Patchwork [1/8] cutils: unsigned int parsing functions

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Submitter Eduardo Habkost
Date Jan. 16, 2013, 3:24 p.m.
Message ID <1358349851-20960-2-git-send-email-ehabkost@redhat.com>
Download mbox | patch
Permalink /patch/212938/
State New
Headers show

Comments

Eduardo Habkost - Jan. 16, 2013, 3:24 p.m.
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>
---
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
---
 include/qemu-common.h |   3 +
 tests/Makefile        |   3 +
 tests/test-cutils.c   | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++
 util/cutils.c         |  76 +++++++++++++++++++++
 4 files changed, 265 insertions(+)
 create mode 100644 tests/test-cutils.c
Eduardo Habkost - Jan. 16, 2013, 5:33 p.m.
On Wed, Jan 16, 2013 at 10:10:42AM -0700, Eric Blake wrote:
> On 01/16/2013 08:24 AM, 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)
> >  - 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>
> > ---
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Eric Blake <eblake@redhat.com>
> > ---
> 
> > +++ b/tests/test-cutils.c
> 
> > + *
> > + * Permission is hereby granted, free of charge, to any person obtaining a copy
> 
> Interesting that you chose a BSD license instead of GPL, but doesn't
> affect my review.

It's a personal preference, but by coincidence is also the license of
cutils.c.

> 
> Your test case lacks test of octal or hexadecimal input strings; is that
> worth adding?

I believe I trust strtoll() enough to not require tests for those cases.
Just like I didn't add tests involving trailing spaces or tabs, except
on the negative-number test case.


> > +++ b/util/cutils.c
> > @@ -270,6 +270,82 @@ 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 -ERANGE).
> 
> Interesting that you chose to reject negative numbers, even though
> strtoull() is required to accept them.  But you documented it and tested
> for it, so I can live with it.

I find this behavior of strtoull() confusing for users. If an
option/field requires positive numbers, I expect QEMU to reject "-1"
instead of silently converting it to ULLONG_MAX.

> 
> > +    errno = 0;
> > +    val = strtoull(s, &endp, 0);
> > +    if (errno) {
> > +        r =  -errno;
> 
> Why two spaces?

Typo. I will send a fixed version (keeping your Reviewed-by, if you
don't mind).

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

Thanks!

Patch

diff --git a/include/qemu-common.h b/include/qemu-common.h
index ca464bb..83f89fd 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -170,6 +170,9 @@  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 parse_uint_full(const char *s, unsigned long long *value);
+
 /*
  * 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 d97a571..2dba3e5 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
 
@@ -84,6 +86,7 @@  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..d573eb1
--- /dev/null
+++ b/tests/test-cutils.c
@@ -0,0 +1,183 @@ 
+/*
+ * 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);
+
+    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);
+
+    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);
+
+    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);
+
+    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);
+
+    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);
+
+    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);
+
+    g_assert_cmpint(r, ==, -ERANGE);
+    g_assert_cmpint(i, ==, 0);
+    g_assert(endptr == str + 3);
+}
+
+
+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);
+
+    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);
+
+    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/trailing", test_parse_uint_trailing);
+    g_test_add_func("/cutils/parse_uint/correct", test_parse_uint_correct);
+    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..b5c4b3d 100644
--- a/util/cutils.c
+++ b/util/cutils.c
@@ -270,6 +270,82 @@  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 -ERANGE).
+ *
+ * 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.
+ *
+ * Returns 0 on success, negative errno value on error.
+ */
+int parse_uint(const char *s, unsigned long long *value, char **endptr)
+{
+    int r = 0;
+    char *endp = (char *)s;
+    unsigned long long val = 0;
+
+    if (!s) {
+        r = -EINVAL;
+        goto out;
+    }
+
+    /* make sure we reject negative numbers: */
+    while (isspace((unsigned char)*s)) {
+        ++s; endp++;
+    }
+    if (*s == '-') {
+        r = -ERANGE;
+        goto out;
+    }
+
+    errno = 0;
+    val = strtoull(s, &endp, 0);
+    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)
+{
+    char *endp;
+    int r;
+
+    r = parse_uint(s, value, &endp);
+    if (r < 0) {
+        return r;
+    }
+    if (*endp) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
 int qemu_parse_fd(const char *param)
 {
     int fd;