* [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
@ 2012-09-07 12:34 Jeff Layton
2012-09-07 12:48 ` Jeff Layton
2012-09-07 17:27 ` [PATCH v2] " Jeff Layton
0 siblings, 2 replies; 7+ messages in thread
From: Jeff Layton @ 2012-09-07 12:34 UTC (permalink / raw)
To: viro; +Cc: linux-fsdevel, linux-kernel
Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/proc/base.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b6c84c..58e801b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name = ERR_PTR(-ENOENT);
if (tgid) {
- name = __getname();
+ /* 10 for max length of an int in decimal + NULL terminator */
+ name = kmalloc(11, GFP_KERNEL);
if (!name)
name = ERR_PTR(-ENOMEM);
else
@@ -2773,7 +2774,7 @@ static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
{
char *s = nd_get_link(nd);
if (!IS_ERR(s))
- __putname(s);
+ kfree(s);
}
static const struct inode_operations proc_self_inode_operations = {
--
1.7.11.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-07 12:34 [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int Jeff Layton
@ 2012-09-07 12:48 ` Jeff Layton
2012-09-07 12:58 ` Pádraig Brady
2012-09-07 17:27 ` [PATCH v2] " Jeff Layton
1 sibling, 1 reply; 7+ messages in thread
From: Jeff Layton @ 2012-09-07 12:48 UTC (permalink / raw)
To: viro; +Cc: linux-fsdevel, linux-kernel
On Fri, 7 Sep 2012 08:34:53 -0400
Jeff Layton <jlayton@redhat.com> wrote:
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
> fs/proc/base.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 1b6c84c..58e801b 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
> pid_t tgid = task_tgid_nr_ns(current, ns);
> char *name = ERR_PTR(-ENOENT);
> if (tgid) {
> - name = __getname();
> + /* 10 for max length of an int in decimal + NULL terminator */
> + name = kmalloc(11, GFP_KERNEL);
^^^^^
Bah...my mistake. This should be "12", since it's possible (though
unlikely) that this value could be negative. Is there a better way to
express "strlen of max representation of an int in decimal" ?
> if (!name)
> name = ERR_PTR(-ENOMEM);
> else
> @@ -2773,7 +2774,7 @@ static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
> {
> char *s = nd_get_link(nd);
> if (!IS_ERR(s))
> - __putname(s);
> + kfree(s);
> }
>
> static const struct inode_operations proc_self_inode_operations = {
--
Jeff Layton <jlayton@poochiereds.net>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-07 12:48 ` Jeff Layton
@ 2012-09-07 12:58 ` Pádraig Brady
2012-09-07 19:44 ` J. Bruce Fields
0 siblings, 1 reply; 7+ messages in thread
From: Pádraig Brady @ 2012-09-07 12:58 UTC (permalink / raw)
To: Jeff Layton; +Cc: viro, linux-fsdevel, linux-kernel
On 09/07/2012 01:48 PM, Jeff Layton wrote:
> On Fri, 7 Sep 2012 08:34:53 -0400
> Jeff Layton<jlayton@redhat.com> wrote:
>
>> Signed-off-by: Jeff Layton<jlayton@redhat.com>
>> ---
>> fs/proc/base.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/proc/base.c b/fs/proc/base.c
>> index 1b6c84c..58e801b 100644
>> --- a/fs/proc/base.c
>> +++ b/fs/proc/base.c
>> @@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
>> pid_t tgid = task_tgid_nr_ns(current, ns);
>> char *name = ERR_PTR(-ENOENT);
>> if (tgid) {
>> - name = __getname();
>> + /* 10 for max length of an int in decimal + NULL terminator */
>> + name = kmalloc(11, GFP_KERNEL);
>
> ^^^^^
> Bah...my mistake. This should be "12", since it's possible (though
> unlikely) that this value could be negative. Is there a better way to
> express "strlen of max representation of an int in decimal" ?
