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 <linux/sched/mm.h>
  11
  12 #include "internal.h"
  13
  14 /*
  15  * Logic: we've got two memory sums for each process, "shared", and
  16  * "non-shared". Shared memory may get counted more than once, for
  17  * each process that owns it. Non-shared memory is counted
  18  * accurately.
  19  */
  20 void task_mem(struct seq_file *m, struct mm_struct *mm)
  21 {
  22         struct vm_area_struct *vma;
  23         struct vm_region *region;
  24         struct rb_node *p;
  25         unsigned long bytes = 0, sbytes = 0, slack = 0, size;
  26
  27         down_read(&mm->mmap_sem);
  28         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  29                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  30
  31                 bytes += kobjsize(vma);
  32
  33                 region = vma->vm_region;
  34                 if (region) {
  35                         size = kobjsize(region);
  36                         size += region->vm_end - region->vm_start;
  37                 } else {
  38                         size = vma->vm_end - vma->vm_start;
  39                 }
  40
  41                 if (atomic_read(&mm->mm_count) > 1 ||
  42                     vma->vm_flags & VM_MAYSHARE) {
  43                         sbytes += size;
  44                 } else {
  45                         bytes += size;
  46                         if (region)
  47                                 slack = region->vm_end - vma->vm_end;
  48                 }
  49         }
  50
  51         if (atomic_read(&mm->mm_count) > 1)
  52                 sbytes += kobjsize(mm);
  53         else
  54                 bytes += kobjsize(mm);
  55
  56         if (current->fs && current->fs->users > 1)
  57                 sbytes += kobjsize(current->fs);
  58         else
  59                 bytes += kobjsize(current->fs);
  60
  61         if (current->files && atomic_read(&current->files->count) > 1)
  62                 sbytes += kobjsize(current->files);
  63         else
  64                 bytes += kobjsize(current->files);
  65
  66         if (current->sighand && atomic_read(&current->sighand->count) > 1)
  67                 sbytes += kobjsize(current->sighand);
  68         else
  69                 bytes += kobjsize(current->sighand);
  70
  71         bytes += kobjsize(current); /* includes kernel stack */
  72
  73         seq_printf(m,
  74                 "Mem:\t%8lu bytes\n"
  75                 "Slack:\t%8lu bytes\n"
  76                 "Shared:\t%8lu bytes\n",
  77                 bytes, slack, sbytes);
  78
  79         up_read(&mm->mmap_sem);
  80 }
  81
  82 unsigned long task_vsize(struct mm_struct *mm)
  83 {
  84         struct vm_area_struct *vma;
  85         struct rb_node *p;
  86         unsigned long vsize = 0;
  87
  88         down_read(&mm->mmap_sem);
  89         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
  90                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
  91                 vsize += vma->vm_end - vma->vm_start;
  92         }
  93         up_read(&mm->mmap_sem);
  94         return vsize;
  95 }
  96
  97 unsigned long task_statm(struct mm_struct *mm,
  98                          unsigned long *shared, unsigned long *text,
  99                          unsigned long *data, unsigned long *resident)
 100 {
 101         struct vm_area_struct *vma;
 102         struct vm_region *region;
 103         struct rb_node *p;
 104         unsigned long size = kobjsize(mm);
 105
 106         down_read(&mm->mmap_sem);
 107         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
 108                 vma = rb_entry(p, struct vm_area_struct, vm_rb);
 109                 size += kobjsize(vma);
 110                 region = vma->vm_region;
 111                 if (region) {
 112                         size += kobjsize(region);
 113                         size += region->vm_end - region->vm_start;
 114                 }
 115         }
 116
 117         *text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
 118                 >> PAGE_SHIFT;
 119         *data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
 120                 >> PAGE_SHIFT;
 121         up_read(&mm->mmap_sem);
 122         size >>= PAGE_SHIFT;
 123         size += *text + *data;
 124         *resident = size;
 125         return size;
 126 }
 127
 128 static int is_stack(struct proc_maps_private *priv,
 129                     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         struct proc_maps_private *priv = m->private;
 150         unsigned long ino = 0;
 151         struct file *file;
 152         dev_t dev = 0;
 153         int flags;
 154         unsigned long long pgoff = 0;
 155
 156         flags = vma->vm_flags;
 157         file = vma->vm_file;
 158
 159         if (file) {
 160                 struct inode *inode = file_inode(vma->vm_file);
 161                 dev = inode->i_sb->s_dev;
 162                 ino = inode->i_ino;
 163                 pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 164         }
 165
