strchrnul is a GNU extension and thus unavailable on a number of targets.
In the review for a commit removing strchrnul from 9p, I was asked to
create a qemu_strchrnul helper to factor out this functionality.
Do so, and use it in a number of other places in the code base that inlined
the replacement pattern in a place where strchrnul could be used.
Signed-off-by: Keno Fischer <keno@juliacomputing.com>
---
Changes since v1: New patch
hw/9pfs/9p-local.c | 2 +-
include/qemu/cutils.h | 1 +
monitor.c | 8 ++------
util/cutils.c | 13 +++++++++++++
util/qemu-option.c | 6 +-----
util/uri.c | 6 ++----
6 files changed, 20 insertions(+), 16 deletions(-)
diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index b37b1db..bcf2798 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -65,7 +65,7 @@ int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
assert(*path != '/');
head = g_strdup(path);
- c = strchrnul(path, '/');
+ c = qemu_strchrnul(path, '/');
if (*c) {
/* Intermediate path element */
head[c - path] = 0;
diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
index a663340..bc40c30 100644
--- a/include/qemu/cutils.h
+++ b/include/qemu/cutils.h
@@ -122,6 +122,7 @@ int qemu_strnlen(const char *s, int max_len);
* Returns: the pointer originally in @input.
*/
char *qemu_strsep(char **input, const char *delim);
+const char *qemu_strchrnul(const char *s, int c);
time_t mktimegm(struct tm *tm);
int qemu_fdatasync(int fd);
int fcntl_setfl(int fd, int flag);
diff --git a/monitor.c b/monitor.c
index 922cfc0..e1f01c4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -798,9 +798,7 @@ static int compare_cmd(const char *name, const char *list)
p = list;
for(;;) {
pstart = p;
- p = strchr(p, '|');
- if (!p)
- p = pstart + strlen(pstart);
+ p = qemu_strchrnul(p, '|');
if ((p - pstart) == len && !memcmp(pstart, name, len))
return 1;
if (*p == '\0')
@@ -3401,9 +3399,7 @@ static void cmd_completion(Monitor *mon, const char *name, const char *list)
p = list;
for(;;) {
pstart = p;
- p = strchr(p, '|');
- if (!p)
- p = pstart + strlen(pstart);
+ p = qemu_strchrnul(p, '|');
len = p - pstart;
if (len > sizeof(cmd) - 2)
len = sizeof(cmd) - 2;
diff --git a/util/cutils.c b/util/cutils.c
index 0de69e6..6e078b0 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -545,6 +545,19 @@ int qemu_strtou64(const char *nptr, const char **endptr, int base,
}
/**
+ * Searches for the first occurrence of 'c' in 's', and returns a pointer
+ * to the trailing null byte if none was found.
+ */
+const char *qemu_strchrnul(const char *s, int c)
+{
+ const char *e = strchr(s, c);
+ if (!e) {
+ e = s + strlen(s);
+ }
+ return e;
+}
+
+/**
* parse_uint:
*
* @s: String to parse
diff --git a/util/qemu-option.c b/util/qemu-option.c
index 58d1c23..54eca12 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -77,11 +77,7 @@ const char *get_opt_value(const char *p, char **value)
*value = NULL;
while (1) {
- offset = strchr(p, ',');
- if (!offset) {
- offset = p + strlen(p);
- }
-
+ offset = qemu_strchrnul(p, ',');
length = offset - p;
if (*offset != '\0' && *(offset + 1) == ',') {
length++;
diff --git a/util/uri.c b/util/uri.c
index 8624a7a..8bdef84 100644
--- a/util/uri.c
+++ b/util/uri.c
@@ -52,6 +52,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include "qemu/uri.h"
@@ -2266,10 +2267,7 @@ struct QueryParams *query_params_parse(const char *query)
/* Find the next separator, or end of the string. */
end = strchr(query, '&');
if (!end) {
- end = strchr(query, ';');
- }
- if (!end) {
- end = query + strlen(query);
+ end = qemu_strchrnul(query, ';');
}
/* Find the first '=' character between here and end. */
--
2.8.1
On Thu, 31 May 2018 21:25:56 -0400
Keno Fischer <keno@juliacomputing.com> wrote:
> strchrnul is a GNU extension and thus unavailable on a number of targets.
