* [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support
@ 2016-01-22 12:08 Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 1/6] scripts/dump-guest-memory.py: Move constants to the top Janosch Frank
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
The dump guest memory script for extracting a Linux core from a qemu
core is currently limited to amd64 and python 2.
With this series we add support for python 3 (while maintaining python
2 support) and add the possibility to extract dumps from VMs with the
most common architectures.
Tested on X86_64, s390 and Aarch64-le (thanks to Andrew Jones).
RFC to PATCH:
Tested on X86_64 and Aarch64-le.
Fix wrongly indented return in get_guest_phys_blocks().
Fix wrong indent for predecessor_size that happened when copying.
Fix inconsistent line wrapping.
Fix python 3 compatibility comment being added in the wrong commit.
Fix docstrings that get displayed by gdb.
Replaced ceil(len_desc / 4.0) with ((len_desc + 3) // 4)
Added patch that fixes module docstring to account for moved gdb
help string.
Janosch Frank (6):
scripts/dump-guest-memory.py: Move constants to the top
scripts/dump-guest-memory.py: Make methods functions
scripts/dump-guest-memory.py: Improve python 3 compatibility
scripts/dump-guest-memory.py: Cleanup functions
scripts/dump-guest-memory.py: Introduce multi-arch support
scripts/dump-guest-memory.py: Fix module docstring
scripts/dump-guest-memory.py | 754 +++++++++++++++++++++++++++----------------
1 file changed, 472 insertions(+), 282 deletions(-)
--
2.3.0
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 1/6] scripts/dump-guest-memory.py: Move constants to the top
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 2/6] scripts/dump-guest-memory.py: Make methods functions Janosch Frank
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
The constants bloated the class definition and were therefore moved to
the top.
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 126 +++++++++++++++++++++----------------------
1 file changed, 63 insertions(+), 63 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index 08796ff..e49c835 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -17,6 +17,55 @@
import struct
+TARGET_PAGE_SIZE = 0x1000
+TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
+
+# Various ELF constants
+EM_X86_64 = 62 # AMD x86-64 target machine
+ELFDATA2LSB = 1 # little endian
+ELFCLASS64 = 2
+ELFMAG = "\x7FELF"
+EV_CURRENT = 1
+ET_CORE = 4
+PT_LOAD = 1
+PT_NOTE = 4
+
+# Special value for e_phnum. This indicates that the real number of
+# program headers is too large to fit into e_phnum. Instead the real
+# value is in the field sh_info of section 0.
+PN_XNUM = 0xFFFF
+
+# Format strings for packing and header size calculation.
+ELF64_EHDR = ("4s" # e_ident/magic
+ "B" # e_ident/class
+ "B" # e_ident/data
+ "B" # e_ident/version
+ "B" # e_ident/osabi
+ "8s" # e_ident/pad
+ "H" # e_type
+ "H" # e_machine
+ "I" # e_version
+ "Q" # e_entry
+ "Q" # e_phoff
+ "Q" # e_shoff
+ "I" # e_flags
+ "H" # e_ehsize
+ "H" # e_phentsize
+ "H" # e_phnum
+ "H" # e_shentsize
+ "H" # e_shnum
+ "H" # e_shstrndx
+ )
+ELF64_PHDR = ("I" # p_type
+ "I" # p_flags
+ "Q" # p_offset
+ "Q" # p_vaddr
+ "Q" # p_paddr
+ "Q" # p_filesz
+ "Q" # p_memsz
+ "Q" # p_align
+ )
+
class DumpGuestMemory(gdb.Command):
"""Extract guest vmcore from qemu process coredump.
@@ -47,62 +96,13 @@ deliberately called abort(), or it was dumped in response to a signal at
a halfway fortunate point, then its coredump should be in reasonable
shape and this command should mostly work."""
- TARGET_PAGE_SIZE = 0x1000
- TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
-
- # Various ELF constants
- EM_X86_64 = 62 # AMD x86-64 target machine
- ELFDATA2LSB = 1 # little endian
- ELFCLASS64 = 2
- ELFMAG = "\x7FELF"
- EV_CURRENT = 1
- ET_CORE = 4
- PT_LOAD = 1
- PT_NOTE = 4
-
- # Special value for e_phnum. This indicates that the real number of
- # program headers is too large to fit into e_phnum. Instead the real
- # value is in the field sh_info of section 0.
- PN_XNUM = 0xFFFF
-
- # Format strings for packing and header size calculation.
- ELF64_EHDR = ("4s" # e_ident/magic
- "B" # e_ident/class
- "B" # e_ident/data
- "B" # e_ident/version
- "B" # e_ident/osabi
- "8s" # e_ident/pad
- "H" # e_type
- "H" # e_machine
- "I" # e_version
- "Q" # e_entry
- "Q" # e_phoff
- "Q" # e_shoff
- "I" # e_flags
- "H" # e_ehsize
- "H" # e_phentsize
- "H" # e_phnum
- "H" # e_shentsize
- "H" # e_shnum
- "H" # e_shstrndx
- )
- ELF64_PHDR = ("I" # p_type
- "I" # p_flags
- "Q" # p_offset
- "Q" # p_vaddr
- "Q" # p_paddr
- "Q" # p_filesz
- "Q" # p_memsz
- "Q" # p_align
- )
-
def __init__(self):
super(DumpGuestMemory, self).__init__("dump-guest-memory",
gdb.COMMAND_DATA,
gdb.COMPLETE_FILENAME)
self.uintptr_t = gdb.lookup_type("uintptr_t")
- self.elf64_ehdr_le = struct.Struct("<%s" % self.ELF64_EHDR)
- self.elf64_phdr_le = struct.Struct("<%s" % self.ELF64_PHDR)
+ self.elf64_ehdr_le = struct.Struct("<%s" % ELF64_EHDR)
+ self.elf64_phdr_le = struct.Struct("<%s" % ELF64_PHDR)
def int128_get64(self, val):
assert (val["hi"] == 0)
@@ -130,7 +130,7 @@ shape and this command should mostly work."""
if (mr["alias"] != 0):
return (self.memory_region_get_ram_ptr(mr["alias"].dereference()) +
mr["alias_offset"])
- return self.qemu_get_ram_ptr(mr["ram_addr"] & self.TARGET_PAGE_MASK)
+ return self.qemu_get_ram_ptr(mr["ram_addr"] & TARGET_PAGE_MASK)
def guest_phys_blocks_init(self):
self.guest_phys_blocks = []
@@ -198,21 +198,21 @@ shape and this command should mostly work."""
