fs/proc/task_nommu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/mm.h>
   4 #include <linux/file.h>
   5 #include <linux/fdtable.h>
   6 #include <linux/fs_struct.h>
   7 #include <linux/mount.h>
   8 #include <linux/ptrace.h>
   9 #include <linux/slab.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/sched/mm.h>
  12
  13 #include "internal.h"
  14
  15 /*
  16  * Logic: we've got two memory sums for each process, "shared", and
  17  * "non-shared". Shared memory may get counted more than once, for
  18  * each process that owns it. Non-shared memory is counted
  19  * accurately.
  20  */
  21 void task_mem(struct seq_file *m, struct mm_struct *mm)
  22 {
  23         VMA_ITERATOR(vmi, mm, 0);
  24         struct vm_area_struct *vma;
  25         struct vm_region *region;
  26         unsigned long bytes = 0, sbytes = 0, slack = 0, size;
  27
  28         mmap_read_lock(mm);
  29         for_each_vma(vmi, vma) {
  30                 bytes += kobjsize(vma);
  31
  32                 region = vma->vm_region;
  33                 if (region) {
  34                         size = kobjsize(region);
  35                         size += region->vm_end - region->vm_start;
  36                 } else {
  37                         size = vma->vm_end - vma->vm_start;
  38                 }
  39
  40                 if (atomic_read(&mm->mm_count) > 1 ||
  41                     is_nommu_shared_mapping(vma->vm_flags)) {
  42                         sbytes += size;
  43                 } else {
  44                         bytes += size;
  45                         if (region)
  46                                 slack = region->vm_end - vma->vm_end;
  47                 }
  48         }
  49
  50         if (atomic_read(&mm->mm_count) > 1)
  51                 sbytes += kobjsize(mm);
  52         else
  53                 bytes += kobjsize(mm);
  54
  55         if (current->fs && current->fs->users > 1)
  56                 sbytes += kobjsize(current->fs);
  57         else
  58                 bytes += kobjsize(current->fs);
  59
  60         if (current->files && atomic_read(&current->files->count) > 1)
  61                 sbytes += kobjsize(current->files);
  62         else
  63                 bytes += kobjsize(current->files);
  64
  65         if (current->sighand && refcount_read(&current->sighand->count) > 1)
  66                 sbytes += kobjsize(current->sighand);
  67         else
  68                 bytes += kobjsize(current->sighand);
  69
  70         bytes += kobjsize(current); /* includes kernel stack */
  71
  72         mmap_read_unlock(mm);
  73
  74         seq_printf(m,
  75                 "Mem:\t%8lu bytes\n"
  76                 "Slack:\t%8lu bytes\n"
  77                 "Shared:\t%8lu bytes\n",
  78                 bytes, slack, sbytes);
  79 }
  80
  81 unsigned long task_vsize(struct mm_struct *mm)
  82 {
  83         VMA_ITERATOR(vmi, mm, 0);
  84         struct vm_area_struct *vma;
  85         unsigned long vsize = 0;
  86
  87         mmap_read_lock(mm);
  88         for_each_vma(vmi, vma)
  89                 vsize += vma->vm_end - vma->vm_start;
  90         mmap_read_unlock(mm);
  91         return vsize;
  92 }
  93
  94 unsigned long task_statm(struct mm_struct *mm,
  95                          unsigned long *shared, unsigned long *text,
  96                          unsigned long *data, unsigned long *resident)
  97 {
  98         VMA_ITERATOR(vmi, mm, 0);
  99         struct vm_area_struct *vma;
 100         struct vm_region *region;
 101         unsigned long size = kobjsize(mm);
 102
 103         mmap_read_lock(mm);
 104         for_each_vma(vmi, vma) {
 105                 size += kobjsize(vma);
 106                 region = vma->vm_region;
 107                 if (region) {
 108                         size += kobjsize(region);
 109                         size += region->vm_end - region->vm_start;
 110                 }
 111         }
 112
 113         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 114                 >> PAGE_SHIFT;
 115         *data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
 116                 >> PAGE_SHIFT;
 117         mmap_read_unlock(mm);
 118         size >>= PAGE_SHIFT;
 119         size += *text + *data;
 120         *resident = size;
 121         return size;
 122 }
 123
 124 /*
 125  * display a single VMA to a sequenced file
 126  */
 127 static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
 128 {
 129         struct mm_struct *mm = vma->vm_mm;
 130         unsigned long ino = 0;
 131         struct file *file;
 132         dev_t dev = 0;
 133         int flags;
 134         unsigned long long pgoff = 0;
 135
 136         flags = vma->vm_flags;
 137         file = vma->vm_file;
 138
 139         if (file) {
 140                 struct inode *inode = file_inode(vma->vm_file);
 141                 dev = inode->i_sb->s_dev;
