1
linux/net/atm/proc.c
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00

498 lines
12 KiB
C

/* net/atm/proc.c - ATM /proc interface
*
* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA
*
* seq_file api usage by romieu@fr.zoreil.com
*
* Evaluating the efficiency of the whole thing if left as an exercise to
* the reader.
*/
#include <linux/module.h> /* for EXPORT_SYMBOL */
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/errno.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/netdevice.h>
#include <linux/atmclip.h>
#include <linux/init.h> /* for __init */
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/atmclip.h>
#include <linux/uaccess.h>
#include <linux/param.h> /* for HZ */
#include <asm/atomic.h>
#include "resources.h"
#include "common.h" /* atm_proc_init prototype */
#include "signaling.h" /* to get sigd - ugly too */
static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
size_t count, loff_t *pos);
static const struct file_operations proc_atm_dev_ops = {
.owner = THIS_MODULE,
.read = proc_dev_atm_read,
.llseek = noop_llseek,
};
static void add_stats(struct seq_file *seq, const char *aal,
const struct k_atm_aal_stats *stats)
{
seq_printf(seq, "%s ( %d %d %d %d %d )", aal,
atomic_read(&stats->tx), atomic_read(&stats->tx_err),
atomic_read(&stats->rx), atomic_read(&stats->rx_err),
atomic_read(&stats->rx_drop));
}
static void atm_dev_info(struct seq_file *seq, const struct atm_dev *dev)
{
int i;
seq_printf(seq, "%3d %-8s", dev->number, dev->type);
for (i = 0; i < ESI_LEN; i++)
seq_printf(seq, "%02x", dev->esi[i]);
seq_puts(seq, " ");
add_stats(seq, "0", &dev->stats.aal0);
seq_puts(seq, " ");
add_stats(seq, "5", &dev->stats.aal5);
seq_printf(seq, "\t[%d]", atomic_read(&dev->refcnt));
seq_putc(seq, '\n');
}
struct vcc_state {
int bucket;
struct sock *sk;
int family;
};
static inline int compare_family(struct sock *sk, int family)
{
return !family || (sk->sk_family == family);
}
static int __vcc_walk(struct sock **sock, int family, int *bucket, loff_t l)
{
struct sock *sk = *sock;
if (sk == SEQ_START_TOKEN) {
for (*bucket = 0; *bucket < VCC_HTABLE_SIZE; ++*bucket) {
struct hlist_head *head = &vcc_hash[*bucket];
sk = hlist_empty(head) ? NULL : __sk_head(head);
if (sk)
break;
}
l--;
}
try_again:
for (; sk; sk = sk_next(sk)) {
l -= compare_family(sk, family);
if (l < 0)
goto out;
}
if (!sk && ++*bucket < VCC_HTABLE_SIZE) {
sk = sk_head(&vcc_hash[*bucket]);
goto try_again;
}
sk = SEQ_START_TOKEN;
out:
*sock = sk;
return (l < 0);
}
static inline void *vcc_walk(struct vcc_state *state, loff_t l)
{
return __vcc_walk(&state->sk, state->family, &state->bucket, l) ?
