[1/8,v4] cutils: unsigned int parsing functions

There are lots of duplicate parsing code using strto*() in QEMU, and
most of that code is broken in one way or another. Even the visitors
code have duplicate integer parsing code[1]. This introduces functions
to help parsing unsigned int values: parse_uint() and parse_uint_full().

Parsing functions for signed ints and floats will be submitted later.

parse_uint_full() has all the checks made by opts_type_uint64() at
opts-visitor.c:

 - Check for NULL (returns -EINVAL)
 - Check for negative numbers (returns -ERANGE)
 - Check for empty string (returns -EINVAL)
 - Check for overflow or other errno values set by strtoll() (returns
   -errno)
 - Check for end of string (reject invalid characters after number)
   (returns -EINVAL)

parse_uint() does everything above except checking for the end of the
string, so callers can continue parsing the remainder of string after
the number.

Unit tests included.

[1] string-input-visitor.c:parse_int() could use the same parsing code
    used by opts-visitor.c:opts_type_int(), instead of duplicating that
    logic.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Changes v2:
 - Trivial whitespace change
 - Add 'base' parameter to the functions

Changes v4:
 - Return -EINVAL in case a minus sign is found
 - Make endptr point to beginning of string in case -EINVAL
   is returned (like the strtoull() behavior)

v3->v4 interdiff:

    diff --git a/tests/test-cutils.c b/tests/test-cutils.c
    index f4f6951..f8395f4 100644
    --- a/tests/test-cutils.c
    +++ b/tests/test-cutils.c
    @@ -61,6 +61,22 @@ static void test_parse_uint_empty(void)
         g_assert(endptr == str);
     }
     
    +static void test_parse_uint_invalid(void)
    +{
    +    unsigned long long i = 999;
    +    char f = 'X';
    +    char *endptr = &f;
    +    const char *str = " \t xxx";
    +    int r;
    +
    +    r = parse_uint(str, &i, &endptr, 0);
    +
    +    g_assert_cmpint(r, ==, -EINVAL);
    +    g_assert_cmpint(i, ==, 0);
    +    g_assert(endptr == str);
    +}
    +
    +
     static void test_parse_uint_trailing(void)
     {
         unsigned long long i = 999;
    @@ -164,9 +180,9 @@ static void test_parse_uint_negative(void)
     
         r = parse_uint(str, &i, &endptr, 0);
     
    -    g_assert_cmpint(r, ==, -ERANGE);
    +    g_assert_cmpint(r, ==, -EINVAL);
         g_assert_cmpint(i, ==, 0);
    -    g_assert(endptr == str + 3);
    +    g_assert(endptr == str);
     }
     
     
    @@ -200,6 +216,7 @@ int main(int argc, char **argv)
     
         g_test_add_func("/cutils/parse_uint/null", test_parse_uint_null);
         g_test_add_func("/cutils/parse_uint/empty", test_parse_uint_empty);
    +    g_test_add_func("/cutils/parse_uint/invalid", test_parse_uint_invalid);
         g_test_add_func("/cutils/parse_uint/trailing", test_parse_uint_trailing);
         g_test_add_func("/cutils/parse_uint/correct", test_parse_uint_correct);
         g_test_add_func("/cutils/parse_uint/octal", test_parse_uint_octal);
    diff --git a/util/cutils.c b/util/cutils.c
    index 7f09251..ce80a2a 100644
    --- a/util/cutils.c
    +++ b/util/cutils.c
    @@ -278,7 +278,7 @@ int64_t strtosz(const char *nptr, char **end)
      * - Overflow errors or other errno values  set by strtoull() will
      *   return -errno (-ERANGE in case of overflow).
      * - Differently from strtoull(), values starting with a minus sign are
    - *   rejected (returning -ERANGE).
    + *   rejected (returning -EINVAL).
      *
      * Sets endptr to point to the first invalid character. Callers may rely
      * on *value and *endptr to be always set by the function, even in case of
    @@ -294,6 +294,7 @@ int parse_uint(const char *s, unsigned long long *value, char **endptr,
         int r = 0;
         char *endp = (char *)s;
         unsigned long long val = 0;
    +    const char *sp;
     
         if (!s) {
             r = -EINVAL;
    @@ -301,11 +302,12 @@ int parse_uint(const char *s, unsigned long long *value, char **endptr,
         }
     
