// SPDX-License-Identifier: GPL-2.0-only
#include <unistd.h>
#include <string.h>
#include <stdbool.h>

#include "bpf_util.h"
#include "bpftool_helpers.h"

#define BPFTOOL_PATH_MAX_LEN            64
#define BPFTOOL_FULL_CMD_MAX_LEN        512

#define BPFTOOL_DEFAULT_PATH            "tools/sbin/bpftool"

static int detect_bpftool_path(char *buffer, size_t size)
{
        char tmp[BPFTOOL_PATH_MAX_LEN];
        const char *env_path;

        /* First, check if BPFTOOL environment variable is set */
        env_path = getenv("BPFTOOL");
        if (env_path && access(env_path, X_OK) == 0) {
                strscpy(buffer, env_path, size);
                return 0;
        } else if (env_path) {
                fprintf(stderr, "bpftool '%s' doesn't exist or is not executable\n", env_path);
                return 1;
        }

        /* Check default bpftool location (will work if we are running the
         * default flavor of test_progs)
         */
        snprintf(tmp, BPFTOOL_PATH_MAX_LEN, "./%s", BPFTOOL_DEFAULT_PATH);
        if (access(tmp, X_OK) == 0) {
                strscpy(buffer, tmp, size);
                return 0;
        }

        /* Check alternate bpftool location (will work if we are running a
         * specific flavor of test_progs, e.g. cpuv4 or no_alu32)
         */
        snprintf(tmp, BPFTOOL_PATH_MAX_LEN, "../%s", BPFTOOL_DEFAULT_PATH);
        if (access(tmp, X_OK) == 0) {
                strscpy(buffer, tmp, size);
                return 0;
        }

        fprintf(stderr, "Failed to detect bpftool path, use BPFTOOL env var to override\n");
        return 1;
}

static int run_command(char *args, char *output_buf, size_t output_max_len)
{
        static char bpftool_path[BPFTOOL_PATH_MAX_LEN] = {0};
        bool suppress_output = !(output_buf && output_max_len);
        char command[BPFTOOL_FULL_CMD_MAX_LEN];
        FILE *f;
        int ret;

        /* Detect and cache bpftool binary location */
        if (bpftool_path[0] == 0 && detect_bpftool_path(bpftool_path, sizeof(bpftool_path)))
                return 1;

        ret = snprintf(command, BPFTOOL_FULL_CMD_MAX_LEN, "%s %s%s",
                       bpftool_path, args,
                       suppress_output ? " > /dev/null 2>&1" : "");

        f = popen(command, "r");
        if (!f)
                return 1;

        if (!suppress_output)
                fread(output_buf, 1, output_max_len, f);
        ret = pclose(f);

        return ret;
}

int run_bpftool_command(char *args)
{
        return run_command(args, NULL, 0);
}

int get_bpftool_command_output(char *args, char *output_buf, size_t output_max_len)
{
        return run_command(args, output_buf, output_max_len);
}