// SPDX-License-Identifier: GPL-2.0
#include "util.h"
#include "debug.h"
#include "event.h"
#include <api/fs/fs.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <dirent.h>
#include <fcntl.h>
#include <inttypes.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/time64.h>
#include <unistd.h>
#include "cap.h"
#include "strlist.h"
#include "string2.h"

/*
 * XXX We need to find a better place for these things...
 */

bool perf_singlethreaded = true;

void perf_set_singlethreaded(void)
{
        perf_singlethreaded = true;
}

void perf_set_multithreaded(void)
{
        perf_singlethreaded = false;
}

int sysctl_perf_event_max_stack = PERF_MAX_STACK_DEPTH;
int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;

int sysctl__max_stack(void)
{
        int value;

        if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
                sysctl_perf_event_max_stack = value;

        if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
                sysctl_perf_event_max_contexts_per_stack = value;

        return sysctl_perf_event_max_stack;
}

bool sysctl__nmi_watchdog_enabled(void)
{
        static bool cached;
        static bool nmi_watchdog;
        int value;

        if (cached)
                return nmi_watchdog;

        if (sysctl__read_int("kernel/nmi_watchdog", &value) < 0)
                return false;

        nmi_watchdog = (value > 0) ? true : false;
        cached = true;

        return nmi_watchdog;
}

bool test_attr__enabled;

bool perf_host  = true;
bool perf_guest = false;

void event_attr_init(struct perf_event_attr *attr)
{
        if (!perf_host)
                attr->exclude_host  = 1;
        if (!perf_guest)
                attr->exclude_guest = 1;
        /* to capture ABI version */
        attr->size = sizeof(*attr);
}

int mkdir_p(char *path, mode_t mode)
{
        struct stat st;
        int err;
        char *d = path;

        if (*d != '/')
                return -1;

        if (stat(path, &st) == 0)
                return 0;

        while (*++d == '/');

        while ((d = strchr(d, '/'))) {
                *d = '\0';
                err = stat(path, &st) && mkdir(path, mode);
                *d++ = '/';
                if (err)
                        return -1;
                while (*d == '/')
                        ++d;
        }
        return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;
}

static bool match_pat(char *file, const char **pat)
{
        int i = 0;

        if (!pat)
                return true;

        while (pat[i]) {
                if (strglobmatch(file, pat[i]))
                        return true;

                i++;
        }

        return false;
}

/*
 * The depth specify how deep the removal will go.
 * 0       - will remove only files under the 'path' directory
 * 1 .. x  - will dive in x-level deep under the 'path' directory
 *
 * If specified the pat is array of string patterns ended with NULL,
 * which are checked upon every file/directory found. Only matching
 * ones are removed.
 *
 * The function returns:
 *    0 on success
 *   -1 on removal failure with errno set
 *   -2 on pattern failure
 */
static int rm_rf_depth_pat(const char *path, int depth, const char **pat)
{
        DIR *dir;
        int ret;
        struct dirent *d;
        char namebuf[PATH_MAX];
        struct stat statbuf;

        /* Do not fail if there's no file. */
        ret = lstat(path, &statbuf);
        if (ret)
                return 0;

        /* Try to remove any file we get. */
        if (!(statbuf.st_mode & S_IFDIR))
                return unlink(path);

        /* We have directory in path. */
        dir = opendir(path);
        if (dir == NULL)
                return -1;

        while ((d = readdir(dir)) != NULL && !ret) {

                if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
                        continue;

                if (!match_pat(d->d_name, pat)) {
                        ret =  -2;
                        break;
                }

                scnprintf(namebuf, sizeof(namebuf), "%s/%s",
                          path, d->d_name);

                /* We have to check symbolic link itself */
                ret = lstat(namebuf, &statbuf);
                if (ret < 0) {
                        pr_debug("stat failed: %s\n", namebuf);
                        break;
                }

                if (S_ISDIR(statbuf.st_mode))
                        ret = depth ? rm_rf_depth_pat(namebuf, depth - 1, pat) : 0;
                else
                        ret = unlink(namebuf);
        }
        closedir(dir);

        if (ret < 0)
                return ret;

        return rmdir(path);
}

static int rm_rf_kcore_dir(const char *path)
{
        char kcore_dir_path[PATH_MAX];
        const char *pat[] = {
                "kcore",
                "kallsyms",
                "modules",
                NULL,
        };

        snprintf(kcore_dir_path, sizeof(kcore_dir_path), "%s/kcore_dir", path);

        return rm_rf_depth_pat(kcore_dir_path, 0, pat);
}

int rm_rf_perf_data(const char *path)
{
        const char *pat[] = {
                "data",
                "data.*",
                NULL,
        };

        rm_rf_kcore_dir(path);

        return rm_rf_depth_pat(path, 0, pat);
}

int rm_rf(const char *path)
{
        return rm_rf_depth_pat(path, INT_MAX, NULL);
}

