Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
3
4#include <test_progs.h>
5#include <network_helpers.h>
6#include "file_reader.skel.h"
7#include "file_reader_fail.skel.h"
8#include <dlfcn.h>
9#include <sys/mman.h>
10
11const char *user_ptr = "hello world";
12char file_contents[256000];
13
14void *get_executable_base_addr(void)
15{
16 Dl_info info;
17
18 if (!dladdr((void *)&get_executable_base_addr, &info)) {
19 fprintf(stderr, "dladdr failed\n");
20 return NULL;
21 }
22
23 return info.dli_fbase;
24}
25
26static int initialize_file_contents(void)
27{
28 int fd, page_sz = sysconf(_SC_PAGESIZE);
29 ssize_t n = 0, cur, off;
30 void *addr;
31
32 fd = open("/proc/self/exe", O_RDONLY);
33 if (!ASSERT_OK_FD(fd, "Open /proc/self/exe\n"))
34 return 1;
35
36 do {
37 cur = read(fd, file_contents + n, sizeof(file_contents) - n);
38 if (!ASSERT_GT(cur, 0, "read success"))
39 break;
40 n += cur;
41 } while (n < sizeof(file_contents));
42
43 close(fd);
44
45 if (!ASSERT_EQ(n, sizeof(file_contents), "Read /proc/self/exe\n"))
46 return 1;
47
48 addr = get_executable_base_addr();
49 if (!ASSERT_NEQ(addr, NULL, "get executable address"))
50 return 1;
51
52 /* page-align base file address */
53 addr = (void *)((unsigned long)addr & ~(page_sz - 1));
54
55 /*
56 * Page out range 0..512K, use 0..256K for positive tests and
57 * 256K..512K for negative tests expecting page faults
58 */
59 for (off = 0; off < sizeof(file_contents) * 2; off += page_sz) {
60 if (!ASSERT_OK(madvise(addr + off, page_sz, MADV_PAGEOUT),
61 "madvise pageout"))
62 return errno;
63 }
64
65 return 0;
66}
67
68static void run_test(const char *prog_name)
69{
70 struct file_reader *skel;
71 struct bpf_program *prog;
72 int err, fd;
73
74 err = initialize_file_contents();
75 if (!ASSERT_OK(err, "initialize file contents"))
76 return;
77
78 skel = file_reader__open();
79 if (!ASSERT_OK_PTR(skel, "file_reader__open"))
80 return;
81
82 bpf_object__for_each_program(prog, skel->obj) {
83 bpf_program__set_autoload(prog, strcmp(bpf_program__name(prog), prog_name) == 0);
84 }
85
86 memcpy(skel->bss->user_buf, file_contents, sizeof(file_contents));
87 skel->bss->pid = getpid();
88
89 err = file_reader__load(skel);
90 if (!ASSERT_OK(err, "file_reader__load"))
91 goto cleanup;
92
93 err = file_reader__attach(skel);
94 if (!ASSERT_OK(err, "file_reader__attach"))
95 goto cleanup;
96
97 fd = open("/proc/self/exe", O_RDONLY);
98 if (fd >= 0)
99 close(fd);
100
101 ASSERT_EQ(skel->bss->err, 0, "err");
102 ASSERT_EQ(skel->bss->run_success, 1, "run_success");
103cleanup:
104 file_reader__destroy(skel);
105}
106
107void test_file_reader(void)
108{
109 if (test__start_subtest("on_open_expect_fault"))
110 run_test("on_open_expect_fault");
111
112 if (test__start_subtest("on_open_validate_file_read"))
113 run_test("on_open_validate_file_read");
114
115 if (test__start_subtest("negative"))
116 RUN_TESTS(file_reader_fail);
117}