Patchwork [2/5] Support human unit formats in strtobytes, eg. 1.0G

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Submitter Jes Sorensen
Date Sept. 16, 2010, 2:52 p.m.
Message ID <1284648749-18479-3-git-send-email-Jes.Sorensen@redhat.com>
Download mbox | patch
Permalink /patch/64980/
State New
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Comments

Jes Sorensen - Sept. 16, 2010, 2:52 p.m.
From: Jes Sorensen <Jes.Sorensen@redhat.com>

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 cutils.c |   34 ++++++++++++++++++++++++++--------
 1 files changed, 26 insertions(+), 8 deletions(-)
Markus Armbruster - Sept. 28, 2010, 9:56 a.m.
Jes.Sorensen@redhat.com writes:

> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  cutils.c |   34 ++++++++++++++++++++++++++--------
>  1 files changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/cutils.c b/cutils.c
> index dabbed4..67767a9 100644
> --- a/cutils.c
> +++ b/cutils.c
> @@ -259,34 +259,52 @@ int fcntl_setfl(int fd, int flag)
>   */
>  uint64_t strtobytes(const char *nptr, char **end)
>  {
> -    uint64_t value;
> +    uint64_t retval = 0;
>      char *endptr;
> +    int mul_required = 0;
> +    double val, mul = 1;
> +
> +    endptr = (char *)nptr + strspn(nptr, " 0123456789");
> +    if (*endptr == '.') {
> +        mul_required = 1;
> +    }
> +
> +    val = strtod(nptr, &endptr);
> +
> +    if (val < 0)
> +        goto fail;

I pointed out several problems with the use of strtoull() in PATCH 1/5,
and now you go ahead and switch over to strtod() in PATCH 2/5.  Gee,
thanks!  For penance, I want you to peruse strtod(3) and figure out its
correct usage ;)

>  
> -    value = strtoll(nptr, &endptr, 0);
>      switch (*endptr++) {
>      case 'K':
>      case 'k':
> -        value <<= 10;
> +        mul = 1 << 10;
>          break;
>      case 0:
> +    case ' ':
> +        if (mul_required) {
> +            goto fail;
> +        }

I wouldn't have bothered catching this case.  Instead, I'd have checked
that the final conversion to uint64_t is exact.  But since you coded it
already, feel free to keep it.

>      case 'M':
>      case 'm':
> -        value <<= 20;
> +        mul = 1ULL << 20;
>          break;
>      case 'G':
>      case 'g':
> -        value <<= 30;
> +        mul = 1ULL << 30;
>          break;
>      case 'T':
>      case 't':
> -        value <<= 40;
> +        mul = 1ULL << 40;
>          break;
>      default:
> -        value = 0;
> +        goto fail;
>      }
>  
> +    retval = (uint64_t)(val * mul);
> +

What if the conversion overflows uint64_t?  Shouldn't we catch that?

>      if (end)
>          *end = endptr;
>  
> -    return value;
> +fail:
> +    return retval;
>  }

Patch

diff --git a/cutils.c b/cutils.c
index dabbed4..67767a9 100644
--- a/cutils.c
+++ b/cutils.c
@@ -259,34 +259,52 @@  int fcntl_setfl(int fd, int flag)
  */
 uint64_t strtobytes(const char *nptr, char **end)
 {
-    uint64_t value;
+    uint64_t retval = 0;
     char *endptr;
+    int mul_required = 0;
+    double val, mul = 1;
+
+    endptr = (char *)nptr + strspn(nptr, " 0123456789");
+    if (*endptr == '.') {
+        mul_required = 1;
+    }
+
+    val = strtod(nptr, &endptr);
+
+    if (val < 0)
+        goto fail;
 
-    value = strtoll(nptr, &endptr, 0);
     switch (*endptr++) {
     case 'K':
     case 'k':
-        value <<= 10;
+        mul = 1 << 10;
         break;
     case 0:
+    case ' ':
+        if (mul_required) {
+            goto fail;
+        }
     case 'M':
     case 'm':
-        value <<= 20;
+        mul = 1ULL << 20;
         break;
     case 'G':
     case 'g':
-        value <<= 30;
+        mul = 1ULL << 30;
         break;
     case 'T':
     case 't':
-        value <<= 40;
+        mul = 1ULL << 40;
         break;
     default:
-        value = 0;
+        goto fail;
     }
 
+    retval = (uint64_t)(val * mul);
+
     if (end)
         *end = endptr;
 
-    return value;
+fail:
+    return retval;
 }