opensnoop
diff --git a/tools/opensnoop b/tools/opensnoop
new file mode 100755
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+++ b/tools/opensnoop
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+#!/usr/bin/python
+#
+# opensnoop Trace open() syscalls.
+# For Linux, uses BCC, eBPF. Embedded C.
+#
+# USAGE: opensnoop [-h] [-t] [-x] [-p PID]
+#
+# Copyright (c) 2015 Brendan Gregg.
+# Licensed under the Apache License, Version 2.0 (the "License")
+#
+# 17-Sep-2015 Brendan Gregg Created this.
+
+from __future__ import print_function
+from bcc import BPF
+import argparse
+
+# arguments
+examples = """examples:
+ ./opensnoop # trace all open() syscalls
+ ./opensnoop -t # include timestamps
+ ./opensnoop -x # only show failed opens
+ ./opensnoop -p 181 # only trace PID 181
+"""
+parser = argparse.ArgumentParser(
+ description="Trace open() syscalls",
+ formatter_class=argparse.RawDescriptionHelpFormatter,
+ epilog=examples)
+parser.add_argument("-t", "--timestamp", action="store_true",
+ help="include timestamp on output")
+parser.add_argument("-x", "--failed", action="store_true",
+ help="only show failed opens")
+parser.add_argument("-p", "--pid",
+ help="trace this PID only")
+args = parser.parse_args()
+debug = 0
+
+# define BPF program
+bpf_text = """
+#include <uapi/linux/ptrace.h>
+
+BPF_HASH(args_filename, u32, const char *);
+
+int kprobe__sys_open(struct pt_regs *ctx, const char __user *filename)
+{
+ u32 pid = bpf_get_current_pid_tgid();
+
+ FILTER
+ args_filename.update(&pid, &filename);
+
+ return 0;
+};
+
+int kretprobe__sys_open(struct pt_regs *ctx)
+{
+ const char **filenamep;
+ int ret = ctx->ax;
+ u32 pid = bpf_get_current_pid_tgid();
+
+ filenamep = args_filename.lookup(&pid);
+ if (filenamep == 0) {
+ // missed entry
+ return 0;
+ }
+
+ bpf_trace_printk("%s %d\\n", *filenamep, ret);
+ args_filename.delete(&pid);
+
+ return 0;
+}
+"""
+if args.pid:
+ bpf_text = bpf_text.replace('FILTER',
+ 'if (pid != %s) { return 0; }' % args.pid)
+else:
+ bpf_text = bpf_text.replace('FILTER', '')
+if debug:
+ print(bpf_text)
+
+# initialize BPF
+b = BPF(text=bpf_text)
+
+# header
+if args.timestamp:
+ print("%-14s" % ("TIME(s)"), end="")
+print("%-6s %-16s %4s %3s %s" % ("PID", "COMM", "FD", "ERR", "PATH"))
+
+start_ts = 0
+
+# format output
+while 1:
+ (task, pid, cpu, flags, ts, msg) = b.trace_fields()
+ (filenamp, ret_s) = msg.split(" ")
+
+ ret = int(ret_s)
+ if (args.failed and (ret >= 0)):
+ continue
+
+ # split return value into FD and errno columns
+ if ret >= 0:
+ fd_s = ret; err = 0
+ else:
+ fd_s = "-1"; err = - ret
+
+ # print columns
+ if args.timestamp:
+ if start_ts == 0:
+ start_ts = ts
+ print("%-14.9f" % (ts - start_ts), end="")
+ print("%-6d %-16s %4s %3s %s" % (pid, task, fd_s, err, filenamp))
