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Avoid accessing guest memory directly in usermode emulation.

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git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@1790 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
pbrook 2006-03-25 19:31:22 +00:00
parent 26f69dc09f
commit 53a5960aad
15 changed files with 1195 additions and 773 deletions
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164
linux-user/mmap.c
View file

@ -29,10 +29,10 @@
//#define DEBUG_MMAP
/* NOTE: all the constants are the HOST ones */
int target_mprotect(unsigned long start, unsigned long len, int prot)
/* NOTE: all the constants are the HOST ones, but addresses are target. */
int target_mprotect(target_ulong start, target_ulong len, int prot)
{
unsigned long end, host_start, host_end, addr;
target_ulong end, host_start, host_end, addr;
int prot1, ret;
#ifdef DEBUG_MMAP
@ -67,7 +67,7 @@ int target_mprotect(unsigned long start, unsigned long len, int prot)
}
end = host_end;
}
ret = mprotect((void *)host_start, qemu_host_page_size, prot1 & PAGE_BITS);
ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
if (ret != 0)
return ret;
host_start += qemu_host_page_size;
@ -77,7 +77,7 @@ int target_mprotect(unsigned long start, unsigned long len, int prot)
for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
prot1 |= page_get_flags(addr);
}
ret = mprotect((void *)(host_end - qemu_host_page_size), qemu_host_page_size,
ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
prot1 & PAGE_BITS);
if (ret != 0)
return ret;
@ -86,7 +86,7 @@ int target_mprotect(unsigned long start, unsigned long len, int prot)
/* handle the pages in the middle */
if (host_start < host_end) {
ret = mprotect((void *)host_start, host_end - host_start, prot);
ret = mprotect(g2h(host_start), host_end - host_start, prot);
if (ret != 0)
return ret;
}
@ -95,28 +95,31 @@ int target_mprotect(unsigned long start, unsigned long len, int prot)
}
/* map an incomplete host page */
int mmap_frag(unsigned long host_start,
unsigned long start, unsigned long end,
int prot, int flags, int fd, unsigned long offset)
static int mmap_frag(target_ulong real_start,
target_ulong start, target_ulong end,
int prot, int flags, int fd, target_ulong offset)
{
unsigned long host_end, ret, addr;
target_ulong real_end, ret, addr;
void *host_start;
int prot1, prot_new;
host_end = host_start + qemu_host_page_size;
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 = host_start; addr < host_end; addr++) {
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 */
ret = (long)mmap((void *)host_start, qemu_host_page_size, prot,
ret = (long)mmap(host_start, qemu_host_page_size, prot,
flags | MAP_ANONYMOUS, -1, 0);
if (ret == -1)
return ret;
prot1 = prot;
}
prot1 &= PAGE_BITS;
@ -130,31 +133,35 @@ int mmap_frag(unsigned long host_start,
/* adjust protection to be able to read */
if (!(prot1 & PROT_WRITE))
mprotect((void *)host_start, qemu_host_page_size, prot1 | PROT_WRITE);
mprotect(host_start, qemu_host_page_size, prot1 | PROT_WRITE);
/* read the corresponding file data */
pread(fd, (void *)start, end - start, offset);
pread(fd, g2h(start), end - start, offset);
/* put final protection */
if (prot_new != (prot1 | PROT_WRITE))
mprotect((void *)host_start, qemu_host_page_size, prot_new);
mprotect(host_start, qemu_host_page_size, prot_new);
} else {
/* just update the protection */
if (prot_new != prot1) {
mprotect((void *)host_start, qemu_host_page_size, prot_new);
mprotect(host_start, qemu_host_page_size, prot_new);
}
}
return 0;
}
/* NOTE: all the constants are the HOST ones */
long target_mmap(unsigned long start, unsigned long len, int prot,
int flags, int fd, unsigned long offset)
long target_mmap(target_ulong start, target_ulong len, int prot,
int flags, int fd, target_ulong offset)
{
unsigned long ret, end, host_start, host_end, retaddr, host_offset, host_len;
