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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(&current->files->count) > 1)
61 		sbytes += kobjsize(current->files);
62 	else
63 		bytes += kobjsize(current->files);
64 
65 	if (current->sighand && refcount_read(&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 	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