log: move qemu_log_close/qemu_log_flush from header to log.c

[qemu.git] / util / oslib-posix.c

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 892d2d8ad29b4b633303e99dd7c9a2cbb299ec6d..20ca141dec11d406291616a5ed33c6257e0f78b8 100644 (file)
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -26,15 +26,6 @@
  * 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__))
    /* Use 2 MiB alignment so transparent hugepages can be used by KVM.
       Valgrind does not support alignments larger than 1 MiB,
@@ -46,26 +37,24 @@ 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__
@@ -340,26 +329,6 @@ 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;
@@ -387,7 +356,7 @@ 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 */
@@ -470,3 +439,74 @@ 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;
+}