target_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
long host_start;
#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
defined(__ia64)
static unsigned long last_start = 0x40000000;
static target_ulong last_start = 0x40000000;
#elif defined(__CYGWIN__)
/* Cygwin doesn't have a whole lot of address space. */
static target_ulong last_start = 0x18000000;
#endif
#ifdef DEBUG_MMAP
@ -191,45 +198,49 @@ long target_mmap(unsigned long start, unsigned long len, int prot,
len = TARGET_PAGE_ALIGN(len);
if (len == 0)
return start;
host_start = start & qemu_host_page_mask;
real_start = start & qemu_host_page_mask;
if (!(flags & MAP_FIXED)) {
#if defined(__alpha__) || defined(__sparc__) || defined(__x86_64__) || \
defined(__ia64)
defined(__ia64) || defined(__CYGWIN__)
/* tell the kenel to search at the same place as i386 */
if (host_start == 0) {
host_start = last_start;
if (real_start == 0) {
real_start = last_start;
last_start += HOST_PAGE_ALIGN(len);
}
#endif
if (qemu_host_page_size != qemu_real_host_page_size) {
/* NOTE: this code is only for debugging with '-p' option */
/* ??? Can also occur when TARGET_PAGE_SIZE > host page size. */
/* reserve a memory area */
/* ??? This needs fixing for remapping. */
abort();
host_len = HOST_PAGE_ALIGN(len) + qemu_host_page_size - TARGET_PAGE_SIZE;
host_start = (long)mmap((void *)host_start, host_len, PROT_NONE,
real_start = (long)mmap(g2h(real_start), host_len, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (host_start == -1)
return host_start;
host_end = host_start + host_len;
start = HOST_PAGE_ALIGN(host_start);
if (real_start == -1)
return real_start;
real_end = real_start + host_len;
start = HOST_PAGE_ALIGN(real_start);
end = start + HOST_PAGE_ALIGN(len);
if (start > host_start)
munmap((void *)host_start, start - host_start);
if (end < host_end)
munmap((void *)end, host_end - end);
if (start > real_start)
munmap((void *)real_start, start - real_start);
if (end < real_end)
munmap((void *)end, real_end - end);
/* use it as a fixed mapping */
flags |= MAP_FIXED;
} else {
/* if not fixed, no need to do anything */
host_offset = offset & qemu_host_page_mask;
host_len = len + offset - host_offset;
start = (long)mmap((void *)host_start, host_len,
prot, flags, fd, host_offset);
if (start == -1)
return start;
host_start = (long)mmap(real_start ? g2h(real_start) : NULL,
host_len, prot, flags, fd, host_offset);
if (host_start == -1)
return host_start;
/* update start so that it points to the file position at 'offset' */
if (!(flags & MAP_ANONYMOUS))
start += offset - host_offset;
host_start += offset - host_offset;
start = h2g(host_start);
goto the_end1;
}
}
@ -239,7 +250,7 @@ long target_mmap(unsigned long start, unsigned long len, int prot,
return -1;
}
end = start + len;
host_end = HOST_PAGE_ALIGN(end);
real_end = HOST_PAGE_ALIGN(end);
/* worst case: we cannot map the file because the offset is not
aligned, so we read it */
@ -257,7 +268,7 @@ long target_mmap(unsigned long start, unsigned long len, int prot,
-1, 0);
if (retaddr == -1)
return retaddr;
pread(fd, (void *)start, len, offset);
pread(fd, g2h(start), len, offset);
if (!(prot & PROT_WRITE)) {
ret = target_mprotect(start, len, prot);
if (ret != 0)
@ -267,40 +278,40 @@ long target_mmap(unsigned long start, unsigned long len, int prot,
}
/* handle the start of the mapping */
if (start > host_start) {
if (host_end == host_start + qemu_host_page_size) {
if (start > real_start) {
if (real_end == real_start + qemu_host_page_size) {
/* one single host page */
ret = mmap_frag(host_start, start, end,
ret = mmap_frag(real_start, start, end,
prot, flags, fd, offset);
if (ret == -1)
return ret;
goto the_end1;
}
ret = mmap_frag(host_start, start, host_start + qemu_host_page_size,
ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
prot, flags, fd, offset);
if (ret == -1)
