Re: [Qemu-devel] [PATCH v2 01/20] cutils: Provide strchrnul

[Dr. David Alan Gilbert]

* Greg Kurz (address@hidden) wrote:
> On Thu, 31 May 2018 21:25:56 -0400
> Keno Fischer <address@hidden> 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 <address@hidden>
> > ---
> > 
> 
> 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 <address@hidden> (supporter:virtio-9p)
> Markus Armbruster <address@hidden> (supporter:QMP)
> "Dr. David Alan Gilbert" <address@hidden> (maintainer:Human Monitor (HMP))
> address@hidden (open list:All patches CC here)
> 
> Anyway,
> 
> Acked-by: Greg Kurz <address@hidden>
> 
> > 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 / address@hidden / Manchester, UK