         /* make sure we reject negative numbers: */
    -    while (isspace((unsigned char)*s)) {
    -        ++s; endp++;
    +    sp = s;
    +    while (isspace((unsigned char)*sp)) {
    +        ++sp;
         }
    -    if (*s == '-') {
    -        r = -ERANGE;
    +    if (*sp == '-') {
    +        r = -EINVAL;
             goto out;
         }

---
 include/qemu-common.h |   4 +
 tests/Makefile        |   3 +
 tests/test-cutils.c   | 233 ++++++++++++++++++++++++++++++++++++++++++++++++++
 util/cutils.c         |  81 ++++++++++++++++++
 4 files changed, 321 insertions(+)
 create mode 100644 tests/test-cutils.c

On Thu, Jan 17, 2013 at 05:06:50PM -0200, Eduardo Habkost wrote:
> There are lots of duplicate parsing code using strto*() in QEMU, and
> most of that code is broken in one way or another. Even the visitors
> code have duplicate integer parsing code[1]. This introduces functions
> to help parsing unsigned int values: parse_uint() and parse_uint_full().
> 
> Parsing functions for signed ints and floats will be submitted later.
> 
> parse_uint_full() has all the checks made by opts_type_uint64() at
> opts-visitor.c:
> 
>  - Check for NULL (returns -EINVAL)
>  - Check for negative numbers (returns -ERANGE)

Oops, I forgot to update the commit message. I hope the commiter can
change it before committing, to avoid having to resubmit it again.


>  - Check for empty string (returns -EINVAL)
>  - Check for overflow or other errno values set by strtoll() (returns
>    -errno)
>  - Check for end of string (reject invalid characters after number)
>    (returns -EINVAL)
> 
> parse_uint() does everything above except checking for the end of the
> string, so callers can continue parsing the remainder of string after
> the number.
> 
> Unit tests included.
> 
> [1] string-input-visitor.c:parse_int() could use the same parsing code
>     used by opts-visitor.c:opts_type_int(), instead of duplicating that
>     logic.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v2:
>  - Trivial whitespace change
>  - Add 'base' parameter to the functions
> 
> Changes v4:
>  - Return -EINVAL in case a minus sign is found
>  - Make endptr point to beginning of string in case -EINVAL
>    is returned (like the strtoull() behavior)
[...]

On 01/17/13 20:06, Eduardo Habkost wrote:

> Changes v4:
>  - Return -EINVAL in case a minus sign is found
>  - Make endptr point to beginning of string in case -EINVAL
>    is returned (like the strtoull() behavior)

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

On 01/17/2013 12:06 PM, Eduardo Habkost wrote:
> There are lots of duplicate parsing code using strto*() in QEMU, and
> most of that code is broken in one way or another. Even the visitors
> code have duplicate integer parsing code[1]. This introduces functions
> to help parsing unsigned int values: parse_uint() and parse_uint_full().
> 
> Parsing functions for signed ints and floats will be submitted later.
> 

> 
> Changes v4:
>  - Return -EINVAL in case a minus sign is found
>  - Make endptr point to beginning of string in case -EINVAL
>    is returned (like the strtoull() behavior)
> 
> v3->v4 interdiff:

Thanks; that helped review.

The rest of the series needs no modifications to enjoy the improvements
of this v4 patch.

Reviewed-by: Eric Blake <eblake@redhat.com>

On Thu, Jan 17, 2013 at 7:06 PM, Eduardo Habkost <ehabkost@redhat.com> wrote:
> There are lots of duplicate parsing code using strto*() in QEMU, and
> most of that code is broken in one way or another. Even the visitors
> code have duplicate integer parsing code[1]. This introduces functions
> to help parsing unsigned int values: parse_uint() and parse_uint_full().
>
> Parsing functions for signed ints and floats will be submitted later.
>
> parse_uint_full() has all the checks made by opts_type_uint64() at
> opts-visitor.c:
>
>  - Check for NULL (returns -EINVAL)
>  - Check for negative numbers (returns -ERANGE)
>  - Check for empty string (returns -EINVAL)
>  - Check for overflow or other errno values set by strtoll() (returns
>    -errno)
>  - Check for end of string (reject invalid characters after number)
>    (returns -EINVAL)
>
> parse_uint() does everything above except checking for the end of the
> string, so callers can continue parsing the remainder of string after
> the number.
>
> Unit tests included.

I think it would be pretty cool if we also used a string fuzzer to
check the robustness of string parsers.

