1 files changed, 96 insertions, 1 deletions

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 11b35e4..4ff577e 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -31,7 +31,7 @@
 
 #include <glib/gprintf.h>
 
-#include "sysemu/sysemu.h"
+#include "system/system.h"
 #include "trace.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
@@ -58,6 +58,7 @@
 #include <lwp.h>
 #endif
 
+#include "qemu/memalign.h"
 #include "qemu/mmap-alloc.h"
 
 #define MAX_MEM_PREALLOC_THREAD_COUNT 16
@@ -111,6 +112,21 @@ int qemu_get_thread_id(void)
 #endif
 }
 
+int qemu_kill_thread(int tid, int sig)
+{
+#if defined(__linux__)
+    return syscall(__NR_tgkill, getpid(), tid, sig);
+#elif defined(__FreeBSD__)
+    return thr_kill2(getpid(), tid, sig);
+#elif defined(__NetBSD__)
+    return _lwp_kill(tid, sig);
+#elif defined(__OpenBSD__)
+    return thrkill(tid, sig, NULL);
+#else
+    return kill(tid, sig);
+#endif
+}
+
 int qemu_daemon(int nochdir, int noclose)
 {
     return daemon(nochdir, noclose);
@@ -195,11 +211,21 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared,
     const uint32_t qemu_map_flags = (shared ? QEMU_MAP_SHARED : 0) |
                                     (noreserve ? QEMU_MAP_NORESERVE : 0);
     size_t align = QEMU_VMALLOC_ALIGN;
+#ifndef EMSCRIPTEN
     void *ptr = qemu_ram_mmap(-1, size, align, qemu_map_flags, 0);
 
     if (ptr == MAP_FAILED) {
         return NULL;
     }
+#else
+    /*
+     * qemu_ram_mmap is not implemented for Emscripten. Use qemu_memalign
+     * for the anonymous allocation. noreserve is ignored as there is no swap
+     * space on Emscripten, and shared is ignored as there is no other
+     * processes on Emscripten.
+     */
+    void *ptr = qemu_memalign(align, size);
+#endif
 
     if (alignment) {
         *alignment = align;
@@ -212,7 +238,16 @@ void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment, bool shared,
 void qemu_anon_ram_free(void *ptr, size_t size)
 {
     trace_qemu_anon_ram_free(ptr, size);
+#ifndef EMSCRIPTEN
     qemu_ram_munmap(-1, ptr, size);
+#else
+    /*
+     * qemu_ram_munmap is not implemented for Emscripten and qemu_memalign
+     * was used for the allocation. Use the corresponding freeing function
+     * here.
+     */
+    qemu_vfree(ptr);
+#endif
 }
 
 void qemu_socket_set_block(int fd)
@@ -573,7 +608,15 @@ bool qemu_prealloc_mem(int fd, char *area, size_t sz, int max_threads,
 {
     static gsize initialized;
     int ret;
+#ifndef EMSCRIPTEN
     size_t hpagesize = qemu_fd_getpagesize(fd);
+#else
+    /*
+     * mmap-alloc.c is excluded from Emscripten build, so qemu_fd_getpagesize
+     * is unavailable. Fallback to the lower level implementation.
+     */
+    size_t hpagesize = qemu_real_host_page_size();
+#endif
     size_t numpages = DIV_ROUND_UP(sz, hpagesize);
     bool use_madv_populate_write;
     struct sigaction act;
@@ -931,3 +974,55 @@ void qemu_close_all_open_fd(const int *skip, unsigned int nskip)
         qemu_close_all_open_fd_fallback(skip, nskip, open_max);
     }
 }
+
+int qemu_shm_alloc(size_t size, Error **errp)
+{
+    g_autoptr(GString) shm_name = g_string_new(NULL);
+    int fd, oflag, cur_sequence;
+    static int sequence;
+    mode_t mode;
+
+    cur_sequence = qatomic_fetch_inc(&sequence);
+
+    /*
+     * Let's use `mode = 0` because we don't want other processes to open our
+     * memory unless we share the file descriptor with them.
+     */
+    mode = 0;
+    oflag = O_RDWR | O_CREAT | O_EXCL;
+
+    /*
+     * Some operating systems allow creating anonymous POSIX shared memory
+     * objects (e.g. FreeBSD provides the SHM_ANON constant), but this is not
+     * defined by POSIX, so let's create a unique name.
+     *
+     * From Linux's shm_open(3) man-page:
+     *   For  portable  use,  a shared  memory  object should be identified
+     *   by a name of the form /somename;"
+     */
+    g_string_printf(shm_name, "/qemu-" FMT_pid "-shm-%d", getpid(),
+                    cur_sequence);
+
+    fd = shm_open(shm_name->str, oflag, mode);
+    if (fd < 0) {
+        error_setg_errno(errp, errno,
+                         "failed to create POSIX shared memory");
+        return -1;
+    }
+
+    /*
+     * We have the file descriptor, so we no longer need to expose the
+     * POSIX shared memory object. However it will remain allocated as long as
+     * there are file descriptors pointing to it.
+     */
+    shm_unlink(shm_name->str);
+
+    if (ftruncate(fd, size) == -1) {
+        error_setg_errno(errp, errno,
+                         "failed to resize POSIX shared memory to %zu", size);
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}