See INT_BUFSIZE_BOUND() in:
http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/intprops.h;hb=HEAD
cheers,
Pádraig.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-07 12:34 [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int Jeff Layton
2012-09-07 12:48 ` Jeff Layton
@ 2012-09-07 17:27 ` Jeff Layton
1 sibling, 0 replies; 7+ messages in thread
From: Jeff Layton @ 2012-09-07 17:27 UTC (permalink / raw)
To: viro; +Cc: linux-fsdevel, linux-kernel
This patch is a minor respin that just increases the buffer size by 1
to account for a potential minus sign at the head.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/proc/base.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b6c84c..3e6ce3f 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name = ERR_PTR(-ENOENT);
if (tgid) {
- name = __getname();
+ /* 11 for max length of signed int in decimal + NULL term */
+ name = kmalloc(12, GFP_KERNEL);
if (!name)
name = ERR_PTR(-ENOMEM);
else
@@ -2773,7 +2774,7 @@ static void proc_self_put_link(struct dentry *dentry, struct nameidata *nd,
{
char *s = nd_get_link(nd);
if (!IS_ERR(s))
- __putname(s);
+ kfree(s);
}
static const struct inode_operations proc_self_inode_operations = {
--
1.7.11.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-07 12:58 ` Pádraig Brady
@ 2012-09-07 19:44 ` J. Bruce Fields
2012-09-10 13:23 ` Jeff Layton
0 siblings, 1 reply; 7+ messages in thread
From: J. Bruce Fields @ 2012-09-07 19:44 UTC (permalink / raw)
To: Pádraig Brady; +Cc: Jeff Layton, viro, linux-fsdevel, linux-kernel
On Fri, Sep 07, 2012 at 01:58:03PM +0100, Pádraig Brady wrote:
> On 09/07/2012 01:48 PM, Jeff Layton wrote:
> >On Fri, 7 Sep 2012 08:34:53 -0400
> >Jeff Layton<jlayton@redhat.com> wrote:
> >
> >>Signed-off-by: Jeff Layton<jlayton@redhat.com>
> >>---
> >> fs/proc/base.c | 5 +++--
> >> 1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >>diff --git a/fs/proc/base.c b/fs/proc/base.c
> >>index 1b6c84c..58e801b 100644
> >>--- a/fs/proc/base.c
> >>+++ b/fs/proc/base.c
> >>@@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
> >> pid_t tgid = task_tgid_nr_ns(current, ns);
> >> char *name = ERR_PTR(-ENOENT);
> >> if (tgid) {
> >>- name = __getname();
> >>+ /* 10 for max length of an int in decimal + NULL terminator */
> >>+ name = kmalloc(11, GFP_KERNEL);
> >
> > ^^^^^
> >Bah...my mistake. This should be "12", since it's possible (though
> >unlikely) that this value could be negative. Is there a better way to
> >express "strlen of max representation of an int in decimal" ?
It'd be nice to have something--I've run across similar mistakes
recently.
>
> See INT_BUFSIZE_BOUND() in:
> http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/intprops.h;hb=HEAD
My lame attempt follows. It's simpler than Pádraig's but possibly also
stupider.
--b.
commit 15e8c46104e0c1dd6a76d09b55563b6f83b61667
Author: J. Bruce Fields <bfields@redhat.com>
Date: Wed Aug 15 17:41:47 2012 -0400
strings: helper for maximum decimal encoding of an unsigned integer
I've seen a couple examples recently where we've gotten this wrong.
Maybe something like this would help?