state : NULL;
}
static int __vcc_seq_open(struct inode *inode, struct file *file,
int family, const struct seq_operations *ops)
{
struct vcc_state *state;
state = __seq_open_private(file, ops, sizeof(*state));
if (state == NULL)
return -ENOMEM;
state->family = family;
return 0;
}
static void *vcc_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(vcc_sklist_lock)
{
struct vcc_state *state = seq->private;
loff_t left = *pos;
read_lock(&vcc_sklist_lock);
state->sk = SEQ_START_TOKEN;
return left ? vcc_walk(state, left) : SEQ_START_TOKEN;
}
static void vcc_seq_stop(struct seq_file *seq, void *v)
__releases(vcc_sklist_lock)
{
read_unlock(&vcc_sklist_lock);
}
static void *vcc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct vcc_state *state = seq->private;
v = vcc_walk(state, 1);
*pos += !!PTR_ERR(v);
return v;
}
static void pvc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
static const char *const class_name[] = {
"off", "UBR", "CBR", "VBR", "ABR"};
static const char *const aal_name[] = {
"---", "1", "2", "3/4", /* 0- 3 */
"???", "5", "???", "???", /* 4- 7 */
"???", "???", "???", "???", /* 8-11 */
"???", "0", "???", "???"}; /* 12-15 */
seq_printf(seq, "%3d %3d %5d %-3s %7d %-5s %7d %-6s",
vcc->dev->number, vcc->vpi, vcc->vci,
vcc->qos.aal >= ARRAY_SIZE(aal_name) ? "err" :
aal_name[vcc->qos.aal], vcc->qos.rxtp.min_pcr,
class_name[vcc->qos.rxtp.traffic_class],
vcc->qos.txtp.min_pcr,
class_name[vcc->qos.txtp.traffic_class]);
if (test_bit(ATM_VF_IS_CLIP, &vcc->flags)) {
struct clip_vcc *clip_vcc = CLIP_VCC(vcc);
struct net_device *dev;
dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : NULL;
seq_printf(seq, "CLIP, Itf:%s, Encap:",
dev ? dev->name : "none?");
seq_printf(seq, "%s", clip_vcc->encap ? "LLC/SNAP" : "None");
}
seq_putc(seq, '\n');
}
static const char *vcc_state(struct atm_vcc *vcc)
{
static const char *const map[] = { ATM_VS2TXT_MAP };
return map[ATM_VF2VS(vcc->flags)];
}
static void vcc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
struct sock *sk = sk_atm(vcc);
seq_printf(seq, "%p ", vcc);
if (!vcc->dev)
seq_printf(seq, "Unassigned ");
else
seq_printf(seq, "%3d %3d %5d ", vcc->dev->number, vcc->vpi,
vcc->vci);
switch (sk->sk_family) {
case AF_ATMPVC:
seq_printf(seq, "PVC");
break;
case AF_ATMSVC:
seq_printf(seq, "SVC");
break;
default:
seq_printf(seq, "%3d", sk->sk_family);
}
seq_printf(seq, " %04lx %5d %7d/%7d %7d/%7d [%d]\n",
vcc->flags, sk->sk_err,
sk_wmem_alloc_get(sk), sk->sk_sndbuf,
sk_rmem_alloc_get(sk), sk->sk_rcvbuf,
atomic_read(&sk->sk_refcnt));
}
static void svc_info(struct seq_file *seq, struct atm_vcc *vcc)
{
if (!vcc->dev)
seq_printf(seq, sizeof(void *) == 4 ?
"N/A@%p%10s" : "N/A@%p%2s", vcc, "");
else
seq_printf(seq, "%3d %3d %5d ",
vcc->dev->number, vcc->vpi, vcc->vci);
seq_printf(seq, "%-10s ", vcc_state(vcc));
seq_printf(seq, "%s%s", vcc->remote.sas_addr.pub,
*vcc->remote.sas_addr.pub && *vcc->remote.sas_addr.prv ? "+" : "");
if (*vcc->remote.sas_addr.prv) {
int i;
for (i = 0; i < ATM_ESA_LEN; i++)
seq_printf(seq, "%02x", vcc->remote.sas_addr.prv[i]);
}
seq_putc(seq, '\n');
}
static int atm_dev_seq_show(struct seq_file *seq, void *v)
{
static char atm_dev_banner[] =
"Itf Type ESI/\"MAC\"addr "
"AAL(TX,err,RX,err,drop) ... [refcnt]\n";
if (v == &atm_devs)
seq_puts(seq, atm_dev_banner);
else {
struct atm_dev *dev = list_entry(v, struct atm_dev, dev_list);
atm_dev_info(seq, dev);
}
return 0;
}
static const struct seq_operations atm_dev_seq_ops = {
.start = atm_dev_seq_start,
.next = atm_dev_seq_next,
.stop = atm_dev_seq_stop,
.show = atm_dev_seq_show,
};
static int atm_dev_seq_open(struct inode *inode, struct file *file)
{
return seq_open(file, &atm_dev_seq_ops);
}
static const struct file_operations devices_seq_fops = {
.open = atm_dev_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int pvc_seq_show(struct seq_file *seq, void *v)
{
static char atm_pvc_banner[] =
"Itf VPI VCI AAL RX(PCR,Class) TX(PCR,Class)\n";
if (v == SEQ_START_TOKEN)
seq_puts(seq, atm_pvc_banner);
