test_clang.py

#!/usr/bin/env python
# Copyright (c) PLUMgrid, Inc.
# Licensed under the Apache License, Version 2.0 (the "License")

from bcc import BPF
import ctypes as ct
from unittest import main, skipUnless, TestCase
import os
import sys
from contextlib import contextmanager
import distutils.version

@contextmanager
def redirect_stderr(to):
    stderr_fd = sys.stderr.fileno()
    with os.fdopen(os.dup(stderr_fd), 'wb') as copied, os.fdopen(to, 'w') as to:
        sys.stderr.flush()
        os.dup2(to.fileno(), stderr_fd)
        try:
            yield sys.stderr
        finally:
            sys.stderr.flush()
            os.dup2(copied.fileno(), stderr_fd)

def kernel_version_ge(major, minor):
    # True if running kernel is >= X.Y
    version = distutils.version.LooseVersion(os.uname()[2]).version
    if version[0] > major:
        return True
    if version[0] < major:
        return False
    if minor and version[1] < minor:
        return False
    return True

class TestClang(TestCase):
    def test_complex(self):
        b = BPF(src_file="test_clang_complex.c", debug=0)
        fn = b.load_func("handle_packet", BPF.SCHED_CLS)
    def test_printk(self):
        text = """
#include <bcc/proto.h>
int handle_packet(void *ctx) {
  u8 *cursor = 0;
  struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
  bpf_trace_printk("ethernet->dst = %llx, ethernet->src = %llx\\n",
                   ethernet->dst, ethernet->src);
  return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("handle_packet", BPF.SCHED_CLS)

    def test_probe_read1(self):
        text = """
#include <linux/sched.h>
#include <uapi/linux/ptrace.h>
int count_sched(struct pt_regs *ctx, struct task_struct *prev) {
    pid_t p = prev->pid;
    return (p != -1);
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("count_sched", BPF.KPROBE)

    def test_probe_read2(self):
        text = """
#include <linux/sched.h>
#include <uapi/linux/ptrace.h>
int count_foo(struct pt_regs *ctx, unsigned long a, unsigned long b) {
    return (a != b);
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("count_foo", BPF.KPROBE)

    def test_probe_read_keys(self):
        text = """
#include <uapi/linux/ptrace.h>
#include <linux/blkdev.h>
BPF_HASH(start, struct request *);
int do_request(struct pt_regs *ctx, struct request *req) {
    u64 ts = bpf_ktime_get_ns();
    start.update(&req, &ts);
    return 0;
}

int do_completion(struct pt_regs *ctx, struct request *req) {
    u64 *tsp = start.lookup(&req);
    if (tsp != 0) {
        start.delete(&req);
    }
    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fns = b.load_funcs(BPF.KPROBE)

    def test_sscanf(self):
        text = """
BPF_HASH(stats, int, struct { u64 a; u64 b; u64 c:36; u64 d:28; struct { u32 a; u32 b; } s; }, 10);
int foo(void *ctx) {
    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("foo", BPF.KPROBE)
        t = b.get_table("stats")
        s1 = t.key_sprintf(t.Key(2))
        self.assertEqual(s1, b"0x2")
        s2 = t.leaf_sprintf(t.Leaf(2, 3, 4, 1, (5, 6)))
        l = t.leaf_scanf(s2)
        self.assertEqual(l.a, 2)
        self.assertEqual(l.b, 3)
        self.assertEqual(l.c, 4)
        self.assertEqual(l.d, 1)
        self.assertEqual(l.s.a, 5)
        self.assertEqual(l.s.b, 6)

    def test_sscanf_array(self):
        text = """
BPF_HASH(stats, int, struct { u32 a[3]; u32 b; }, 10);
"""
        b = BPF(text=text, debug=0)
        t = b.get_table("stats")
        s1 = t.key_sprintf(t.Key(2))
        self.assertEqual(s1, b"0x2")
        s2 = t.leaf_sprintf(t.Leaf((ct.c_uint * 3)(1,2,3), 4))
        self.assertEqual(s2, b"{ [ 0x1 0x2 0x3 ] 0x4 }")
        l = t.leaf_scanf(s2)
        self.assertEqual(l.a[0], 1)
        self.assertEqual(l.a[1], 2)
        self.assertEqual(l.a[2], 3)
        self.assertEqual(l.b, 4)