Suggested-by: Jim Rees <rees@umich.edu>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/string.h b/include/linux/string.h
index ffe0442..3674cf5 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -126,6 +126,12 @@ extern void argv_free(char **argv);
extern bool sysfs_streq(const char *s1, const char *s2);
extern int strtobool(const char *s, bool *res);
+/*
+ * length of the decimal representation of an unsigned integer. Just an
+ * approximation, but it's right for types of size 1 to 26 bytes:
+ */
+#define base10len(i) (sizeof(i) * 24 / 10 + 1)
+
#ifdef CONFIG_BINARY_PRINTF
int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 2afd2a8..1dcd2b3 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1409,7 +1409,7 @@ static ssize_t read_flush(struct file *file, char __user *buf,
size_t count, loff_t *ppos,
struct cache_detail *cd)
{
- char tbuf[20];
+ char tbuf[base10len(unsigned long) + 2];
unsigned long p = *ppos;
size_t len;
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-07 19:44 ` J. Bruce Fields
@ 2012-09-10 13:23 ` Jeff Layton
2012-09-10 14:28 ` J. Bruce Fields
0 siblings, 1 reply; 7+ messages in thread
From: Jeff Layton @ 2012-09-10 13:23 UTC (permalink / raw)
To: J. Bruce Fields; +Cc: Pádraig Brady, viro, linux-fsdevel, linux-kernel
On Fri, 7 Sep 2012 15:44:16 -0400
"J. Bruce Fields" <bfields@fieldses.org> wrote:
> On Fri, Sep 07, 2012 at 01:58:03PM +0100, Pádraig Brady wrote:
> > On 09/07/2012 01:48 PM, Jeff Layton wrote:
> > >On Fri, 7 Sep 2012 08:34:53 -0400
> > >Jeff Layton<jlayton@redhat.com> wrote:
> > >
> > >>Signed-off-by: Jeff Layton<jlayton@redhat.com>
> > >>---
> > >> fs/proc/base.c | 5 +++--
> > >> 1 file changed, 3 insertions(+), 2 deletions(-)
> > >>
> > >>diff --git a/fs/proc/base.c b/fs/proc/base.c
> > >>index 1b6c84c..58e801b 100644
> > >>--- a/fs/proc/base.c
> > >>+++ b/fs/proc/base.c
> > >>@@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
> > >> pid_t tgid = task_tgid_nr_ns(current, ns);
> > >> char *name = ERR_PTR(-ENOENT);
> > >> if (tgid) {
> > >>- name = __getname();
> > >>+ /* 10 for max length of an int in decimal + NULL terminator */
> > >>+ name = kmalloc(11, GFP_KERNEL);
> > >
> > > ^^^^^
> > >Bah...my mistake. This should be "12", since it's possible (though
> > >unlikely) that this value could be negative. Is there a better way to
> > >express "strlen of max representation of an int in decimal" ?
>
> It'd be nice to have something--I've run across similar mistakes
> recently.
>
> >
> > See INT_BUFSIZE_BOUND() in:
> > http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/intprops.h;hb=HEAD
>
> My lame attempt follows. It's simpler than Pádraig's but possibly also
> stupider.
>
> --b.
>
> commit 15e8c46104e0c1dd6a76d09b55563b6f83b61667
> Author: J. Bruce Fields <bfields@redhat.com>
> Date: Wed Aug 15 17:41:47 2012 -0400
>
> strings: helper for maximum decimal encoding of an unsigned integer
>
> I've seen a couple examples recently where we've gotten this wrong.
> Maybe something like this would help?
>
> Suggested-by: Jim Rees <rees@umich.edu>
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
>
> diff --git a/include/linux/string.h b/include/linux/string.h
> index ffe0442..3674cf5 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -126,6 +126,12 @@ extern void argv_free(char **argv);
> extern bool sysfs_streq(const char *s1, const char *s2);
> extern int strtobool(const char *s, bool *res);
>
> +/*
> + * length of the decimal representation of an unsigned integer. Just an
> + * approximation, but it's right for types of size 1 to 26 bytes:
> + */
> +#define base10len(i) (sizeof(i) * 24 / 10 + 1)
> +
> #ifdef CONFIG_BINARY_PRINTF
> int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
> int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 2afd2a8..1dcd2b3 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -1409,7 +1409,7 @@ static ssize_t read_flush(struct file *file, char __user *buf,
> size_t count, loff_t *ppos,
> struct cache_detail *cd)
> {
> - char tbuf[20];
> + char tbuf[base10len(unsigned long) + 2];
> unsigned long p = *ppos;
> size_t len;
>
Thanks Bruce and Pádraig...
Bruce, are you planning to push that patch for 3.7? If so, I'll base
mine on top of yours...
