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         struct vm_area_struct *vma;
  24         struct vm_region *region;
  25         struct rb_node *p;
  26         unsigned long bytes = 0, sbytes = 0, slack = 0, size;
  27
  28         down_read(&mm->mmap_sem);
  29         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  30                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  31
  32                 bytes += kobjsize(vma);
  33
  34                 region = vma->vm_region;
  35                 if (region) {
  36                         size = kobjsize(region);
  37                         size += region->vm_end - region->vm_start;
  38                 } else {
  39                         size = vma->vm_end - vma->vm_start;
  40                 }
  41
  42                 if (atomic_read(&mm->mm_count) > 1 ||
  43                     vma->vm_flags & VM_MAYSHARE) {
  44                         sbytes += size;
  45                 } else {
  46                         bytes += size;
  47                         if (region)
  48                                 slack = region->vm_end - vma->vm_end;
  49                 }
  50         }
  51
  52         if (atomic_read(&mm->mm_count) > 1)
  53                 sbytes += kobjsize(mm);
  54         else
  55                 bytes += kobjsize(mm);
  56
  57         if (current->fs && current->fs->users > 1)
  58                 sbytes += kobjsize(current->fs);
  59         else
  60                 bytes += kobjsize(current->fs);
  61
  62         if (current->files && atomic_read(&current->files->count) > 1)
  63                 sbytes += kobjsize(current->files);
  64         else
  65                 bytes += kobjsize(current->files);
  66
  67         if (current->sighand && atomic_read(&current->sighand->count) > 1)
  68                 sbytes += kobjsize(current->sighand);
  69         else
  70                 bytes += kobjsize(current->sighand);
  71
  72         bytes += kobjsize(current); /* includes kernel stack */
  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         up_read(&mm->mmap_sem);
  81 }
  82
  83 unsigned long task_vsize(struct mm_struct *mm)
  84 {
  85         struct vm_area_struct *vma;
  86         struct rb_node *p;
  87         unsigned long vsize = 0;
  88
  89         down_read(&mm->mmap_sem);
  90         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  91                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  92                 vsize += vma->vm_end - vma->vm_start;
  93         }
  94         up_read(&mm->mmap_sem);
  95         return vsize;
  96 }
  97
  98 unsigned long task_statm(struct mm_struct *mm,
  99                          unsigned long *shared, unsigned long *text,
 100                          unsigned long *data, unsigned long *resident)
 101 {
 102         struct vm_area_struct *vma;
 103         struct vm_region *region;
 104         struct rb_node *p;
 105         unsigned long size = kobjsize(mm);
 106
 107         down_read(&mm->mmap_sem);
 108         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
 109                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
 110                 size += kobjsize(vma);
 111                 region = vma->vm_region;
 112                 if (region) {
 113                         size += kobjsize(region);
 114                         size += region->vm_end - region->vm_start;
 115                 }
 116         }
 117
 118         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 119                 >> PAGE_SHIFT;
 120         *data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
 121                 >> PAGE_SHIFT;
 122         up_read(&mm->mmap_sem);
 123         size >>= PAGE_SHIFT;
 124         size += *text + *data;
 125         *resident = size;
 126         return size;
 127 }
 128
 129 static int is_stack(struct vm_area_struct *vma)
 130 {
 131         struct mm_struct *mm = vma->vm_mm;
 132
 133         /*
 134          * We make no effort to guess what a given thread considers to be
 135          * its "stack".  It's not even well-defined for programs written
 136          * languages like Go.
