1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Module proc support
  4 *
  5 * Copyright (C) 2008 Alexey Dobriyan
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/kallsyms.h>
 10#include <linux/mutex.h>
 11#include <linux/seq_file.h>
 12#include <linux/proc_fs.h>
 13#include "internal.h"
 14
 15#ifdef CONFIG_MODULE_UNLOAD
 16static inline void print_unload_info(struct seq_file *m, struct module *mod)
 17{
 18	struct module_use *use;
 19	int printed_something = 0;
 20
 21	seq_printf(m, " %i ", module_refcount(mod));
 22
 23	/*
 24	 * Always include a trailing , so userspace can differentiate
 25	 * between this and the old multi-field proc format.
 26	 */
 27	list_for_each_entry(use, &mod->source_list, source_list) {
 28		printed_something = 1;
 29		seq_printf(m, "%s,", use->source->name);
 30	}
 31
 32	if (mod->init && !mod->exit) {
 33		printed_something = 1;
 34		seq_puts(m, "[permanent],");
 35	}
 36
 37	if (!printed_something)
 38		seq_puts(m, "-");
 39}
 40#else /* !CONFIG_MODULE_UNLOAD */
 41static inline void print_unload_info(struct seq_file *m, struct module *mod)
 42{
 43	/* We don't know the usage count, or what modules are using. */
 44	seq_puts(m, " - -");
 45}
 46#endif /* CONFIG_MODULE_UNLOAD */
 47
 48/* Called by the /proc file system to return a list of modules. */
 49static void *m_start(struct seq_file *m, loff_t *pos)
 50{
 51	mutex_lock(&module_mutex);
 52	return seq_list_start(&modules, *pos);
 53}
 54
 55static void *m_next(struct seq_file *m, void *p, loff_t *pos)
 56{
 57	return seq_list_next(p, &modules, pos);
 58}
 59
 60static void m_stop(struct seq_file *m, void *p)
 61{
 62	mutex_unlock(&module_mutex);
 63}
 64
 65static int m_show(struct seq_file *m, void *p)
 66{
 67	struct module *mod = list_entry(p, struct module, list);
 68	char buf[MODULE_FLAGS_BUF_SIZE];
 69	void *value;
 70	unsigned int size;
 71
 72	/* We always ignore unformed modules. */
 73	if (mod->state == MODULE_STATE_UNFORMED)
 74		return 0;
 75
 76	size = mod->init_layout.size + mod->core_layout.size;
 77#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
 78	size += mod->data_layout.size;
 79#endif
 80	seq_printf(m, "%s %u", mod->name, size);
 81	print_unload_info(m, mod);
 82
 83	/* Informative for users. */
 84	seq_printf(m, " %s",
 85		   mod->state == MODULE_STATE_GOING ? "Unloading" :
 86		   mod->state == MODULE_STATE_COMING ? "Loading" :
 87		   "Live");
 88	/* Used by oprofile and other similar tools. */
 89	value = m->private ? NULL : mod->core_layout.base;
 90	seq_printf(m, " 0x%px", value);
 91
 92	/* Taints info */
 93	if (mod->taints)
 94		seq_printf(m, " %s", module_flags(mod, buf, true));
 95
 96	seq_puts(m, "\n");
 97	return 0;
 98}
 99
100/*
101 * Format: modulename size refcount deps address
102 *
103 * Where refcount is a number or -, and deps is a comma-separated list
104 * of depends or -.
105 */
106static const struct seq_operations modules_op = {
107	.start	= m_start,
108	.next	= m_next,
109	.stop	= m_stop,
110	.show	= m_show
111};
112
113/*
114 * This also sets the "private" pointer to non-NULL if the
115 * kernel pointers should be hidden (so you can just test
116 * "m->private" to see if you should keep the values private).
117 *
118 * We use the same logic as for /proc/kallsyms.
119 */
120static int modules_open(struct inode *inode, struct file *file)
121{
122	int err = seq_open(file, &modules_op);
123
124	if (!err) {
125		struct seq_file *m = file->private_data;
126
127		m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
128	}
129
130	return err;
131}
132
133static const struct proc_ops modules_proc_ops = {
134	.proc_flags	= PROC_ENTRY_PERMANENT,
135	.proc_open	= modules_open,
136	.proc_read	= seq_read,
137	.proc_lseek	= seq_lseek,
138	.proc_release	= seq_release,
139};
140
141static int __init proc_modules_init(void)
142{
143	proc_create("modules", 0, NULL, &modules_proc_ops);
144	return 0;
145}
146module_init(proc_modules_init);