--
Jeff Layton <jlayton@redhat.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int
2012-09-10 13:23 ` Jeff Layton
@ 2012-09-10 14:28 ` J. Bruce Fields
0 siblings, 0 replies; 7+ messages in thread
From: J. Bruce Fields @ 2012-09-10 14:28 UTC (permalink / raw)
To: Jeff Layton; +Cc: Pádraig Brady, viro, linux-fsdevel, linux-kernel
On Mon, Sep 10, 2012 at 09:23:28AM -0400, Jeff Layton wrote:
> On Fri, 7 Sep 2012 15:44:16 -0400
> "J. Bruce Fields" <bfields@fieldses.org> wrote:
>
> > On Fri, Sep 07, 2012 at 01:58:03PM +0100, Pádraig Brady wrote:
> > > On 09/07/2012 01:48 PM, Jeff Layton wrote:
> > > >On Fri, 7 Sep 2012 08:34:53 -0400
> > > >Jeff Layton<jlayton@redhat.com> wrote:
> > > >
> > > >>Signed-off-by: Jeff Layton<jlayton@redhat.com>
> > > >>---
> > > >> fs/proc/base.c | 5 +++--
> > > >> 1 file changed, 3 insertions(+), 2 deletions(-)
> > > >>
> > > >>diff --git a/fs/proc/base.c b/fs/proc/base.c
> > > >>index 1b6c84c..58e801b 100644
> > > >>--- a/fs/proc/base.c
> > > >>+++ b/fs/proc/base.c
> > > >>@@ -2758,7 +2758,8 @@ static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
> > > >> pid_t tgid = task_tgid_nr_ns(current, ns);
> > > >> char *name = ERR_PTR(-ENOENT);
> > > >> if (tgid) {
> > > >>- name = __getname();
> > > >>+ /* 10 for max length of an int in decimal + NULL terminator */
> > > >>+ name = kmalloc(11, GFP_KERNEL);
> > > >
> > > > ^^^^^
> > > >Bah...my mistake. This should be "12", since it's possible (though
> > > >unlikely) that this value could be negative. Is there a better way to
> > > >express "strlen of max representation of an int in decimal" ?
> >
> > It'd be nice to have something--I've run across similar mistakes
> > recently.
> >
> > >
> > > See INT_BUFSIZE_BOUND() in:
> > > http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=blob;f=lib/intprops.h;hb=HEAD
> >
> > My lame attempt follows. It's simpler than Pádraig's but possibly also
> > stupider.
> >
> > --b.
> >
> > commit 15e8c46104e0c1dd6a76d09b55563b6f83b61667
> > Author: J. Bruce Fields <bfields@redhat.com>
> > Date: Wed Aug 15 17:41:47 2012 -0400
> >
> > strings: helper for maximum decimal encoding of an unsigned integer
> >
> > I've seen a couple examples recently where we've gotten this wrong.
> > Maybe something like this would help?
> >
> > Suggested-by: Jim Rees <rees@umich.edu>
> > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> >
> > diff --git a/include/linux/string.h b/include/linux/string.h
> > index ffe0442..3674cf5 100644
> > --- a/include/linux/string.h
> > +++ b/include/linux/string.h
> > @@ -126,6 +126,12 @@ extern void argv_free(char **argv);
> > extern bool sysfs_streq(const char *s1, const char *s2);
> > extern int strtobool(const char *s, bool *res);
> >
> > +/*
> > + * length of the decimal representation of an unsigned integer. Just an
> > + * approximation, but it's right for types of size 1 to 26 bytes:
> > + */
> > +#define base10len(i) (sizeof(i) * 24 / 10 + 1)
> > +
> > #ifdef CONFIG_BINARY_PRINTF
> > int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
> > int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
> > diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> > index 2afd2a8..1dcd2b3 100644
> > --- a/net/sunrpc/cache.c
> > +++ b/net/sunrpc/cache.c
> > @@ -1409,7 +1409,7 @@ static ssize_t read_flush(struct file *file, char __user *buf,
> > size_t count, loff_t *ppos,
> > struct cache_detail *cd)
> > {
> > - char tbuf[20];
> > + char tbuf[base10len(unsigned long) + 2];
> > unsigned long p = *ppos;
> > size_t len;
> >
>
> Thanks Bruce and Pádraig...
>
> Bruce, are you planning to push that patch for 3.7? If so, I'll base
> mine on top of yours...
I assumed string.h is outside my baliwick--I'm not sure where it should
go. Linus or Andrew?
--b.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2012-09-10 14:28 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-09-07 12:34 [PATCH] procfs: don't need a PATH_MAX allocation to hold a string representation of an int Jeff Layton
2012-09-07 12:48 ` Jeff Layton
2012-09-07 12:58 ` Pádraig Brady
2012-09-07 19:44 ` J. Bruce Fields
2012-09-10 13:23 ` Jeff Layton
2012-09-10 14:28 ` J. Bruce Fields
2012-09-07 17:27 ` [PATCH v2] " Jeff Layton
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).