Preliminary BSD user emulator support

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5544 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 545 insertions, 0 deletions

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
new file mode 100644
index 0000000..754268c
--- /dev/null
+++ b/bsd-user/mmap.c
@@ -0,0 +1,545 @@
+/*
+ *  mmap support for qemu
+ *
+ *  Copyright (c) 2003 - 2008 Fabrice Bellard
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "qemu.h"
+#include "qemu-common.h"
+
+//#define DEBUG_MMAP
+
+#if defined(USE_NPTL)
+pthread_mutex_t mmap_mutex;
+static int __thread mmap_lock_count;
+
+void mmap_lock(void)
+{
+    if (mmap_lock_count++ == 0) {
+        pthread_mutex_lock(&mmap_mutex);
+    }
+}
+
+void mmap_unlock(void)
+{
+    if (--mmap_lock_count == 0) {
+        pthread_mutex_unlock(&mmap_mutex);
+    }
+}
+
+/* Grab lock to make sure things are in a consistent state after fork().  */
+void mmap_fork_start(void)
+{
+    if (mmap_lock_count)
+        abort();
+    pthread_mutex_lock(&mmap_mutex);
+}
+
+void mmap_fork_end(int child)
+{
+    if (child)
+        pthread_mutex_init(&mmap_mutex, NULL);
+    else
+        pthread_mutex_unlock(&mmap_mutex);
+}
+#else
+/* We aren't threadsafe to start with, so no need to worry about locking.  */
+void mmap_lock(void)
+{
+}
+
+void mmap_unlock(void)
+{
+}
+#endif
+
+void *qemu_vmalloc(size_t size)
+{
+    void *p;
+    unsigned long addr;
+    mmap_lock();
+    /* Use map and mark the pages as used.  */
+    p = mmap(NULL, size, PROT_READ | PROT_WRITE,
+             MAP_PRIVATE | MAP_ANON, -1, 0);
+
+    addr = (unsigned long)p;
+    if (addr == (target_ulong) addr) {
+        /* Allocated region overlaps guest address space.
+           This may recurse.  */
+        page_set_flags(addr & TARGET_PAGE_MASK, TARGET_PAGE_ALIGN(addr + size),
+                       PAGE_RESERVED);
+    }
+
+    mmap_unlock();
+    return p;
+}
+
+void *qemu_malloc(size_t size)
+{
+    char * p;
+    size += 16;
+    p = qemu_vmalloc(size);
+    *(size_t *)p = size;
+    return p + 16;
+}
+
+/* We use map, which is always zero initialized.  */
+void * qemu_mallocz(size_t size)
+{
+    return qemu_malloc(size);
+}
+
+void qemu_free(void *ptr)
+{
+    /* FIXME: We should unmark the reserved pages here.  However this gets
+       complicated when one target page spans multiple host pages, so we
+       don't bother.  */
+    size_t *p;
+    p = (size_t *)((char *)ptr - 16);
+    munmap(p, *p);
+}
+
+/* NOTE: all the constants are the HOST ones, but addresses are target. */
+int target_mprotect(abi_ulong start, abi_ulong len, int prot)
+{
+    abi_ulong end, host_start, host_end, addr;
+    int prot1, ret;
+
+#ifdef DEBUG_MMAP
+    printf("mprotect: start=0x" TARGET_FMT_lx
+           " len=0x" TARGET_FMT_lx " prot=%c%c%c\n", start, len,
+           prot & PROT_READ ? 'r' : '-',
+           prot & PROT_WRITE ? 'w' : '-',
+           prot & PROT_EXEC ? 'x' : '-');
+#endif
+
+    if ((start & ~TARGET_PAGE_MASK) != 0)
+        return -EINVAL;
+    len = TARGET_PAGE_ALIGN(len);
+    end = start + len;
+    if (end < start)
+        return -EINVAL;
+    prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
+    if (len == 0)
+        return 0;
+
+    mmap_lock();
+    host_start = start & qemu_host_page_mask;
+    host_end = HOST_PAGE_ALIGN(end);
+    if (start > host_start) {
+        /* handle host page containing start */
+        prot1 = prot;
+        for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
+            prot1 |= page_get_flags(addr);
+        }
+        if (host_end == host_start + qemu_host_page_size) {