 142                 ino = inode->i_ino;
 143                 pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 144         }
 145
 146         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 147         seq_printf(m,
 148                    "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
 149                    vma->vm_start,
 150                    vma->vm_end,
 151                    flags & VM_READ ? 'r' : '-',
 152                    flags & VM_WRITE ? 'w' : '-',
 153                    flags & VM_EXEC ? 'x' : '-',
 154                    flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
 155                    pgoff,
 156                    MAJOR(dev), MINOR(dev), ino);
 157
 158         if (file) {
 159                 seq_pad(m, ' ');
 160                 seq_path(m, file_user_path(file), "");
 161         } else if (mm && vma_is_initial_stack(vma)) {
 162                 seq_pad(m, ' ');
 163                 seq_puts(m, "[stack]");
 164         }
 165
 166         seq_putc(m, '\n');
 167         return 0;
 168 }
 169
 170 /*
 171  * display mapping lines for a particular process's /proc/pid/maps
 172  */
 173 static int show_map(struct seq_file *m, void *_p)
 174 {
 175         return nommu_vma_show(m, _p);
 176 }
 177
 178 static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
 179                                                 loff_t *ppos)
 180 {
 181         struct vm_area_struct *vma = vma_next(&priv->iter);
 182
 183         if (vma) {
 184                 *ppos = vma->vm_start;
 185         } else {
 186                 *ppos = -1UL;
 187         }
 188
 189         return vma;
 190 }
 191
 192 static void *m_start(struct seq_file *m, loff_t *ppos)
 193 {
 194         struct proc_maps_private *priv = m->private;
 195         unsigned long last_addr = *ppos;
 196         struct mm_struct *mm;
 197
 198         /* See proc_get_vma(). Zero at the start or after lseek. */
 199         if (last_addr == -1UL)
 200                 return NULL;
 201
 202         /* pin the task and mm whilst we play with them */
 203         priv->task = get_proc_task(priv->inode);
 204         if (!priv->task)
 205                 return ERR_PTR(-ESRCH);
 206
 207         mm = priv->mm;
 208         if (!mm || !mmget_not_zero(mm)) {
 209                 put_task_struct(priv->task);
 210                 priv->task = NULL;
 211                 return NULL;
 212         }
 213
 214         if (mmap_read_lock_killable(mm)) {
 215                 mmput(mm);
 216                 put_task_struct(priv->task);
 217                 priv->task = NULL;
 218                 return ERR_PTR(-EINTR);
 219         }
 220
 221         vma_iter_init(&priv->iter, mm, last_addr);
 222
 223         return proc_get_vma(priv, ppos);
 224 }
 225
 226 static void m_stop(struct seq_file *m, void *v)
 227 {
 228         struct proc_maps_private *priv = m->private;
 229         struct mm_struct *mm = priv->mm;
 230
 231         if (!priv->task)
 232                 return;
 233
 234         mmap_read_unlock(mm);
 235         mmput(mm);
 236         put_task_struct(priv->task);
 237         priv->task = NULL;
 238 }
 239
 240 static void *m_next(struct seq_file *m, void *_p, loff_t *ppos)
 241 {
 242         return proc_get_vma(m->private, ppos);
 243 }
 244
 245 static const struct seq_operations proc_pid_maps_ops = {
 246         .start  = m_start,
 247         .next   = m_next,
 248         .stop   = m_stop,
 249         .show   = show_map
 250 };
 251
 252 static int maps_open(struct inode *inode, struct file *file,
 253                      const struct seq_operations *ops)
 254 {
 255         struct proc_maps_private *priv;
 256
 257         priv = __seq_open_private(file, ops, sizeof(*priv));
 258         if (!priv)
 259                 return -ENOMEM;
 260
 261         priv->inode = inode;
 262         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 263         if (IS_ERR(priv->mm)) {
 264                 int err = PTR_ERR(priv->mm);
 265
 266                 seq_release_private(inode, file);
 267                 return err;
 268         }
 269
 270         return 0;
 271 }
 272
 273
 274 static int map_release(struct inode *inode, struct file *file)
 275 {
 276         struct seq_file *seq = file->private_data;
 277         struct proc_maps_private *priv = seq->private;
 278
 279         if (priv->mm)
 280                 mmdrop(priv->mm);
 281
 282         return seq_release_private(inode, file);
 283 }
 284
 285 static int pid_maps_open(struct inode *inode, struct file *file)
 286 {
 287         return maps_open(inode, file, &proc_pid_maps_ops);
 288 }
 289
 290 const struct file_operations proc_pid_maps_operations = {
 291         .open           = pid_maps_open,
 292         .read           = seq_read,
 293         .llseek         = seq_lseek,
 294         .release        = map_release,
 295 };
 296