# most common values. This also means that instruction pointer
# etc. will be bogus in the dump, but at least the RAM contents
# should be valid.
- self.dump_info = {"d_machine": self.EM_X86_64,
- "d_endian" : self.ELFDATA2LSB,
- "d_class" : self.ELFCLASS64}
+ self.dump_info = {"d_machine": EM_X86_64,
+ "d_endian" : ELFDATA2LSB,
+ "d_class" : ELFCLASS64}
def encode_elf64_ehdr_le(self):
return self.elf64_ehdr_le.pack(
- self.ELFMAG, # e_ident/magic
+ ELFMAG, # e_ident/magic
self.dump_info["d_class"], # e_ident/class
self.dump_info["d_endian"], # e_ident/data
- self.EV_CURRENT, # e_ident/version
+ EV_CURRENT, # e_ident/version
0, # e_ident/osabi
"", # e_ident/pad
- self.ET_CORE, # e_type
+ ET_CORE, # e_type
self.dump_info["d_machine"], # e_machine
- self.EV_CURRENT, # e_version
+ EV_CURRENT, # e_version
0, # e_entry
self.elf64_ehdr_le.size, # e_phoff
0, # e_shoff
@@ -226,7 +226,7 @@ shape and this command should mostly work."""
)
def encode_elf64_note_le(self):
- return self.elf64_phdr_le.pack(self.PT_NOTE, # p_type
+ return self.elf64_phdr_le.pack(PT_NOTE, # p_type
0, # p_flags
(self.memory_offset -
len(self.note)), # p_offset
@@ -238,7 +238,7 @@ shape and this command should mostly work."""
)
def encode_elf64_load_le(self, offset, start_hwaddr, range_size):
- return self.elf64_phdr_le.pack(self.PT_LOAD, # p_type
+ return self.elf64_phdr_le.pack(PT_LOAD, # p_type
0, # p_flags
offset, # p_offset
0, # p_vaddr
@@ -276,7 +276,7 @@ shape and this command should mostly work."""
# We should never reach PN_XNUM for paging=false dumps: there's
# just a handful of discontiguous ranges after merging.
self.phdr_num += len(self.guest_phys_blocks)
- assert (self.phdr_num < self.PN_XNUM)
+ assert (self.phdr_num < PN_XNUM)
# Calculate the ELF file offset where the memory dump commences:
#
@@ -312,7 +312,7 @@ shape and this command should mostly work."""
print ("dumping range at %016x for length %016x" %
(cur.cast(self.uintptr_t), left))
while (left > 0):
- chunk_size = min(self.TARGET_PAGE_SIZE, left)
+ chunk_size = min(TARGET_PAGE_SIZE, left)
chunk = qemu_core.read_memory(cur, chunk_size)
vmcore.write(chunk)
cur += chunk_size
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 2/6] scripts/dump-guest-memory.py: Make methods functions
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 1/6] scripts/dump-guest-memory.py: Move constants to the top Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 3/6] scripts/dump-guest-memory.py: Improve python 3 compatibility Janosch Frank
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
The functions dealing with qemu components rarely used parts of the
class, so they were moved out of the class.
As the uintptr_t variable is needed both within and outside the class,
it was made a constant and moved to the top.
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 184 ++++++++++++++++++++++---------------------
1 file changed, 93 insertions(+), 91 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index e49c835..d0b927a 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -17,6 +17,8 @@
import struct
+UINTPTR_T = gdb.lookup_type("uintptr_t")
+
TARGET_PAGE_SIZE = 0x1000
TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
@@ -66,6 +68,94 @@ ELF64_PHDR = ("I" # p_type
"Q" # p_align
)
+def int128_get64(val):
+ assert (val["hi"] == 0)
+ return val["lo"]
+
+def qlist_foreach(head, field_str):
+ var_p = head["lh_first"]
+ while (var_p != 0):
+ var = var_p.dereference()
+ yield var
+ var_p = var[field_str]["le_next"]
+
+def qemu_get_ram_block(ram_addr):
+ ram_blocks = gdb.parse_and_eval("ram_list.blocks")
+ for block in qlist_foreach(ram_blocks, "next"):
+ if (ram_addr - block["offset"] < block["used_length"]):
+ return block
+ raise gdb.GdbError("Bad ram offset %x" % ram_addr)
+
+def qemu_get_ram_ptr(ram_addr):
+ block = qemu_get_ram_block(ram_addr)
+ return block["host"] + (ram_addr - block["offset"])
+
+def memory_region_get_ram_ptr(mr):
+ if (mr["alias"] != 0):
+ return (memory_region_get_ram_ptr(mr["alias"].dereference()) +
+ mr["alias_offset"])
+ return qemu_get_ram_ptr(mr["ram_addr"] & TARGET_PAGE_MASK)
+
+def get_guest_phys_blocks():
+ guest_phys_blocks = []
+ print "guest RAM blocks:"
+ print ("target_start target_end host_addr message "
+ "count")
+ print ("---------------- ---------------- ---------------- ------- "
+ "-----")
+
+ current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
+ current_map = current_map_p.dereference()
+ for cur in range(current_map["nr"]):
+ flat_range = (current_map["ranges"] + cur).dereference()
+ mr = flat_range["mr"].dereference()
+
+ # we only care about RAM
+ if (not mr["ram"]):
+ continue
+
+ section_size = int128_get64(flat_range["addr"]["size"])
+ target_start = int128_get64(flat_range["addr"]["start"])
+ target_end = target_start + section_size
+ host_addr = (memory_region_get_ram_ptr(mr) +
+ flat_range["offset_in_region"])
+ predecessor = None
+
+ # find continuity in guest physical address space
+ if (len(guest_phys_blocks) > 0):
+ predecessor = guest_phys_blocks[-1]
+ predecessor_size = (predecessor["target_end"] -
+ predecessor["target_start"])
+
+ # the memory API guarantees monotonically increasing
+ # traversal
+ assert (predecessor["target_end"] <= target_start)
+
+ # we want continuity in both guest-physical and
+ # host-virtual memory
+ if (predecessor["target_end"] < target_start or
+ predecessor["host_addr"] + predecessor_size != host_addr):
+ predecessor = None
+
+ if (predecessor is None):
+ # isolated mapping, add it to the list
+ guest_phys_blocks.append({"target_start": target_start,
+ "target_end" : target_end,
+ "host_addr" : host_addr})
+ message = "added"
+ else:
+ # expand predecessor until @target_end; predecessor's
+ # start doesn't change
+ predecessor["target_end"] = target_end
+ message = "joined"
+
+ print ("%016x %016x %016x %-7s %5u" %
+ (target_start, target_end, host_addr.cast(UINTPTR_T),
+ message, len(guest_phys_blocks)))
+
+ return guest_phys_blocks
+
+
class DumpGuestMemory(gdb.Command):
"""Extract guest vmcore from qemu process coredump.