 137          */
 138         return vma->vm_start <= mm->start_stack &&
 139                 vma->vm_end >= mm->start_stack;
 140 }
 141
 142 /*
 143  * display a single VMA to a sequenced file
 144  */
 145 static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 146                           int is_pid)
 147 {
 148         struct mm_struct *mm = vma->vm_mm;
 149         unsigned long ino = 0;
 150         struct file *file;
 151         dev_t dev = 0;
 152         int flags;
 153         unsigned long long pgoff = 0;
 154
 155         flags = vma->vm_flags;
 156         file = vma->vm_file;
 157
 158         if (file) {
 159                 struct inode *inode = file_inode(vma->vm_file);
 160                 dev = inode->i_sb->s_dev;
 161                 ino = inode->i_ino;
 162                 pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 163         }
 164
 165         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 166         seq_printf(m,
 167                    "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
 168                    vma->vm_start,
 169                    vma->vm_end,
 170                    flags & VM_READ ? 'r' : '-',
 171                    flags & VM_WRITE ? 'w' : '-',
 172                    flags & VM_EXEC ? 'x' : '-',
 173                    flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
 174                    pgoff,
 175                    MAJOR(dev), MINOR(dev), ino);
 176
 177         if (file) {
 178                 seq_pad(m, ' ');
 179                 seq_file_path(m, file, "");
 180         } else if (mm && is_stack(vma)) {
 181                 seq_pad(m, ' ');
 182                 seq_printf(m, "[stack]");
 183         }
 184
 185         seq_putc(m, '\n');
 186         return 0;
 187 }
 188
 189 /*
 190  * display mapping lines for a particular process's /proc/pid/maps
 191  */
 192 static int show_map(struct seq_file *m, void *_p, int is_pid)
 193 {
 194         struct rb_node *p = _p;
 195
 196         return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb),
 197                               is_pid);
 198 }
 199
 200 static int show_pid_map(struct seq_file *m, void *_p)
 201 {
 202         return show_map(m, _p, 1);
 203 }
 204
 205 static int show_tid_map(struct seq_file *m, void *_p)
 206 {
 207         return show_map(m, _p, 0);
 208 }
 209
 210 static void *m_start(struct seq_file *m, loff_t *pos)
 211 {
 212         struct proc_maps_private *priv = m->private;
 213         struct mm_struct *mm;
 214         struct rb_node *p;
 215         loff_t n = *pos;
 216
 217         /* pin the task and mm whilst we play with them */
 218         priv->task = get_proc_task(priv->inode);
 219         if (!priv->task)
 220                 return ERR_PTR(-ESRCH);
 221
 222         mm = priv->mm;
 223         if (!mm || !mmget_not_zero(mm))
 224                 return NULL;
 225
 226         down_read(&mm->mmap_sem);
 227         /* start from the Nth VMA */
 228         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
 229                 if (n-- == 0)
 230                         return p;
 231
 232         up_read(&mm->mmap_sem);
 233         mmput(mm);
 234         return NULL;
 235 }
 236
 237 static void m_stop(struct seq_file *m, void *_vml)
 238 {
 239         struct proc_maps_private *priv = m->private;
 240
 241         if (!IS_ERR_OR_NULL(_vml)) {
 242                 up_read(&priv->mm->mmap_sem);
 243                 mmput(priv->mm);
 244         }
 245         if (priv->task) {
 246                 put_task_struct(priv->task);
 247                 priv->task = NULL;
 248         }
 249 }
 250
 251 static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
 252 {
 253         struct rb_node *p = _p;
 254
 255         (*pos)++;
 256         return p ? rb_next(p) : NULL;
 257 }
 258
 259 static const struct seq_operations proc_pid_maps_ops = {
 260         .start  = m_start,
 261         .next   = m_next,
 262         .stop   = m_stop,
 263         .show   = show_pid_map
 264 };
 265
 266 static const struct seq_operations proc_tid_maps_ops = {
 267         .start  = m_start,
 268         .next   = m_next,
 269         .stop   = m_stop,
 270         .show   = show_tid_map
 271 };
 272
 273 static int maps_open(struct inode *inode, struct file *file,
 274                      const struct seq_operations *ops)
 275 {
 276         struct proc_maps_private *priv;
 277
 278         priv = __seq_open_private(file, ops, sizeof(*priv));
 279         if (!priv)
 280                 return -ENOMEM;
 281
 282         priv->inode = inode;
 283         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 284         if (IS_ERR(priv->mm)) {
 285                 int err = PTR_ERR(priv->mm);
 286
 287                 seq_release_private(inode, file);
 288                 return err;
 289         }
 290
 291         return 0;
 292 }
 293
 294
 295 static int map_release(struct inode *inode, struct file *file)
 296 {
 297         struct seq_file *seq = file->private_data;
 298         struct proc_maps_private *priv = seq->private;
 299
 300         if (priv->mm)
 301                 mmdrop(priv->mm);
 302
 303         return seq_release_private(inode, file);
 304 }
 305
 306 static int pid_maps_open(struct inode *inode, struct file *file)
 307 {
 308         return maps_open(inode, file, &proc_pid_maps_ops);
 309 }
 310
 311 static int tid_maps_open(struct inode *inode, struct file *file)
 312 {
 313         return maps_open(inode, file, &proc_tid_maps_ops);
 314 }
 315
 316 const struct file_operations proc_pid_maps_operations = {
 317         .open           = pid_maps_open,
 318         .read           = seq_read,
 319         .llseek         = seq_lseek,
 320         .release        = map_release,
 321 };
 322
 323 const struct file_operations proc_tid_maps_operations = {
 324         .open           = tid_maps_open,
 325         .read           = seq_read,
 326         .llseek         = seq_lseek,
 327         .release        = map_release,
 328 };
 329