fs/proc/task_nommu.c

   1
   2 #include <linux/mm.h>
   3 #include <linux/file.h>
   4 #include <linux/fdtable.h>
   5 #include <linux/fs_struct.h>
   6 #include <linux/mount.h>
   7 #include <linux/ptrace.h>
   8 #include <linux/slab.h>
   9 #include <linux/seq_file.h>
  10 #include "internal.h"
  11
  12 /*
  13  * Logic: we've got two memory sums for each process, "shared", and
  14  * "non-shared". Shared memory may get counted more than once, for
  15  * each process that owns it. Non-shared memory is counted
  16  * accurately.
  17  */
  18 void task_mem(struct seq_file *m, struct mm_struct *mm)
  19 {
  20         struct vm_area_struct *vma;
  21         struct vm_region *region;
  22         struct rb_node *p;
  23         unsigned long bytes = 0, sbytes = 0, slack = 0, size;
  24
  25         down_read(&mm->mmap_sem);
  26         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  27                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  28
  29                 bytes += kobjsize(vma);
  30
  31                 region = vma->vm_region;
  32                 if (region) {
  33                         size = kobjsize(region);
  34                         size += region->vm_end - region->vm_start;
  35                 } else {
  36                         size = vma->vm_end - vma->vm_start;
  37                 }
  38
  39                 if (atomic_read(&mm->mm_count) > 1 ||
  40                     vma->vm_flags & VM_MAYSHARE) {
  41                         sbytes += size;
  42                 } else {
  43                         bytes += size;
  44                         if (region)
  45                                 slack = region->vm_end - vma->vm_end;
  46                 }
  47         }
  48
  49         if (atomic_read(&mm->mm_count) > 1)
  50                 sbytes += kobjsize(mm);
  51         else
  52                 bytes += kobjsize(mm);
  53
  54         if (current->fs && current->fs->users > 1)
  55                 sbytes += kobjsize(current->fs);
  56         else
  57                 bytes += kobjsize(current->fs);
  58
  59         if (current->files && atomic_read(&current->files->count) > 1)
  60                 sbytes += kobjsize(current->files);
  61         else
  62                 bytes += kobjsize(current->files);
  63
  64         if (current->sighand && atomic_read(&current->sighand->count) > 1)
  65                 sbytes += kobjsize(current->sighand);
  66         else
  67                 bytes += kobjsize(current->sighand);
  68
  69         bytes += kobjsize(current); /* includes kernel stack */
  70
  71         seq_printf(m,
  72                 "Mem:\t%8lu bytes\n"
  73                 "Slack:\t%8lu bytes\n"
  74                 "Shared:\t%8lu bytes\n",
  75                 bytes, slack, sbytes);
  76
  77         up_read(&mm->mmap_sem);
  78 }
  79
  80 unsigned long task_vsize(struct mm_struct *mm)
  81 {
  82         struct vm_area_struct *vma;
  83         struct rb_node *p;
  84         unsigned long vsize = 0;
  85
  86         down_read(&mm->mmap_sem);
  87         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  88                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  89                 vsize += vma->vm_end - vma->vm_start;
  90         }
  91         up_read(&mm->mmap_sem);
  92         return vsize;
  93 }
  94
  95 unsigned long task_statm(struct mm_struct *mm,
  96                          unsigned long *shared, unsigned long *text,
  97                          unsigned long *data, unsigned long *resident)
  98 {
  99         struct vm_area_struct *vma;
 100         struct vm_region *region;
 101         struct rb_node *p;
 102         unsigned long size = kobjsize(mm);
 103
 104         down_read(&mm->mmap_sem);
 105         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
 106                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
 107                 size += kobjsize(vma);
 108                 region = vma->vm_region;
 109                 if (region) {
 110                         size += kobjsize(region);
 111                         size += region->vm_end - region->vm_start;
 112                 }
 113         }
 114
 115         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 116                 >> PAGE_SHIFT;
 117         *data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
 118                 >> PAGE_SHIFT;
 119         up_read(&mm->mmap_sem);
 120         size >>= PAGE_SHIFT;
 121         size += *text + *data;
 122         *resident = size;
 123         return size;
 124 }
 125
 126 static int is_stack(struct proc_maps_private *priv,
 127                     struct vm_area_struct *vma)
 128 {
 129         struct mm_struct *mm = vma->vm_mm;
 130
 131         /*
 132          * We make no effort to guess what a given thread considers to be
 133          * its "stack".  It's not even well-defined for programs written
 134          * languages like Go.