>
> [1] string-input-visitor.c:parse_int() could use the same parsing code
>     used by opts-visitor.c:opts_type_int(), instead of duplicating that
>     logic.
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v2:
>  - Trivial whitespace change
>  - Add 'base' parameter to the functions
>
> Changes v4:
>  - Return -EINVAL in case a minus sign is found
>  - Make endptr point to beginning of string in case -EINVAL
>    is returned (like the strtoull() behavior)
>
> v3->v4 interdiff:
>
>     diff --git a/tests/test-cutils.c b/tests/test-cutils.c
>     index f4f6951..f8395f4 100644
>     --- a/tests/test-cutils.c
>     +++ b/tests/test-cutils.c
>     @@ -61,6 +61,22 @@ static void test_parse_uint_empty(void)
>          g_assert(endptr == str);
>      }
>
>     +static void test_parse_uint_invalid(void)
>     +{
>     +    unsigned long long i = 999;
>     +    char f = 'X';
>     +    char *endptr = &f;
>     +    const char *str = " \t xxx";
>     +    int r;
>     +
>     +    r = parse_uint(str, &i, &endptr, 0);
>     +
>     +    g_assert_cmpint(r, ==, -EINVAL);
>     +    g_assert_cmpint(i, ==, 0);
>     +    g_assert(endptr == str);
>     +}
>     +
>     +
>      static void test_parse_uint_trailing(void)
>      {
>          unsigned long long i = 999;
>     @@ -164,9 +180,9 @@ static void test_parse_uint_negative(void)
>
>          r = parse_uint(str, &i, &endptr, 0);
>
>     -    g_assert_cmpint(r, ==, -ERANGE);
>     +    g_assert_cmpint(r, ==, -EINVAL);
>          g_assert_cmpint(i, ==, 0);
>     -    g_assert(endptr == str + 3);
>     +    g_assert(endptr == str);
>      }
>
>
>     @@ -200,6 +216,7 @@ int main(int argc, char **argv)
>
>          g_test_add_func("/cutils/parse_uint/null", test_parse_uint_null);
>          g_test_add_func("/cutils/parse_uint/empty", test_parse_uint_empty);
>     +    g_test_add_func("/cutils/parse_uint/invalid", test_parse_uint_invalid);
>          g_test_add_func("/cutils/parse_uint/trailing", test_parse_uint_trailing);
>          g_test_add_func("/cutils/parse_uint/correct", test_parse_uint_correct);
>          g_test_add_func("/cutils/parse_uint/octal", test_parse_uint_octal);
>     diff --git a/util/cutils.c b/util/cutils.c
>     index 7f09251..ce80a2a 100644
>     --- a/util/cutils.c
>     +++ b/util/cutils.c
>     @@ -278,7 +278,7 @@ int64_t strtosz(const char *nptr, char **end)
>       * - Overflow errors or other errno values  set by strtoull() will
>       *   return -errno (-ERANGE in case of overflow).
>       * - Differently from strtoull(), values starting with a minus sign are
>     - *   rejected (returning -ERANGE).
>     + *   rejected (returning -EINVAL).
>       *
>       * Sets endptr to point to the first invalid character. Callers may rely
>       * on *value and *endptr to be always set by the function, even in case of
>     @@ -294,6 +294,7 @@ int parse_uint(const char *s, unsigned long long *value, char **endptr,
>          int r = 0;
>          char *endp = (char *)s;
>          unsigned long long val = 0;
>     +    const char *sp;
>
>          if (!s) {
>              r = -EINVAL;
>     @@ -301,11 +302,12 @@ int parse_uint(const char *s, unsigned long long *value, char **endptr,
>          }
>
>          /* make sure we reject negative numbers: */
>     -    while (isspace((unsigned char)*s)) {
>     -        ++s; endp++;
>     +    sp = s;
>     +    while (isspace((unsigned char)*sp)) {
>     +        ++sp;
>          }
>     -    if (*s == '-') {
>     -        r = -ERANGE;
>     +    if (*sp == '-') {
>     +        r = -EINVAL;
>              goto out;
>          }
>
> ---
>  include/qemu-common.h |   4 +
>  tests/Makefile        |   3 +
>  tests/test-cutils.c   | 233 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  util/cutils.c         |  81 ++++++++++++++++++
>  4 files changed, 321 insertions(+)
>  create mode 100644 tests/test-cutils.c
>
> diff --git a/include/qemu-common.h b/include/qemu-common.h
> index ca464bb..f134629 100644
> --- a/include/qemu-common.h
> +++ b/include/qemu-common.h
> @@ -170,6 +170,10 @@ int qemu_fdatasync(int fd);
>  int fcntl_setfl(int fd, int flag);
>  int qemu_parse_fd(const char *param);
>
> +int parse_uint(const char *s, unsigned long long *value, char **endptr,
