kernel/module/procfs.c

   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
  16 static 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 */
  41 static 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. */
  49 static 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
  55 static void *m_next(struct seq_file *m, void *p, loff_t *pos)
  56 {
  57         return seq_list_next(p, &modules, pos);
  58 }
  59
  60 static void m_stop(struct seq_file *m, void *p)
  61 {
  62         mutex_unlock(&module_mutex);
  63 }
  64
  65 static unsigned int module_total_size(struct module *mod)
  66 {
  67         int size = 0;
  68
  69         for_each_mod_mem_type(type)
  70                 size += mod->mem[type].size;
  71         return size;
  72 }
  73
  74 static int m_show(struct seq_file *m, void *p)
  75 {
  76         struct module *mod = list_entry(p, struct module, list);
  77         char buf[MODULE_FLAGS_BUF_SIZE];
  78         void *value;
  79         unsigned int size;
  80
  81         /* We always ignore unformed modules. */
  82         if (mod->state == MODULE_STATE_UNFORMED)
  83                 return 0;
  84
  85         size = module_total_size(mod);
  86         seq_printf(m, "%s %u", mod->name, size);
  87         print_unload_info(m, mod);
  88
  89         /* Informative for users. */
  90         seq_printf(m, " %s",
  91                    mod->state == MODULE_STATE_GOING ? "Unloading" :
  92                    mod->state == MODULE_STATE_COMING ? "Loading" :
  93                    "Live");
  94         /* Used by oprofile and other similar tools. */
  95         value = m->private ? NULL : mod->mem[MOD_TEXT].base;
  96         seq_printf(m, " 0x%px", value);
  97
  98         /* Taints info */
  99         if (mod->taints)
 100                 seq_printf(m, " %s", module_flags(mod, buf, true));
 101
 102         seq_puts(m, "\n");
 103         return 0;
 104 }
 105
 106 /*
 107  * Format: modulename size refcount deps address
 108  *
 109  * Where refcount is a number or -, and deps is a comma-separated list
 110  * of depends or -.
 111  */
 112 static const struct seq_operations modules_op = {
 113         .start  = m_start,
 114         .next   = m_next,
 115         .stop   = m_stop,
 116         .show   = m_show
 117 };
 118
 119 /*
 120  * This also sets the "private" pointer to non-NULL if the
 121  * kernel pointers should be hidden (so you can just test
 122  * "m->private" to see if you should keep the values private).
 123  *
 124  * We use the same logic as for /proc/kallsyms.
 125  */
 126 static int modules_open(struct inode *inode, struct file *file)
 127 {
 128         int err = seq_open(file, &modules_op);
 129
 130         if (!err) {
 131                 struct seq_file *m = file->private_data;
 132
 133                 m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
 134         }
 135
 136         return err;
 137 }
 138
 139 static const struct proc_ops modules_proc_ops = {
 140         .proc_flags     = PROC_ENTRY_PERMANENT,
 141         .proc_open      = modules_open,
 142         .proc_read      = seq_read,
 143         .proc_lseek     = seq_lseek,
 144         .proc_release   = seq_release,
 145 };
 146
 147 static int __init proc_modules_init(void)
 148 {
 149         proc_create("modules", 0, NULL, &modules_proc_ops);
 150         return 0;
 151 }
 152 module_init(proc_modules_init);