 135          */
 136         return vma->vm_start <= mm->start_stack &&
 137                 vma->vm_end >= mm->start_stack;
 138 }
 139
 140 /*
 141  * display a single VMA to a sequenced file
 142  */
 143 static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 144                           int is_pid)
 145 {
 146         struct mm_struct *mm = vma->vm_mm;
 147         struct proc_maps_private *priv = m->private;
 148         unsigned long ino = 0;
 149         struct file *file;
 150         dev_t dev = 0;
 151         int flags;
 152         unsigned long long pgoff = 0;
 153
 154         flags = vma->vm_flags;
 155         file = vma->vm_file;
 156
 157         if (file) {
 158                 struct inode *inode = file_inode(vma->vm_file);
 159                 dev = inode->i_sb->s_dev;
 160                 ino = inode->i_ino;
 161                 pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 162         }
 163
 164         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 165         seq_printf(m,
 166                    "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
 167                    vma->vm_start,
 168                    vma->vm_end,
 169                    flags & VM_READ ? 'r' : '-',
 170                    flags & VM_WRITE ? 'w' : '-',
 171                    flags & VM_EXEC ? 'x' : '-',
 172                    flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
 173                    pgoff,
 174                    MAJOR(dev), MINOR(dev), ino);
 175
 176         if (file) {
 177                 seq_pad(m, ' ');
 178                 seq_file_path(m, file, "");
 179         } else if (mm && is_stack(priv, vma)) {
 180                 seq_pad(m, ' ');
 181                 seq_printf(m, "[stack]");
 182         }
 183
 184         seq_putc(m, '\n');
 185         return 0;
 186 }
 187
 188 /*
 189  * display mapping lines for a particular process's /proc/pid/maps
 190  */
 191 static int show_map(struct seq_file *m, void *_p, int is_pid)
 192 {
 193         struct rb_node *p = _p;
 194
 195         return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb),
 196                               is_pid);
 197 }
 198
 199 static int show_pid_map(struct seq_file *m, void *_p)
 200 {
 201         return show_map(m, _p, 1);
 202 }
 203
 204 static int show_tid_map(struct seq_file *m, void *_p)
 205 {
 206         return show_map(m, _p, 0);
 207 }
 208
 209 static void *m_start(struct seq_file *m, loff_t *pos)
 210 {
 211         struct proc_maps_private *priv = m->private;
 212         struct mm_struct *mm;
 213         struct rb_node *p;
 214         loff_t n = *pos;
 215
 216         /* pin the task and mm whilst we play with them */
 217         priv->task = get_proc_task(priv->inode);
 218         if (!priv->task)
 219                 return ERR_PTR(-ESRCH);
 220
 221         mm = priv->mm;
 222         if (!mm || !mmget_not_zero(mm))
 223                 return NULL;
 224
 225         down_read(&mm->mmap_sem);
 226         /* start from the Nth VMA */
 227         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
 228                 if (n-- == 0)
 229                         return p;
 230
 231         up_read(&mm->mmap_sem);
 232         mmput(mm);
 233         return NULL;
 234 }
 235
 236 static void m_stop(struct seq_file *m, void *_vml)
 237 {
 238         struct proc_maps_private *priv = m->private;
 239
 240         if (!IS_ERR_OR_NULL(_vml)) {
 241                 up_read(&priv->mm->mmap_sem);
 242                 mmput(priv->mm);
 243         }
 244         if (priv->task) {
 245                 put_task_struct(priv->task);
 246                 priv->task = NULL;
 247         }
 248 }
 249
 250 static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
 251 {
 252         struct rb_node *p = _p;
 253
 254         (*pos)++;
 255         return p ? rb_next(p) : NULL;
 256 }
 257
 258 static const struct seq_operations proc_pid_maps_ops = {
 259         .start  = m_start,
 260         .next   = m_next,
 261         .stop   = m_stop,
 262         .show   = show_pid_map
 263 };
 264
 265 static const struct seq_operations proc_tid_maps_ops = {
 266         .start  = m_start,
 267         .next   = m_next,
 268         .stop   = m_stop,
 269         .show   = show_tid_map
 270 };
 271
 272 static int maps_open(struct inode *inode, struct file *file,
 273                      const struct seq_operations *ops)
 274 {
 275         struct proc_maps_private *priv;
 276
 277         priv = __seq_open_private(file, ops, sizeof(*priv));
 278         if (!priv)
 279                 return -ENOMEM;
 280
 281         priv->inode = inode;
 282         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 283         if (IS_ERR(priv->mm)) {
 284                 int err = PTR_ERR(priv->mm);
 285
 286                 seq_release_private(inode, file);
 287                 return err;
 288         }
 289
 290         return 0;
 291 }
 292
 293
 294 static int map_release(struct inode *inode, struct file *file)
 295 {
 296         struct seq_file *seq = file->private_data;
 297         struct proc_maps_private *priv = seq->private;
 298
 299         if (priv->mm)
 300                 mmdrop(priv->mm);
 301
 302         return seq_release_private(inode, file);
 303 }
 304
 305 static int pid_maps_open(struct inode *inode, struct file *file)
 306 {
 307         return maps_open(inode, file, &proc_pid_maps_ops);
 308 }
 309
 310 static int tid_maps_open(struct inode *inode, struct file *file)
 311 {
 312         return maps_open(inode, file, &proc_tid_maps_ops);
 313 }
 314
 315 const struct file_operations proc_pid_maps_operations = {
 316         .open           = pid_maps_open,
 317         .read           = seq_read,
 318         .llseek         = seq_lseek,
 319         .release        = map_release,
 320 };
 321
 322 const struct file_operations proc_tid_maps_operations = {
 323         .open           = tid_maps_open,
 324         .read           = seq_read,
 325         .llseek         = seq_lseek,
 326         .release        = map_release,
 327 };
 328