> +               int base);
> +int parse_uint_full(const char *s, unsigned long long *value, int base);
> +
>  /*
>   * strtosz() suffixes used to specify the default treatment of an
>   * argument passed to strtosz() without an explicit suffix.
> diff --git a/tests/Makefile b/tests/Makefile
> index d86e95a..e5929cd 100644
> --- a/tests/Makefile
> +++ b/tests/Makefile
> @@ -45,6 +45,8 @@ gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
>  gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
>  check-unit-y += tests/test-thread-pool$(EXESUF)
>  gcov-files-test-thread-pool-y = thread-pool.c
> +check-unit-y += tests/test-cutils$(EXESUF)
> +gcov-files-test-cutils-y += util/cutils.c
>
>  check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
>
> @@ -86,6 +88,7 @@ tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(block-obj-y) libqemuutil
>  tests/test-aio$(EXESUF): tests/test-aio.o $(block-obj-y) libqemuutil.a libqemustub.a
>  tests/test-thread-pool$(EXESUF): tests/test-thread-pool.o $(block-obj-y) libqemuutil.a libqemustub.a
>  tests/test-iov$(EXESUF): tests/test-iov.o libqemuutil.a
> +tests/test-cutils$(EXESUF): tests/test-cutils.o util/cutils.o
>
>  tests/test-qapi-types.c tests/test-qapi-types.h :\
>  $(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-types.py
> diff --git a/tests/test-cutils.c b/tests/test-cutils.c
> new file mode 100644
> index 0000000..f8395f4
> --- /dev/null
> +++ b/tests/test-cutils.c
> @@ -0,0 +1,233 @@
> +/*
> + * cutils.c unit-tests
> + *
> + * Copyright (C) 2013 Red Hat Inc.
> + *
> + * Authors:
> + *  Eduardo Habkost <ehabkost@redhat.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include <glib.h>
> +#include <errno.h>
> +#include <string.h>
> +
> +#include "qemu-common.h"
> +
> +
> +static void test_parse_uint_null(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    int r;
> +
> +    r = parse_uint(NULL, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, -EINVAL);
> +    g_assert_cmpint(i, ==, 0);
> +    g_assert(endptr == NULL);
> +}
> +
> +static void test_parse_uint_empty(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, -EINVAL);
> +    g_assert_cmpint(i, ==, 0);
> +    g_assert(endptr == str);
> +}
> +
> +static void test_parse_uint_invalid(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = " \t xxx";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, -EINVAL);
> +    g_assert_cmpint(i, ==, 0);
> +    g_assert(endptr == str);
> +}
> +
> +
> +static void test_parse_uint_trailing(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "123xxx";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, 123);
> +    g_assert(endptr == str + 3);
> +}
> +
> +static void test_parse_uint_correct(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "123";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, 123);
> +    g_assert(endptr == str + strlen(str));
> +}
> +
> +static void test_parse_uint_octal(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "0123";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, 0123);
> +    g_assert(endptr == str + strlen(str));
> +}
> +
> +static void test_parse_uint_decimal(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "0123";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 10);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, 123);
> +    g_assert(endptr == str + strlen(str));
> +}
> +
> +
> +static void test_parse_uint_llong_max(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    char *str = g_strdup_printf("%llu", (unsigned long long)LLONG_MAX + 1);
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, (unsigned long long)LLONG_MAX + 1);
> +    g_assert(endptr == str + strlen(str));
> +
> +    g_free(str);
> +}
> +
> +static void test_parse_uint_overflow(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = "99999999999999999999999999999999999999";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, -ERANGE);
> +    g_assert_cmpint(i, ==, ULLONG_MAX);
> +    g_assert(endptr == str + strlen(str));
> +}
> +
> +static void test_parse_uint_negative(void)
> +{
> +    unsigned long long i = 999;
> +    char f = 'X';
> +    char *endptr = &f;
> +    const char *str = " \t -321";
> +    int r;
> +
> +    r = parse_uint(str, &i, &endptr, 0);
