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 */
task_mem(struct seq_file * m,struct mm_struct * mm)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 vma->vm_flags & VM_MAYSHARE) {
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(¤t->files->count) > 1)
61 sbytes += kobjsize(current->files);
62 else
63 bytes += kobjsize(current->files);
64
65 if (current->sighand && refcount_read(¤t->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 seq_printf(m,
73 "Mem:\t%8lu bytes\n"
74 "Slack:\t%8lu bytes\n"
75 "Shared:\t%8lu bytes\n",
76 bytes, slack, sbytes);
77
78 mmap_read_unlock(mm);
79 }
80
task_vsize(struct mm_struct * mm)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
task_statm(struct mm_struct * mm,unsigned long * shared,unsigned long * text,unsigned long * data,unsigned long * resident)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
is_stack(struct vm_area_struct * vma)124 static int is_stack(struct vm_area_struct *vma)
125 {
126 struct mm_struct *mm = vma->vm_mm;
127
128 /*
129 * We make no effort to guess what a given thread considers to be
130 * its "stack". It's not even well-defined for programs written
131 * languages like Go.
132 */
133 return vma->vm_start <= mm->start_stack &&
134 vma->vm_end >= mm->start_stack;
135 }
136
137 /*
138 * display a single VMA to a sequenced file
139 */
nommu_vma_show(struct seq_file * m,struct vm_area_struct * vma)140 static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
141 {
142 struct mm_struct *mm = vma->vm_mm;
143 unsigned long ino = 0;
144 struct file *file;
145 dev_t dev = 0;
146 int flags;
147 unsigned long long pgoff = 0;
148
149 flags = vma->vm_flags;
150 file = vma->vm_file;
151
152 if (file) {
153 struct inode *inode = file_inode(vma->vm_file);
154 dev = inode->i_sb->s_dev;
155 ino = inode->i_ino;
156 pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
157 }
158
159 seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
160 seq_printf(m,
161 "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
162 vma->vm_start,
163 vma->vm_end,
164 flags & VM_READ ? 'r' : '-',
165 flags & VM_WRITE ? 'w' : '-',
166 flags & VM_EXEC ? 'x' : '-',
167 flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
168 pgoff,
169 MAJOR(dev), MINOR(dev), ino);
170
171 if (file) {
172 seq_pad(m, ' ');
173 seq_file_path(m, file, "");
174 } else if (mm && is_stack(vma)) {
175 seq_pad(m, ' ');
176 seq_puts(m, "[stack]");
177 }
178
179 seq_putc(m, '\n');
180 return 0;
181 }
182
183 /*
184 * display mapping lines for a particular process's /proc/pid/maps
185 */
show_map(struct seq_file * m,void * _p)186 static int show_map(struct seq_file *m, void *_p)
187 {
188 return nommu_vma_show(m, _p);
189 }
190
proc_get_vma(struct proc_maps_private * priv,loff_t * ppos)191 static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
192 loff_t *ppos)
193 {
194 struct vm_area_struct *vma = vma_next(&priv->iter);
195
196 if (vma) {
197 *ppos = vma->vm_start;
198 } else {
199 *ppos = -1UL;
200 }
201
202 return vma;
203 }
204
m_start(struct seq_file * m,loff_t * ppos)205 static void *m_start(struct seq_file *m, loff_t *ppos)
206 {
207 struct proc_maps_private *priv = m->private;
208 unsigned long last_addr = *ppos;
209 struct mm_struct *mm;
210
211 /* See proc_get_vma(). Zero at the start or after lseek. */
212 if (last_addr == -1UL)
213 return NULL;
214
215 /* pin the task and mm whilst we play with them */
216 priv->task = get_proc_task(priv->inode);
217 if (!priv->task)
218 return ERR_PTR(-ESRCH);
219
220 mm = priv->mm;
221 if (!mm || !mmget_not_zero(mm)) {
222 put_task_struct(priv->task);
223 priv->task = NULL;
224 return NULL;
225 }
226
227 if (mmap_read_lock_killable(mm)) {
228 mmput(mm);
229 put_task_struct(priv->task);
230 priv->task = NULL;
231 return ERR_PTR(-EINTR);
232 }
233
234 vma_iter_init(&priv->iter, mm, last_addr);
235
236 return proc_get_vma(priv, ppos);
237 }
238
m_stop(struct seq_file * m,void * v)239 static void m_stop(struct seq_file *m, void *v)
240 {
241 struct proc_maps_private *priv = m->private;
242 struct mm_struct *mm = priv->mm;
243
244 if (!priv->task)
245 return;
246
247 mmap_read_unlock(mm);
248 mmput(mm);
249 put_task_struct(priv->task);
250 priv->task = NULL;
251 }
252
m_next(struct seq_file * m,void * _p,loff_t * ppos)253 static void *m_next(struct seq_file *m, void *_p, loff_t *ppos)
254 {
255 return proc_get_vma(m->private, ppos);
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_map
263 };
264
maps_open(struct inode * inode,struct file * file,const struct seq_operations * ops)265 static int maps_open(struct inode *inode, struct file *file,
266 const struct seq_operations *ops)
267 {
268 struct proc_maps_private *priv;
269
270 priv = __seq_open_private(file, ops, sizeof(*priv));
271 if (!priv)
272 return -ENOMEM;
273
274 priv->inode = inode;
275 priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
276 if (IS_ERR(priv->mm)) {
277 int err = PTR_ERR(priv->mm);
278
279 seq_release_private(inode, file);
280 return err;
281 }
282
283 return 0;
284 }
285
286
map_release(struct inode * inode,struct file * file)287 static int map_release(struct inode *inode, struct file *file)
288 {
289 struct seq_file *seq = file->private_data;
290 struct proc_maps_private *priv = seq->private;
291
292 if (priv->mm)
293 mmdrop(priv->mm);
294
295 return seq_release_private(inode, file);
296 }
297
pid_maps_open(struct inode * inode,struct file * file)298 static int pid_maps_open(struct inode *inode, struct file *file)
299 {
300 return maps_open(inode, file, &proc_pid_maps_ops);
301 }
302
303 const struct file_operations proc_pid_maps_operations = {
304 .open = pid_maps_open,
305 .read = seq_read,
306 .llseek = seq_lseek,
307 .release = map_release,
308 };
309
310