net/wireless/debugfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * cfg80211 debugfs
   4  *
   5  * Copyright 2009       Luis R. Rodriguez <lrodriguez@atheros.com>
   6  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
   7  * Copyright (C) 2023 Intel Corporation
   8  */
   9
  10 #include <linux/slab.h>
  11 #include "core.h"
  12 #include "debugfs.h"
  13
  14 #define DEBUGFS_READONLY_FILE(name, buflen, fmt, value...)              \
  15 static ssize_t name## _read(struct file *file, char __user *userbuf,    \
  16                             size_t count, loff_t *ppos)                 \
  17 {                                                                       \
  18         struct wiphy *wiphy = file->private_data;                       \
  19         char buf[buflen];                                               \
  20         int res;                                                        \
  21                                                                         \
  22         res = scnprintf(buf, buflen, fmt "\n", ##value);                \
  23         return simple_read_from_buffer(userbuf, count, ppos, buf, res); \
  24 }                                                                       \
  25                                                                         \
  26 static const struct file_operations name## _ops = {                     \
  27         .read = name## _read,                                           \
  28         .open = simple_open,                                            \
  29         .llseek = generic_file_llseek,                                  \
  30 }
  31
  32 DEBUGFS_READONLY_FILE(rts_threshold, 20, "%d",
  33                       wiphy->rts_threshold);
  34 DEBUGFS_READONLY_FILE(fragmentation_threshold, 20, "%d",
  35                       wiphy->frag_threshold);
  36 DEBUGFS_READONLY_FILE(short_retry_limit, 20, "%d",
  37                       wiphy->retry_short);
  38 DEBUGFS_READONLY_FILE(long_retry_limit, 20, "%d",
  39                       wiphy->retry_long);
  40
  41 static int ht_print_chan(struct ieee80211_channel *chan,
  42                          char *buf, int buf_size, int offset)
  43 {
  44         if (WARN_ON(offset > buf_size))
  45                 return 0;
  46
  47         if (chan->flags & IEEE80211_CHAN_DISABLED)
  48                 return scnprintf(buf + offset,
  49                                  buf_size - offset,
  50                                  "%d Disabled\n",
  51                                  chan->center_freq);
  52
  53         return scnprintf(buf + offset,
  54                          buf_size - offset,
  55                          "%d HT40 %c%c\n",
  56                          chan->center_freq,
  57                          (chan->flags & IEEE80211_CHAN_NO_HT40MINUS) ?
  58                                 ' ' : '-',
  59                          (chan->flags & IEEE80211_CHAN_NO_HT40PLUS) ?
  60                                 ' ' : '+');
  61 }
  62
  63 static ssize_t ht40allow_map_read(struct file *file,
  64                                   char __user *user_buf,
  65                                   size_t count, loff_t *ppos)
  66 {
  67         struct wiphy *wiphy = file->private_data;
  68         char *buf;
  69         unsigned int offset = 0, buf_size = PAGE_SIZE, i;
  70         enum nl80211_band band;
  71         struct ieee80211_supported_band *sband;
  72         ssize_t r;
  73
  74         buf = kzalloc(buf_size, GFP_KERNEL);
  75         if (!buf)
  76                 return -ENOMEM;
  77
  78         for (band = 0; band < NUM_NL80211_BANDS; band++) {
  79                 sband = wiphy->bands[band];
  80                 if (!sband)
  81                         continue;
  82                 for (i = 0; i < sband->n_channels; i++)
  83                         offset += ht_print_chan(&sband->channels[i],
  84                                                 buf, buf_size, offset);
  85         }
  86
  87         r = simple_read_from_buffer(user_buf, count, ppos, buf, offset);
  88
  89         kfree(buf);
  90
  91         return r;
  92 }
  93
  94 static const struct file_operations ht40allow_map_ops = {
  95         .read = ht40allow_map_read,
  96         .open = simple_open,
  97         .llseek = default_llseek,
  98 };
  99
 100 #define DEBUGFS_ADD(name)                                               \
 101         debugfs_create_file(#name, 0444, phyd, &rdev->wiphy, &name## _ops)
 102
 103 void cfg80211_debugfs_rdev_add(struct cfg80211_registered_device *rdev)
 104 {
 105         struct dentry *phyd = rdev->wiphy.debugfsdir;
 106
 107         DEBUGFS_ADD(rts_threshold);
 108         DEBUGFS_ADD(fragmentation_threshold);
 109         DEBUGFS_ADD(short_retry_limit);
 110         DEBUGFS_ADD(long_retry_limit);
 111         DEBUGFS_ADD(ht40allow_map);
 112 }
 113
 114 struct debugfs_read_work {
 115         struct wiphy_work work;
 116         ssize_t (*handler)(struct wiphy *wiphy,
 117                            struct file *file,
 118                            char *buf,
 119                            size_t count,
 120                            void *data);
 121         struct wiphy *wiphy;
 122         struct file *file;
 123         char *buf;
 124         size_t bufsize;
 125         void *data;
 126         ssize_t ret;
 127         struct completion completion;
 128 };
 129
 130 static void wiphy_locked_debugfs_read_work(struct wiphy *wiphy,
 131                                            struct wiphy_work *work)
 132 {
 133         struct debugfs_read_work *w = container_of(work, typeof(*w), work);