> +
> +    g_assert_cmpint(r, ==, -EINVAL);
> +    g_assert_cmpint(i, ==, 0);
> +    g_assert(endptr == str);
> +}
> +
> +
> +static void test_parse_uint_full_trailing(void)
> +{
> +    unsigned long long i = 999;
> +    const char *str = "123xxx";
> +    int r;
> +
> +    r = parse_uint_full(str, &i, 0);
> +
> +    g_assert_cmpint(r, ==, -EINVAL);
> +    g_assert_cmpint(i, ==, 123);
> +}
> +
> +static void test_parse_uint_full_correct(void)
> +{
> +    unsigned long long i = 999;
> +    const char *str = "123";
> +    int r;
> +
> +    r = parse_uint_full(str, &i, 0);
> +
> +    g_assert_cmpint(r, ==, 0);
> +    g_assert_cmpint(i, ==, 123);
> +}
> +
> +int main(int argc, char **argv)
> +{
> +    g_test_init(&argc, &argv, NULL);
> +
> +    g_test_add_func("/cutils/parse_uint/null", test_parse_uint_null);
> +    g_test_add_func("/cutils/parse_uint/empty", test_parse_uint_empty);
> +    g_test_add_func("/cutils/parse_uint/invalid", test_parse_uint_invalid);
> +    g_test_add_func("/cutils/parse_uint/trailing", test_parse_uint_trailing);
> +    g_test_add_func("/cutils/parse_uint/correct", test_parse_uint_correct);
> +    g_test_add_func("/cutils/parse_uint/octal", test_parse_uint_octal);
> +    g_test_add_func("/cutils/parse_uint/decimal", test_parse_uint_decimal);
> +    g_test_add_func("/cutils/parse_uint/llong_max", test_parse_uint_llong_max);
> +    g_test_add_func("/cutils/parse_uint/overflow", test_parse_uint_overflow);
> +    g_test_add_func("/cutils/parse_uint/negative", test_parse_uint_negative);
> +    g_test_add_func("/cutils/parse_uint_full/trailing",
> +                    test_parse_uint_full_trailing);
> +    g_test_add_func("/cutils/parse_uint_full/correct",
> +                    test_parse_uint_full_correct);
> +
> +    return g_test_run();
> +}
> diff --git a/util/cutils.c b/util/cutils.c
> index 80bb1dc..ce80a2a 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -270,6 +270,87 @@ int64_t strtosz(const char *nptr, char **end)
>      return strtosz_suffix(nptr, end, STRTOSZ_DEFSUFFIX_MB);
>  }
>
> +/* Try to parse an unsigned integer
> + *
> + * Error checks done by the function:
> + * - NULL pointer will return -EINVAL.
> + * - Empty strings will return -EINVAL.
> + * - Overflow errors or other errno values  set by strtoull() will
> + *   return -errno (-ERANGE in case of overflow).
> + * - Differently from strtoull(), values starting with a minus sign are
> + *   rejected (returning -EINVAL).
> + *
> + * Sets endptr to point to the first invalid character. Callers may rely
> + * on *value and *endptr to be always set by the function, even in case of
> + * errors.
> + *
> + * The 'base' parameter has the same meaning of 'base' on strtoull().
> + *
> + * Returns 0 on success, negative errno value on error.
> + */
> +int parse_uint(const char *s, unsigned long long *value, char **endptr,
> +               int base)
> +{
> +    int r = 0;
> +    char *endp = (char *)s;
> +    unsigned long long val = 0;
> +    const char *sp;
> +
> +    if (!s) {
> +        r = -EINVAL;
> +        goto out;
> +    }
> +
> +    /* make sure we reject negative numbers: */
> +    sp = s;
> +    while (isspace((unsigned char)*sp)) {
> +        ++sp;
> +    }
> +    if (*sp == '-') {
> +        r = -EINVAL;
> +        goto out;
> +    }
> +
> +    errno = 0;
> +    val = strtoull(s, &endp, base);
> +    if (errno) {
> +        r = -errno;
> +        goto out;
> +    }
> +
> +    if (endp == s) {
> +        r = -EINVAL;
> +        goto out;
> +    }
> +
> +out:
> +    *value = val;
> +    *endptr = endp;
> +    return r;
> +}
> +
> +/* Try to parse an unsigned integer, making sure the whole string is parsed
> + *
> + * Have the same behavior of parse_uint(), but with an additional check
> + * for additional data after the parsed number (in that case, the function
> + * will return -EINVAL).
> + */
> +int parse_uint_full(const char *s, unsigned long long *value, int base)
> +{
> +    char *endp;
> +    int r;
> +
> +    r = parse_uint(s, value, &endp, base);
> +    if (r < 0) {
> +        return r;
> +    }
> +    if (*endp) {
> +        return -EINVAL;
> +    }
> +
> +    return 0;
> +}
> +
>  int qemu_parse_fd(const char *param)
>  {
>      int fd;
> --
> 1.7.11.7
>
>