// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <linux/err.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <asm/bug.h>
#include <dirent.h>

#include "data.h"
#include "util.h" // rm_rf_perf_data()
#include "debug.h"
#include "header.h"
#include "rlimit.h"
#include <internal/lib.h>

static void close_dir(struct perf_data_file *files, int nr)
{
        while (--nr >= 0) {
                close(files[nr].fd);
                zfree(&files[nr].path);
        }
        free(files);
}

void perf_data__close_dir(struct perf_data *data)
{
        close_dir(data->dir.files, data->dir.nr);
}

int perf_data__create_dir(struct perf_data *data, int nr)
{
        enum rlimit_action set_rlimit = NO_CHANGE;
        struct perf_data_file *files = NULL;
        int i, ret;

        if (WARN_ON(!data->is_dir))
                return -EINVAL;

        files = zalloc(nr * sizeof(*files));
        if (!files)
                return -ENOMEM;

        for (i = 0; i < nr; i++) {
                struct perf_data_file *file = &files[i];

                ret = asprintf(&file->path, "%s/data.%d", data->path, i);
                if (ret < 0) {
                        ret = -ENOMEM;
                        goto out_err;
                }

retry_open:
                ret = open(file->path, O_RDWR|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
                if (ret < 0) {
                        /*
                         * If using parallel threads to collect data,
                         * perf record needs at least 6 fds per CPU.
                         * When we run out of them try to increase the limits.
                         */
                        if (errno == EMFILE && rlimit__increase_nofile(&set_rlimit))
                                goto retry_open;

                        ret = -errno;
                        goto out_err;
                }
                set_rlimit = NO_CHANGE;

                file->fd = ret;
        }

        data->dir.version = PERF_DIR_VERSION;
        data->dir.files   = files;
        data->dir.nr      = nr;
        return 0;

out_err:
        close_dir(files, i);
        return ret;
}

int perf_data__open_dir(struct perf_data *data)
{
        struct perf_data_file *files = NULL;
        struct dirent *dent;
        int ret = -1;
        DIR *dir;
        int nr = 0;

        /*
         * Directory containing a single regular perf data file which is already
         * open, means there is nothing more to do here.
         */
        if (perf_data__is_single_file(data))
                return 0;

        if (WARN_ON(!data->is_dir))
                return -EINVAL;

        /* The version is provided by DIR_FORMAT feature. */
        if (WARN_ON(data->dir.version != PERF_DIR_VERSION))
                return -1;

        dir = opendir(data->path);
        if (!dir)
                return -EINVAL;

        while ((dent = readdir(dir)) != NULL) {
                struct perf_data_file *file;
                char path[PATH_MAX];
                struct stat st;

                snprintf(path, sizeof(path), "%s/%s", data->path, dent->d_name);
                if (stat(path, &st))
                        continue;

                if (!S_ISREG(st.st_mode) || strncmp(dent->d_name, "data.", 5))
                        continue;

                ret = -ENOMEM;

                file = realloc(files, (nr + 1) * sizeof(*files));
                if (!file)
                        goto out_err;

                files = file;
                file = &files[nr++];

                file->path = strdup(path);
                if (!file->path)
                        goto out_err;

                ret = open(file->path, O_RDONLY);
                if (ret < 0)
                        goto out_err;

                file->fd = ret;
                file->size = st.st_size;
        }

        closedir(dir);
        if (!files)
                return -EINVAL;

        data->dir.files = files;
        data->dir.nr    = nr;
        return 0;

out_err:
        closedir(dir);
        close_dir(files, nr);
        return ret;
}

static bool check_pipe(struct perf_data *data)
{
        struct stat st;
        bool is_pipe = false;
        int fd = perf_data__is_read(data) ?
                 STDIN_FILENO : STDOUT_FILENO;

        if (!data->path) {
                if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
                        is_pipe = true;
        } else {
                if (!strcmp(data->path, "-"))
                        is_pipe = true;
        }

        if (is_pipe) {
                if (data->use_stdio) {
                        const char *mode;

