bpf/prog_tests/probe_read_user_str.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <test_progs.h>
0003 #include "test_probe_read_user_str.skel.h"
0004
0005 static const char str1[] = "mestring";
0006 static const char str2[] = "mestringalittlebigger";
0007 static const char str3[] = "mestringblubblubblubblubblub";
0008
0009 static int test_one_str(struct test_probe_read_user_str *skel, const char *str,
0010             size_t len)
0011 {
0012     int err, duration = 0;
0013     char buf[256];
0014
0015     /* Ensure bytes after string are ones */
0016     memset(buf, 1, sizeof(buf));
0017     memcpy(buf, str, len);
0018
0019     /* Give prog our userspace pointer */
0020     skel->bss->user_ptr = buf;
0021
0022     /* Trigger tracepoint */
0023     usleep(1);
0024
0025     /* Did helper fail? */
0026     if (CHECK(skel->bss->ret < 0, "prog_ret", "prog returned: %ld\n",
0027           skel->bss->ret))
0028         return 1;
0029
0030     /* Check that string was copied correctly */
0031     err = memcmp(skel->bss->buf, str, len);
0032     if (CHECK(err, "memcmp", "prog copied wrong string"))
0033         return 1;
0034
0035     /* Now check that no extra trailing bytes were copied */
0036     memset(buf, 0, sizeof(buf));
0037     err = memcmp(skel->bss->buf + len, buf, sizeof(buf) - len);
0038     if (CHECK(err, "memcmp", "trailing bytes were not stripped"))
0039         return 1;
0040
0041     return 0;
0042 }
0043
0044 void test_probe_read_user_str(void)
0045 {
0046     struct test_probe_read_user_str *skel;
0047     int err, duration = 0;
0048
0049     skel = test_probe_read_user_str__open_and_load();
0050     if (CHECK(!skel, "test_probe_read_user_str__open_and_load",
0051           "skeleton open and load failed\n"))
0052         return;
0053
0054     /* Give pid to bpf prog so it doesn't read from anyone else */
0055     skel->bss->pid = getpid();
0056
0057     err = test_probe_read_user_str__attach(skel);
0058     if (CHECK(err, "test_probe_read_user_str__attach",
0059           "skeleton attach failed: %d\n", err))
0060         goto out;
0061
0062     if (test_one_str(skel, str1, sizeof(str1)))
0063         goto out;
0064     if (test_one_str(skel, str2, sizeof(str2)))
0065         goto out;
0066     if (test_one_str(skel, str3, sizeof(str3)))
0067         goto out;
0068
0069 out:
0070     test_probe_read_user_str__destroy(skel);
0071 }