return ret;
host_start += qemu_host_page_size;
real_start += qemu_host_page_size;
}
/* handle the end of the mapping */
if (end < host_end) {
ret = mmap_frag(host_end - qemu_host_page_size,
host_end - qemu_host_page_size, host_end,
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 + host_end - qemu_host_page_size - start);
offset + real_end - qemu_host_page_size - start);
if (ret == -1)
return ret;
host_end -= qemu_host_page_size;
real_end -= qemu_host_page_size;
}
/* map the middle (easier) */
if (host_start < host_end) {
if (real_start < real_end) {
unsigned long offset1;
if (flags & MAP_ANONYMOUS)
offset1 = 0;
else
offset1 = offset + host_start - start;
ret = (long)mmap((void *)host_start, host_end - host_start,
offset1 = offset + real_start - start;
ret = (long)mmap(g2h(real_start), real_end - real_start,
prot, flags, fd, offset1);
if (ret == -1)
return ret;
@ -316,9 +327,9 @@ long target_mmap(unsigned long start, unsigned long len, int prot,
return start;
}
int target_munmap(unsigned long start, unsigned long len)
int target_munmap(target_ulong start, target_ulong len)
{
unsigned long end, host_start, host_end, addr;
target_ulong end, real_start, real_end, addr;
int prot, ret;
#ifdef DEBUG_MMAP
@ -330,36 +341,36 @@ int target_munmap(unsigned long start, unsigned long len)
if (len == 0)
return -EINVAL;
end = start + len;
host_start = start & qemu_host_page_mask;
host_end = HOST_PAGE_ALIGN(end);
real_start = start & qemu_host_page_mask;
real_end = HOST_PAGE_ALIGN(end);
if (start > host_start) {
if (start > real_start) {
/* handle host page containing start */
prot = 0;
for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
for(addr = real_start; addr < start; addr += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr);
}
if (host_end == host_start + qemu_host_page_size) {
for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
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 = host_end;
end = real_end;
}
if (prot != 0)
host_start += qemu_host_page_size;
real_start += qemu_host_page_size;
}
if (end < host_end) {
if (end < real_end) {
prot = 0;
for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
for(addr = end; addr < real_end; addr += TARGET_PAGE_SIZE) {
prot |= page_get_flags(addr);
}
if (prot != 0)
host_end -= qemu_host_page_size;
real_end -= qemu_host_page_size;
}
/* unmap what we can */
if (host_start < host_end) {
ret = munmap((void *)host_start, host_end - host_start);
if (real_start < real_end) {
ret = munmap((void *)real_start, real_end - real_start);
if (ret != 0)
return ret;
}
@ -370,25 +381,26 @@ int target_munmap(unsigned long start, unsigned long len)
/* XXX: currently, we only handle MAP_ANONYMOUS and not MAP_FIXED
blocks which have been allocated starting on a host page */
long target_mremap(unsigned long old_addr, unsigned long old_size,
unsigned long new_size, unsigned long flags,
unsigned long new_addr)
long target_mremap(target_ulong old_addr, target_ulong old_size,
target_ulong new_size, unsigned long flags,
target_ulong new_addr)
{
int prot;
/* XXX: use 5 args syscall */
new_addr = (long)mremap((void *)old_addr, old_size, new_size, flags);
new_addr = (long)mremap(g2h(old_addr), old_size, new_size, flags);
if (new_addr == -1)
return new_addr;
new_addr = h2g(new_addr);
prot = page_get_flags(old_addr);
page_set_flags(old_addr, old_addr + old_size, 0);
page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
return new_addr;
}
int target_msync(unsigned long start, unsigned long len, int flags)
int target_msync(target_ulong start, target_ulong len, int flags)
{
unsigned long end;
target_ulong end;
if (start & ~TARGET_PAGE_MASK)
return -EINVAL;
@ -400,6 +412,6 @@ int target_msync(unsigned long start, unsigned long len, int flags)
return 0;
start &= qemu_host_page_mask;
return msync((void *)start, end - start, flags);
return msync(g2h(start), end - start, flags);
}