                        mode = perf_data__is_read(data) ? "r" : "w";
                        data->file.fptr = fdopen(fd, mode);

                        if (data->file.fptr == NULL) {
                                data->file.fd = fd;
                                data->use_stdio = false;
                        }

                /*
                 * When is_pipe and data->file.fd is given, use given fd
                 * instead of STDIN_FILENO or STDOUT_FILENO
                 */
                } else if (data->file.fd <= 0) {
                        data->file.fd = fd;
                }
        }

        return data->is_pipe = is_pipe;
}

static int check_backup(struct perf_data *data)
{
        struct stat st;

        if (perf_data__is_read(data))
                return 0;

        if (!stat(data->path, &st) && st.st_size) {
                char oldname[PATH_MAX];
                int ret;

                snprintf(oldname, sizeof(oldname), "%s.old",
                         data->path);

                ret = rm_rf_perf_data(oldname);
                if (ret) {
                        if (ret == -2)
                                pr_err("Can't remove old data: Unknown file found (%s)\n", oldname);
                        else
                                pr_err("Can't remove old data: %m (%s)\n", oldname);
                        return -1;
                }

                if (rename(data->path, oldname)) {
                        pr_err("Can't move data: %m (%s to %s)\n", data->path, oldname);
                        return -1;
                }
        }

        return 0;
}

static bool is_dir(struct perf_data *data)
{
        struct stat st;

        if (stat(data->path, &st))
                return false;

        return (st.st_mode & S_IFMT) == S_IFDIR;
}

static int open_file_read(struct perf_data *data)
{
        int flags = data->in_place_update ? O_RDWR : O_RDONLY;
        struct stat st;
        int fd;

        fd = open(data->file.path, flags);
        if (fd < 0) {
                int err = errno;

                pr_err("failed to open %s: %m", data->file.path);
                if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
                        pr_err("  (try 'perf record' first)");
                pr_err("\n");
                return -err;
        }

        if (fstat(fd, &st) < 0)
                goto out_close;

        if (!data->force && st.st_uid && (st.st_uid != geteuid())) {
                pr_err("File %s not owned by current user or root (use -f to override)\n",
                       data->file.path);
                goto out_close;
        }

        if (!st.st_size) {
                pr_info("zero-sized data (%s), nothing to do!\n",
                        data->file.path);
                goto out_close;
        }

        data->file.size = st.st_size;
        return fd;

 out_close:
        close(fd);
        return -1;
}

static int open_file_write(struct perf_data *data)
{
        int fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC, S_IRUSR|S_IWUSR);

        if (fd < 0)
                pr_err("failed to open %s : %m\n", data->file.path);

        return fd;
}

static int open_file(struct perf_data *data)
{
        int fd;

        fd = perf_data__is_read(data) ?
             open_file_read(data) : open_file_write(data);

        if (fd < 0) {
                zfree(&data->file.path);
                return -1;
        }

        data->file.fd = fd;
        return 0;
}

static int open_file_dup(struct perf_data *data)
{
        data->file.path = strdup(data->path);
        if (!data->file.path)
                return -ENOMEM;

        return open_file(data);
}

static int open_dir(struct perf_data *data)
{
        int ret;

        /*
         * So far we open only the header, so we can read the data version and
         * layout.
         */
        if (asprintf(&data->file.path, "%s/data", data->path) < 0)
                return -1;

        if (perf_data__is_write(data) &&
            mkdir(data->path, S_IRWXU) < 0)
                return -1;

        ret = open_file(data);

        /* Cleanup whatever we managed to create so far. */
        if (ret && perf_data__is_write(data))
                rm_rf_perf_data(data->path);

        return ret;
}

int perf_data__open(struct perf_data *data)
{
        if (check_pipe(data))
                return 0;