    def test_sscanf_string(self):
        text = """
struct Symbol {
    char name[128];
    char path[128];
};
struct Event {
    uint32_t pid;
    uint32_t tid;
    struct Symbol stack[64];
};
BPF_TABLE("array", int, struct Event, comms, 1);
"""
        b = BPF(text=text)
        t = b.get_table("comms")
        s1 = t.leaf_sprintf(t[0])
        fill = b' { "" "" }' * 63
        self.assertEqual(s1, b'{ 0x0 0x0 [ { "" "" }%s ] }' % fill)
        l = t.Leaf(1, 2)
        name = b"libxyz"
        path = b"/usr/lib/libxyz.so"
        l.stack[0].name = name
        l.stack[0].path = path
        s2 = t.leaf_sprintf(l)
        self.assertEqual(s2,
                b'{ 0x1 0x2 [ { "%s" "%s" }%s ] }' % (name, path, fill))
        l = t.leaf_scanf(s2)
        self.assertEqual(l.pid, 1)
        self.assertEqual(l.tid, 2)
        self.assertEqual(l.stack[0].name, name)
        self.assertEqual(l.stack[0].path, path)

    def test_iosnoop(self):
        text = """
#include <linux/blkdev.h>
#include <uapi/linux/ptrace.h>

struct key_t {
    struct request *req;
};

BPF_HASH(start, struct key_t, u64, 1024);
int do_request(struct pt_regs *ctx, struct request *req) {
    struct key_t key = {};

    bpf_trace_printk("traced start %d\\n", req->__data_len);

    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("do_request", BPF.KPROBE)

    def test_blk_start_request(self):
        text = """
#include <linux/blkdev.h>
#include <uapi/linux/ptrace.h>
int do_request(struct pt_regs *ctx, int req) {
    bpf_trace_printk("req ptr: 0x%x\\n", req);
    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("do_request", BPF.KPROBE)

    def test_bpf_hash(self):
        text = """
BPF_HASH(table1);
BPF_HASH(table2, u32);
BPF_HASH(table3, u32, int);
"""
        b = BPF(text=text, debug=0)

    def test_consecutive_probe_read(self):
        text = """
#include <linux/fs.h>
#include <linux/mount.h>
BPF_HASH(table1, struct super_block *);
int trace_entry(struct pt_regs *ctx, struct file *file) {
    if (!file) return 0;
    struct vfsmount *mnt = file->f_path.mnt;
    if (mnt) {
        struct super_block *k = mnt->mnt_sb;
        u64 zero = 0;
        table1.update(&k, &zero);
        k = mnt->mnt_sb;
        table1.update(&k, &zero);
    }

    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("trace_entry", BPF.KPROBE)

    def test_nested_probe_read(self):
        text = """
#include <linux/fs.h>
int trace_entry(struct pt_regs *ctx, struct file *file) {
    if (!file) return 0;
    const char *name = file->f_path.dentry->d_name.name;
    bpf_trace_printk("%s\\n", name);
    return 0;
}
"""
        b = BPF(text=text, debug=0)
        fn = b.load_func("trace_entry", BPF.KPROBE)

    def test_char_array_probe(self):
        BPF(text="""#include <linux/blkdev.h>
int kprobe__blk_update_request(struct pt_regs *ctx, struct request *req) {
    bpf_trace_printk("%s\\n", req->rq_disk->disk_name);
    return 0;
}""")

