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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] libxc: xc_ptrace cleanup
There are some bugs in PTRACE_PEEK/POKE. - can't track 2MB pages in 32bit pae mode. - leakage of mmap/munmap. Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx> diff -r 84af3ded5b02 tools/libxc/xc_ptrace.c
--- a/tools/libxc/xc_ptrace.c Thu Feb 19 11:07:33 2009 +0000
+++ b/tools/libxc/xc_ptrace.c Fri Feb 20 15:30:51 2009 +0900
@@ -149,173 +149,6 @@ online_vcpus_changed(uint64_t cpumap)
}
-/* --------------------- */
-/* XXX application state */
-static long nr_pages = 0;
-static uint64_t *page_array = NULL;
-
-static uint64_t to_ma(int cpu, uint64_t maddr)
-{
- return maddr;
-}
-
-static void *
-map_domain_va_32(
- int xc_handle,
- int cpu,
- void *guest_va,
- int perm)
-{
- unsigned long l2e, l1e, l1p, p, va = (unsigned long)guest_va;
- uint32_t *l2, *l1;
- static void *v[MAX_VIRT_CPUS];
-
- l2 = xc_map_foreign_range(
- xc_handle, current_domid, PAGE_SIZE, PROT_READ,
- xen_cr3_to_pfn(ctxt[cpu].c.ctrlreg[3]));
- if ( l2 == NULL )
- return NULL;
-
- l2e = l2[l2_table_offset_i386(va)];
- munmap(l2, PAGE_SIZE);
- if ( !(l2e & _PAGE_PRESENT) )
- return NULL;
- l1p = to_ma(cpu, l2e);
- l1 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, PROT_READ,
l1p >> PAGE_SHIFT);
- if ( l1 == NULL )
- return NULL;
-
- l1e = l1[l1_table_offset_i386(va)];
- munmap(l1, PAGE_SIZE);
- if ( !(l1e & _PAGE_PRESENT) )
- return NULL;
- p = to_ma(cpu, l1e);
- if ( v[cpu] != NULL )
- munmap(v[cpu], PAGE_SIZE);
- v[cpu] = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, perm, p
>> PAGE_SHIFT);
- if ( v[cpu] == NULL )
- return NULL;
-
- return (void *)((unsigned long)v[cpu] | (va & (PAGE_SIZE - 1)));
-}
-
-
-static void *
-map_domain_va_pae(
- int xc_handle,
- int cpu,
- void *guest_va,
- int perm)
-{
- uint64_t l3e, l2e, l1e, l2p, l1p, p;
- unsigned long va = (unsigned long)guest_va;
- uint64_t *l3, *l2, *l1;
- static void *v[MAX_VIRT_CPUS];
-
- l3 = xc_map_foreign_range(
- xc_handle, current_domid, PAGE_SIZE, PROT_READ,
- xen_cr3_to_pfn(ctxt[cpu].c.ctrlreg[3]));
- if ( l3 == NULL )
- return NULL;
-
- l3e = l3[l3_table_offset_pae(va)];
- munmap(l3, PAGE_SIZE);
- if ( !(l3e & _PAGE_PRESENT) )
- return NULL;
- l2p = to_ma(cpu, l3e);
- l2 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, PROT_READ,
l2p >> PAGE_SHIFT);
- if ( l2 == NULL )
- return NULL;
-
- l2e = l2[l2_table_offset_pae(va)];
- munmap(l2, PAGE_SIZE);
- if ( !(l2e & _PAGE_PRESENT) )
- return NULL;
- l1p = to_ma(cpu, l2e);
- l1 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, PROT_READ,
l1p >> PAGE_SHIFT);
- if ( l1 == NULL )
- return NULL;
-
- l1e = l1[l1_table_offset_pae(va)];
- munmap(l1, PAGE_SIZE);
- if ( !(l1e & _PAGE_PRESENT) )
- return NULL;
- p = to_ma(cpu, l1e);
- if ( v[cpu] != NULL )
- munmap(v[cpu], PAGE_SIZE);
- v[cpu] = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, perm, p
>> PAGE_SHIFT);
- if ( v[cpu] == NULL )
- return NULL;
-
- return (void *)((unsigned long)v[cpu] | (va & (PAGE_SIZE - 1)));
-}
-
-#ifdef __x86_64__
-static void *
-map_domain_va_64(
- int xc_handle,
- int cpu,
- void *guest_va,
- int perm)
-{
- unsigned long l4e, l3e, l2e, l1e, l3p, l2p, l1p, p, va = (unsigned
long)guest_va;
- uint64_t *l4, *l3, *l2, *l1;
- static void *v[MAX_VIRT_CPUS];
-
- if ((ctxt[cpu].c.ctrlreg[4] & 0x20) == 0 ) /* legacy ia32 mode */
- return map_domain_va_32(xc_handle, cpu, guest_va, perm);
-
- l4 = xc_map_foreign_range(
- xc_handle, current_domid, PAGE_SIZE, PROT_READ,
- xen_cr3_to_pfn(ctxt[cpu].c.ctrlreg[3]));
- if ( l4 == NULL )
- return NULL;
-
- l4e = l4[l4_table_offset(va)];
- munmap(l4, PAGE_SIZE);
- if ( !(l4e & _PAGE_PRESENT) )
- return NULL;
- l3p = to_ma(cpu, l4e);
- l3 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, PROT_READ,