 134
 135         w->ret = w->handler(w->wiphy, w->file, w->buf, w->bufsize, w->data);
 136         complete(&w->completion);
 137 }
 138
 139 static void wiphy_locked_debugfs_read_cancel(struct dentry *dentry,
 140                                              void *data)
 141 {
 142         struct debugfs_read_work *w = data;
 143
 144         wiphy_work_cancel(w->wiphy, &w->work);
 145         complete(&w->completion);
 146 }
 147
 148 ssize_t wiphy_locked_debugfs_read(struct wiphy *wiphy, struct file *file,
 149                                   char *buf, size_t bufsize,
 150                                   char __user *userbuf, size_t count,
 151                                   loff_t *ppos,
 152                                   ssize_t (*handler)(struct wiphy *wiphy,
 153                                                      struct file *file,
 154                                                      char *buf,
 155                                                      size_t bufsize,
 156                                                      void *data),
 157                                   void *data)
 158 {
 159         struct debugfs_read_work work = {
 160                 .handler = handler,
 161                 .wiphy = wiphy,
 162                 .file = file,
 163                 .buf = buf,
 164                 .bufsize = bufsize,
 165                 .data = data,
 166                 .ret = -ENODEV,
 167                 .completion = COMPLETION_INITIALIZER_ONSTACK(work.completion),
 168         };
 169         struct debugfs_cancellation cancellation = {
 170                 .cancel = wiphy_locked_debugfs_read_cancel,
 171                 .cancel_data = &work,
 172         };
 173
 174         /* don't leak stack data or whatever */
 175         memset(buf, 0, bufsize);
 176
 177         wiphy_work_init(&work.work, wiphy_locked_debugfs_read_work);
 178         wiphy_work_queue(wiphy, &work.work);
 179
 180         debugfs_enter_cancellation(file, &cancellation);
 181         wait_for_completion(&work.completion);
 182         debugfs_leave_cancellation(file, &cancellation);
 183
 184         if (work.ret < 0)
 185                 return work.ret;
 186
 187         if (WARN_ON(work.ret > bufsize))
 188                 return -EINVAL;
 189
 190         return simple_read_from_buffer(userbuf, count, ppos, buf, work.ret);
 191 }
 192 EXPORT_SYMBOL_GPL(wiphy_locked_debugfs_read);
 193
 194 struct debugfs_write_work {
 195         struct wiphy_work work;
 196         ssize_t (*handler)(struct wiphy *wiphy,
 197                            struct file *file,
 198                            char *buf,
 199                            size_t count,
 200                            void *data);
 201         struct wiphy *wiphy;
 202         struct file *file;
 203         char *buf;
 204         size_t count;
 205         void *data;
 206         ssize_t ret;
 207         struct completion completion;
 208 };
 209
 210 static void wiphy_locked_debugfs_write_work(struct wiphy *wiphy,
 211                                             struct wiphy_work *work)
 212 {
 213         struct debugfs_write_work *w = container_of(work, typeof(*w), work);
 214
 215         w->ret = w->handler(w->wiphy, w->file, w->buf, w->count, w->data);
 216         complete(&w->completion);
 217 }
 218
 219 static void wiphy_locked_debugfs_write_cancel(struct dentry *dentry,
 220                                               void *data)
 221 {
 222         struct debugfs_write_work *w = data;
 223
 224         wiphy_work_cancel(w->wiphy, &w->work);
 225         complete(&w->completion);
 226 }
 227
 228 ssize_t wiphy_locked_debugfs_write(struct wiphy *wiphy,
 229                                    struct file *file, char *buf, size_t bufsize,
 230                                    const char __user *userbuf, size_t count,
 231                                    ssize_t (*handler)(struct wiphy *wiphy,
 232                                                       struct file *file,
 233                                                       char *buf,
 234                                                       size_t count,
 235                                                       void *data),
 236                                    void *data)
 237 {
 238         struct debugfs_write_work work = {
 239                 .handler = handler,
 240                 .wiphy = wiphy,
 241                 .file = file,
 242                 .buf = buf,
 243                 .count = count,
 244                 .data = data,
 245                 .ret = -ENODEV,
 246                 .completion = COMPLETION_INITIALIZER_ONSTACK(work.completion),
 247         };
 248         struct debugfs_cancellation cancellation = {
 249                 .cancel = wiphy_locked_debugfs_write_cancel,
 250                 .cancel_data = &work,
 251         };
 252
 253         /* mostly used for strings so enforce NUL-termination for safety */
 254         if (count >= bufsize)
 255                 return -EINVAL;
 256
 257         memset(buf, 0, bufsize);
 258
 259         if (copy_from_user(buf, userbuf, count))
 260                 return -EFAULT;
 261
 262         wiphy_work_init(&work.work, wiphy_locked_debugfs_write_work);
 263         wiphy_work_queue(wiphy, &work.work);
 264
 265         debugfs_enter_cancellation(file, &cancellation);
 266         wait_for_completion(&work.completion);
 267         debugfs_leave_cancellation(file, &cancellation);
 268
 269         return work.ret;
 270 }
 271 EXPORT_SYMBOL_GPL(wiphy_locked_debugfs_write);