xref: /openbmc/linux/fs/proc/task_nommu.c (revision 643d1f7f)
1 
2 #include <linux/mm.h>
3 #include <linux/file.h>
4 #include <linux/mount.h>
5 #include <linux/ptrace.h>
6 #include <linux/seq_file.h>
7 #include "internal.h"
8 
9 /*
10  * Logic: we've got two memory sums for each process, "shared", and
11  * "non-shared". Shared memory may get counted more then once, for
12  * each process that owns it. Non-shared memory is counted
13  * accurately.
14  */
15 char *task_mem(struct mm_struct *mm, char *buffer)
16 {
17 	struct vm_list_struct *vml;
18 	unsigned long bytes = 0, sbytes = 0, slack = 0;
19 
20 	down_read(&mm->mmap_sem);
21 	for (vml = mm->context.vmlist; vml; vml = vml->next) {
22 		if (!vml->vma)
23 			continue;
24 
25 		bytes += kobjsize(vml);
26 		if (atomic_read(&mm->mm_count) > 1 ||
27 		    atomic_read(&vml->vma->vm_usage) > 1
28 		    ) {
29 			sbytes += kobjsize((void *) vml->vma->vm_start);
30 			sbytes += kobjsize(vml->vma);
31 		} else {
32 			bytes += kobjsize((void *) vml->vma->vm_start);
33 			bytes += kobjsize(vml->vma);
34 			slack += kobjsize((void *) vml->vma->vm_start) -
35 				(vml->vma->vm_end - vml->vma->vm_start);
36 		}
37 	}
38 
39 	if (atomic_read(&mm->mm_count) > 1)
40 		sbytes += kobjsize(mm);
41 	else
42 		bytes += kobjsize(mm);
43 
44 	if (current->fs && atomic_read(&current->fs->count) > 1)
45 		sbytes += kobjsize(current->fs);
46 	else
47 		bytes += kobjsize(current->fs);
48 
49 	if (current->files && atomic_read(&current->files->count) > 1)
50 		sbytes += kobjsize(current->files);
51 	else
52 		bytes += kobjsize(current->files);
53 
54 	if (current->sighand && atomic_read(&current->sighand->count) > 1)
55 		sbytes += kobjsize(current->sighand);
56 	else
57 		bytes += kobjsize(current->sighand);
58 
59 	bytes += kobjsize(current); /* includes kernel stack */
60 
61 	buffer += sprintf(buffer,
62 		"Mem:\t%8lu bytes\n"
63 		"Slack:\t%8lu bytes\n"
64 		"Shared:\t%8lu bytes\n",
65 		bytes, slack, sbytes);
66 
67 	up_read(&mm->mmap_sem);
68 	return buffer;
69 }
70 
71 unsigned long task_vsize(struct mm_struct *mm)
72 {
73 	struct vm_list_struct *tbp;
74 	unsigned long vsize = 0;
75 
76 	down_read(&mm->mmap_sem);
77 	for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
78 		if (tbp->vma)
79 			vsize += kobjsize((void *) tbp->vma->vm_start);
80 	}
81 	up_read(&mm->mmap_sem);
82 	return vsize;
83 }
84 
85 int task_statm(struct mm_struct *mm, int *shared, int *text,
86 	       int *data, int *resident)
87 {
88 	struct vm_list_struct *tbp;
89 	int size = kobjsize(mm);
90 
91 	down_read(&mm->mmap_sem);
92 	for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
93 		size += kobjsize(tbp);
94 		if (tbp->vma) {
95 			size += kobjsize(tbp->vma);
96 			size += kobjsize((void *) tbp->vma->vm_start);
97 		}
98 	}
99 
100 	size += (*text = mm->end_code - mm->start_code);
101 	size += (*data = mm->start_stack - mm->start_data);
102 	up_read(&mm->mmap_sem);
103 	*resident = size;
104 	return size;
105 }
106 
107 int proc_exe_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
108 {