@@ -100,96 +190,9 @@ shape and this command should mostly work."""
super(DumpGuestMemory, self).__init__("dump-guest-memory",
gdb.COMMAND_DATA,
gdb.COMPLETE_FILENAME)
- self.uintptr_t = gdb.lookup_type("uintptr_t")
self.elf64_ehdr_le = struct.Struct("<%s" % ELF64_EHDR)
self.elf64_phdr_le = struct.Struct("<%s" % ELF64_PHDR)
-
- def int128_get64(self, val):
- assert (val["hi"] == 0)
- return val["lo"]
-
- def qlist_foreach(self, head, field_str):
- var_p = head["lh_first"]
- while (var_p != 0):
- var = var_p.dereference()
- yield var
- var_p = var[field_str]["le_next"]
-
- def qemu_get_ram_block(self, ram_addr):
- ram_blocks = gdb.parse_and_eval("ram_list.blocks")
- for block in self.qlist_foreach(ram_blocks, "next"):
- if (ram_addr - block["offset"] < block["used_length"]):
- return block
- raise gdb.GdbError("Bad ram offset %x" % ram_addr)
-
- def qemu_get_ram_ptr(self, ram_addr):
- block = self.qemu_get_ram_block(ram_addr)
- return block["host"] + (ram_addr - block["offset"])
-
- def memory_region_get_ram_ptr(self, mr):
- if (mr["alias"] != 0):
- return (self.memory_region_get_ram_ptr(mr["alias"].dereference()) +
- mr["alias_offset"])
- return self.qemu_get_ram_ptr(mr["ram_addr"] & TARGET_PAGE_MASK)
-
- def guest_phys_blocks_init(self):
- self.guest_phys_blocks = []
-
- def guest_phys_blocks_append(self):
- print "guest RAM blocks:"
- print ("target_start target_end host_addr message "
- "count")
- print ("---------------- ---------------- ---------------- ------- "
- "-----")
-
- current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
- current_map = current_map_p.dereference()
- for cur in range(current_map["nr"]):
- flat_range = (current_map["ranges"] + cur).dereference()
- mr = flat_range["mr"].dereference()
-
- # we only care about RAM
- if (not mr["ram"]):
- continue
-
- section_size = self.int128_get64(flat_range["addr"]["size"])
- target_start = self.int128_get64(flat_range["addr"]["start"])
- target_end = target_start + section_size
- host_addr = (self.memory_region_get_ram_ptr(mr) +
- flat_range["offset_in_region"])
- predecessor = None
-
- # find continuity in guest physical address space
- if (len(self.guest_phys_blocks) > 0):
- predecessor = self.guest_phys_blocks[-1]
- predecessor_size = (predecessor["target_end"] -
- predecessor["target_start"])
-
- # the memory API guarantees monotonically increasing
- # traversal
- assert (predecessor["target_end"] <= target_start)
-
- # we want continuity in both guest-physical and
- # host-virtual memory
- if (predecessor["target_end"] < target_start or
- predecessor["host_addr"] + predecessor_size != host_addr):
- predecessor = None
-
- if (predecessor is None):
- # isolated mapping, add it to the list
- self.guest_phys_blocks.append({"target_start": target_start,
- "target_end" : target_end,
- "host_addr" : host_addr})
- message = "added"
- else:
- # expand predecessor until @target_end; predecessor's
- # start doesn't change
- predecessor["target_end"] = target_end
- message = "joined"
-
- print ("%016x %016x %016x %-7s %5u" %
- (target_start, target_end, host_addr.cast(self.uintptr_t),
- message, len(self.guest_phys_blocks)))
+ self.guest_phys_blocks = None
def cpu_get_dump_info(self):
# We can't synchronize the registers with KVM post-mortem, and
@@ -263,8 +266,7 @@ shape and this command should mostly work."""
len(name) + 1, len(desc), type, name, desc)
def dump_init(self):
- self.guest_phys_blocks_init()
- self.guest_phys_blocks_append()
+ self.guest_phys_blocks = get_guest_phys_blocks()
self.cpu_get_dump_info()
# we have no way to retrieve the VCPU status from KVM
# post-mortem
@@ -310,7 +312,7 @@ shape and this command should mostly work."""
cur = block["host_addr"]
left = block["target_end"] - block["target_start"]
print ("dumping range at %016x for length %016x" %
- (cur.cast(self.uintptr_t), left))
+ (cur.cast(UINTPTR_T), left))
while (left > 0):
chunk_size = min(TARGET_PAGE_SIZE, left)
chunk = qemu_core.read_memory(cur, chunk_size)
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 3/6] scripts/dump-guest-memory.py: Improve python 3 compatibility
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 1/6] scripts/dump-guest-memory.py: Move constants to the top Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 2/6] scripts/dump-guest-memory.py: Make methods functions Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 4/6] scripts/dump-guest-memory.py: Cleanup functions Janosch Frank
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
This commit does not make the script python 3 compatible, it is a
preparation that fixes the easy and common incompatibilities.
Print is a function in python 3 and therefore needs braces around its
arguments.
Range does not cast a gdb.Value object to int in python 3, we have to
do it ourselves.
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index d0b927a..bb4ca8e 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -98,15 +98,19 @@ def memory_region_get_ram_ptr(mr):
def get_guest_phys_blocks():
guest_phys_blocks = []
- print "guest RAM blocks:"
- print ("target_start target_end host_addr message "
- "count")
- print ("---------------- ---------------- ---------------- ------- "
- "-----")
+ print("guest RAM blocks:")
+ print("target_start target_end host_addr message "
+ "count")
+ print("---------------- ---------------- ---------------- ------- "
+ "-----")
current_map_p = gdb.parse_and_eval("address_space_memory.current_map")
current_map = current_map_p.dereference()
- for cur in range(current_map["nr"]):
+
+ # Conversion to int is needed for python 3
+ # compatibility. Otherwise range doesn't cast the value itself and
+ # breaks.
+ for cur in range(int(current_map["nr"])):
flat_range = (current_map["ranges"] + cur).dereference()
mr = flat_range["mr"].dereference()
@@ -149,9 +153,9 @@ def get_guest_phys_blocks():
predecessor["target_end"] = target_end
message = "joined"
- print ("%016x %016x %016x %-7s %5u" %
- (target_start, target_end, host_addr.cast(UINTPTR_T),
- message, len(guest_phys_blocks)))
+ print("%016x %016x %016x %-7s %5u" %
+ (target_start, target_end, host_addr.cast(UINTPTR_T),
+ message, len(guest_phys_blocks)))
return guest_phys_blocks
@@ -311,8 +315,8 @@ shape and this command should mostly work."""
for block in self.guest_phys_blocks:
cur = block["host_addr"]
left = block["target_end"] - block["target_start"]
- print ("dumping range at %016x for length %016x" %
- (cur.cast(UINTPTR_T), left))
+ print("dumping range at %016x for length %016x" %
+ (cur.cast(UINTPTR_T), left))
while (left > 0):
chunk_size = min(TARGET_PAGE_SIZE, left)
chunk = qemu_core.read_memory(cur, chunk_size)
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 4/6] scripts/dump-guest-memory.py: Cleanup functions
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
` (2 preceding siblings ...)