> In the review for a commit removing strchrnul from 9p, I was asked to
> create a qemu_strchrnul helper to factor out this functionality.
> Do so, and use it in a number of other places in the code base that inlined
> the replacement pattern in a place where strchrnul could be used.
>
> Signed-off-by: Keno Fischer <keno@juliacomputing.com>
> ---
>
And possibly we could detect in configure if the host has strchrnul() and
use it, but this optimization can be done later.
I haven't checked if there could be other candidates in the current code
base though. Also, this patch touches some other subsystems, so I'm Cc'ing
to the other maintainers as reported by ./scripts/get_maintainer.pl:
Greg Kurz <groug@kaod.org> (supporter:virtio-9p)
Markus Armbruster <armbru@redhat.com> (supporter:QMP)
"Dr. David Alan Gilbert" <dgilbert@redhat.com> (maintainer:Human Monitor (HMP))
qemu-devel@nongnu.org (open list:All patches CC here)
Anyway,
Acked-by: Greg Kurz <groug@kaod.org>
> Changes since v1: New patch
>
> hw/9pfs/9p-local.c | 2 +-
> include/qemu/cutils.h | 1 +
> monitor.c | 8 ++------
> util/cutils.c | 13 +++++++++++++
> util/qemu-option.c | 6 +-----
> util/uri.c | 6 ++----
> 6 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index b37b1db..bcf2798 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -65,7 +65,7 @@ int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
> assert(*path != '/');
>
> head = g_strdup(path);
> - c = strchrnul(path, '/');
> + c = qemu_strchrnul(path, '/');
> if (*c) {
> /* Intermediate path element */
> head[c - path] = 0;
> diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
> index a663340..bc40c30 100644
> --- a/include/qemu/cutils.h
> +++ b/include/qemu/cutils.h
> @@ -122,6 +122,7 @@ int qemu_strnlen(const char *s, int max_len);
> * Returns: the pointer originally in @input.
> */
> char *qemu_strsep(char **input, const char *delim);
> +const char *qemu_strchrnul(const char *s, int c);
> time_t mktimegm(struct tm *tm);
> int qemu_fdatasync(int fd);
> int fcntl_setfl(int fd, int flag);
> diff --git a/monitor.c b/monitor.c
> index 922cfc0..e1f01c4 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -798,9 +798,7 @@ static int compare_cmd(const char *name, const char *list)
> p = list;
> for(;;) {
> pstart = p;
> - p = strchr(p, '|');
> - if (!p)
> - p = pstart + strlen(pstart);
> + p = qemu_strchrnul(p, '|');
> if ((p - pstart) == len && !memcmp(pstart, name, len))
> return 1;
> if (*p == '\0')
> @@ -3401,9 +3399,7 @@ static void cmd_completion(Monitor *mon, const char *name, const char *list)
> p = list;
> for(;;) {
> pstart = p;
> - p = strchr(p, '|');
> - if (!p)
> - p = pstart + strlen(pstart);
> + p = qemu_strchrnul(p, '|');
> len = p - pstart;
> if (len > sizeof(cmd) - 2)
> len = sizeof(cmd) - 2;
> diff --git a/util/cutils.c b/util/cutils.c
> index 0de69e6..6e078b0 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -545,6 +545,19 @@ int qemu_strtou64(const char *nptr, const char **endptr, int base,
> }
>
> /**
> + * Searches for the first occurrence of 'c' in 's', and returns a pointer
> + * to the trailing null byte if none was found.