l3p >> PAGE_SHIFT);
- if ( l3 == NULL )
- return NULL;
-
- l3e = l3[l3_table_offset(va)];
- munmap(l3, PAGE_SIZE);
- if ( !(l3e & _PAGE_PRESENT) )
- return NULL;
- l2p = to_ma(cpu, l3e);
- l2 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, PROT_READ,
l2p >> PAGE_SHIFT);
- if ( l2 == NULL )
- return NULL;
-
- l2e = l2[l2_table_offset(va)];
- munmap(l2, PAGE_SIZE);
- if ( !(l2e & _PAGE_PRESENT) )
- return NULL;
- l1p = to_ma(cpu, l2e);
- if (l2e & 0x80) { /* 2M pages */
- p = to_ma(cpu, l1p + (l1_table_offset(va) << PAGE_SHIFT));
- } else { /* 4K pages */
- l1 = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE,
PROT_READ, l1p >> PAGE_SHIFT);
- if ( l1 == NULL )
- return NULL;
-
- l1e = l1[l1_table_offset(va)];
- munmap(l1, PAGE_SIZE);
- if ( !(l1e & _PAGE_PRESENT) )
- return NULL;
- p = to_ma(cpu, l1e);
- }
- if ( v[cpu] != NULL )
- munmap(v[cpu], PAGE_SIZE);
- v[cpu] = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE, perm, p
>> PAGE_SHIFT);
- if ( v[cpu] == NULL )
- return NULL;
-
- return (void *)((unsigned long)v[cpu] | (va & (PAGE_SIZE - 1)));
-}
-#endif
static void *
map_domain_va(
@@ -324,68 +157,30 @@ map_domain_va(
void *guest_va,
int perm)
{
- unsigned long va = (unsigned long) guest_va;
- long npgs = xc_get_tot_pages(xc_handle, current_domid);
- static enum { MODE_UNKNOWN, MODE_64, MODE_32, MODE_PAE } mode;
+ unsigned long va = (unsigned long)guest_va;
+ unsigned long mfn;
+ void *map;
- if ( mode == MODE_UNKNOWN )
- {
- xen_capabilities_info_t caps;
- (void)xc_version(xc_handle, XENVER_capabilities, caps);
- if ( strstr(caps, "-x86_64") )
- mode = MODE_64;
- else if ( strstr(caps, "-x86_32p") )
- mode = MODE_PAE;
- else if ( strstr(caps, "-x86_32") )
- mode = MODE_32;
- }
-
- if ( nr_pages != npgs )
- {
- if ( nr_pages > 0 )
- free(page_array);
- nr_pages = npgs;
- if ( (page_array = malloc(nr_pages * sizeof(*page_array))) == NULL )
- {
- IPRINTF("Could not allocate memory\n");
- return NULL;
- }
- if ( xc_get_pfn_list(xc_handle, current_domid,
- page_array, nr_pages) != nr_pages )
- {
- IPRINTF("Could not get the page frame list\n");
- return NULL;
- }
- }
-
- if (fetch_regs(xc_handle, cpu, NULL))
+ /* cross page boundary */
+ if ( (va & ~PAGE_MASK) + sizeof(long) > PAGE_SIZE )
return NULL;
- if (!paging_enabled(&ctxt[cpu])) {
- static void * v;
- uint64_t page;
+ mfn = xc_translate_foreign_address(xc_handle, current_domid, cpu, va);
+ if ( mfn == 0 )
+ return NULL;
- if ( v != NULL )
- munmap(v, PAGE_SIZE);
+ map = xc_map_foreign_range(xc_handle, current_domid, PAGE_SIZE,
+ perm, mfn);
+ if (map == NULL)
+ return NULL;
- page = to_ma(cpu, va);
+ return map + (va & ~PAGE_MASK);
+}
- v = xc_map_foreign_range( xc_handle, current_domid, PAGE_SIZE,
- perm, page >> PAGE_SHIFT);
-
- if ( v == NULL )
- return NULL;
-
- return (void *)(((unsigned long)v) | (va & BSD_PAGE_MASK));
- }
-#ifdef __x86_64__
- if ( mode == MODE_64 )
- return map_domain_va_64(xc_handle, cpu, guest_va, perm);
-#endif
- if ( mode == MODE_PAE )
- return map_domain_va_pae(xc_handle, cpu, guest_va, perm);
- /* else ( mode == MODE_32 ) */
- return map_domain_va_32(xc_handle, cpu, guest_va, perm);
+static void
+unmap_domain_va(void *guest_va)
+{
+ munmap((void *)((unsigned long)guest_va & PAGE_MASK), PAGE_SIZE);
}
int control_c_pressed_flag = 0;
@@ -473,6 +268,8 @@ xc_ptrace(
if ( guest_va == NULL )
goto out_error;
retval = *guest_va;
+ if (!current_isfile)
+ unmap_domain_va(guest_va);
break;
case PTRACE_POKETEXT:
@@ -486,7 +283,9 @@ xc_ptrace(
xc_handle, cpu, addr, PROT_READ|PROT_WRITE);
if ( guest_va == NULL )
goto out_error;
- *guest_va = (unsigned long)data;
+ *guest_va = edata;
+ if (!current_isfile)
+ unmap_domain_va(guest_va);
break;
case PTRACE_GETREGS:
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