2016-01-22 12:08 ` [Qemu-devel] [PATCH 3/6] scripts/dump-guest-memory.py: Improve python 3 compatibility Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 5/6] scripts/dump-guest-memory.py: Introduce multi-arch support Janosch Frank
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
Increase readability by adding newlines and comments, as well as
removing wrong whitespaces and C style braces around conditionals and
loops.
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 75 +++++++++++++++++++++++++++++---------------
1 file changed, 50 insertions(+), 25 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index bb4ca8e..2cf7365 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -69,35 +69,60 @@ ELF64_PHDR = ("I" # p_type
)
def int128_get64(val):
- assert (val["hi"] == 0)
+ """Returns low 64bit part of Int128 struct."""
+
+ assert val["hi"] == 0
return val["lo"]
+
def qlist_foreach(head, field_str):
+ """Generator for qlists."""
+
var_p = head["lh_first"]
- while (var_p != 0):
+ while var_p != 0:
var = var_p.dereference()
- yield var
var_p = var[field_str]["le_next"]
+ yield var
+
def qemu_get_ram_block(ram_addr):
+ """Returns the RAMBlock struct to which the given address belongs."""
+
ram_blocks = gdb.parse_and_eval("ram_list.blocks")
+
for block in qlist_foreach(ram_blocks, "next"):
- if (ram_addr - block["offset"] < block["used_length"]):
+ if (ram_addr - block["offset"]) < block["used_length"]:
return block
+
raise gdb.GdbError("Bad ram offset %x" % ram_addr)
+
def qemu_get_ram_ptr(ram_addr):
+ """Returns qemu vaddr for given guest physical address."""
+
block = qemu_get_ram_block(ram_addr)
return block["host"] + (ram_addr - block["offset"])
-def memory_region_get_ram_ptr(mr):
- if (mr["alias"] != 0):
- return (memory_region_get_ram_ptr(mr["alias"].dereference()) +
- mr["alias_offset"])
- return qemu_get_ram_ptr(mr["ram_addr"] & TARGET_PAGE_MASK)
+
+def memory_region_get_ram_ptr(memory_region):
+ if memory_region["alias"] != 0:
+ return (memory_region_get_ram_ptr(memory_region["alias"].dereference())
+ + memory_region["alias_offset"])
+
+ return qemu_get_ram_ptr(memory_region["ram_addr"] & TARGET_PAGE_MASK)
+
def get_guest_phys_blocks():
+ """Returns a list of ram blocks.
+
+ Each block entry contains:
+ 'target_start': guest block phys start address
+ 'target_end': guest block phys end address
+ 'host_addr': qemu vaddr of the block's start
+ """
+
guest_phys_blocks = []
+
print("guest RAM blocks:")
print("target_start target_end host_addr message "
"count")
@@ -111,29 +136,29 @@ def get_guest_phys_blocks():
# compatibility. Otherwise range doesn't cast the value itself and
# breaks.
for cur in range(int(current_map["nr"])):
- flat_range = (current_map["ranges"] + cur).dereference()
- mr = flat_range["mr"].dereference()
+ flat_range = (current_map["ranges"] + cur).dereference()
+ memory_region = flat_range["mr"].dereference()
# we only care about RAM
- if (not mr["ram"]):
+ if not memory_region["ram"]:
continue
section_size = int128_get64(flat_range["addr"]["size"])
target_start = int128_get64(flat_range["addr"]["start"])
- target_end = target_start + section_size
- host_addr = (memory_region_get_ram_ptr(mr) +
- flat_range["offset_in_region"])
+ target_end = target_start + section_size
+ host_addr = (memory_region_get_ram_ptr(memory_region)
+ + flat_range["offset_in_region"])
predecessor = None
# find continuity in guest physical address space
- if (len(guest_phys_blocks) > 0):
+ if len(guest_phys_blocks) > 0:
predecessor = guest_phys_blocks[-1]
predecessor_size = (predecessor["target_end"] -
predecessor["target_start"])
# the memory API guarantees monotonically increasing
# traversal
- assert (predecessor["target_end"] <= target_start)
+ assert predecessor["target_end"] <= target_start
# we want continuity in both guest-physical and
# host-virtual memory
@@ -141,11 +166,11 @@ def get_guest_phys_blocks():
predecessor["host_addr"] + predecessor_size != host_addr):
predecessor = None
- if (predecessor is None):
+ if predecessor is None:
# isolated mapping, add it to the list
guest_phys_blocks.append({"target_start": target_start,
- "target_end" : target_end,
- "host_addr" : host_addr})
+ "target_end": target_end,
+ "host_addr": host_addr})
message = "added"
else:
# expand predecessor until @target_end; predecessor's
@@ -282,7 +307,7 @@ shape and this command should mostly work."""
# We should never reach PN_XNUM for paging=false dumps: there's
# just a handful of discontiguous ranges after merging.
self.phdr_num += len(self.guest_phys_blocks)
- assert (self.phdr_num < PN_XNUM)
+ assert self.phdr_num < PN_XNUM
# Calculate the ELF file offset where the memory dump commences:
#
@@ -313,15 +338,15 @@ shape and this command should mostly work."""
def dump_iterate(self, vmcore):
qemu_core = gdb.inferiors()[0]
for block in self.guest_phys_blocks:
- cur = block["host_addr"]
+ cur = block["host_addr"]
left = block["target_end"] - block["target_start"]
print("dumping range at %016x for length %016x" %
(cur.cast(UINTPTR_T), left))
- while (left > 0):
+ while left > 0:
chunk_size = min(TARGET_PAGE_SIZE, left)
chunk = qemu_core.read_memory(cur, chunk_size)
vmcore.write(chunk)
- cur += chunk_size
+ cur += chunk_size
left -= chunk_size
def create_vmcore(self, filename):
@@ -336,7 +361,7 @@ shape and this command should mostly work."""
self.dont_repeat()
argv = gdb.string_to_argv(args)
- if (len(argv) != 1):
+ if len(argv) != 1:
raise gdb.GdbError("usage: dump-guest-memory FILE")
self.dump_init()
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 5/6] scripts/dump-guest-memory.py: Introduce multi-arch support
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
` (3 preceding siblings ...)
