util.c

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// 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;
}

static 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;
}