| Message ID | 1249291608-14766-1-git-send-email-kraxel@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
Gerd Hoffmann <kraxel@redhat.com> writes: > snprintf returns number of bytes needed for the output, not the number > of bytes actually written. Thus the math is wrong ... > > Spotted by Markus Armbruster. > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> > --- > hw/qdev.c | 26 +++++++++++++++++--------- > 1 files changed, 17 insertions(+), 9 deletions(-) > > diff --git a/hw/qdev.c b/hw/qdev.c > index 9488dba..fc95115 100644 > --- a/hw/qdev.c > +++ b/hw/qdev.c > @@ -108,15 +108,23 @@ DeviceState *qdev_create(BusState *bus, const char *name) > static int qdev_print_devinfo(DeviceInfo *info, char *dest, int len) > { > int pos = 0; > + int ret; > > - pos += snprintf(dest+pos, len-pos, "name \"%s\", bus %s", > - info->name, info->bus_info->name); > - if (info->alias) > - pos += snprintf(dest+pos, len-pos, ", alias \"%s\"", info->alias); > - if (info->desc) > - pos += snprintf(dest+pos, len-pos, ", desc \"%s\"", info->desc); > - if (info->no_user) > - pos += snprintf(dest+pos, len-pos, ", no-user"); > + ret = snprintf(dest+pos, len-pos, "name \"%s\", bus %s", > + info->name, info->bus_info->name); > + pos += MIN(len-pos,ret); > + if (info->alias) { > + ret = snprintf(dest+pos, len-pos, ", alias \"%s\"", info->alias); > + pos += MIN(len-pos,ret); > + } > + if (info->desc) { > + ret = snprintf(dest+pos, len-pos, ", desc \"%s\"", info->desc); > + pos += MIN(len-pos,ret); > + } > + if (info->no_user) { > + ret = snprintf(dest+pos, len-pos, ", no-user"); > + pos += MIN(len-pos,ret); > + } > return pos; > } Looks good. For a general purpose formatting function, I'd return how much buffer is needed to avoid truncation, just like snprintf(), to let the caller resize its buffer. But qdev_print_devinfo()'s callers don't care.
diff --git a/hw/qdev.c b/hw/qdev.c index 9488dba..fc95115 100644 --- a/hw/qdev.c +++ b/hw/qdev.c @@ -108,15 +108,23 @@ DeviceState *qdev_create(BusState *bus, const char *name) static int qdev_print_devinfo(DeviceInfo *info, char *dest, int len) { int pos = 0; + int ret; - pos += snprintf(dest+pos, len-pos, "name \"%s\", bus %s", - info->name, info->bus_info->name); - if (info->alias) - pos += snprintf(dest+pos, len-pos, ", alias \"%s\"", info->alias); - if (info->desc) - pos += snprintf(dest+pos, len-pos, ", desc \"%s\"", info->desc); - if (info->no_user) - pos += snprintf(dest+pos, len-pos, ", no-user"); + ret = snprintf(dest+pos, len-pos, "name \"%s\", bus %s", + info->name, info->bus_info->name); + pos += MIN(len-pos,ret); + if (info->alias) { + ret = snprintf(dest+pos, len-pos, ", alias \"%s\"", info->alias); + pos += MIN(len-pos,ret); + } + if (info->desc) { + ret = snprintf(dest+pos, len-pos, ", desc \"%s\"", info->desc); + pos += MIN(len-pos,ret); + } + if (info->no_user) { + ret = snprintf(dest+pos, len-pos, ", no-user"); + pos += MIN(len-pos,ret); + } return pos; }
snprintf returns number of bytes needed for the output, not the number of bytes actually written. Thus the math is wrong ... Spotted by Markus Armbruster. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> --- hw/qdev.c | 26 +++++++++++++++++--------- 1 files changed, 17 insertions(+), 9 deletions(-)