2016-01-22 12:08 ` [Qemu-devel] [PATCH 4/6] scripts/dump-guest-memory.py: Cleanup functions Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 6/6] scripts/dump-guest-memory.py: Fix module docstring Janosch Frank
2016-01-22 12:39 ` [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Paolo Bonzini
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
By modelling the ELF with ctypes we not only gain full python 3
support but can also create dumps for different architectures more easily.
Tested-by: Andrew Jones <drjones@redhat.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 486 ++++++++++++++++++++++++++++---------------
1 file changed, 322 insertions(+), 164 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index 2cf7365..7acce65 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -6,6 +6,7 @@
#
# Authors:
# Laszlo Ersek <lersek@redhat.com>
+# Janosch Frank <frankja@linux.vnet.ibm.com>
#
# This work is licensed under the terms of the GNU GPL, version 2 or later. See
# the COPYING file in the top-level directory.
@@ -15,58 +16,303 @@
# "help data" summary), and it should match how other help texts look in
# gdb.
-import struct
+import ctypes
UINTPTR_T = gdb.lookup_type("uintptr_t")
TARGET_PAGE_SIZE = 0x1000
TARGET_PAGE_MASK = 0xFFFFFFFFFFFFF000
-# Various ELF constants
-EM_X86_64 = 62 # AMD x86-64 target machine
-ELFDATA2LSB = 1 # little endian
-ELFCLASS64 = 2
-ELFMAG = "\x7FELF"
-EV_CURRENT = 1
-ET_CORE = 4
-PT_LOAD = 1
-PT_NOTE = 4
-
# Special value for e_phnum. This indicates that the real number of
# program headers is too large to fit into e_phnum. Instead the real
# value is in the field sh_info of section 0.
PN_XNUM = 0xFFFF
-# Format strings for packing and header size calculation.
-ELF64_EHDR = ("4s" # e_ident/magic
- "B" # e_ident/class
- "B" # e_ident/data
- "B" # e_ident/version
- "B" # e_ident/osabi
- "8s" # e_ident/pad
- "H" # e_type
- "H" # e_machine
- "I" # e_version
- "Q" # e_entry
- "Q" # e_phoff
- "Q" # e_shoff
- "I" # e_flags
- "H" # e_ehsize
- "H" # e_phentsize
- "H" # e_phnum
- "H" # e_shentsize
- "H" # e_shnum
- "H" # e_shstrndx
- )
-ELF64_PHDR = ("I" # p_type
- "I" # p_flags
- "Q" # p_offset
- "Q" # p_vaddr
- "Q" # p_paddr
- "Q" # p_filesz
- "Q" # p_memsz
- "Q" # p_align
- )
+EV_CURRENT = 1
+
+ELFCLASS32 = 1
+ELFCLASS64 = 2
+
+ELFDATA2LSB = 1
+ELFDATA2MSB = 2
+
+ET_CORE = 4
+
+PT_LOAD = 1
+PT_NOTE = 4
+
+EM_386 = 3
+EM_PPC = 20
+EM_PPC64 = 21
+EM_S390 = 22
+EM_AARCH = 183
+EM_X86_64 = 62
+
+class ELF(object):
+ """Representation of a ELF file."""
+
+ def __init__(self, arch):
+ self.ehdr = None
+ self.notes = []
+ self.segments = []
+ self.notes_size = 0
+ self.endianess = None
+ self.elfclass = ELFCLASS64
+
+ if arch == 'aarch64-le':
+ self.endianess = ELFDATA2LSB
+ self.elfclass = ELFCLASS64
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_AARCH
+
+ elif arch == 'aarch64-be':
+ self.endianess = ELFDATA2MSB
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_AARCH
+
+ elif arch == 'X86_64':
+ self.endianess = ELFDATA2LSB
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_X86_64
+
+ elif arch == '386':
+ self.endianess = ELFDATA2LSB
+ self.elfclass = ELFCLASS32
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_386
+
+ elif arch == 's390':
+ self.endianess = ELFDATA2MSB
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_S390
+
+ elif arch == 'ppc64-le':
+ self.endianess = ELFDATA2LSB
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_PPC64
+
+ elif arch == 'ppc64-be':
+ self.endianess = ELFDATA2MSB
+ self.ehdr = get_arch_ehdr(self.endianess, self.elfclass)
+ self.ehdr.e_machine = EM_PPC64
+
+ else:
+ raise gdb.GdbError("No valid arch type specified.\n"
+ "Currently supported types:\n"
+ "aarch64-be, aarch64-le, X86_64, 386, s390, "
+ "ppc64-be, ppc64-le")
+
+ self.add_segment(PT_NOTE, 0, 0)
+
+ def add_note(self, n_name, n_desc, n_type):
+ """Adds a note to the ELF."""
+
+ note = get_arch_note(self.endianess, len(n_name), len(n_desc))
+ note.n_namesz = len(n_name) + 1
+ note.n_descsz = len(n_desc)
+ note.n_name = n_name.encode()
+ note.n_type = n_type
+
+ # Desc needs to be 4 byte aligned (although the 64bit spec
+ # specifies 8 byte). When defining n_desc as uint32 it will be
+ # automatically aligned but we need the memmove to copy the
+ # string into it.
+ ctypes.memmove(note.n_desc, n_desc.encode(), len(n_desc))
+
+ self.notes.append(note)
+ self.segments[0].p_filesz += ctypes.sizeof(note)
+ self.segments[0].p_memsz += ctypes.sizeof(note)
+
+ def add_segment(self, p_type, p_paddr, p_size):
+ """Adds a segment to the elf."""
+
+ phdr = get_arch_phdr(self.endianess, self.elfclass)
+ phdr.p_type = p_type
+ phdr.p_paddr = p_paddr
+ phdr.p_filesz = p_size
+ phdr.p_memsz = p_size
+ self.segments.append(phdr)
+ self.ehdr.e_phnum += 1
+
+ def to_file(self, elf_file):
+ """Writes all ELF structures to the the passed file.
+
+ Structure:
+ Ehdr
+ Segment 0:PT_NOTE
+ Segment 1:PT_LOAD
+ Segment N:PT_LOAD
+ Note 0..N
+ Dump contents
+ """
+ elf_file.write(self.ehdr)
+ off = ctypes.sizeof(self.ehdr) + \
+ len(self.segments) * ctypes.sizeof(self.segments[0])
+
+ for phdr in self.segments:
+ phdr.p_offset = off
+ elf_file.write(phdr)
+ off += phdr.p_filesz
+
+ for note in self.notes:
+ elf_file.write(note)
+
+
+def get_arch_note(endianess, len_name, len_desc):
+ """Returns a Note class with the specified endianess."""