    def test_probe_read_helper(self):
        b = BPF(text="""
#include <linux/fs.h>
static void print_file_name(struct file *file) {
    if (!file) return;
    const char *name = file->f_path.dentry->d_name.name;
    bpf_trace_printk("%s\\n", name);
}
static void print_file_name2(int unused, struct file *file) {
    print_file_name(file);
}
int trace_entry1(struct pt_regs *ctx, struct file *file) {
    print_file_name(file);
    return 0;
}
int trace_entry2(struct pt_regs *ctx, int unused, struct file *file) {
    print_file_name2(unused, file);
    return 0;
}
""")
        fn = b.load_func("trace_entry1", BPF.KPROBE)
        fn = b.load_func("trace_entry2", BPF.KPROBE)

    def test_probe_unnamed_union_deref(self):
        text = """
#include <linux/mm_types.h>
int trace(struct pt_regs *ctx, struct page *page) {
    void *p = page->mapping;
    return p != NULL;
}
"""
        # depending on llvm, compile may pass/fail, but at least shouldn't crash
        try:
            b = BPF(text=text)
        except:
            pass

    def test_probe_struct_assign(self):
        b = BPF(text = """
#include <uapi/linux/ptrace.h>
struct args_t {
    const char *filename;
    int flags;
    int mode;
};
int kprobe__sys_open(struct pt_regs *ctx, const char *filename,
        int flags, int mode) {
    struct args_t args = {};
    args.filename = filename;
    args.flags = flags;
    args.mode = mode;
    bpf_trace_printk("%s\\n", args.filename);
    return 0;
};
""")

    def test_task_switch(self):
        b = BPF(text="""
#include <uapi/linux/ptrace.h>
#include <linux/sched.h>
struct key_t {
  u32 prev_pid;
  u32 curr_pid;
};
BPF_HASH(stats, struct key_t, u64, 1024);
int kprobe__finish_task_switch(struct pt_regs *ctx, struct task_struct *prev) {
  struct key_t key = {};
  u64 zero = 0, *val;
  key.curr_pid = bpf_get_current_pid_tgid();
  key.prev_pid = prev->pid;

  val = stats.lookup_or_init(&key, &zero);
  (*val)++;
  return 0;
}
""")

    def test_probe_simple_assign(self):
        b = BPF(text="""
#include <uapi/linux/ptrace.h>
#include <linux/gfp.h>
struct leaf { size_t size; };
BPF_HASH(simple_map, u32, struct leaf);
int kprobe____kmalloc(struct pt_regs *ctx, size_t size) {
    u32 pid = bpf_get_current_pid_tgid();
    struct leaf* leaf = simple_map.lookup(&pid);
    if (leaf)
        leaf->size += size;
    return 0;
}""")

    def test_unop_probe_read(self):
        text = """
#include <linux/blkdev.h>
int trace_entry(struct pt_regs *ctx, struct request *req) {
    if (!(req->bio->bi_flags & 1))
        return 1;
    if (((req->bio->bi_flags)))
        return 1;
    return 0;
}
"""
        b = BPF(text=text)
        fn = b.load_func("trace_entry", BPF.KPROBE)

    def test_paren_probe_read(self):
        text = """
#include <net/inet_sock.h>
int trace_entry(struct pt_regs *ctx, struct sock *sk) {
    u16 sport = ((struct inet_sock *)sk)->inet_sport;
    return sport;
}
"""
        b = BPF(text=text)
        fn = b.load_func("trace_entry", BPF.KPROBE)

    def test_complex_leaf_types(self):
        text = """
struct list;
struct list {
  struct list *selfp;
  struct list *another_selfp;
  struct list *selfp_array[2];
};
struct empty {
};
union emptyu {
  struct empty *em1;
  struct empty em2;
  struct empty em3;
  struct empty em4;
};
BPF_ARRAY(t1, struct list, 1);
BPF_ARRAY(t2, struct list *, 1);
BPF_ARRAY(t3, union emptyu, 1);
"""
        b = BPF(text=text)
        self.assertEqual(ct.sizeof(b["t3"].Leaf), 8)

