// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Module proc support
 *
 * Copyright (C) 2008 Alexey Dobriyan
 */

#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include "internal.h"

#ifdef CONFIG_MODULE_UNLOAD
static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
        struct module_use *use;
        int printed_something = 0;

        seq_printf(m, " %i ", module_refcount(mod));

        /*
         * Always include a trailing , so userspace can differentiate
         * between this and the old multi-field proc format.
         */
        list_for_each_entry(use, &mod->source_list, source_list) {
                printed_something = 1;
                seq_printf(m, "%s,", use->source->name);
        }

        if (mod->init && !mod->exit) {
                printed_something = 1;
                seq_puts(m, "[permanent],");
        }

        if (!printed_something)
                seq_puts(m, "-");
}
#else /* !CONFIG_MODULE_UNLOAD */
static inline void print_unload_info(struct seq_file *m, struct module *mod)
{
        /* We don't know the usage count, or what modules are using. */
        seq_puts(m, " - -");
}
#endif /* CONFIG_MODULE_UNLOAD */

/* Called by the /proc file system to return a list of modules. */
static void *m_start(struct seq_file *m, loff_t *pos)
{
        mutex_lock(&module_mutex);
        return seq_list_start(&modules, *pos);
}

static void *m_next(struct seq_file *m, void *p, loff_t *pos)
{
        return seq_list_next(p, &modules, pos);
}

static void m_stop(struct seq_file *m, void *p)
{
        mutex_unlock(&module_mutex);
}

static unsigned int module_total_size(struct module *mod)
{
        int size = 0;

        for_each_mod_mem_type(type)
                size += mod->mem[type].size;
        return size;
}

static int m_show(struct seq_file *m, void *p)
{
        struct module *mod = list_entry(p, struct module, list);
        char buf[MODULE_FLAGS_BUF_SIZE];
        void *value;
        unsigned int size;

        /* We always ignore unformed modules. */
        if (mod->state == MODULE_STATE_UNFORMED)
                return 0;

        size = module_total_size(mod);
        seq_printf(m, "%s %u", mod->name, size);
        print_unload_info(m, mod);

        /* Informative for users. */
        seq_printf(m, " %s",
                   mod->state == MODULE_STATE_GOING ? "Unloading" :
                   mod->state == MODULE_STATE_COMING ? "Loading" :
                   "Live");
        /* Used by oprofile and other similar tools. */
        value = m->private ? NULL : mod->mem[MOD_TEXT].base;
        seq_printf(m, " 0x%px", value);

        /* Taints info */
        if (mod->taints)
                seq_printf(m, " %s", module_flags(mod, buf, true));

        seq_puts(m, "\n");
        return 0;
}

/*
 * Format: modulename size refcount deps address
 *
 * Where refcount is a number or -, and deps is a comma-separated list
 * of depends or -.
 */
static const struct seq_operations modules_op = {
        .start  = m_start,
        .next   = m_next,
        .stop   = m_stop,
        .show   = m_show
};

/*
 * This also sets the "private" pointer to non-NULL if the
 * kernel pointers should be hidden (so you can just test
 * "m->private" to see if you should keep the values private).
 *
 * We use the same logic as for /proc/kallsyms.
 */
static int modules_open(struct inode *inode, struct file *file)
{
        int err = seq_open(file, &modules_op);

        if (!err) {
                struct seq_file *m = file->private_data;

                m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
        }

        return err;
}

static const struct proc_ops modules_proc_ops = {
        .proc_flags     = PROC_ENTRY_PERMANENT,
        .proc_open      = modules_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_release   = seq_release,
};

static int __init proc_modules_init(void)
{
        proc_create("modules", 0, NULL, &modules_proc_ops);
        return 0;
}
module_init(proc_modules_init);