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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2019 Netronome Systems, Inc. */
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/utsname.h>
#include <linux/filter.h>
#include <linux/limits.h>
#include <bpf.h>
#include "main.h"
enum probe_component {
COMPONENT_UNSPEC,
COMPONENT_KERNEL,
};
/* Printing utility functions */
static void
print_bool_feature(const char *feat_name, const char *plain_name, bool res)
{
if (json_output)
jsonw_bool_field(json_wtr, feat_name, res);
else
printf("%s is %savailable\n", plain_name, res ? "" : "NOT ");
}
static void
print_start_section(const char *json_title, const char *plain_title)
{
if (json_output) {
jsonw_name(json_wtr, json_title);
jsonw_start_object(json_wtr);
} else {
printf("%s\n", plain_title);
}
}
/* Probing functions */
static bool probe_bpf_syscall(void)
{
bool res;
bpf_load_program(BPF_PROG_TYPE_UNSPEC, NULL, 0, NULL, 0, NULL, 0);
res = (errno != ENOSYS);
print_bool_feature("have_bpf_syscall",
"bpf() syscall",
res);
return res;
}
static int do_probe(int argc, char **argv)
{
enum probe_component target = COMPONENT_UNSPEC;
/* Detection assumes user has sufficient privileges (CAP_SYS_ADMIN).
* Let's approximate, and restrict usage to root user only.
*/
if (geteuid()) {
p_err("please run this command as root user");
return -1;
}
set_max_rlimit();
while (argc) {
if (is_prefix(*argv, "kernel")) {
if (target != COMPONENT_UNSPEC) {
p_err("component to probe already specified");
return -1;
}
target = COMPONENT_KERNEL;
NEXT_ARG();
} else {
p_err("expected no more arguments, 'kernel', got: '%s'?",
*argv);
return -1;
}
}
if (json_output)
jsonw_start_object(json_wtr);
print_start_section("syscall_config",
"Scanning system call availability...");
probe_bpf_syscall();
if (json_output) {
/* End current "section" of probes */
jsonw_end_object(json_wtr);
/* End root object */
jsonw_end_object(json_wtr);
}
return 0;
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %s %s probe [kernel]\n"
" %s %s help\n"
"",
bin_name, argv[-2], bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "help", do_help },
{ "probe", do_probe },
{ 0 }
};
int do_feature(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}
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