+
+ if endianess == ELFDATA2LSB:
+ superclass = ctypes.LittleEndianStructure
+ else:
+ superclass = ctypes.BigEndianStructure
+
+ len_name = len_name + 1
+
+ class Note(superclass):
+ """Represents an ELF note, includes the content."""
+
+ _fields_ = [("n_namesz", ctypes.c_uint32),
+ ("n_descsz", ctypes.c_uint32),
+ ("n_type", ctypes.c_uint32),
+ ("n_name", ctypes.c_char * len_name),
+ ("n_desc", ctypes.c_uint32 * ((len_desc + 3) // 4))]
+ return Note()
+
+
+class Ident(ctypes.Structure):
+ """Represents the ELF ident array in the ehdr structure."""
+
+ _fields_ = [('ei_mag0', ctypes.c_ubyte),
+ ('ei_mag1', ctypes.c_ubyte),
+ ('ei_mag2', ctypes.c_ubyte),
+ ('ei_mag3', ctypes.c_ubyte),
+ ('ei_class', ctypes.c_ubyte),
+ ('ei_data', ctypes.c_ubyte),
+ ('ei_version', ctypes.c_ubyte),
+ ('ei_osabi', ctypes.c_ubyte),
+ ('ei_abiversion', ctypes.c_ubyte),
+ ('ei_pad', ctypes.c_ubyte * 7)]
+
+ def __init__(self, endianess, elfclass):
+ self.ei_mag0 = 0x7F
+ self.ei_mag1 = ord('E')
+ self.ei_mag2 = ord('L')
+ self.ei_mag3 = ord('F')
+ self.ei_class = elfclass
+ self.ei_data = endianess
+ self.ei_version = EV_CURRENT
+
+
+def get_arch_ehdr(endianess, elfclass):
+ """Returns a EHDR64 class with the specified endianess."""
+
+ if endianess == ELFDATA2LSB:
+ superclass = ctypes.LittleEndianStructure
+ else:
+ superclass = ctypes.BigEndianStructure
+
+ class EHDR64(superclass):
+ """Represents the 64 bit ELF header struct."""
+
+ _fields_ = [('e_ident', Ident),
+ ('e_type', ctypes.c_uint16),
+ ('e_machine', ctypes.c_uint16),
+ ('e_version', ctypes.c_uint32),
+ ('e_entry', ctypes.c_uint64),
+ ('e_phoff', ctypes.c_uint64),
+ ('e_shoff', ctypes.c_uint64),
+ ('e_flags', ctypes.c_uint32),
+ ('e_ehsize', ctypes.c_uint16),
+ ('e_phentsize', ctypes.c_uint16),
+ ('e_phnum', ctypes.c_uint16),
+ ('e_shentsize', ctypes.c_uint16),
+ ('e_shnum', ctypes.c_uint16),
+ ('e_shstrndx', ctypes.c_uint16)]
+
+ def __init__(self):
+ super(superclass, self).__init__()
+ self.e_ident = Ident(endianess, elfclass)
+ self.e_type = ET_CORE
+ self.e_version = EV_CURRENT
+ self.e_ehsize = ctypes.sizeof(self)
+ self.e_phoff = ctypes.sizeof(self)
+ self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianess, elfclass))
+ self.e_phnum = 0
+
+
+ class EHDR32(superclass):
+ """Represents the 32 bit ELF header struct."""
+
+ _fields_ = [('e_ident', Ident),
+ ('e_type', ctypes.c_uint16),
+ ('e_machine', ctypes.c_uint16),
+ ('e_version', ctypes.c_uint32),
+ ('e_entry', ctypes.c_uint32),
+ ('e_phoff', ctypes.c_uint32),
+ ('e_shoff', ctypes.c_uint32),
+ ('e_flags', ctypes.c_uint32),
+ ('e_ehsize', ctypes.c_uint16),
+ ('e_phentsize', ctypes.c_uint16),
+ ('e_phnum', ctypes.c_uint16),
+ ('e_shentsize', ctypes.c_uint16),
+ ('e_shnum', ctypes.c_uint16),
+ ('e_shstrndx', ctypes.c_uint16)]
+
+ def __init__(self):
+ super(superclass, self).__init__()
+ self.e_ident = Ident(endianess, elfclass)
+ self.e_type = ET_CORE
+ self.e_version = EV_CURRENT
+ self.e_ehsize = ctypes.sizeof(self)
+ self.e_phoff = ctypes.sizeof(self)
+ self.e_phentsize = ctypes.sizeof(get_arch_phdr(endianess, elfclass))
+ self.e_phnum = 0
+
+ # End get_arch_ehdr
+ if elfclass == ELFCLASS64:
+ return EHDR64()
+ else:
+ return EHDR32()
+
+
+def get_arch_phdr(endianess, elfclass):
+ """Returns a 32 or 64 bit PHDR class with the specified endianess."""
+
+ if endianess == ELFDATA2LSB:
+ superclass = ctypes.LittleEndianStructure
+ else:
+ superclass = ctypes.BigEndianStructure
+
+ class PHDR64(superclass):
+ """Represents the 64 bit ELF program header struct."""
+
+ _fields_ = [('p_type', ctypes.c_uint32),
+ ('p_flags', ctypes.c_uint32),
+ ('p_offset', ctypes.c_uint64),
+ ('p_vaddr', ctypes.c_uint64),
+ ('p_paddr', ctypes.c_uint64),
+ ('p_filesz', ctypes.c_uint64),
+ ('p_memsz', ctypes.c_uint64),
+ ('p_align', ctypes.c_uint64)]
+
+ class PHDR32(superclass):
+ """Represents the 32 bit ELF program header struct."""
+
+ _fields_ = [('p_type', ctypes.c_uint32),
+ ('p_offset', ctypes.c_uint32),
+ ('p_vaddr', ctypes.c_uint32),
+ ('p_paddr', ctypes.c_uint32),
+ ('p_filesz', ctypes.c_uint32),
+ ('p_memsz', ctypes.c_uint32),
+ ('p_flags', ctypes.c_uint32),
+ ('p_align', ctypes.c_uint32)]
+
+ # End get_arch_phdr
+ if elfclass == ELFCLASS64:
+ return PHDR64()
+ else:
+ return PHDR32()
+
def int128_get64(val):
"""Returns low 64bit part of Int128 struct."""
@@ -188,20 +434,22 @@ def get_guest_phys_blocks():
class DumpGuestMemory(gdb.Command):
"""Extract guest vmcore from qemu process coredump.
