Change API of attach_kprobe to take a name argument

Per feedback on the attach_kprobe api, change up the arguments to remove
the load_func that typically preceeds the call. Instead, move this
inside the attach_kprobe implementation. Also, this makes attach_kprobe
need to be non-static. The same applies to attach_kretprobe.

Old:
fn = b.load_func("hello", BPF.KPROBE)
BPF.attach_kprobe(fn, "sys_clone")

New:
b.attach_kprobe(event="sys_clone", fn_name="hello")

Note that the kwarg style is not required, but I fixed up the current
usages to provide readability.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

examples/bitehist.py

@@ -39,7 +39,7 @@ if len(argv) > 1:
 
 # load BPF program
 b = BPF(src_file = "bitehist.c")
-BPF.attach_kprobe(b.load_func("do_request", BPF.KPROBE), "blk_start_request")
+b.attach_kprobe(event="blk_start_request", fn_name="do_request")
 dist = b.get_table("dist")
 dist_max = 64
 

examples/disksnoop.py

@@ -18,8 +18,8 @@ REQ_WRITE = 1		# from include/linux/blk_types.h
 
 # load BPF program
 b = BPF(src_file="disksnoop.c")
-BPF.attach_kprobe(b.load_func("do_request", BPF.KPROBE), "blk_start_request")
-BPF.attach_kprobe(b.load_func("do_completion", BPF.KPROBE), "blk_update_request")
+b.attach_kprobe(event="blk_start_request", fn_name="do_request")
+b.attach_kprobe(event="blk_update_request", fn_name="do_completion")
 
 # header
 print("%-18s %-2s %-7s %8s" % ("TIME(s)", "T", "BYTES", "LAT(ms)"))

examples/hello_world.py

@@ -15,8 +15,7 @@ int hello(void *ctx) {
 };
 """
 b = BPF(text=prog)
-fn = b.load_func("hello", BPF.KPROBE)
-BPF.attach_kprobe(fn, "sys_clone")
+b.attach_kprobe(event="sys_clone", fn_name="hello")
 try:
     call(["cat", "/sys/kernel/debug/tracing/trace_pipe"])
 except KeyboardInterrupt:

examples/task_switch.py

@@ -6,9 +6,8 @@ from bpf import BPF
 from time import sleep
 
 b = BPF(src_file="task_switch.c")
-fn = b.load_func("count_sched", BPF.KPROBE)
 stats = b.get_table("stats")
-BPF.attach_kprobe(fn, "finish_task_switch")
+b.attach_kprobe(event="finish_task_switch", fn_name="count_sched")
 
 # generate many schedule events
 for i in range(0, 100): sleep(0.01)

examples/vfsreadlat.py

@@ -39,8 +39,8 @@ if len(argv) > 1:
 
 # load BPF program
 b = BPF(src_file = "vfsreadlat.c")
-BPF.attach_kprobe(b.load_func("do_entry", BPF.KPROBE), "vfs_read")
-BPF.attach_kretprobe(b.load_func("do_return", BPF.KPROBE), "vfs_read")
+b.attach_kprobe(event="vfs_read", fn_name="do_entry")
+b.attach_kretprobe(event="vfs_read", fn_name="do_return")
 dist = b.get_table("dist")
 dist_max = 64
 

src/python/bpf/__init__.py

@@ -325,10 +325,8 @@ class BPF(object):
                     % (dev, errstr))
         fn.sock = sock
 
-    @staticmethod
-    def attach_kprobe(fn, event, pid=0, cpu=-1, group_fd=-1):
-        if not isinstance(fn, BPF.Function):
-            raise Exception("arg 1 must be of type BPF.Function")
+    def attach_kprobe(self, event="", fn_name="", pid=0, cpu=-1, group_fd=-1):
+        fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = "p_" + event.replace("+", "_")
         desc = "p:kprobes/%s %s" % (ev_name, event)
         res = lib.bpf_attach_kprobe(fn.fd, ev_name.encode("ascii"),
@@ -350,10 +348,8 @@ class BPF(object):
             raise Exception("Failed to detach BPF from kprobe")
         del open_kprobes[ev_name]
 
-    @staticmethod
-    def attach_kretprobe(fn, event, pid=-1, cpu=0, group_fd=-1):
-        if not isinstance(fn, BPF.Function):
-            raise Exception("arg 1 must be of type BPF.Function")
+    def attach_kretprobe(self, event="", fn_name="", pid=-1, cpu=0, group_fd=-1):
+        fn = self.load_func(fn_name, BPF.KPROBE)
         ev_name = "r_" + event.replace("+", "_")
         desc = "r:kprobes/%s %s" % (ev_name, event)
         res = lib.bpf_attach_kprobe(fn.fd, ev_name.encode("ascii"),