        /* currently it allows stdio for pipe only */
        data->use_stdio = false;

        if (!data->path)
                data->path = "perf.data";

        if (check_backup(data))
                return -1;

        if (perf_data__is_read(data))
                data->is_dir = is_dir(data);

        return perf_data__is_dir(data) ?
               open_dir(data) : open_file_dup(data);
}

void perf_data__close(struct perf_data *data)
{
        if (perf_data__is_dir(data))
                perf_data__close_dir(data);

        zfree(&data->file.path);

        if (data->use_stdio)
                fclose(data->file.fptr);
        else
                close(data->file.fd);
}

ssize_t perf_data__read(struct perf_data *data, void *buf, size_t size)
{
        if (data->use_stdio) {
                if (fread(buf, size, 1, data->file.fptr) == 1)
                        return size;
                return feof(data->file.fptr) ? 0 : -1;
        }
        return readn(data->file.fd, buf, size);
}

ssize_t perf_data_file__write(struct perf_data_file *file,
                              void *buf, size_t size)
{
        return writen(file->fd, buf, size);
}

ssize_t perf_data__write(struct perf_data *data,
                         void *buf, size_t size)
{
        if (data->use_stdio) {
                if (fwrite(buf, size, 1, data->file.fptr) == 1)
                        return size;
                return -1;
        }
        return perf_data_file__write(&data->file, buf, size);
}

int perf_data__switch(struct perf_data *data,
                      const char *postfix,
                      size_t pos, bool at_exit,
                      char **new_filepath)
{
        int ret;

        if (perf_data__is_read(data))
                return -EINVAL;

        if (asprintf(new_filepath, "%s.%s", data->path, postfix) < 0)
                return -ENOMEM;

        /*
         * Only fire a warning, don't return error, continue fill
         * original file.
         */
        if (rename(data->path, *new_filepath))
                pr_warning("Failed to rename %s to %s\n", data->path, *new_filepath);

        if (!at_exit) {
                close(data->file.fd);
                ret = perf_data__open(data);
                if (ret < 0)
                        goto out;

                if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
                        ret = -errno;
                        pr_debug("Failed to lseek to %zu: %m\n",
                                 pos);
                        goto out;
                }
        }
        ret = data->file.fd;
out:
        return ret;
}

unsigned long perf_data__size(struct perf_data *data)
{
        u64 size = data->file.size;
        int i;

        if (perf_data__is_single_file(data))
                return size;

        for (i = 0; i < data->dir.nr; i++) {
                struct perf_data_file *file = &data->dir.files[i];

                size += file->size;
        }

        return size;
}

int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
{
        int ret;

        if (!data->is_dir)
                return -1;

        ret = snprintf(buf, buf_sz, "%s/kcore_dir", data->path);
        if (ret < 0 || (size_t)ret >= buf_sz)
                return -1;

        return mkdir(buf, S_IRWXU);
}

bool has_kcore_dir(const char *path)
{
        struct dirent *d = ERR_PTR(-EINVAL);
        const char *name = "kcore_dir";
        DIR *dir = opendir(path);
        size_t n = strlen(name);
        bool result = false;

        if (dir) {
                while (d && !result) {
                        d = readdir(dir);
                        result = d ? strncmp(d->d_name, name, n) : false;
                }
                closedir(dir);
        }

        return result;
}

char *perf_data__kallsyms_name(struct perf_data *data)
{
        char *kallsyms_name;
        struct stat st;

        if (!data->is_dir)
                return NULL;

        if (asprintf(&kallsyms_name, "%s/kcore_dir/kallsyms", data->path) < 0)
                return NULL;

        if (stat(kallsyms_name, &st)) {
                free(kallsyms_name);
                return NULL;
        }

        return kallsyms_name;
}

char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
{
        char *kallsyms_name;
        struct stat st;

        if (!data->is_dir)
                return NULL;

        if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
                return NULL;

        if (stat(kallsyms_name, &st)) {
                free(kallsyms_name);
                return NULL;
        }

        return kallsyms_name;
}

bool is_perf_data(const char *path)
{
        bool ret = false;
        FILE *file;
        u64 magic;

        file = fopen(path, "r");
        if (!file)
                return false;

        if (fread(&magic, 1, 8, file) < 8)
                goto out;

        ret = is_perf_magic(magic);
out:
        fclose(file);
        return ret;
}