> + */
> +const char *qemu_strchrnul(const char *s, int c)
> +{
> + const char *e = strchr(s, c);
> + if (!e) {
> + e = s + strlen(s);
> + }
> + return e;
> +}
> +
> +/**
> * parse_uint:
> *
> * @s: String to parse
> diff --git a/util/qemu-option.c b/util/qemu-option.c
> index 58d1c23..54eca12 100644
> --- a/util/qemu-option.c
> +++ b/util/qemu-option.c
> @@ -77,11 +77,7 @@ const char *get_opt_value(const char *p, char **value)
>
> *value = NULL;
> while (1) {
> - offset = strchr(p, ',');
> - if (!offset) {
> - offset = p + strlen(p);
> - }
> -
> + offset = qemu_strchrnul(p, ',');
> length = offset - p;
> if (*offset != '\0' && *(offset + 1) == ',') {
> length++;
> diff --git a/util/uri.c b/util/uri.c
> index 8624a7a..8bdef84 100644
> --- a/util/uri.c
> +++ b/util/uri.c
> @@ -52,6 +52,7 @@
> */
>
> #include "qemu/osdep.h"
> +#include "qemu/cutils.h"
>
> #include "qemu/uri.h"
>
> @@ -2266,10 +2267,7 @@ struct QueryParams *query_params_parse(const char *query)
> /* Find the next separator, or end of the string. */
> end = strchr(query, '&');
> if (!end) {
> - end = strchr(query, ';');
> - }
> - if (!end) {
> - end = query + strlen(query);
> + end = qemu_strchrnul(query, ';');
> }
>
> /* Find the first '=' character between here and end. */
* Greg Kurz (groug@kaod.org) wrote:
> On Thu, 31 May 2018 21:25:56 -0400
> Keno Fischer <keno@juliacomputing.com> wrote:
>
> > strchrnul is a GNU extension and thus unavailable on a number of targets.
> > In the review for a commit removing strchrnul from 9p, I was asked to
> > create a qemu_strchrnul helper to factor out this functionality.
> > Do so, and use it in a number of other places in the code base that inlined
> > the replacement pattern in a place where strchrnul could be used.
> >
> > Signed-off-by: Keno Fischer <keno@juliacomputing.com>
> > ---
> >
>
> And possibly we could detect in configure if the host has strchrnul() and
> use it, but this optimization can be done later.
>
> I haven't checked if there could be other candidates in the current code
> base though. Also, this patch touches some other subsystems, so I'm Cc'ing
> to the other maintainers as reported by ./scripts/get_maintainer.pl:
That looks fine from my point of view; I can see you could probably
also use it in the code at the start of the while loop in hmp_sendkey:
while (1) {
separator = strchr(keys, '-');
keyname_len = separator ? separator - keys : strlen(keys);
Dave
> Greg Kurz <groug@kaod.org> (supporter:virtio-9p)
> Markus Armbruster <armbru@redhat.com> (supporter:QMP)
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> (maintainer:Human Monitor (HMP))
> qemu-devel@nongnu.org (open list:All patches CC here)
>
> Anyway,
>
> Acked-by: Greg Kurz <groug@kaod.org>
>
> > Changes since v1: New patch
> >
> > hw/9pfs/9p-local.c | 2 +-
> > include/qemu/cutils.h | 1 +
> > monitor.c | 8 ++------
> > util/cutils.c | 13 +++++++++++++
> > util/qemu-option.c | 6 +-----
> > util/uri.c | 6 ++----
> > 6 files changed, 20 insertions(+), 16 deletions(-)
> >
> > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> > index b37b1db..bcf2798 100644
> > --- a/hw/9pfs/9p-local.c
> > +++ b/hw/9pfs/9p-local.c
> > @@ -65,7 +65,7 @@ int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
> > assert(*path != '/');
> >
> > head = g_strdup(path);
> > - c = strchrnul(path, '/');
> > + c = qemu_strchrnul(path, '/');
> > if (*c) {
> > /* Intermediate path element */
> > head[c - path] = 0;
> > diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
> > index a663340..bc40c30 100644
> > --- a/include/qemu/cutils.h
> > +++ b/include/qemu/cutils.h
> > @@ -122,6 +122,7 @@ int qemu_strnlen(const char *s, int max_len);
> > * Returns: the pointer originally in @input.
