal.h> +#include "qemu/cutils.h" #ifdef CONFIG_LINUX #include <sys/syscall.h> -#include <sys/vfs.h> #endif #ifdef __FreeBSD__ #include <sys/sysctl.h> #endif +#include <qemu/mmap-alloc.h> + int qemu_get_thread_id(void) { #if defined(__linux__) @@ -128,10 +120,7 @@ void *qemu_memalign(size_t alignment, size_t size) void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) { size_t align = QEMU_VMALLOC_ALIGN; - size_t total = size + align - getpagesize(); - void *ptr = mmap(0, total, PROT_READ | PROT_WRITE, - MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); - size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; + void *ptr = qemu_ram_mmap(-1, size, align, false); if (ptr == MAP_FAILED) { return NULL; @@ -140,15 +129,6 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment) if (alignment) { *alignment = align; } - ptr += offset; - total -= offset; - - if (offset > 0) { - munmap(ptr - offset, offset); - } - if (total > size) { - munmap(ptr + size, total - size); - } trace_qemu_anon_ram_alloc(size, ptr); return ptr; @@ -163,9 +143,7 @@ void qemu_vfree(void *ptr) void qemu_anon_ram_free(void *ptr, size_t size) { trace_qemu_anon_ram_free(ptr, size); - if (ptr) { - munmap(ptr, size); - } + qemu_ram_munmap(ptr, size); } void qemu_set_block(int fd) @@ -352,26 +330,6 @@ static void sigbus_handler(int signal) siglongjmp(sigjump, 1); } -static size_t fd_getpagesize(int fd) -{ -#ifdef CONFIG_LINUX - struct statfs fs; - int ret; - - if (fd != -1) { - do { - ret = fstatfs(fd, &fs); - } while (ret != 0 && errno == EINTR); - - if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) { - return fs.f_bsize; - } - } -#endif - - return getpagesize(); -} - void os_mem_prealloc(int fd, char *area, size_t memory) { int ret; @@ -399,7 +357,7 @@ void os_mem_prealloc(int fd, char *area, size_t memory) exit(1); } else { int i; - size_t hpagesize = fd_getpagesize(fd); + size_t hpagesize = qemu_fd_getpagesize(fd); size_t numpages = DIV_ROUND_UP(memory, hpagesize); /* MAP_POPULATE silently ignores failures */ @@ -482,3 +440,74 @@ int qemu_read_password(char *buf, int buf_size) printf("\n"); return ret; } + + +pid_t qemu_fork(Error **errp) +{ + sigset_t oldmask, newmask; + struct sigaction sig_action; + int saved_errno; + pid_t pid; + + /* + * Need to block signals now, so that child process can safely + * kill off caller's signal handlers without a race. + */ + sigfillset(&newmask); + if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) { + error_setg_errno(errp, errno, + "cannot block signals"); + return -1; + } + + pid = fork(); + saved_errno = errno; + + if (pid < 0) { + /* attempt to restore signal mask, but ignore failure, to + * avoid obscuring the fork failure */ + (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); + error_setg_errno(errp, saved_errno, + "cannot fork child process"); + errno = saved_errno; + return -1; + } else if (pid) { + /* parent process */ + + /* Restore our original signal mask now that the child is + * safely running. Only documented failures are EFAULT (not + * possible, since we are using just-grabbed mask) or EINVAL + * (not possible, since we are using correct arguments). */ + (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL); + } else { + /* child process */ + size_t i; + + /* Clear out all signal handlers from parent so nothing + * unexpected can happen in our child once we unblock + * signals */ + sig_action.sa_handler = SIG_DFL; + sig_action.sa_flags = 0; + sigemptyset(&sig_action.sa_mask); + + for (i = 1; i < NSIG; i++) { + /* Only possible errors are EFAULT or EINVAL The former + * won't happen, the latter we expect, so no need to check + * return value */ + (void)sigaction(i, &sig_action, NULL); + } + + /* Unmask all signals in child, since we've no idea what the + * caller's done with their signal mask and don't want to + * propagate that to children */ + sigemptyset(&newmask); + if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) { + Error *local_err = NULL; + error_setg_errno(&local_err, errno, + "cannot unblock signals"); + error_report_err(local_err); + _exit(1); + } + } + return pid; +} |