-The sole argument is FILE, identifying the target file to write the
-guest vmcore to.
+The two required arguments are FILE and ARCH:
+FILE identifies the target file to write the guest vmcore to.
+ARCH specifies the architecture for which the core will be generated.
This GDB command reimplements the dump-guest-memory QMP command in
python, using the representation of guest memory as captured in the qemu
coredump. The qemu process that has been dumped must have had the
-command line option "-machine dump-guest-core=on".
+command line option "-machine dump-guest-core=on" which is the default.
For simplicity, the "paging", "begin" and "end" parameters of the QMP
command are not supported -- no attempt is made to get the guest's
internal paging structures (ie. paging=false is hard-wired), and guest
memory is always fully dumped.
-Only x86_64 guests are supported.
+Currently aarch64-be, aarch64-le, X86_64, 386, s390, ppc64-be,
+ppc64-le guests are supported.
The CORE/NT_PRSTATUS and QEMU notes (that is, the VCPUs' statuses) are
not written to the vmcore. Preparing these would require context that is
@@ -219,129 +467,39 @@ shape and this command should mostly work."""
super(DumpGuestMemory, self).__init__("dump-guest-memory",
gdb.COMMAND_DATA,
gdb.COMPLETE_FILENAME)
- self.elf64_ehdr_le = struct.Struct("<%s" % ELF64_EHDR)
- self.elf64_phdr_le = struct.Struct("<%s" % ELF64_PHDR)
+ self.elf = None
self.guest_phys_blocks = None
- def cpu_get_dump_info(self):
- # We can't synchronize the registers with KVM post-mortem, and
- # the bits in (first_x86_cpu->env.hflags) seem to be stale; they
- # may not reflect long mode for example. Hence just assume the
- # most common values. This also means that instruction pointer
- # etc. will be bogus in the dump, but at least the RAM contents
- # should be valid.
- self.dump_info = {"d_machine": EM_X86_64,
- "d_endian" : ELFDATA2LSB,
- "d_class" : ELFCLASS64}
+ def dump_init(self, vmcore):
+ """Prepares and writes ELF structures to core file."""
- def encode_elf64_ehdr_le(self):
- return self.elf64_ehdr_le.pack(
- ELFMAG, # e_ident/magic
- self.dump_info["d_class"], # e_ident/class
- self.dump_info["d_endian"], # e_ident/data
- EV_CURRENT, # e_ident/version
- 0, # e_ident/osabi
- "", # e_ident/pad
- ET_CORE, # e_type
- self.dump_info["d_machine"], # e_machine
- EV_CURRENT, # e_version
- 0, # e_entry
- self.elf64_ehdr_le.size, # e_phoff
- 0, # e_shoff
- 0, # e_flags
- self.elf64_ehdr_le.size, # e_ehsize
- self.elf64_phdr_le.size, # e_phentsize
- self.phdr_num, # e_phnum
- 0, # e_shentsize
- 0, # e_shnum
- 0 # e_shstrndx
- )
+ # Needed to make crash happy, data for more useful notes is
+ # not available in a qemu core.
+ self.elf.add_note("NONE", "EMPTY", 0)
- def encode_elf64_note_le(self):
- return self.elf64_phdr_le.pack(PT_NOTE, # p_type
- 0, # p_flags
- (self.memory_offset -
- len(self.note)), # p_offset
- 0, # p_vaddr
- 0, # p_paddr
- len(self.note), # p_filesz
- len(self.note), # p_memsz
- 0 # p_align
- )
+ # We should never reach PN_XNUM for paging=false dumps,
+ # there's just a handful of discontiguous ranges after
+ # merging.
+ # The constant is needed to account for the PT_NOTE segment.
+ phdr_num = len(self.guest_phys_blocks) + 1
+ assert phdr_num < PN_XNUM
- def encode_elf64_load_le(self, offset, start_hwaddr, range_size):
- return self.elf64_phdr_le.pack(PT_LOAD, # p_type
- 0, # p_flags
- offset, # p_offset
- 0, # p_vaddr
- start_hwaddr, # p_paddr
- range_size, # p_filesz
- range_size, # p_memsz
- 0 # p_align
- )
-
- def note_init(self, name, desc, type):
- # name must include a trailing NUL
- namesz = (len(name) + 1 + 3) / 4 * 4
- descsz = (len(desc) + 3) / 4 * 4
- fmt = ("<" # little endian
- "I" # n_namesz
- "I" # n_descsz
- "I" # n_type
- "%us" # name
- "%us" # desc
- % (namesz, descsz))
- self.note = struct.pack(fmt,
- len(name) + 1, len(desc), type, name, desc)
-
- def dump_init(self):
- self.guest_phys_blocks = get_guest_phys_blocks()
- self.cpu_get_dump_info()
- # we have no way to retrieve the VCPU status from KVM
- # post-mortem
- self.note_init("NONE", "EMPTY", 0)
-
- # Account for PT_NOTE.
- self.phdr_num = 1
-
- # We should never reach PN_XNUM for paging=false dumps: there's
- # just a handful of discontiguous ranges after merging.
- self.phdr_num += len(self.guest_phys_blocks)
- assert self.phdr_num < PN_XNUM
-
- # Calculate the ELF file offset where the memory dump commences:
- #
- # ELF header
- # PT_NOTE
- # PT_LOAD: 1
- # PT_LOAD: 2
- # ...
- # PT_LOAD: len(self.guest_phys_blocks)
- # ELF note
- # memory dump
- self.memory_offset = (self.elf64_ehdr_le.size +
- self.elf64_phdr_le.size * self.phdr_num +
- len(self.note))
-
- def dump_begin(self, vmcore):
- vmcore.write(self.encode_elf64_ehdr_le())
- vmcore.write(self.encode_elf64_note_le())
- running = self.memory_offset
for block in self.guest_phys_blocks:
- range_size = block["target_end"] - block["target_start"]
- vmcore.write(self.encode_elf64_load_le(running,
- block["target_start"],
- range_size))
- running += range_size
- vmcore.write(self.note)
+ block_size = block["target_end"] - block["target_start"]
+ self.elf.add_segment(PT_LOAD, block["target_start"], block_size)
+
+ self.elf.to_file(vmcore)
def dump_iterate(self, vmcore):
+ """Writes guest core to file."""
