Programming

In the last post we introduced the BCC framework to interface Python code with eBPF facility. Now we are ready to make one step further! #!/usr/bin/python3 import bcc bpf = bcc.BPF(text=""" #include <uapi/linux/ptrace.h> int trace_malloc(struct pt_regs *ctx, size_t size) { bpf_trace_printk("size=%d\\n",size); return 0; };""") bpf.attach_uprobe(name="c",sym="malloc",fn_name="trace_malloc") while 1: (task, pid, cpu, flags, ts, msg) = bpf.trace_fields() print(f"task={task}\tmsg={msg}") This code is a little more complex, but still quite easy: first of all we use bcc to attach an “user space probe” instead of a kernel probe, and the function being observed will be libc’s malloc. ...

eBPF is a revolutionary technology that can run sandboxed programs in the Linux kernel without changing kernel source code or loading kernel modules. Basically any user can write code for a virtual machine that can interact with the kernel data structure and functions. bcc is an high-level helper interface to eBPF (another is bpftrace). To use it, start by following installation guide , but if you have a recent Debian system, it’s just a matter of installing some packages: ...

When I write small command line utilities in Python, I often take advantage of the fileinput module that makes working with text files very convenient: the library permits to write quickly and easily a loop over standard input or a list of files, something like perl -a or awk line processing. Then the size of input data grew, and also for a language comparison, I wanted to port my utility in the D programming language, but I cannot find an equivalent module, so I decided to write one myself. ...

Nim is a statically typed compiled systems programming language. It combines successful concepts from mature languages like Python, Ada and Modula. It’s Efficient, expressive, elegant and definitely worth to check. While I was playing with it, I stumbled upon an interesting module that allows almost seamless interoperability betweeen Nim and Python; so I’m building a small proof of concept on this github project. first of all the Nim code: # file: demo.nim - file name should match the module name you're going to import from python import nimpy import unicode proc greet(name: string): string {.exportpy.} = return "Hello, " & name & "!" proc count(names: seq[string]): int {.exportpy.} = return names.len proc lowercase(names: seq[string]): seq[string] {.exportpy.} = for n in names: result.add tolower(n) ...