tests/cc/test_trace1.py

@@ -26,13 +26,10 @@ if arg1.endswith(".b"):
 class TestKprobe(TestCase):
     def setUp(self):
         b = BPF(arg1, arg2, debug=0)
-        fn1 = b.load_func("sys_wr", BPF.KPROBE)
-        fn2 = b.load_func("sys_rd", BPF.KPROBE)
-        fn3 = b.load_func("sys_bpf", BPF.KPROBE)
         self.stats = b.get_table("stats", Key, Leaf)
-        BPF.attach_kprobe(fn1, "sys_write", 0, -1)
-        BPF.attach_kprobe(fn2, "sys_read", 0, -1)
-        BPF.attach_kprobe(fn2, "htab_map_get_next_key", 0, -1)
+        b.attach_kprobe(event="sys_write", fn_name="sys_wr", pid=0, cpu=-1)
+        b.attach_kprobe(event="sys_read", fn_name="sys_rd", pid=0, cpu=-1)
+        b.attach_kprobe(event="htab_map_get_next_key", fn_name="sys_rd", pid=0, cpu=-1)
 
     def test_trace1(self):
         with open("/dev/null", "a") as f:

tests/cc/test_trace2.py

@@ -25,9 +25,8 @@ int count_sched(struct pt_regs *ctx) {
 class TestTracingEvent(TestCase):
     def setUp(self):
         b = BPF(text=text, debug=0)
-        fn = b.load_func("count_sched", BPF.KPROBE)
         self.stats = b.get_table("stats")
-        BPF.attach_kprobe(fn, "schedule+50", 0, -1)
+        b.attach_kprobe(event="schedule+50", fn_name="count_sched", pid=0, cpu=-1)
 
     def test_sched1(self):
         for i in range(0, 100):

tests/cc/test_trace3.py

@@ -17,11 +17,11 @@ if len(sys.argv) > 1:
 class TestBlkRequest(TestCase):
     def setUp(self):
         b = BPF(arg1, arg2, debug=0)
-        fn1 = b.load_func("probe_blk_start_request", BPF.KPROBE)
-        fn2 = b.load_func("probe_blk_update_request", BPF.KPROBE)
         self.latency = b.get_table("latency", c_uint, c_ulong)
-        BPF.attach_kprobe(fn1, "blk_start_request", -1, 0)
-        BPF.attach_kprobe(fn2, "blk_update_request", -1, 0)
+        b.attach_kprobe(event="blk_start_request",
+                fn_name="probe_blk_start_request", pid=-1, cpu=0)
+        b.attach_kprobe(event="blk_update_request",
+                fn_name="probe_blk_update_request", pid=-1, cpu=0)
 
     def test_blk1(self):
         import subprocess

tools/pidpersec

@@ -18,7 +18,7 @@ from time import sleep, strftime
 
 # load BPF program
 b = BPF(src_file = "pidpersec.c")
-BPF.attach_kprobe(b.load_func("do_count", BPF.KPROBE), "sched_fork")
+b.attach_kprobe(event="sched_fork", fn_name="do_count")
 stats = b.get_table("stats")
 
 # stat indexes

tools/syncsnoop

@@ -22,7 +22,7 @@ int do_sync(void *ctx) {
 	return 0;
 };
 """)
-BPF.attach_kprobe(b.load_func("do_sync", BPF.KPROBE), "sys_sync")
+b.attach_kprobe(event="sys_sync")
 
 # header
 print("%-18s %s" % ("TIME(s)", "CALL"))

tools/vfscount

@@ -52,12 +52,11 @@ load_kallsyms()
 
 # load BPF program
 b = BPF(src_file = "vfscount.c")
-fn = b.load_func("do_count", BPF.KPROBE)
-BPF.attach_kprobe(fn, "vfs_read")
-BPF.attach_kprobe(fn, "vfs_write")
-BPF.attach_kprobe(fn, "vfs_fsync")
-BPF.attach_kprobe(fn, "vfs_open")
-BPF.attach_kprobe(fn, "vfs_create")
+b.attach_kprobe(event="vfs_read", fn_name="do_count")
+b.attach_kprobe(event="vfs_write", fn_name="do_count")
+b.attach_kprobe(event="vfs_fsync", fn_name="do_count")
+b.attach_kprobe(event="vfs_open", fn_name="do_count")
+b.attach_kprobe(event="vfs_create", fn_name="do_count")
 counts = b.get_table("counts")
 
 # header

tools/vfsstat

@@ -37,11 +37,11 @@ if len(argv) > 1:
 
 # load BPF program
 b = BPF(src_file = "vfsstat.c")
-BPF.attach_kprobe(b.load_func("do_read", BPF.KPROBE), "vfs_read")
-BPF.attach_kprobe(b.load_func("do_write", BPF.KPROBE), "vfs_write")
-BPF.attach_kprobe(b.load_func("do_fsync", BPF.KPROBE), "vfs_fsync")
-BPF.attach_kprobe(b.load_func("do_open", BPF.KPROBE), "vfs_open")
-BPF.attach_kprobe(b.load_func("do_create", BPF.KPROBE), "vfs_create")
+b.attach_kprobe(event="vfs_read", fn_name="do_read")
+b.attach_kprobe(event="vfs_write", fn_name="do_write")
+b.attach_kprobe(event="vfs_fsync", fn_name="do_fsync")
+b.attach_kprobe(event="vfs_open", fn_name="do_open")
+b.attach_kprobe(event="vfs_create", fn_name="do_create")
 stats = b.get_table("stats")
 
 # stat column labels and indexes