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SubjectRe: [PATCH V2] sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output
From
Date
On Sat, 2020-08-29 at 16:48 -0700, Joe Perches wrote:
> Output defects can exist in sysfs content using sprintf and snprintf.
>
> sprintf does not know the PAGE_SIZE maximum of the temporary buffer
> used for outputting sysfs content and it's possible to overrun the
> PAGE_SIZE buffer length.
>
> Add a generic sysfs_emit function that knows that the size of the
> temporary buffer and ensures that no overrun is done.
>
> Add a generic sysfs_emit_at function that can be used in multiple
> call situations that also ensures that no overrun is done.

This preliminary coccinelle script converts ~5000 instances treewide.
There are still many remaining instances that could be converted.

$ git grep -w sysfs_emit -- '*.[ch]'|wc -l
4702
$ git grep -w sysfs_emit_at -- '*.[ch]'|wc -l
229

$ cat sysfs_emit.cocci
@@
identifier d_show =~ "^.*show.*$";
identifier arg1, arg2, arg3;
@@
ssize_t d_show(struct device *
- arg1
+ dev
, struct device_attribute *
- arg2
+ attr
, char *
- arg3
+ buf
)
{
...
(
- arg1
+ dev
|
- arg2
+ attr
|
- arg3
+ buf
)
...
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
return
- strcpy(buf, chr);
+ sysfs_emit(buf, chr);
...>
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
len =
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
<...
- len += scnprintf(buf + len, PAGE_SIZE - len,
+ len += sysfs_emit_at(buf, len,
...);
...>
return len;
}

@@
identifier d_show =~ "^.*show.*$";
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
- strcpy(buf, chr);
- return strlen(buf);
+ return sysfs_emit(buf, chr);
}

@@
identifier k_show =~ "^.*show.*$";
identifier arg1, arg2, arg3;
@@
ssize_t k_show(struct kobject *
- arg1
+ kobj
, struct kobj_attribute *
- arg2
+ attr
, char *
- arg3
+ buf
)
{
...
(
- arg1
+ kobj
|
- arg2
+ attr
|
- arg3
+ buf
)
...
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
return
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
return
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
return
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
expression chr;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
return
- strcpy(buf, chr);
+ sysfs_emit(buf, chr);
...>
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
identifier len;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
len =
- sprintf(buf,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
identifier len;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
len =
- snprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
identifier len;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
len =
- scnprintf(buf, PAGE_SIZE,
+ sysfs_emit(buf,
...);
...>
return len;
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
identifier len;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
<...
- len += scnprintf(buf + len, PAGE_SIZE - len,
+ len += sysfs_emit_at(buf, len,
...);
...>
return len;
}

@@
identifier k_show =~ "^.*show.*$";
identifier kobj, attr, buf;
expression chr;
@@

ssize_t k_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
- strcpy(buf, chr);
- return strlen(buf);
+ return sysfs_emit(buf, chr);
}


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