> > */
> > char *qemu_strsep(char **input, const char *delim);
> > +const char *qemu_strchrnul(const char *s, int c);
> > time_t mktimegm(struct tm *tm);
> > int qemu_fdatasync(int fd);
> > int fcntl_setfl(int fd, int flag);
> > diff --git a/monitor.c b/monitor.c
> > index 922cfc0..e1f01c4 100644
> > --- a/monitor.c
> > +++ b/monitor.c
> > @@ -798,9 +798,7 @@ static int compare_cmd(const char *name, const char *list)
> > p = list;
> > for(;;) {
> > pstart = p;
> > - p = strchr(p, '|');
> > - if (!p)
> > - p = pstart + strlen(pstart);
> > + p = qemu_strchrnul(p, '|');
> > if ((p - pstart) == len && !memcmp(pstart, name, len))
> > return 1;
> > if (*p == '\0')
> > @@ -3401,9 +3399,7 @@ static void cmd_completion(Monitor *mon, const char *name, const char *list)
> > p = list;
> > for(;;) {
> > pstart = p;
> > - p = strchr(p, '|');
> > - if (!p)
> > - p = pstart + strlen(pstart);
> > + p = qemu_strchrnul(p, '|');
> > len = p - pstart;
> > if (len > sizeof(cmd) - 2)
> > len = sizeof(cmd) - 2;
> > diff --git a/util/cutils.c b/util/cutils.c
> > index 0de69e6..6e078b0 100644
> > --- a/util/cutils.c
> > +++ b/util/cutils.c
> > @@ -545,6 +545,19 @@ int qemu_strtou64(const char *nptr, const char **endptr, int base,
> > }
> >
> > /**
> > + * Searches for the first occurrence of 'c' in 's', and returns a pointer
> > + * to the trailing null byte if none was found.
> > + */
> > +const char *qemu_strchrnul(const char *s, int c)
> > +{
> > + const char *e = strchr(s, c);
> > + if (!e) {
> > + e = s + strlen(s);
> > + }
> > + return e;
> > +}
> > +
> > +/**
> > * parse_uint:
> > *
> > * @s: String to parse
> > diff --git a/util/qemu-option.c b/util/qemu-option.c
> > index 58d1c23..54eca12 100644
> > --- a/util/qemu-option.c
> > +++ b/util/qemu-option.c
> > @@ -77,11 +77,7 @@ const char *get_opt_value(const char *p, char **value)
> >
> > *value = NULL;
> > while (1) {
> > - offset = strchr(p, ',');
> > - if (!offset) {
> > - offset = p + strlen(p);
> > - }
> > -
> > + offset = qemu_strchrnul(p, ',');
> > length = offset - p;
> > if (*offset != '\0' && *(offset + 1) == ',') {
> > length++;
> > diff --git a/util/uri.c b/util/uri.c
> > index 8624a7a..8bdef84 100644
> > --- a/util/uri.c
> > +++ b/util/uri.c
> > @@ -52,6 +52,7 @@
> > */
> >
> > #include "qemu/osdep.h"
> > +#include "qemu/cutils.h"
> >
> > #include "qemu/uri.h"
> >
> > @@ -2266,10 +2267,7 @@ struct QueryParams *query_params_parse(const char *query)
> > /* Find the next separator, or end of the string. */
> > end = strchr(query, '&');
> > if (!end) {
> > - end = strchr(query, ';');
> > - }
> > - if (!end) {
> > - end = query + strlen(query);
> > + end = qemu_strchrnul(query, ';');
> > }
> >
> > /* Find the first '=' character between here and end. */
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 05/31/2018 08:25 PM, Keno Fischer wrote:
> strchrnul is a GNU extension and thus unavailable on a number of targets.
> In the review for a commit removing strchrnul from 9p, I was asked to
> create a qemu_strchrnul helper to factor out this functionality.
> Do so, and use it in a number of other places in the code base that inlined
> the replacement pattern in a place where strchrnul could be used.
>
> Signed-off-by: Keno Fischer <keno@juliacomputing.com>
> ---
>
> +++ b/util/cutils.c
> @@ -545,6 +545,19 @@ int qemu_strtou64(const char *nptr, const char **endptr, int base,
> }
>
> /**
> + * Searches for the first occurrence of 'c' in 's', and returns a pointer
> + * to the trailing null byte if none was found.
> + */
> +const char *qemu_strchrnul(const char *s, int c)
> +{
> + const char *e = strchr(s, c);
> + if (!e) {
> + e = s + strlen(s);
> + }
> + return e;
> +}
This is twice as slow on glibc systems when the pointer to NUL is
returned (because it has to traverse the string twice); it's better to
have a configure check for whether strchrnul exists, and if so, use that
directly.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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