else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
pvc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations pvc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = pvc_seq_show,
};
static int pvc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, PF_ATMPVC, &pvc_seq_ops);
}
static const struct file_operations pvc_seq_fops = {
.open = pvc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int vcc_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN) {
seq_printf(seq, sizeof(void *) == 4 ? "%-8s%s" : "%-16s%s",
"Address ", "Itf VPI VCI Fam Flags Reply "
"Send buffer Recv buffer [refcnt]\n");
} else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
vcc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations vcc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = vcc_seq_show,
};
static int vcc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, 0, &vcc_seq_ops);
}
static const struct file_operations vcc_seq_fops = {
.open = vcc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int svc_seq_show(struct seq_file *seq, void *v)
{
static const char atm_svc_banner[] =
"Itf VPI VCI State Remote\n";
if (v == SEQ_START_TOKEN)
seq_puts(seq, atm_svc_banner);
else {
struct vcc_state *state = seq->private;
struct atm_vcc *vcc = atm_sk(state->sk);
svc_info(seq, vcc);
}
return 0;
}
static const struct seq_operations svc_seq_ops = {
.start = vcc_seq_start,
.next = vcc_seq_next,
.stop = vcc_seq_stop,
.show = svc_seq_show,
};
static int svc_seq_open(struct inode *inode, struct file *file)
{
return __vcc_seq_open(inode, file, PF_ATMSVC, &svc_seq_ops);
}
static const struct file_operations svc_seq_fops = {
.open = svc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
struct atm_dev *dev;
unsigned long page;
int length;
if (count == 0)
return 0;
page = get_zeroed_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
dev = PDE(file->f_path.dentry->d_inode)->data;
if (!dev->ops->proc_read)
length = -EINVAL;
else {
length = dev->ops->proc_read(dev, pos, (char *)page);
if (length > count)
length = -EINVAL;
}
if (length >= 0) {
if (copy_to_user(buf, (char *)page, length))
length = -EFAULT;
(*pos)++;
}
free_page(page);
return length;
}
struct proc_dir_entry *atm_proc_root;
EXPORT_SYMBOL(atm_proc_root);
int atm_proc_dev_register(struct atm_dev *dev)
{
int error;
/* No proc info */
if (!dev->ops->proc_read)
return 0;
error = -ENOMEM;
dev->proc_name = kasprintf(GFP_KERNEL, "%s:%d", dev->type, dev->number);
if (!dev->proc_name)
goto err_out;
dev->proc_entry = proc_create_data(dev->proc_name, 0, atm_proc_root,
&proc_atm_dev_ops, dev);
if (!dev->proc_entry)
goto err_free_name;
return 0;
err_free_name:
kfree(dev->proc_name);
err_out:
return error;
}
void atm_proc_dev_deregister(struct atm_dev *dev)
{
if (!dev->ops->proc_read)
return;
remove_proc_entry(dev->proc_name, atm_proc_root);
kfree(dev->proc_name);
}
static struct atm_proc_entry {
char *name;
const struct file_operations *proc_fops;
struct proc_dir_entry *dirent;
} atm_proc_ents[] = {
{ .name = "devices", .proc_fops = &devices_seq_fops },
{ .name = "pvc", .proc_fops = &pvc_seq_fops },
{ .name = "svc", .proc_fops = &svc_seq_fops },
{ .name = "vc", .proc_fops = &vcc_seq_fops },
{ .name = NULL, .proc_fops = NULL }
};
static void atm_proc_dirs_remove(void)
{
static struct atm_proc_entry *e;
for (e = atm_proc_ents; e->name; e++) {
if (e->dirent)
remove_proc_entry(e->name, atm_proc_root);
}
proc_net_remove(&init_net, "atm");
}
int __init atm_proc_init(void)
{
static struct atm_proc_entry *e;
int ret;
atm_proc_root = proc_net_mkdir(&init_net, "atm", init_net.proc_net);
if (!atm_proc_root)
goto err_out;
for (e = atm_proc_ents; e->name; e++) {
struct proc_dir_entry *dirent;
dirent = proc_create(e->name, S_IRUGO,
atm_proc_root, e->proc_fops);
if (!dirent)
goto err_out_remove;
e->dirent = dirent;
}
ret = 0;
out:
return ret;
err_out_remove:
atm_proc_dirs_remove();
err_out:
ret = -ENOMEM;
goto out;
}
void atm_proc_exit(void)
{
atm_proc_dirs_remove();
}