On Tue, 12 Jun 2018 23:48:31 -0400 Keno Fischer <k...@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 <k...@juliacomputing.com> > Acked-by: Greg Kurz <gr...@kaod.org> > --- > 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 <string.h> > +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; > if (len > sizeof(cmd) - 2) > len = sizeof(cmd) - 2; > diff --git a/util/cutils.c b/util/cutils.c > index 0de69e6..9205e09 100644 > --- a/util/cutils.c > +++ b/util/cutils.c > @@ -545,6 +545,21 @@ 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. > + */ > +#ifndef HAVE_STRCHRNUL > +const char *qemu_strchrnul(const char *s, int c) > +{ > + const char *e = strchr(s, c); > + if (!e) { > + e = s + strlen(s); > + } > + return e; > +} > +#endif > + > +/** > * 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. */
