tmp_suning_uos_patched/fs/proc/task_nommu.c
Matt Helsley 925d1c401f procfs task exe symlink
The kernel implements readlink of /proc/pid/exe by getting the file from
the first executable VMA.  Then the path to the file is reconstructed and
reported as the result.

Because of the VMA walk the code is slightly different on nommu systems.
This patch avoids separate /proc/pid/exe code on nommu systems.  Instead of
walking the VMAs to find the first executable file-backed VMA we store a
reference to the exec'd file in the mm_struct.

That reference would prevent the filesystem holding the executable file
from being unmounted even after unmapping the VMAs.  So we track the number
of VM_EXECUTABLE VMAs and drop the new reference when the last one is
unmapped.  This avoids pinning the mounted filesystem.

[akpm@linux-foundation.org: improve comments]
[yamamoto@valinux.co.jp: fix dup_mmap]
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: David Howells <dhowells@redhat.com>
Cc:"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:17 -07:00

200 lines
4.5 KiB
C

#include <linux/mm.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>
#include "internal.h"
/*
* Logic: we've got two memory sums for each process, "shared", and
* "non-shared". Shared memory may get counted more then once, for
* each process that owns it. Non-shared memory is counted
* accurately.
*/
void task_mem(struct seq_file *m, struct mm_struct *mm)
{
struct vm_list_struct *vml;
unsigned long bytes = 0, sbytes = 0, slack = 0;
down_read(&mm->mmap_sem);
for (vml = mm->context.vmlist; vml; vml = vml->next) {
if (!vml->vma)
continue;
bytes += kobjsize(vml);
if (atomic_read(&mm->mm_count) > 1 ||
atomic_read(&vml->vma->vm_usage) > 1
) {
sbytes += kobjsize((void *) vml->vma->vm_start);
sbytes += kobjsize(vml->vma);
} else {
bytes += kobjsize((void *) vml->vma->vm_start);
bytes += kobjsize(vml->vma);
slack += kobjsize((void *) vml->vma->vm_start) -
(vml->vma->vm_end - vml->vma->vm_start);
}
}
if (atomic_read(&mm->mm_count) > 1)
sbytes += kobjsize(mm);
else
bytes += kobjsize(mm);
if (current->fs && atomic_read(&current->fs->count) > 1)
sbytes += kobjsize(current->fs);
else
bytes += kobjsize(current->fs);
if (current->files && atomic_read(&current->files->count) > 1)
sbytes += kobjsize(current->files);
else
bytes += kobjsize(current->files);
if (current->sighand && atomic_read(&current->sighand->count) > 1)
sbytes += kobjsize(current->sighand);
else
bytes += kobjsize(current->sighand);
bytes += kobjsize(current); /* includes kernel stack */
seq_printf(m,
"Mem:\t%8lu bytes\n"
"Slack:\t%8lu bytes\n"
"Shared:\t%8lu bytes\n",
bytes, slack, sbytes);
up_read(&mm->mmap_sem);
}
unsigned long task_vsize(struct mm_struct *mm)
{
struct vm_list_struct *tbp;
unsigned long vsize = 0;
down_read(&mm->mmap_sem);
for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
if (tbp->vma)
vsize += kobjsize((void *) tbp->vma->vm_start);
}
up_read(&mm->mmap_sem);
return vsize;
}
int task_statm(struct mm_struct *mm, int *shared, int *text,
int *data, int *resident)
{
struct vm_list_struct *tbp;
int size = kobjsize(mm);
down_read(&mm->mmap_sem);
for (tbp = mm->context.vmlist; tbp; tbp = tbp->next) {
size += kobjsize(tbp);
if (tbp->vma) {
size += kobjsize(tbp->vma);
size += kobjsize((void *) tbp->vma->vm_start);
}
}
size += (*text = mm->end_code - mm->start_code);
size += (*data = mm->start_stack - mm->start_data);
up_read(&mm->mmap_sem);
*resident = size;
return size;
}
/*
* display mapping lines for a particular process's /proc/pid/maps
*/
static int show_map(struct seq_file *m, void *_vml)
{
struct vm_list_struct *vml = _vml;
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
if (maps_protect && !ptrace_may_attach(task))
return -EACCES;
return nommu_vma_show(m, vml->vma);
}
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
struct vm_list_struct *vml;
struct mm_struct *mm;
loff_t n = *pos;
/* pin the task and mm whilst we play with them */
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
return NULL;
mm = mm_for_maps(priv->task);
if (!mm) {
put_task_struct(priv->task);
priv->task = NULL;
return NULL;
}
/* start from the Nth VMA */
for (vml = mm->context.vmlist; vml; vml = vml->next)
if (n-- == 0)
return vml;
return NULL;
}
static void m_stop(struct seq_file *m, void *_vml)
{
struct proc_maps_private *priv = m->private;
if (priv->task) {
struct mm_struct *mm = priv->task->mm;
up_read(&mm->mmap_sem);
mmput(mm);
put_task_struct(priv->task);
}
}
static void *m_next(struct seq_file *m, void *_vml, loff_t *pos)
{
struct vm_list_struct *vml = _vml;
(*pos)++;
return vml ? vml->next : NULL;
}
static const struct seq_operations proc_pid_maps_ops = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_map
};
static int maps_open(struct inode *inode, struct file *file)
{
struct proc_maps_private *priv;
int ret = -ENOMEM;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (priv) {
priv->pid = proc_pid(inode);
ret = seq_open(file, &proc_pid_maps_ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = priv;
} else {
kfree(priv);
}
}
return ret;
}
const struct file_operations proc_maps_operations = {
.open = maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};