* [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
* 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> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ 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. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ 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
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
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