// SPDX-License-Identifier: GPL-2.0
#include "../perf.h"
#include "util.h"
#include "debug.h"
#include <api/fs/fs.h>
#include <sys/mman.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/kernel.h>
#include <linux/log2.h>
#include <linux/time64.h>
#include <unistd.h>
#include "strlist.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;
}

unsigned int page_size;

#ifdef _SC_LEVEL1_DCACHE_LINESIZE
#define cache_line_size(cacheline_sizep) *cacheline_sizep = sysconf(_SC_LEVEL1_DCACHE_LINESIZE)
#else
static void cache_line_size(int *cacheline_sizep)
{
        if (sysfs__read_int("devices/system/cpu/cpu0/cache/index0/coherency_line_size", cacheline_sizep))
                pr_debug("cannot determine cache line size");
}
#endif

int cacheline_size(void)
{
        static int size;

        if (!size)
                cache_line_size(&size);

        return size;
}

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 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;
}

int rm_rf(const char *path)
{
        DIR *dir;
        int ret = 0;
        struct dirent *d;
        char namebuf[PATH_MAX];

        dir = opendir(path);
        if (dir == NULL)
                return 0;

        while ((d = readdir(dir)) != NULL && !ret) {
                struct stat statbuf;

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

                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 = rm_rf(namebuf);
                else
                        ret = unlink(namebuf);
        }
        closedir(dir);

        if (ret < 0)
                return ret;

        return rmdir(path);
}

/* 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;
}

static int slow_copyfile(const char *from, const char *to, struct nsinfo *nsi)
{
        int err = -1;
        char *line = NULL;
        size_t n;
        FILE *from_fp, *to_fp;
        struct nscookie nsc;

        nsinfo__mountns_enter(nsi, &nsc);
        from_fp = fopen(from, "r");
        nsinfo__mountns_exit(&nsc);
        if (from_fp == NULL)
                goto out;

        to_fp = fopen(to, "w");
        if (to_fp == NULL)
                goto out_fclose_from;

        while (getline(&line, &n, from_fp) > 0)
                if (fputs(line, to_fp) == EOF)
                        goto out_fclose_to;
        err = 0;
out_fclose_to:
        fclose(to_fp);
        free(line);
out_fclose_from:
        fclose(from_fp);
out:
        return err;
}

int copyfile_offset(int ifd, loff_t off_in, int ofd, loff_t off_out, u64 size)
{
        void *ptr;
        loff_t pgoff;

        pgoff = off_in & ~(page_size - 1);
        off_in -= pgoff;

        ptr = mmap(NULL, off_in + size, PROT_READ, MAP_PRIVATE, ifd, pgoff);
        if (ptr == MAP_FAILED)
                return -1;

        while (size) {
                ssize_t ret = pwrite(ofd, ptr + off_in, size, off_out);
                if (ret < 0 && errno == EINTR)
                        continue;
                if (ret <= 0)
                        break;

                size -= ret;
                off_in += ret;
                off_out += ret;
        }
        munmap(ptr, off_in + size);

        return size ? -1 : 0;
}

static int copyfile_mode_ns(const char *from, const char *to, mode_t mode,
                            struct nsinfo *nsi)
{
        int fromfd, tofd;
        struct stat st;
        int err;
        char *tmp = NULL, *ptr = NULL;
        struct nscookie nsc;

        nsinfo__mountns_enter(nsi, &nsc);
        err = stat(from, &st);
        nsinfo__mountns_exit(&nsc);
        if (err)
                goto out;
        err = -1;

        /* extra 'x' at the end is to reserve space for '.' */
        if (asprintf(&tmp, "%s.XXXXXXx", to) < 0) {
                tmp = NULL;
                goto out;
        }
        ptr = strrchr(tmp, '/');
        if (!ptr)
                goto out;
        ptr = memmove(ptr + 1, ptr, strlen(ptr) - 1);
        *ptr = '.';

        tofd = mkstemp(tmp);
        if (tofd < 0)
                goto out;

        if (fchmod(tofd, mode))
                goto out_close_to;

        if (st.st_size == 0) { /* /proc? do it slowly... */
                err = slow_copyfile(from, tmp, nsi);
                goto out_close_to;
        }

        nsinfo__mountns_enter(nsi, &nsc);
        fromfd = open(from, O_RDONLY);
        nsinfo__mountns_exit(&nsc);
        if (fromfd < 0)
                goto out_close_to;

        err = copyfile_offset(fromfd, 0, tofd, 0, st.st_size);

        close(fromfd);
out_close_to:
        close(tofd);
        if (!err)
                err = link(tmp, to);
        unlink(tmp);
out:
        free(tmp);
        return err;
}

int copyfile_ns(const char *from, const char *to, struct nsinfo *nsi)
{
        return copyfile_mode_ns(from, to, 0755, nsi);
}

int copyfile_mode(const char *from, const char *to, mode_t mode)
{
        return copyfile_mode_ns(from, to, mode, NULL);
}

int copyfile(const char *from, const char *to)
{
        return copyfile_mode(from, to, 0755);
}

static ssize_t ion(bool is_read, int fd, void *buf, size_t n)
{
        void *buf_start = buf;
        size_t left = n;

        while (left) {
                /* buf must be treated as const if !is_read. */
                ssize_t ret = is_read ? read(fd, buf, left) :
                                        write(fd, buf, left);

                if (ret < 0 && errno == EINTR)
                        continue;
                if (ret <= 0)
                        return ret;

                left -= ret;
                buf  += ret;
        }

        BUG_ON((size_t)(buf - buf_start) != n);
        return n;
}

/*
 * Read exactly 'n' bytes or return an error.
 */
ssize_t readn(int fd, void *buf, size_t n)
{
        return ion(true, fd, buf, n);
}

/*
 * Write exactly 'n' bytes or return an error.
 */
ssize_t writen(int fd, const void *buf, size_t n)
{
        /* ion does not modify buf. */
        return ion(false, fd, (void *)buf, n);
}

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

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

        return n;
}

/*
 * While we find nice hex chars, build a long_val.
 * Return number of chars processed.
 */
int hex2u64(const char *ptr, u64 *long_val)
{
        char *p;

        *long_val = strtoull(ptr, &p, 16);

        return p - ptr;
}

int perf_event_paranoid(void)
{
        int value;

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

        return value;
}
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;
}