    def test_cflags(self):
        text = """
#ifndef MYFLAG
#error "MYFLAG not set as expected"
#endif
"""
        b = BPF(text=text, cflags=["-DMYFLAG"])

    def test_exported_maps(self):
        b1 = BPF(text="""BPF_TABLE_PUBLIC("hash", int, int, table1, 10);""")
        b2 = BPF(text="""BPF_TABLE("extern", int, int, table1, 10);""")

    def test_syntax_error(self):
        with self.assertRaises(Exception):
            b = BPF(text="""int failure(void *ctx) { if (); return 0; }""")

    def test_nested_union(self):
        text = """
BPF_HASH(t1, struct bpf_tunnel_key, int, 1);
"""
        b = BPF(text=text)
        t1 = b["t1"]
        print(t1.Key().remote_ipv4)

    def test_too_many_args(self):
        text = """
#include <uapi/linux/ptrace.h>
int many(struct pt_regs *ctx, int a, int b, int c, int d, int e, int f, int g) {
    return 0;
}
"""
        with self.assertRaises(Exception):
            b = BPF(text=text)

    def test_call_macro_arg(self):
        text = """
BPF_TABLE("prog", u32, u32, jmp, 32);

#define JMP_IDX_PIPE (1U << 1)

enum action {
    ACTION_PASS
};

int process(struct xdp_md *ctx) {
    jmp.call((void *)ctx, ACTION_PASS);
    jmp.call((void *)ctx, JMP_IDX_PIPE);
    return XDP_PASS;
}
        """
        b = BPF(text=text)
        t = b["jmp"]
        self.assertEquals(len(t), 32);

    def test_update_macro_arg(self):
        text = """
BPF_ARRAY(act, u32, 32);

#define JMP_IDX_PIPE (1U << 1)

enum action {
    ACTION_PASS
};

int process(struct xdp_md *ctx) {
    act.increment(ACTION_PASS);
    act.increment(JMP_IDX_PIPE);
    return XDP_PASS;
}
        """
        b = BPF(text=text)
        t = b["act"]
        self.assertEquals(len(t), 32);

    def test_ext_ptr_maps(self):
        bpf_text = """
#include <uapi/linux/ptrace.h>
#include <net/sock.h>
#include <bcc/proto.h>

BPF_HASH(currsock, u32, struct sock *);

int trace_entry(struct pt_regs *ctx, struct sock *sk,
    struct sockaddr *uaddr, int addr_len) {
    u32 pid = bpf_get_current_pid_tgid();
    currsock.update(&pid, &sk);
    return 0;
};

int trace_exit(struct pt_regs *ctx) {
    u32 pid = bpf_get_current_pid_tgid();
    struct sock **skpp;
    skpp = currsock.lookup(&pid);
    if (skpp) {
        struct sock *skp = *skpp;
        return skp->__sk_common.skc_dport;
    }
    return 0;
}
        """
        b = BPF(text=bpf_text)
        b.load_func("trace_entry", BPF.KPROBE)
        b.load_func("trace_exit", BPF.KPROBE)

    def test_bpf_dins_pkt_rewrite(self):
        text = """
#include <bcc/proto.h>
int dns_test(struct __sk_buff *skb) {
    u8 *cursor = 0;
    struct ethernet_t *ethernet = cursor_advance(cursor, sizeof(*ethernet));
    if(ethernet->type == ETH_P_IP) {
        struct ip_t *ip = cursor_advance(cursor, sizeof(*ip));
        ip->src = ip->dst;
        return 0;
    }
    return -1;
}
        """
        b = BPF(text=text)