+            for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+                prot1 |= page_get_flags(addr);
+            }
+            end = host_end;
+        }
+        ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
+        if (ret != 0)
+            goto error;
+        host_start += qemu_host_page_size;
+    }
+    if (end < host_end) {
+        prot1 = prot;
+        for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+            prot1 |= page_get_flags(addr);
+        }
+        ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
+                       prot1 & PAGE_BITS);
+        if (ret != 0)
+            goto error;
+        host_end -= qemu_host_page_size;
+    }
+
+    /* handle the pages in the middle */
+    if (host_start < host_end) {
+        ret = mprotect(g2h(host_start), host_end - host_start, prot);
+        if (ret != 0)
+            goto error;
+    }
+    page_set_flags(start, start + len, prot | PAGE_VALID);
+    mmap_unlock();
+    return 0;
+error:
+    mmap_unlock();
+    return ret;
+}
+
+/* map an incomplete host page */
+static int mmap_frag(abi_ulong real_start,
+                     abi_ulong start, abi_ulong end,
+                     int prot, int flags, int fd, abi_ulong offset)
+{
+    abi_ulong real_end, addr;
+    void *host_start;
+    int prot1, prot_new;
+
+    real_end = real_start + qemu_host_page_size;
+    host_start = g2h(real_start);
+
+    /* get the protection of the target pages outside the mapping */
+    prot1 = 0;
+    for(addr = real_start; addr < real_end; addr++) {
+        if (addr < start || addr >= end)
+            prot1 |= page_get_flags(addr);
+    }
+
+    if (prot1 == 0) {
+        /* no page was there, so we allocate one */
+        void *p = mmap(host_start, qemu_host_page_size, prot,
+                       flags | MAP_ANON, -1, 0);
+        if (p == MAP_FAILED)
+            return -1;
+        prot1 = prot;
+    }
+    prot1 &= PAGE_BITS;
+
+    prot_new = prot | prot1;
+    if (!(flags & MAP_ANON)) {
+        /* msync() won't work here, so we return an error if write is
+           possible while it is a shared mapping */
+        if ((flags & MAP_FLAGMASK) == MAP_SHARED &&
+            (prot & PROT_WRITE))
+            return -EINVAL;
+
+        /* adjust protection to be able to read */
+        if (!(prot1 & PROT_WRITE))
+            mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
+
+        /* read the corresponding file data */
+        pread(fd, g2h(start), end - start, offset);
+
+        /* put final protection */
+        if (prot_new != (prot1 | PROT_WRITE))
+            mprotect(host_start, qemu_host_page_size, prot_new);
+    } else {
+        /* just update the protection */
+        if (prot_new != prot1) {
+            mprotect(host_start, qemu_host_page_size, prot_new);
+        }
+    }
+    return 0;
+}
+
+#if defined(__CYGWIN__)
+/* Cygwin doesn't have a whole lot of address space.  */
+static abi_ulong mmap_next_start = 0x18000000;
+#else
+static abi_ulong mmap_next_start = 0x40000000;
+#endif
+
+unsigned long last_brk;
+
+/* find a free memory area of size 'size'. The search starts at
+   'start'. If 'start' == 0, then a default start address is used.
+   Return -1 if error.
+*/
+/* page_init() marks pages used by the host as reserved to be sure not
+   to use them. */
+static abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
+{
+    abi_ulong addr, addr1, addr_start;
+    int prot;
+    unsigned long new_brk;
+
+    new_brk = (unsigned long)sbrk(0);
+    if (last_brk && last_brk < new_brk && last_brk == (target_ulong)last_brk) {
+        /* This is a hack to catch the host allocating memory with brk().
+           If it uses mmap then we loose.
