Re: [Qemu-devel] [PATCH 21/24] util/cutils: Let qemu_strtosz*() optionally reject trailing crap

[Dr. David Alan Gilbert]

* Markus Armbruster (arm...@redhat.com) wrote:
> "Dr. David Alan Gilbert"  writes:
> 
> > * Markus Armbruster (arm...@redhat.com) wrote:
> >> Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
> >> null and the conversion doesn't consume the string completely.
> >> Matches how qemu_strtol() & friends work.
> >> 
> >> Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
> >> change there, because its conversion consumes the string.
> >> 
> >> Simplify callers that use @endptr only to fail when it doesn't point
> >> to '\0' to pass a null @endptr instead.
> >> 
> >> Cc: Dr. David Alan Gilbert 
> >> Cc: Eduardo Habkost  (maintainer:X86)
> >> Cc: Kevin Wolf  (supporter:Block layer core)
> >> Cc: Max Reitz  (supporter:Block layer core)
> >> Cc: qemu-bl...@nongnu.org (open list:Block layer core)
> >> Signed-off-by: Markus Armbruster 
> >
> > Reviewed-by: Dr. David Alan Gilbert 
> >
> > (end and endptr are horribly confusing names in do_strtosz)
> 
> Could rename for consistency with qemu_strtol() & friends:
> 
> * Parameter @end to @endptr
> 
> * Local variable @endptr to @ep
> 
> Would that be useful?

Oh I wouldn't worry too much about it; and those perhaps aren't
that much clearer.

Dave

--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK

Re: [Qemu-devel] [PATCH 21/24] util/cutils: Let qemu_strtosz*() optionally reject trailing crap

[Markus Armbruster]

"Dr. David Alan Gilbert"  writes:

> * Markus Armbruster (arm...@redhat.com) wrote:
>> Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
>> null and the conversion doesn't consume the string completely.
>> Matches how qemu_strtol() & friends work.
>> 
>> Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
>> change there, because its conversion consumes the string.
>> 
>> Simplify callers that use @endptr only to fail when it doesn't point
>> to '\0' to pass a null @endptr instead.
>> 
>> Cc: Dr. David Alan Gilbert 
>> Cc: Eduardo Habkost  (maintainer:X86)
>> Cc: Kevin Wolf  (supporter:Block layer core)
>> Cc: Max Reitz  (supporter:Block layer core)
>> Cc: qemu-bl...@nongnu.org (open list:Block layer core)
>> Signed-off-by: Markus Armbruster 
>
> Reviewed-by: Dr. David Alan Gilbert 
>
> (end and endptr are horribly confusing names in do_strtosz)

Could rename for consistency with qemu_strtol() & friends:

* Parameter @end to @endptr

* Local variable @endptr to @ep

Would that be useful?

Re: [Qemu-devel] [PATCH 21/24] util/cutils: Let qemu_strtosz*() optionally reject trailing crap

[Dr. David Alan Gilbert]

* Markus Armbruster (arm...@redhat.com) wrote:
> Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
> null and the conversion doesn't consume the string completely.
> Matches how qemu_strtol() & friends work.
> 
> Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
> change there, because its conversion consumes the string.
> 
> Simplify callers that use @endptr only to fail when it doesn't point
> to '\0' to pass a null @endptr instead.
> 
> Cc: Dr. David Alan Gilbert 
> Cc: Eduardo Habkost  (maintainer:X86)
> Cc: Kevin Wolf  (supporter:Block layer core)
> Cc: Max Reitz  (supporter:Block layer core)
> Cc: qemu-bl...@nongnu.org (open list:Block layer core)
> Signed-off-by: Markus Armbruster 

Reviewed-by: Dr. David Alan Gilbert 

(end and endptr are horribly confusing names in do_strtosz)

