Commit bb34fe7e authored by 4ast's avatar 4ast

Merge pull request #160 from iovisor/bblanco_dev

Add field support to trace_print and friends
parents ee286326 022f3d77
......@@ -6,14 +6,13 @@
# sudo ./hello_world.py"
from bpf import BPF
from subprocess import call
prog = """
int hello(void *ctx) {
bpf_trace_printk("Hello, World!\\n");
return 0;
};
}
"""
b = BPF(text=prog)
b.attach_kprobe(event="sys_clone", fn_name="hello")
b.trace_print()
b.trace_print(fmt="{1} {5}")
......@@ -389,7 +389,7 @@ class BPF(object):
if res < 0:
raise Exception("Failed to attach BPF to kprobe")
open_kprobes[ev_name] = res
return res
return self
@staticmethod
def detach_kprobe(event):
......@@ -412,7 +412,7 @@ class BPF(object):
if res < 0:
raise Exception("Failed to attach BPF to kprobe")
open_kprobes[ev_name] = res
return res
return self
@staticmethod
def detach_kretprobe(event):
......@@ -437,14 +437,33 @@ class BPF(object):
if not tracefile:
tracefile = open("%s/trace_pipe" % TRACEFS)
if nonblocking:
fd = trace.fileno()
fd = tracefile.fileno()
fl = fcntl.fcntl(fd, fcntl.F_GETFL)
fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
return tracefile
@staticmethod
def trace_readline(nonblocking=True):
"""trace_readline(nonblocking=True)
def trace_readline_fields(nonblocking=False):
"""trace_readline_fields(nonblocking=False)
Read from the kernel debug trace pipe and return a tuple of the
fields (task, pid, cpu, flags, timestamp, msg) or None if no
line was read (nonblocking=True)
"""
line = BPF.trace_readline(nonblocking)
if line:
task = line[:16].lstrip()
line = line[17:]
ts_end = line.find(":")
pid, cpu, flags, ts = line[:ts_end].split()
cpu = cpu[1:-1]
msg = line[ts_end + 4:]
return (task, int(pid), int(cpu), flags, float(ts), msg)
return
@staticmethod
def trace_readline(nonblocking=False):
"""trace_readline(nonblocking=False)
Read from the kernel debug trace pipe and return one line
If nonblocking is False, this will block until ctrl-C is pressed.
......@@ -454,17 +473,28 @@ class BPF(object):
line = None
try:
line = trace.readline(128).rstrip()
except BlockingIOError:
line = trace.readline(1024).rstrip()
except IOError:
pass
except KeyboardInterrupt:
exit()
return line
@staticmethod
def trace_print():
try:
def trace_print(fmt=None):
"""trace_print(fmt=None)
Read from the kernel debug trace pipe and print on stdout.
If fmt is specified, apply as a format string to the output. See
trace_readline_fields for the members of the tuple
example: trace_print(fmt="pid {1}, msg = {5}")
"""
while True:
if fmt:
fields = BPF.trace_readline_fields(nonblocking=False)
line = fmt.format(*fields)
else:
line = BPF.trace_readline(nonblocking=False)
print(line)
sys.stdout.flush()
except KeyboardInterrupt:
exit()
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment