bpf/progs/test_snprintf.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (c) 2021 Google LLC. */
0003
0004 #include <linux/bpf.h>
0005 #include <bpf/bpf_helpers.h>
0006
0007 __u32 pid = 0;
0008
0009 char num_out[64] = {};
0010 long num_ret = 0;
0011
0012 char ip_out[64] = {};
0013 long ip_ret = 0;
0014
0015 char sym_out[64] = {};
0016 long sym_ret = 0;
0017
0018 char addr_out[64] = {};
0019 long addr_ret = 0;
0020
0021 char str_out[64] = {};
0022 long str_ret = 0;
0023
0024 char over_out[6] = {};
0025 long over_ret = 0;
0026
0027 char pad_out[10] = {};
0028 long pad_ret = 0;
0029
0030 char noarg_out[64] = {};
0031 long noarg_ret = 0;
0032
0033 long nobuf_ret = 0;
0034
0035 extern const void schedule __ksym;
0036
0037 SEC("raw_tp/sys_enter")
0038 int handler(const void *ctx)
0039 {
0040     /* Convenient values to pretty-print */
0041     const __u8 ex_ipv4[] = {127, 0, 0, 1};
0042     const __u8 ex_ipv6[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
0043     static const char str1[] = "str1";
0044     static const char longstr[] = "longstr";
0045
0046     if ((int)bpf_get_current_pid_tgid() != pid)
0047         return 0;
0048
0049     /* Integer types */
0050     num_ret  = BPF_SNPRINTF(num_out, sizeof(num_out),
0051                 "%d %u %x %li %llu %lX",
0052                 -8, 9, 150, -424242, 1337, 0xDABBAD00);
0053     /* IP addresses */
0054     ip_ret   = BPF_SNPRINTF(ip_out, sizeof(ip_out), "%pi4 %pI6",
0055                 &ex_ipv4, &ex_ipv6);
0056     /* Symbol lookup formatting */
0057     sym_ret  = BPF_SNPRINTF(sym_out,  sizeof(sym_out), "%ps %pS %pB",
0058                 &schedule, &schedule, &schedule);
0059     /* Kernel pointers */
0060     addr_ret = BPF_SNPRINTF(addr_out, sizeof(addr_out), "%pK %px %p",
0061                 0, 0xFFFF00000ADD4E55, 0xFFFF00000ADD4E55);
0062     /* Strings and single-byte character embedding */
0063     str_ret  = BPF_SNPRINTF(str_out, sizeof(str_out), "%s % 9c %+2c %-3c %04c %0c %+05s",
0064                 str1, 'a', 'b', 'c', 'd', 'e', longstr);
0065     /* Overflow */
0066     over_ret = BPF_SNPRINTF(over_out, sizeof(over_out), "%%overflow");
0067     /* Padding of fixed width numbers */
0068     pad_ret = BPF_SNPRINTF(pad_out, sizeof(pad_out), "%5d %0900000X", 4, 4);
0069     /* No args */
0070     noarg_ret = BPF_SNPRINTF(noarg_out, sizeof(noarg_out), "simple case");
0071     /* No buffer */
0072     nobuf_ret = BPF_SNPRINTF(NULL, 0, "only interested in length %d", 60);
0073
0074     return 0;
0075 }
0076
0077 char _license[] SEC("license") = "GPL";