+
qemu_core = gdb.inferiors()[0]
for block in self.guest_phys_blocks:
cur = block["host_addr"]
left = block["target_end"] - block["target_start"]
print("dumping range at %016x for length %016x" %
(cur.cast(UINTPTR_T), left))
+
while left > 0:
chunk_size = min(TARGET_PAGE_SIZE, left)
chunk = qemu_core.read_memory(cur, chunk_size)
@@ -349,22 +507,22 @@ shape and this command should mostly work."""
cur += chunk_size
left -= chunk_size
- def create_vmcore(self, filename):
- vmcore = open(filename, "wb")
- self.dump_begin(vmcore)
- self.dump_iterate(vmcore)
- vmcore.close()
-
def invoke(self, args, from_tty):
+ """Handles command invocation from gdb."""
+
# Unwittingly pressing the Enter key after the command should
# not dump the same multi-gig coredump to the same file.
self.dont_repeat()
argv = gdb.string_to_argv(args)
- if len(argv) != 1:
- raise gdb.GdbError("usage: dump-guest-memory FILE")
+ if len(argv) != 2:
+ raise gdb.GdbError("usage: dump-guest-memory FILE ARCH")
- self.dump_init()
- self.create_vmcore(argv[0])
+ self.elf = ELF(argv[1])
+ self.guest_phys_blocks = get_guest_phys_blocks()
+
+ with open(argv[0], "wb") as vmcore:
+ self.dump_init(vmcore)
+ self.dump_iterate(vmcore)
DumpGuestMemory()
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Qemu-devel] [PATCH 6/6] scripts/dump-guest-memory.py: Fix module docstring
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
` (4 preceding siblings ...)
2016-01-22 12:08 ` [Qemu-devel] [PATCH 5/6] scripts/dump-guest-memory.py: Introduce multi-arch support Janosch Frank
@ 2016-01-22 12:08 ` Janosch Frank
2016-01-22 12:39 ` [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Paolo Bonzini
6 siblings, 0 replies; 8+ messages in thread
From: Janosch Frank @ 2016-01-22 12:08 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, drjones, lersek, frankja
The module docstring is changed into a multi-line comment to comply
with pep 257.
The comment about the docstring that gets used by gdb to print the
help is moved to the location of the docstring.
Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
---
scripts/dump-guest-memory.py | 35 ++++++++++++++++++-----------------
1 file changed, 18 insertions(+), 17 deletions(-)
diff --git a/scripts/dump-guest-memory.py b/scripts/dump-guest-memory.py
index 7acce65..f274bf8 100644
--- a/scripts/dump-guest-memory.py
+++ b/scripts/dump-guest-memory.py
@@ -1,20 +1,17 @@
-# This python script adds a new gdb command, "dump-guest-memory". It
-# should be loaded with "source dump-guest-memory.py" at the (gdb)
-# prompt.
-#
-# Copyright (C) 2013, Red Hat, Inc.
-#
-# Authors:
-# Laszlo Ersek <lersek@redhat.com>
-# Janosch Frank <frankja@linux.vnet.ibm.com>
-#
-# This work is licensed under the terms of the GNU GPL, version 2 or later. See
-# the COPYING file in the top-level directory.
-#
-# The leading docstring doesn't have idiomatic Python formatting. It is
-# printed by gdb's "help" command (the first line is printed in the
-# "help data" summary), and it should match how other help texts look in
-# gdb.
+"""
+This python script adds a new gdb command, "dump-guest-memory". It
+should be loaded with "source dump-guest-memory.py" at the (gdb)
+prompt.
+
+Copyright (C) 2013, Red Hat, Inc.
+
+Authors:
+ Laszlo Ersek <lersek@redhat.com>
+ Janosch Frank <frankja@linux.vnet.ibm.com>
+
+This work is licensed under the terms of the GNU GPL, version 2 or later. See
+the COPYING file in the top-level directory.
+"""
import ctypes
@@ -431,6 +428,10 @@ def get_guest_phys_blocks():
return guest_phys_blocks
+# The leading docstring doesn't have idiomatic Python formatting. It is
+# printed by gdb's "help" command (the first line is printed in the
+# "help data" summary), and it should match how other help texts look in
+# gdb.
class DumpGuestMemory(gdb.Command):
"""Extract guest vmcore from qemu process coredump.
--
2.3.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support
2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
` (5 preceding siblings ...)
2016-01-22 12:08 ` [Qemu-devel] [PATCH 6/6] scripts/dump-guest-memory.py: Fix module docstring Janosch Frank
@ 2016-01-22 12:39 ` Paolo Bonzini
6 siblings, 0 replies; 8+ messages in thread
From: Paolo Bonzini @ 2016-01-22 12:39 UTC (permalink / raw)
To: Janosch Frank, qemu-devel; +Cc: drjones, lersek
On 22/01/2016 13:08, Janosch Frank wrote:
> The dump guest memory script for extracting a Linux core from a qemu
> core is currently limited to amd64 and python 2.
>
> With this series we add support for python 3 (while maintaining python
> 2 support) and add the possibility to extract dumps from VMs with the
> most common architectures.
>
> Tested on X86_64, s390 and Aarch64-le (thanks to Andrew Jones).
>
> RFC to PATCH:
> Tested on X86_64 and Aarch64-le.
> Fix wrongly indented return in get_guest_phys_blocks().
> Fix wrong indent for predecessor_size that happened when copying.
> Fix inconsistent line wrapping.
> Fix python 3 compatibility comment being added in the wrong commit.
> Fix docstrings that get displayed by gdb.
> Replaced ceil(len_desc / 4.0) with ((len_desc + 3) // 4)
> Added patch that fixes module docstring to account for moved gdb
> help string.
>
> Janosch Frank (6):
> scripts/dump-guest-memory.py: Move constants to the top
> scripts/dump-guest-memory.py: Make methods functions
> scripts/dump-guest-memory.py: Improve python 3 compatibility
> scripts/dump-guest-memory.py: Cleanup functions
> scripts/dump-guest-memory.py: Introduce multi-arch support
> scripts/dump-guest-memory.py: Fix module docstring
>
> scripts/dump-guest-memory.py | 754 +++++++++++++++++++++++++++----------------
> 1 file changed, 472 insertions(+), 282 deletions(-)
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-01-22 12:40 UTC | newest]
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2016-01-22 12:08 [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 1/6] scripts/dump-guest-memory.py: Move constants to the top Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 2/6] scripts/dump-guest-memory.py: Make methods functions Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 3/6] scripts/dump-guest-memory.py: Improve python 3 compatibility Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 4/6] scripts/dump-guest-memory.py: Cleanup functions Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 5/6] scripts/dump-guest-memory.py: Introduce multi-arch support Janosch Frank
2016-01-22 12:08 ` [Qemu-devel] [PATCH 6/6] scripts/dump-guest-memory.py: Fix module docstring Janosch Frank
2016-01-22 12:39 ` [Qemu-devel] [PATCH 0/6] scripts/dump-guest-memory.py: Add multi-arch support Paolo Bonzini
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