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 */
21void 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(v: &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(v: &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(v: &current->files->count) > 1)
61 sbytes += kobjsize(current->files);
62 else
63 bytes += kobjsize(current->files);
64
65 if (current->sighand && refcount_read(r: &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 fmt: "Mem:\t%8lu bytes\n"
76 "Slack:\t%8lu bytes\n"
77 "Shared:\t%8lu bytes\n",
78 bytes, slack, sbytes);
79}
80
81unsigned 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
94unsigned 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 */
127static 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(f: 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, size: 25 + sizeof(void *) * 6 - 1);
147 seq_printf(m,
148 fmt: "%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, c: ' ');
160 seq_path(m, file_user_path(f: file), "");
161 } else if (mm && vma_is_initial_stack(vma)) {
162 seq_pad(m, c: ' ');
163 seq_puts(m, s: "[stack]");
164 }
165
166 seq_putc(m, c: '\n');
167 return 0;
168}
169
170/*
171 * display mapping lines for a particular process's /proc/pid/maps
172 */
173static int show_map(struct seq_file *m, void *_p)
174{
175 return nommu_vma_show(m, vma: _p);
176}
177
178static 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(vmi: &priv->iter);
182
183 if (vma) {
184 *ppos = vma->vm_start;
185 } else {
186 *ppos = -1UL;
187 }
188
189 return vma;
190}
191
192static 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(inode: priv->inode);
204 if (!priv->task)
205 return ERR_PTR(error: -ESRCH);
206
207 mm = priv->lock_ctx.mm;
208 if (!mm || !mmget_not_zero(mm)) {
209 put_task_struct(t: 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(t: priv->task);
217 priv->task = NULL;
218 return ERR_PTR(error: -EINTR);
219 }
220
221 vma_iter_init(vmi: &priv->iter, mm, addr: last_addr);
222
223 return proc_get_vma(priv, ppos);
224}
225
226static void m_stop(struct seq_file *m, void *v)
227{
228 struct proc_maps_private *priv = m->private;
229 struct mm_struct *mm = priv->lock_ctx.mm;
230
231 if (!priv->task)
232 return;
233
234 mmap_read_unlock(mm);
235 mmput(mm);
236 put_task_struct(t: priv->task);
237 priv->task = NULL;
238}
239
240static void *m_next(struct seq_file *m, void *_p, loff_t *ppos)
241{
242 return proc_get_vma(priv: m->private, ppos);
243}
244
245static 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
252static 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->lock_ctx.mm = proc_mem_open(inode, PTRACE_MODE_READ);
263 if (IS_ERR_OR_NULL(ptr: priv->lock_ctx.mm)) {
264 int err = priv->lock_ctx.mm ? PTR_ERR(ptr: priv->lock_ctx.mm) : -ESRCH;
265
266 seq_release_private(inode, file);
267 return err;
268 }
269
270 return 0;
271}
272
273
274static 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->lock_ctx.mm)
280 mmdrop(mm: priv->lock_ctx.mm);
281
282 return seq_release_private(inode, file);
283}
284
285static int pid_maps_open(struct inode *inode, struct file *file)
286{
287 return maps_open(inode, file, ops: &proc_pid_maps_ops);
288}
289
290const 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
297

source code of linux/fs/proc/task_nommu.c