import gdb

class sd_dump_hashmaps(gdb.Command):

"dump systemd's hashmaps"

def __init__(self):

super(sd_dump_hashmaps, self).__init__("sd_dump_hashmaps", gdb.COMMAND_DATA, gdb.COMPLETE_NONE)

def invoke(self, arg, from_tty):

d = gdb.parse_and_eval("hashmap_debug_list")

all_entry_sizes = gdb.parse_and_eval("all_entry_sizes")

all_direct_buckets = gdb.parse_and_eval("all_direct_buckets")

hashmap_base_t = gdb.lookup_type("HashmapBase")

uchar_t = gdb.lookup_type("unsigned char")

ulong_t = gdb.lookup_type("unsigned long")

debug_offset = gdb.parse_and_eval("(unsigned long)&((HashmapBase*)0)->debug")

print "type, hash, indirect, entries, max_entries, buckets, creator"

while d:

h = gdb.parse_and_eval("(HashmapBase*)((char*)%d - %d)" % (int(d.cast(ulong_t)), debug_offset))

if h["has_indirect"]:

storage_ptr = h["indirect"]["storage"].cast(uchar_t.pointer())

n_entries = h["indirect"]["n_entries"]

n_buckets = h["indirect"]["n_buckets"]

else:

storage_ptr = h["direct"]["storage"].cast(uchar_t.pointer())

n_entries = h["n_direct_entries"]

n_buckets = all_direct_buckets[int(h["type"])];

t = ["plain", "ordered", "set"][int(h["type"])]

print "%s, %s, %s, %d, %d, %d, %s (%s:%d)" % (t, h["hash_ops"], bool(h["has_indirect"]), n_entries, d["max_entries"], n_buckets, d["func"], d["file"], d["line"])

if arg != "" and n_entries > 0:

dib_raw_addr = storage_ptr + (all_entry_sizes[h["type"]] * n_buckets)

histogram = {}

for i in xrange(0, n_buckets):

dib = int(dib_raw_addr[i])

histogram[dib] = histogram.get(dib, 0) + 1

for dib in sorted(iter(histogram)):

if dib != 255:

print "%3d %8d %f%% of entries" % (dib, histogram[dib], 100.0*histogram[dib]/n_entries)

else:

print "%3d %8d %f%% of slots" % (dib, histogram[dib], 100.0*histogram[dib]/n_buckets)

print "mean DIB of entries: %f" % (sum([dib*histogram[dib] for dib in iter(histogram) if dib != 255])*1.0/n_entries)

blocks = []

current_len = 1

prev = int(dib_raw_addr[0])

for i in xrange(1, n_buckets):

dib = int(dib_raw_addr[i])

if (dib == 255) != (prev == 255):

if prev != 255:

blocks += [[i, current_len]]

current_len = 1

else:

current_len += 1

prev = dib

if prev != 255:

blocks += [[i, current_len]]

# a block may be wrapped around

if len(blocks) > 1 and blocks[0][0] == blocks[0][1] and blocks[-1][0] == n_buckets - 1:

blocks[0][1] += blocks[-1][1]

blocks = blocks[0:-1]

print "max block: %s" % max(blocks, key=lambda a: a[1])

print "sum block lens: %d" % sum(b[1] for b in blocks)

print "mean block len: %f" % (1.0 * sum(b[1] for b in blocks) / len(blocks))

d = d["debug_list_next"]

sd_dump_hashmaps()