+           FIXME: We really want to avoid the host allocating memory in
+           the first place, and maybe leave some slack to avoid switching
+           to mmap.  */
+        page_set_flags(last_brk & TARGET_PAGE_MASK,
+                       TARGET_PAGE_ALIGN(new_brk),
+                       PAGE_RESERVED);
+    }
+    last_brk = new_brk;
+
+    size = HOST_PAGE_ALIGN(size);
+    start = start & qemu_host_page_mask;
+    addr = start;
+    if (addr == 0)
+        addr = mmap_next_start;
+    addr_start = addr;
+    for(;;) {
+        prot = 0;
+        for(addr1 = addr; addr1 < (addr + size); addr1 += TARGET_PAGE_SIZE) {
+            prot |= page_get_flags(addr1);
+        }
+        if (prot == 0)
+            break;
+        addr += qemu_host_page_size;
+        /* we found nothing */
+        if (addr == addr_start)
+            return (abi_ulong)-1;
+    }
+    if (start == 0)
+        mmap_next_start = addr + size;
+    return addr;
+}
+
+/* NOTE: all the constants are the HOST ones */
+abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
+                     int flags, int fd, abi_ulong offset)
+{
+    abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
+    unsigned long host_start;
+
+    mmap_lock();
+#ifdef DEBUG_MMAP
+    {
+        printf("mmap: start=0x" TARGET_FMT_lx
+               " len=0x" TARGET_FMT_lx " prot=%c%c%c flags=",
+               start, len,
+               prot & PROT_READ ? 'r' : '-',
+               prot & PROT_WRITE ? 'w' : '-',
+               prot & PROT_EXEC ? 'x' : '-');
+        if (flags & MAP_FIXED)
+            printf("MAP_FIXED ");
+        if (flags & MAP_ANON)
+            printf("MAP_ANON ");
+        switch(flags & MAP_FLAGMASK) {
+        case MAP_PRIVATE:
+            printf("MAP_PRIVATE ");
+            break;
+        case MAP_SHARED:
+            printf("MAP_SHARED ");
+            break;
+        default:
+            printf("[MAP_FLAGMASK=0x%x] ", flags & MAP_FLAGMASK);
+            break;
+        }
+        printf("fd=%d offset=" TARGET_FMT_lx "\n", fd, offset);
+    }
+#endif
+
+    if (offset & ~TARGET_PAGE_MASK) {
+        errno = EINVAL;
+        goto fail;
+    }
+
+    len = TARGET_PAGE_ALIGN(len);
+    if (len == 0)
+        goto the_end;
+    real_start = start & qemu_host_page_mask;
+
+    if (!(flags & MAP_FIXED)) {
+        abi_ulong mmap_start;
+        void *p;
+        host_offset = offset & qemu_host_page_mask;
+        host_len = len + offset - host_offset;
+        host_len = HOST_PAGE_ALIGN(host_len);
+        mmap_start = mmap_find_vma(real_start, host_len);
+        if (mmap_start == (abi_ulong)-1) {
+            errno = ENOMEM;
+            goto fail;
+        }
+        /* Note: we prefer to control the mapping address. It is
+           especially important if qemu_host_page_size >
+           qemu_real_host_page_size */
+        p = mmap(g2h(mmap_start),
+                 host_len, prot, flags | MAP_FIXED, fd, host_offset);
+        if (p == MAP_FAILED)
+            goto fail;
+        /* update start so that it points to the file position at 'offset' */
+        host_start = (unsigned long)p;
+        if (!(flags & MAP_ANON))
+            host_start += offset - host_offset;
+        start = h2g(host_start);
+    } else {
+        int flg;
+        target_ulong addr;
+
+        if (start & ~TARGET_PAGE_MASK) {
+            errno = EINVAL;
+            goto fail;
+        }
+        end = start + len;
+        real_end = HOST_PAGE_ALIGN(end);
+
+        for(addr = real_start; addr < real_end; addr += TARGET_PAGE_SIZE) {
+            flg = page_get_flags(addr);
+            if (flg & PAGE_RESERVED) {
+                errno = ENXIO;
+                goto fail;
+            }
+        }
+
+        /* worst case: we cannot map the file because the offset is not
+           aligned, so we read it */
+        if (!(flags & MAP_ANON) &&
+            (offset & ~qemu_host_page_mask) != (start & ~qemu_host_page_mask)) {
+            /* msync() won't work here, so we return an error if write is
+               possible while it is a shared mapping */
+            if ((flags & MAP_FLAGMASK) == MAP_SHARED &&
+                (prot & PROT_WRITE)) {
+                errno = EINVAL;
+                goto fail;
+            }