/* A filter which removes dot files */
bool lsdir_no_dot_filter(const char *name __maybe_unused, struct dirent *d)
{
        return d->d_name[0] != '.';
}

/* lsdir reads a directory and store it in strlist */
struct strlist *lsdir(const char *name,
                      bool (*filter)(const char *, struct dirent *))
{
        struct strlist *list = NULL;
        DIR *dir;
        struct dirent *d;

        dir = opendir(name);
        if (!dir)
                return NULL;

        list = strlist__new(NULL, NULL);
        if (!list) {
                errno = ENOMEM;
                goto out;
        }

        while ((d = readdir(dir)) != NULL) {
                if (!filter || filter(name, d))
                        strlist__add(list, d->d_name);
        }

out:
        closedir(dir);
        return list;
}

size_t hex_width(u64 v)
{
        size_t n = 1;

        while ((v >>= 4))
                ++n;

        return n;
}

int perf_event_paranoid(void)
{
        int value;

        if (sysctl__read_int("kernel/perf_event_paranoid", &value))
                return INT_MAX;

        return value;
}

bool perf_event_paranoid_check(int max_level)
{
        return perf_cap__capable(CAP_SYS_ADMIN) ||
                        perf_cap__capable(CAP_PERFMON) ||
                        perf_event_paranoid() <= max_level;
}

static int
fetch_ubuntu_kernel_version(unsigned int *puint)
{
        ssize_t len;
        size_t line_len = 0;
        char *ptr, *line = NULL;
        int version, patchlevel, sublevel, err;
        FILE *vsig;

        if (!puint)
                return 0;

        vsig = fopen("/proc/version_signature", "r");
        if (!vsig) {
                pr_debug("Open /proc/version_signature failed: %s\n",
                         strerror(errno));
                return -1;
        }

        len = getline(&line, &line_len, vsig);
        fclose(vsig);
        err = -1;
        if (len <= 0) {
                pr_debug("Reading from /proc/version_signature failed: %s\n",
                         strerror(errno));
                goto errout;
        }

        ptr = strrchr(line, ' ');
        if (!ptr) {
                pr_debug("Parsing /proc/version_signature failed: %s\n", line);
                goto errout;
        }

        err = sscanf(ptr + 1, "%d.%d.%d",
                     &version, &patchlevel, &sublevel);
        if (err != 3) {
                pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
                         line);
                goto errout;
        }

        *puint = (version << 16) + (patchlevel << 8) + sublevel;
        err = 0;
errout:
        free(line);
        return err;
}

int
fetch_kernel_version(unsigned int *puint, char *str,
                     size_t str_size)
{
        struct utsname utsname;
        int version, patchlevel, sublevel, err;
        bool int_ver_ready = false;

        if (access("/proc/version_signature", R_OK) == 0)
                if (!fetch_ubuntu_kernel_version(puint))
                        int_ver_ready = true;

        if (uname(&utsname))
                return -1;

        if (str && str_size) {
                strncpy(str, utsname.release, str_size);
                str[str_size - 1] = '\0';
        }

        if (!puint || int_ver_ready)
                return 0;

        err = sscanf(utsname.release, "%d.%d.%d",
                     &version, &patchlevel, &sublevel);

        if (err != 3) {
                pr_debug("Unable to get kernel version from uname '%s'\n",
                         utsname.release);
                return -1;
        }

        *puint = (version << 16) + (patchlevel << 8) + sublevel;
        return 0;
}

const char *perf_tip(const char *dirpath)
{
        struct strlist *tips;
        struct str_node *node;
        char *tip = NULL;
        struct strlist_config conf = {
                .dirname = dirpath,
                .file_only = true,
        };

        tips = strlist__new("tips.txt", &conf);
        if (tips == NULL)
                return errno == ENOENT ? NULL :
                        "Tip: check path of tips.txt or get more memory! ;-p";

        if (strlist__nr_entries(tips) == 0)
                goto out;

        node = strlist__entry(tips, random() % strlist__nr_entries(tips));
        if (asprintf(&tip, "Tip: %s", node->s) < 0)
                tip = (char *)"Tip: get more memory! ;-)";

out:
        strlist__delete(tips);

        return tip;
}

char *perf_exe(char *buf, int len)
{
        int n = readlink("/proc/self/exe", buf, len);
        if (n > 0) {
                buf[n] = 0;
                return buf;
        }
        return strcpy(buf, "perf");
}