> ---
>  hmp.c   |  6 ++
>  hw/misc/ivshmem.c   |  6 ++
>  qapi/opts-visitor.c |  5 ++---
>  qemu-img.c  |  7 +--
>  qemu-io-cmds.c  |  7 +--
>  target/i386/cpu.c   |  5 ++---
>  tests/test-cutils.c |  6 ++
>  util/cutils.c   | 14 +-
>  8 files changed, 25 insertions(+), 31 deletions(-)
> 
> diff --git a/hmp.c b/hmp.c
> index 6d0d05b..0eb5b6d 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -1340,7 +1340,6 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>  const char *valuestr = qdict_get_str(qdict, "value");
>  int64_t valuebw = 0;
>  long valueint = 0;
> -char *endp;
>  Error *err = NULL;
>  bool use_int_value = false;
>  int i;
> @@ -1379,9 +1378,8 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>  break;
>  case MIGRATION_PARAMETER_MAX_BANDWIDTH:
>  p.has_max_bandwidth = true;
> -valuebw = qemu_strtosz_mebi(valuestr, );
> -if (valuebw < 0 || (size_t)valuebw != valuebw
> -|| *endp != '\0') {
> +valuebw = qemu_strtosz_mebi(valuestr, NULL);
> +if (valuebw < 0 || (size_t)valuebw != valuebw) {
>  error_setg(, "Invalid size %s", valuestr);
>  goto cleanup;
>  }
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index 382dd8b..f00cd75 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -1267,10 +1267,8 @@ static void ivshmem_realize(PCIDevice *dev, Error 
> **errp)
>  if (s->sizearg == NULL) {
>  s->legacy_size = 4 << 20; /* 4 MB default */
>  } else {
> -char *end;
> -int64_t size = qemu_strtosz_mebi(s->sizearg, );
> -if (size < 0 || (size_t)size != size || *end != '\0'
> -|| !is_power_of_2(size)) {
> +int64_t size = qemu_strtosz_mebi(s->sizearg, NULL);
> +if (size < 0 || (size_t)size != size || !is_power_of_2(size)) {
>  error_setg(errp, "Invalid size %s", s->sizearg);
>  return;
>  }
> diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
> index 360d337..911a0ee 100644
> --- a/qapi/opts-visitor.c
> +++ b/qapi/opts-visitor.c
> @@ -482,15 +482,14 @@ opts_type_size(Visitor *v, const char *name, uint64_t 
> *obj, Error **errp)
>  OptsVisitor *ov = to_ov(v);
>  const QemuOpt *opt;
>  int64_t val;
> -char *endptr;
>  
>  opt = lookup_scalar(ov, name, errp);
>  if (!opt) {
>  return;
>  }
>  
> -val = qemu_strtosz(opt->str ? opt->str : "", );
> -if (val < 0 || *endptr) {
> +val = qemu_strtosz(opt->str ? opt->str : "", NULL);
> +if (val < 0) {
>  error_setg(errp, QERR_INVALID_PARAMETER_VALUE, opt->name,
> "a size value representible as a non-negative int64");
>  return;
> diff --git a/qemu-img.c b/qemu-img.c
> index 2a47966..adcb511 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -370,14 +370,9 @@ static int add_old_style_options(const char *fmt, 
> QemuOpts *opts,
>  
>  static int64_t cvtnum(const char *s)
>  {
> -char *end;
>  int64_t ret;
>  
> -ret = qemu_strtosz(s, );
> -if (*end != '\0') {
> -/* Detritus at the end of the string */
> -return -EINVAL;
> -}
> +ret = qemu_strtosz(s, NULL);
>  return ret;
>  }
>  
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index 6b7a89c..417a4e0 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -137,14 +137,9 @@ static char **breakline(char *input, int *count)
>  
>  static int64_t cvtnum(const char *s)
>  {
> -char *end;
>  int64_t ret;
>  
> -ret = qemu_strtosz(s, );
> -if (*end != '\0') {
> -/* Detritus at the end of the string */
> -return -EINVAL;
> -}
> +ret = qemu_strtosz(s, NULL);
>  return ret;
>  }
>  
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 3a8d72d..5cb0b4b 100644
> --- a/target/i386/cpu.c
> +++ 

Re: [Qemu-devel] [PATCH 21/24] util/cutils: Let qemu_strtosz*() optionally reject trailing crap

[Markus Armbruster]

Eric Blake  writes:

> On 02/14/2017 04:26 AM, Markus Armbruster wrote:
>> Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
>> null and the conversion doesn't consume the string completely.
>> Matches how qemu_strtol() & friends work.
>> 
>> Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
>> change there, because its conversion consumes the string.
>> 
>> Simplify callers that use @endptr only to fail when it doesn't point
>> to '\0' to pass a null @endptr instead.
>> 
>> Cc: Dr. David Alan Gilbert 
>> Cc: Eduardo Habkost  (maintainer:X86)
>> Cc: Kevin Wolf  (supporter:Block layer core)
>> Cc: Max Reitz  (supporter:Block layer core)
>> Cc: qemu-bl...@nongnu.org (open list:Block layer core)
>> Signed-off-by: Markus Armbruster 
>> ---
>>  hmp.c   |  6 ++
>>  hw/misc/ivshmem.c   |  6 ++
>>  qapi/opts-visitor.c |  5 ++---
>>  qemu-img.c  |  7 +--
>>  qemu-io-cmds.c  |  7 +--
>>  target/i386/cpu.c   |  5 ++---
>>  tests/test-cutils.c |  6 ++
>>  util/cutils.c   | 14 +-
>>  8 files changed, 25 insertions(+), 31 deletions(-)
>
> Nice cleanup.
>
> Reviewed-by: Eric Blake 
>
>
>> +++ b/qemu-img.c
>> @@ -370,14 +370,9 @@ static int add_old_style_options(const char *fmt, 
>> QemuOpts *opts,
>>  
>>  static int64_t cvtnum(const char *s)
>>  {
>
>> +++ b/qemu-io-cmds.c
>> @@ -137,14 +137,9 @@ static char **breakline(char *input, int *count)
>>  
>>  static int64_t cvtnum(const char *s)
>>  {
>> -char *end;
>
> Why do we reimplement cvtnum() as copied static functions instead of
> exporting it?  But that would be a separate cleanup (perhaps squashed
> into 20/24, where you use cvtnum in qemu-img).

