[Qemu-devel] [PATCH v5] cutils: Provide strchrnul
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 Acked-by: Greg Kurz --- Changes since v4: - `CONFIG_STRCHRNUL` -> `HAVE_STRCHRNUL` name change - In the strchrnul configure check - Return the value of strchrnul to avoid it being optimized away - Use `&main` (i.e. the assembly of the generated function as the haystack) to avoid concerns about constant folding. `main` seemed like the simplest symbol guaranteed to exist, but with non-foldable content. configure | 18 ++ hmp.c | 8 hw/9pfs/9p-local.c| 2 +- include/qemu/cutils.h | 8 monitor.c | 8 ++-- util/cutils.c | 15 +++ util/qemu-option.c| 6 +- util/uri.c| 6 ++ 8 files changed, 51 insertions(+), 20 deletions(-) diff --git a/configure b/configure index 14b1113..8a75745 100755 --- a/configure +++ b/configure @@ -4747,6 +4747,21 @@ if compile_prog "" "" ; then fi ## +# check if we have strchrnul + +strchrnul=no +cat > $TMPC << EOF +#include +int main(void); +// Use a haystack that the compiler shouldn't be able to constant fold +char *haystack = (char*)&main; +int main(void) { return strchrnul(haystack, 'x') != &haystack[6]; } +EOF +if compile_prog "" "" ; then +strchrnul=yes +fi + +## # check if trace backend exists $python "$source_path/scripts/tracetool.py" "--backends=$trace_backends" --check-backends > /dev/null 2> /dev/null @@ -6229,6 +6244,9 @@ fi if test "$sem_timedwait" = "yes" ; then echo "CONFIG_SEM_TIMEDWAIT=y" >> $config_host_mak fi +if test "$strchrnul" = "yes" ; then + echo "HAVE_STRCHRNUL=y" >> $config_host_mak +fi if test "$byteswap_h" = "yes" ; then echo "CONFIG_BYTESWAP_H=y" >> $config_host_mak fi diff --git a/hmp.c b/hmp.c index ef93f48..416d4c9 100644 --- a/hmp.c +++ b/hmp.c @@ -2123,12 +2123,12 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) int has_hold_time = qdict_haskey(qdict, "hold-time"); int hold_time = qdict_get_try_int(qdict, "hold-time", -1); Error *err = NULL; -char *separator; +const char *separator; int keyname_len; while (1) { -separator = strchr(keys, '-'); -keyname_len = separator ? separator - keys : strlen(keys); +separator = qemu_strchrnul(keys, '-'); +keyname_len = separator - keys; /* Be compatible with old interface, convert user inputted "<" */ if (keys[0] == '<' && keyname_len == 1) { @@ -2165,7 +2165,7 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) keylist->value->u.qcode.data = idx; } -if (!separator) { +if (!*separator) { break; } keys = separator + 1; diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index 5721eff..828e8d6 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..274d419 100644 --- a/include/qemu/cutils.h +++ b/include/qemu/cutils.h @@ -122,6 +122,14 @@ int qemu_strnlen(const char *s, int max_len); * Returns: the pointer originally in @input. */ char *qemu_strsep(char **input, const char *delim); +#ifdef HAVE_STRCHRNUL +static inline const char *qemu_strchrnul(const char *s, int c) +{ +return strchrnul(s, c); +} +#else +const char *qemu_strchrnul(const char *s, int c); +#endif 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 6d0cec5..4484d74 100644 --- a/monitor.c +++ b/monitor.c @@ -797,9 +797,7 @@ 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') @@ -3400,9 +3398,7 @@ 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;
Re: [Qemu-devel] [PATCH v5] cutils: Provide strchrnul
Keno Fischer writes: > 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 > Acked-by: Greg Kurz Reviewed-by: Markus Armbruster
Re: [Qemu-devel] [PATCH v5] cutils: Provide strchrnul
On Wed, 13 Jun 2018 07:42:57 +0200 Markus Armbruster wrote: > Keno Fischer writes: > > > 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 > > Acked-by: Greg Kurz > > Reviewed-by: Markus Armbruster Maybe I can take this through my 9p-next tree since it is a pre-requisite for the Darwin support series ? Keno, BTW, if you want Darwin support to go in the next QEMU release, please pay attention that I have to send a pull req for it before 2018-07-03. https://wiki.qemu.org/Planning/3.0 Cheers, -- Greg
Re: [Qemu-devel] [PATCH v5] cutils: Provide strchrnul
Greg Kurz writes: > On Wed, 13 Jun 2018 07:42:57 +0200 > Markus Armbruster wrote: > >> Keno Fischer writes: >> >> > 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 >> > Acked-by: Greg Kurz >> >> Reviewed-by: Markus Armbruster > > Maybe I can take this through my 9p-next tree since it is a pre-requisite > for the Darwin support series ? Go ahead :) [...]