+            retaddr = target_mmap(start, len, prot | PROT_WRITE,
+                                  MAP_FIXED | MAP_PRIVATE | MAP_ANON,
+                                  -1, 0);
+            if (retaddr == -1)
+                goto fail;
+            pread(fd, g2h(start), len, offset);
+            if (!(prot & PROT_WRITE)) {
+                ret = target_mprotect(start, len, prot);
+                if (ret != 0) {
+                    start = ret;
+                    goto the_end;
+                }
+            }
+            goto the_end;
+        }
+
+        /* handle the start of the mapping */
+        if (start > real_start) {
+            if (real_end == real_start + qemu_host_page_size) {
+                /* one single host page */
+                ret = mmap_frag(real_start, start, end,
+                                prot, flags, fd, offset);
+                if (ret == -1)
+                    goto fail;
+                goto the_end1;
+            }
+            ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
+                            prot, flags, fd, offset);
+            if (ret == -1)
+                goto fail;
+            real_start += qemu_host_page_size;
+        }
+        /* handle the end of the mapping */
+        if (end < real_end) {
+            ret = mmap_frag(real_end - qemu_host_page_size,
+                            real_end - qemu_host_page_size, real_end,
+                            prot, flags, fd,
+                            offset + real_end - qemu_host_page_size - start);
+            if (ret == -1)
+                goto fail;
+            real_end -= qemu_host_page_size;
+        }
+
+        /* map the middle (easier) */
+        if (real_start < real_end) {
+            void *p;
+            unsigned long offset1;
+            if (flags & MAP_ANON)
+                offset1 = 0;
+            else
+                offset1 = offset + real_start - start;
+            p = mmap(g2h(real_start), real_end - real_start,
+                     prot, flags, fd, offset1);
+            if (p == MAP_FAILED)
+                goto fail;
+        }
+    }
+ the_end1:
+    page_set_flags(start, start + len, prot | PAGE_VALID);
+ the_end:
+#ifdef DEBUG_MMAP
+    printf("ret=0x" TARGET_FMT_lx "\n", start);
+    page_dump(stdout);
+    printf("\n");
+#endif
+    mmap_unlock();
+    return start;
+fail:
+    mmap_unlock();
+    return -1;
+}
+
+int target_munmap(abi_ulong start, abi_ulong len)
+{
+    abi_ulong end, real_start, real_end, addr;
+    int prot, ret;
+
+#ifdef DEBUG_MMAP
+    printf("munmap: start=0x%lx len=0x%lx\n", start, len);
+#endif
+    if (start & ~TARGET_PAGE_MASK)
+        return -EINVAL;
+    len = TARGET_PAGE_ALIGN(len);
+    if (len == 0)
+        return -EINVAL;
+    mmap_lock();
+    end = start + len;
+    real_start = start & qemu_host_page_mask;
+    real_end = HOST_PAGE_ALIGN(end);
+
+    if (start > real_start) {
+        /* handle host page containing start */
+        prot = 0;
+        for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
+            prot |= page_get_flags(addr);
+        }
+        if (real_end == real_start + qemu_host_page_size) {
+            for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+                prot |= page_get_flags(addr);
+            }
+            end = real_end;
+        }
+        if (prot != 0)
+            real_start += qemu_host_page_size;
+    }
+    if (end < real_end) {
+        prot = 0;
+        for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
+            prot |= page_get_flags(addr);
+        }
+        if (prot != 0)
+            real_end -= qemu_host_page_size;
+    }
+
+    ret = 0;
+    /* unmap what we can */
+    if (real_start < real_end) {
+        ret = munmap(g2h(real_start), real_end - real_start);
+    }
+
+    if (ret == 0)
+        page_set_flags(start, start + len, 0);
+    mmap_unlock();
+    return ret;
+}
+
+int target_msync(abi_ulong start, abi_ulong len, int flags)
+{
+    abi_ulong end;
+
+    if (start & ~TARGET_PAGE_MASK)
+        return -EINVAL;
+    len = TARGET_PAGE_ALIGN(len);
+    end = start + len;
+    if (end < start)
+        return -EINVAL;
+    if (end == start)
+        return 0;
+
+    start &= qemu_host_page_mask;
+    return msync(g2h(start), end - start, flags);
+}