At the end of this series, the two cvtnum() look like this:

static int64_t cvtnum(const char *s)
{
int err;
uint64_t value;

err = qemu_strtosz(s, NULL, );
if (err < 0) {
return err;
}
if (value > INT64_MAX) {
return -ERANGE;
}
return value;
}

Does two things: limit value range to 0..INT64_MAX, merge error into
value.

Perhaps their callers should simply use qemu_strtosz() directly.  I
chose not to go there to limit churn in this series.

>> @@ -217,7 +217,8 @@ static int64_t do_strtosz(const char *nptr, char **end,
>>  errno = 0;
>>  val = strtod(nptr, );
>>  if (isnan(val) || endptr == nptr || errno != 0) {
>
> Hmm - we explicitly reject "NaN", but not "infinity".  But when strtod()
> accepts infinity, ...
>
>> -goto fail;
>> +retval = -EINVAL;
>> +goto out;
>>  }
>>  fraction = modf(val, );
>
> then modf() returns 0 with integral left at infinity...
>
>>  if (fraction != 0) {
>> @@ -232,17 +233,20 @@ static int64_t do_strtosz(const char *nptr, char **end,
>>  assert(mul >= 0);
>>  }
>>  if (mul == 1 && mul_required) {
>> -goto fail;
>> +retval = -EINVAL;
>> +goto out;
>>  }
>>  if ((val * mul >= INT64_MAX) || val < 0) {
>
> ...and the multiply exceeds INT64_MAX, so we still end up rejecting it
> (with ERANGE instead of EINVAL).  Weird way but seems to work, and is
> pre-existing, so not this patch's problem.

Yes.

We could easily check !isfinite() rather than isnan(), but then we'd get
-EINVAL rather than -ERANGE for infinities.  Matter of taste, I guess.

Re: [Qemu-devel] [PATCH 21/24] util/cutils: Let qemu_strtosz*() optionally reject trailing crap

[Eric Blake]

On 02/14/2017 04:26 AM, Markus Armbruster wrote:
> Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
> null and the conversion doesn't consume the string completely.
> Matches how qemu_strtol() & friends work.
> 
> Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
> change there, because its conversion consumes the string.
> 
> Simplify callers that use @endptr only to fail when it doesn't point
> to '\0' to pass a null @endptr instead.
> 
> Cc: Dr. David Alan Gilbert 
> Cc: Eduardo Habkost  (maintainer:X86)
> Cc: Kevin Wolf  (supporter:Block layer core)
> Cc: Max Reitz  (supporter:Block layer core)
> Cc: qemu-bl...@nongnu.org (open list:Block layer core)
> Signed-off-by: Markus Armbruster 
> ---
>  hmp.c   |  6 ++
>  hw/misc/ivshmem.c   |  6 ++
>  qapi/opts-visitor.c |  5 ++---
>  qemu-img.c  |  7 +--
>  qemu-io-cmds.c  |  7 +--
>  target/i386/cpu.c   |  5 ++---
>  tests/test-cutils.c |  6 ++
>  util/cutils.c   | 14 +-
>  8 files changed, 25 insertions(+), 31 deletions(-)

Nice cleanup.

Reviewed-by: Eric Blake 


> +++ b/qemu-img.c
> @@ -370,14 +370,9 @@ static int add_old_style_options(const char *fmt, 
> QemuOpts *opts,
>  
>  static int64_t cvtnum(const char *s)
>  {

> +++ b/qemu-io-cmds.c
> @@ -137,14 +137,9 @@ static char **breakline(char *input, int *count)
>  
>  static int64_t cvtnum(const char *s)
>  {
> -char *end;

Why do we reimplement cvtnum() as copied static functions instead of
exporting it?  But that would be a separate cleanup (perhaps squashed
into 20/24, where you use cvtnum in qemu-img).

> @@ -217,7 +217,8 @@ static int64_t do_strtosz(const char *nptr, char **end,
>  errno = 0;
>  val = strtod(nptr, );
>  if (isnan(val) || endptr == nptr || errno != 0) {

Hmm - we explicitly reject "NaN", but not "infinity".  But when strtod()
accepts infinity, ...

> -goto fail;
> +retval = -EINVAL;
> +goto out;
>  }
>  fraction = modf(val, );

then modf() returns 0 with integral left at infinity...

>  if (fraction != 0) {
> @@ -232,17 +233,20 @@ static int64_t do_strtosz(const char *nptr, char **end,
>  assert(mul >= 0);
>  }
>  if (mul == 1 && mul_required) {
> -goto fail;
> +retval = -EINVAL;
> +goto out;
>  }
>  if ((val * mul >= INT64_MAX) || val < 0) {

...and the multiply exceeds INT64_MAX, so we still end up rejecting it
(with ERANGE instead of EINVAL).  Weird way but seems to work, and is
pre-existing, so not this patch's problem.

-- 
Eric Blake   eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org



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