109 	struct vm_list_struct *vml;
110 	struct vm_area_struct *vma;
111 	struct task_struct *task = get_proc_task(inode);
112 	struct mm_struct *mm = get_task_mm(task);
113 	int result = -ENOENT;
114 
115 	if (!mm)
116 		goto out;
117 	down_read(&mm->mmap_sem);
118 
119 	vml = mm->context.vmlist;
120 	vma = NULL;
121 	while (vml) {
122 		if ((vml->vma->vm_flags & VM_EXECUTABLE) && vml->vma->vm_file) {
123 			vma = vml->vma;
124 			break;
125 		}
126 		vml = vml->next;
127 	}
128 
129 	if (vma) {
130 		*mnt = mntget(vma->vm_file->f_path.mnt);
131 		*dentry = dget(vma->vm_file->f_path.dentry);
132 		result = 0;
133 	}
134 
135 	up_read(&mm->mmap_sem);
136 	mmput(mm);
137 out:
138 	return result;
139 }
140 
141 /*
142  * display mapping lines for a particular process's /proc/pid/maps
143  */
144 static int show_map(struct seq_file *m, void *_vml)
145 {
146 	struct vm_list_struct *vml = _vml;
147 	struct proc_maps_private *priv = m->private;
148 	struct task_struct *task = priv->task;
149 
150 	if (maps_protect && !ptrace_may_attach(task))
151 		return -EACCES;
152 
153 	return nommu_vma_show(m, vml->vma);
154 }
155 
156 static void *m_start(struct seq_file *m, loff_t *pos)
157 {
158 	struct proc_maps_private *priv = m->private;
159 	struct vm_list_struct *vml;
160 	struct mm_struct *mm;
161 	loff_t n = *pos;
162 
163 	/* pin the task and mm whilst we play with them */
164 	priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
165 	if (!priv->task)
166 		return NULL;
167 
168 	mm = mm_for_maps(priv->task);
169 	if (!mm) {
170 		put_task_struct(priv->task);
171 		priv->task = NULL;
172 		return NULL;
173 	}
174 
175 	/* start from the Nth VMA */
176 	for (vml = mm->context.vmlist; vml; vml = vml->next)
177 		if (n-- == 0)
178 			return vml;
179 	return NULL;
180 }
181 
182 static void m_stop(struct seq_file *m, void *_vml)
183 {
184 	struct proc_maps_private *priv = m->private;
185 
186 	if (priv->task) {
187 		struct mm_struct *mm = priv->task->mm;
188 		up_read(&mm->mmap_sem);
189 		mmput(mm);
190 		put_task_struct(priv->task);
191 	}
192 }
193 
194 static void *m_next(struct seq_file *m, void *_vml, loff_t *pos)
195 {
196 	struct vm_list_struct *vml = _vml;
197 
198 	(*pos)++;
199 	return vml ? vml->next : NULL;
200 }
201 
202 static struct seq_operations proc_pid_maps_ops = {
203 	.start	= m_start,
204 	.next	= m_next,
205 	.stop	= m_stop,
206 	.show	= show_map
207 };
208 
209 static int maps_open(struct inode *inode, struct file *file)
210 {
211 	struct proc_maps_private *priv;
212 	int ret = -ENOMEM;
213 
214 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
215 	if (priv) {
216 		priv->pid = proc_pid(inode);
217 		ret = seq_open(file, &proc_pid_maps_ops);
218 		if (!ret) {
219 			struct seq_file *m = file->private_data;
220 			m->private = priv;
221 		} else {
222 			kfree(priv);
223 		}
224 	}
225 	return ret;
226 }
227 
228 const struct file_operations proc_maps_operations = {
229 	.open		= maps_open,
230 	.read		= seq_read,
231 	.llseek		= seq_lseek,
232 	.release	= seq_release_private,
233 };
234 
235