    @skipUnless(kernel_version_ge(4,8), "requires kernel >= 4.8")
    def test_ext_ptr_from_helper(self):
        text = """
#include <linux/sched.h>
int test(struct pt_regs *ctx) {
    struct task_struct *task = (struct task_struct *)bpf_get_current_task();
    return task->prio;
}
"""
        b = BPF(text=text)
        fn = b.load_func("test", BPF.KPROBE)

    def test_unary_operator(self):
        text = """
#include <linux/fs.h>
#include <uapi/linux/ptrace.h>
int trace_read_entry(struct pt_regs *ctx, struct file *file) {
    return !file->f_op->read_iter;
}
        """
        b = BPF(text=text)
        b.attach_kprobe(event="__vfs_read", fn_name="trace_read_entry")

    def test_printk_f(self):
        text = """
#include <uapi/linux/ptrace.h>
int trace_entry(struct pt_regs *ctx) {
  bpf_trace_printk("%0.2f\\n", 1);
  return 0;
}
"""
        r, w = os.pipe()
        with redirect_stderr(to=w):
            BPF(text=text)
        r = os.fdopen(r)
        output = r.read()
        expectedWarn = "warning: only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed"
        self.assertIn(expectedWarn, output)
        r.close()

    def test_printk_lf(self):
        text = """
#include <uapi/linux/ptrace.h>
int trace_entry(struct pt_regs *ctx) {
  bpf_trace_printk("%lf\\n", 1);
  return 0;
}
"""
        r, w = os.pipe()
        with redirect_stderr(to=w):
            BPF(text=text)
        r = os.fdopen(r)
        output = r.read()
        expectedWarn = "warning: only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed"
        self.assertIn(expectedWarn, output)
        r.close()

    def test_printk_2s(self):
        text = """
#include <uapi/linux/ptrace.h>
int trace_entry(struct pt_regs *ctx) {
  char s1[] = "hello", s2[] = "world";
  bpf_trace_printk("%s %s\\n", s1, s2);
  return 0;
}
"""
        r, w = os.pipe()
        with redirect_stderr(to=w):
            BPF(text=text)
        r = os.fdopen(r)
        output = r.read()
        expectedWarn = "warning: cannot use several %s conversion specifiers"
        self.assertIn(expectedWarn, output)
        r.close()

    def test_map_insert(self):
        text = """
BPF_HASH(dummy);
void do_trace(struct pt_regs *ctx) {
    u64 key = 0, val = 2;
    dummy.insert(&key, &val);
    key = 1;
    dummy.update(&key, &val);
}
"""
        b = BPF(text=text)
        c_val = ct.c_ulong(1)
        b["dummy"][ct.c_ulong(0)] = c_val
        b["dummy"][ct.c_ulong(1)] = c_val
        b.attach_kprobe(event="sys_sync", fn_name="do_trace")
        libc = ct.CDLL("libc.so.6")
        libc.sync()
        self.assertEqual(1, b["dummy"][ct.c_ulong(0)].value)
        self.assertEqual(2, b["dummy"][ct.c_ulong(1)].value)

    def test_prog_array_delete(self):
        text = """
BPF_TABLE("prog", int, int, dummy, 256);
"""
        b1 = BPF(text=text)
        text = """
int do_next(struct pt_regs *ctx) {
    return 0;
}
"""
        b2 = BPF(text=text)
        fn = b2.load_func("do_next", BPF.KPROBE)
        c_key = ct.c_int(0)
        b1["dummy"][c_key] = ct.c_int(fn.fd)
        b1["dummy"].__delitem__(c_key);
        with self.assertRaises(KeyError):
            b1["dummy"][c_key]

    def test_invalid_noninline_call(self):
        text = """
int bar(void) {
    return 0;
}
int foo(struct pt_regs *ctx) {
    return bar();
}
"""
        with self.assertRaises(Exception):
            b = BPF(text=text)

    def test_incomplete_type(self):
        text = """
BPF_HASH(drops, struct key_t);
struct key_t {
    u64 location;
};
"""
        with self.assertRaises(Exception):
            b = BPF(text=text)

    def test_enumerations(self):
        text = """
enum b {
    CHOICE_A,
};
struct a {
    enum b test;
};
BPF_HASH(drops, struct a);
        """
        b = BPF(text=text)


if __name__ == "__main__":
    main()