 166         seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 167         seq_printf(m,
 168                    "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
 169                    vma->vm_start,
 170                    vma->vm_end,
 171                    flags & VM_READ ? 'r' : '-',
 172                    flags & VM_WRITE ? 'w' : '-',
 173                    flags & VM_EXEC ? 'x' : '-',
 174                    flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
 175                    pgoff,
 176                    MAJOR(dev), MINOR(dev), ino);
 177
 178         if (file) {
 179                 seq_pad(m, ' ');
 180                 seq_file_path(m, file, "");
 181         } else if (mm && is_stack(priv, vma)) {
 182                 seq_pad(m, ' ');
 183                 seq_printf(m, "[stack]");
 184         }
 185
 186         seq_putc(m, '\n');
 187         return 0;
 188 }
 189
 190 /*
 191  * display mapping lines for a particular process's /proc/pid/maps
 192  */
 193 static int show_map(struct seq_file *m, void *_p, int is_pid)
 194 {
 195         struct rb_node *p = _p;
 196
 197         return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb),
 198                               is_pid);
 199 }
 200
 201 static int show_pid_map(struct seq_file *m, void *_p)
 202 {
 203         return show_map(m, _p, 1);
 204 }
 205
 206 static int show_tid_map(struct seq_file *m, void *_p)
 207 {
 208         return show_map(m, _p, 0);
 209 }
 210
 211 static void *m_start(struct seq_file *m, loff_t *pos)
 212 {
 213         struct proc_maps_private *priv = m->private;
 214         struct mm_struct *mm;
 215         struct rb_node *p;
 216         loff_t n = *pos;
 217
 218         /* pin the task and mm whilst we play with them */
 219         priv->task = get_proc_task(priv->inode);
 220         if (!priv->task)
 221                 return ERR_PTR(-ESRCH);
 222
 223         mm = priv->mm;
 224         if (!mm || !mmget_not_zero(mm))
 225                 return NULL;
 226
 227         down_read(&mm->mmap_sem);
 228         /* start from the Nth VMA */
 229         for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
 230                 if (n-- == 0)
 231                         return p;
 232
 233         up_read(&mm->mmap_sem);
 234         mmput(mm);
 235         return NULL;
 236 }
 237
 238 static void m_stop(struct seq_file *m, void *_vml)
 239 {
 240         struct proc_maps_private *priv = m->private;
 241
 242         if (!IS_ERR_OR_NULL(_vml)) {
 243                 up_read(&priv->mm->mmap_sem);
 244                 mmput(priv->mm);
 245         }
 246         if (priv->task) {
 247                 put_task_struct(priv->task);
 248                 priv->task = NULL;
 249         }
 250 }
 251
 252 static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
 253 {
 254         struct rb_node *p = _p;
 255
 256         (*pos)++;
 257         return p ? rb_next(p) : NULL;
 258 }
 259
 260 static const struct seq_operations proc_pid_maps_ops = {
 261         .start  = m_start,
 262         .next   = m_next,
 263         .stop   = m_stop,
 264         .show   = show_pid_map
 265 };
 266
 267 static const struct seq_operations proc_tid_maps_ops = {
 268         .start  = m_start,
 269         .next   = m_next,
 270         .stop   = m_stop,
 271         .show   = show_tid_map
 272 };
 273
 274 static int maps_open(struct inode *inode, struct file *file,
 275                      const struct seq_operations *ops)
 276 {
 277         struct proc_maps_private *priv;
 278
 279         priv = __seq_open_private(file, ops, sizeof(*priv));
 280         if (!priv)
 281                 return -ENOMEM;
 282
 283         priv->inode = inode;
 284         priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
 285         if (IS_ERR(priv->mm)) {
 286                 int err = PTR_ERR(priv->mm);
 287
 288                 seq_release_private(inode, file);
 289                 return err;
 290         }
 291
 292         return 0;
 293 }
 294
 295
 296 static int map_release(struct inode *inode, struct file *file)
 297 {
 298         struct seq_file *seq = file->private_data;
 299         struct proc_maps_private *priv = seq->private;
 300
 301         if (priv->mm)
 302                 mmdrop(priv->mm);
 303
 304         return seq_release_private(inode, file);
 305 }
 306
 307 static int pid_maps_open(struct inode *inode, struct file *file)
 308 {
 309         return maps_open(inode, file, &proc_pid_maps_ops);
 310 }
 311
 312 static int tid_maps_open(struct inode *inode, struct file *file)
 313 {
 314         return maps_open(inode, file, &proc_tid_maps_ops);
 315 }
 316
 317 const struct file_operations proc_pid_maps_operations = {
 318         .open           = pid_maps_open,
 319         .read           = seq_read,
 320         .llseek         = seq_lseek,
 321         .release        = map_release,
 322 };
 323
 324 const struct file_operations proc_tid_maps_operations = {
 325         .open           = tid_maps_open,
 326         .read           = seq_read,
 327         .llseek         = seq_lseek,
 328         .release        = map_release,
 329 };
 330