Re: [Qemu-devel] [PATCH v5] cutils: Provide strchrnul
On Tue, 12 Jun 2018 23:48:31 -0400 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 > Acked-by: Greg Kurz > --- > Applied to 9p-next. You can rebase your patches against: https://github.com/gkurz/qemu/commits/9p-next Thanks! > Changes since v4: > - `CONFIG_STRCHRNUL` -> `HAVE_STRCHRNUL` name change > - In the strchrnul configure check >- Return the value of strchrnul to avoid it being optimized away >- Use `&main` (i.e. the assembly of the generated function as > the haystack) to avoid concerns about constant folding. `main` > seemed like the simplest symbol guaranteed to exist, but with > non-foldable content. > > configure | 18 ++ > hmp.c | 8 > hw/9pfs/9p-local.c| 2 +- > include/qemu/cutils.h | 8 > monitor.c | 8 ++-- > util/cutils.c | 15 +++ > util/qemu-option.c| 6 +- > util/uri.c| 6 ++ > 8 files changed, 51 insertions(+), 20 deletions(-) > > diff --git a/configure b/configure > index 14b1113..8a75745 100755 > --- a/configure > +++ b/configure > @@ -4747,6 +4747,21 @@ if compile_prog "" "" ; then > fi > > ## > +# check if we have strchrnul > + > +strchrnul=no > +cat > $TMPC << EOF > +#include > +int main(void); > +// Use a haystack that the compiler shouldn't be able to constant fold > +char *haystack = (char*)&main; > +int main(void) { return strchrnul(haystack, 'x') != &haystack[6]; } > +EOF > +if compile_prog "" "" ; then > +strchrnul=yes > +fi > + > +## > # check if trace backend exists > > $python "$source_path/scripts/tracetool.py" "--backends=$trace_backends" > --check-backends > /dev/null 2> /dev/null > @@ -6229,6 +6244,9 @@ fi > if test "$sem_timedwait" = "yes" ; then >echo "CONFIG_SEM_TIMEDWAIT=y" >> $config_host_mak > fi > +if test "$strchrnul" = "yes" ; then > + echo "HAVE_STRCHRNUL=y" >> $config_host_mak > +fi > if test "$byteswap_h" = "yes" ; then >echo "CONFIG_BYTESWAP_H=y" >> $config_host_mak > fi > diff --git a/hmp.c b/hmp.c > index ef93f48..416d4c9 100644 > --- a/hmp.c > +++ b/hmp.c > @@ -2123,12 +2123,12 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) > int has_hold_time = qdict_haskey(qdict, "hold-time"); > int hold_time = qdict_get_try_int(qdict, "hold-time", -1); > Error *err = NULL; > -char *separator; > +const char *separator; > int keyname_len; > > while (1) { > -separator = strchr(keys, '-'); > -keyname_len = separator ? separator - keys : strlen(keys); > +separator = qemu_strchrnul(keys, '-'); > +keyname_len = separator - keys; > > /* Be compatible with old interface, convert user inputted "<" */ > if (keys[0] == '<' && keyname_len == 1) { > @@ -2165,7 +2165,7 @@ void hmp_sendkey(Monitor *mon, const QDict *qdict) > keylist->value->u.qcode.data = idx; > } > > -if (!separator) { > +if (!*separator) { > break; > } > keys = separator + 1; > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c > index 5721eff..828e8d6 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..274d419 100644 > --- a/include/qemu/cutils.h > +++ b/include/qemu/cutils.h > @@ -122,6 +122,14 @@ int qemu_strnlen(const char *s, int max_len); > * Returns: the pointer originally in @input. > */ > char *qemu_strsep(char **input, const char *delim); > +#ifdef HAVE_STRCHRNUL > +static inline const char *qemu_strchrnul(const char *s, int c) > +{ > +return strchrnul(s, c); > +} > +#else > +const char *qemu_strchrnul(const char *s, int c); > +#endif > 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 6d0cec5..4484d74 100644 > --- a/monitor.c > +++ b/monitor.c > @@ -797,9 +797,7 @@ static int compare_cmd(const char *name, const char *list) > p = list; > for(;;) { > pstart = p; > -p = strchr(p, '|'); > -if (!p) > -p = pstart + strlen(pstart); > +