[libvirt] [PATCH v3.2] json: fix interface locale dependency

Martin Kletzander mkletzan at redhat.com
Sun Aug 12 07:55:26 UTC 2012


libvirt creates invalid commands if wrong locale is selected.  For
example with locale that uses comma as a decimal point, JSON commands
created with decimal numbers are invalid because comma separates the
entries in JSON. Fortunately even when decimal point is affected,
thousands grouping is not, because for grouping to be enabled with
*printf, there has to be an apostrophe flag specified (and supported).

This patch adds specific internal function for converting numbers to
strings with C locale and helper functions for each of the float,
double and long double.
---
 bootstrap.conf           |    1 +
 configure.ac             |    2 +-
 src/libvirt_private.syms |    3 +
 src/util/json.c          |    2 +-
 src/util/util.c          |  137 ++++++++++++++++++++++++++++++++++++++++++++++
 src/util/util.h          |    7 ++
 6 files changed, 150 insertions(+), 2 deletions(-)

diff --git a/bootstrap.conf b/bootstrap.conf
index c112ccd..a4e1c2f 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -62,6 +62,7 @@ ioctl
 isatty
 largefile
 listen
+localeconv
 maintainer-makefile
 manywarnings
 mkstemp
diff --git a/configure.ac b/configure.ac
index 8a04d91..e614b48 100644
--- a/configure.ac
+++ b/configure.ac
@@ -133,7 +133,7 @@ dnl Availability of various common functions (non-fatal if missing),
 dnl and various less common threadsafe functions
 AC_CHECK_FUNCS_ONCE([cfmakeraw geteuid getgid getgrnam_r getmntent_r \
   getpwuid_r getuid initgroups kill mmap posix_fallocate posix_memalign \
-  regexec sched_getaffinity])
+  regexec sched_getaffinity newlocale])

 dnl Availability of pthread functions (if missing, win32 threading is
 dnl assumed).  Because of $LIB_PTHREAD, we cannot use AC_CHECK_FUNCS_ONCE.
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index c023dbf..ba7fc76 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1140,6 +1140,7 @@ virArgvToString;
 virAsprintf;
 virBuildPathInternal;
 virDirCreate;
+virDoubleToStr;
 virEnumFromString;
 virEnumToString;
 virEventAddHandle;
@@ -1172,6 +1173,7 @@ virFileUnlock;
 virFileWaitForDevices;
 virFileWriteStr;
 virFindFileInPath;
+virFloatToStr;
 virGetGroupID;
 virGetGroupName;
 virGetHostname;
@@ -1185,6 +1187,7 @@ virHexToBin;
 virIndexToDiskName;
 virIsDevMapperDevice;
 virKillProcess;
+virLongDoubleToStr;
 virParseNumber;
 virParseVersionString;
 virPipeReadUntilEOF;
diff --git a/src/util/json.c b/src/util/json.c
index 5132989..1a58a16 100644
--- a/src/util/json.c
+++ b/src/util/json.c
@@ -201,7 +201,7 @@ virJSONValuePtr virJSONValueNewNumberDouble(double data)
 {
     virJSONValuePtr val = NULL;
     char *str;
-    if (virAsprintf(&str, "%lf", data) < 0)
+    if (virDoubleToStr(&str, 'f', data) < 0)
         return NULL;
     val = virJSONValueNewNumber(str);
     VIR_FREE(str);
diff --git a/src/util/util.c b/src/util/util.c
index e5bb27b..903a249 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -44,6 +44,7 @@
 #include <signal.h>
 #include <termios.h>
 #include <pty.h>
+#include <locale.h>

 #if HAVE_LIBDEVMAPPER_H
 # include <libdevmapper.h>
@@ -2060,6 +2061,142 @@ int virEnumFromString(const char *const*types,
     return -1;
 }

+/* In case thread-safe locales are available */
+#if HAVE_NEWLOCALE
+
+locale_t virLocale;
+
+static int
+virLocaleOnceInit(void) {
+    virLocale = newlocale(LC_ALL_MASK, "C", NULL);
+    if (!virLocale)
+        return -1;
+    return 0;
+}
+
+VIR_ONCE_GLOBAL_INIT(virLocale)
+#endif
+
+/**
+ * virNumberToStr
+ *
+ * converts *one* number to string with C locale (thread-safe).
+ *
+ * This function is intended for use in helper files only (hence static).
+ * For converting numbers in other code, use the helper functions below.
+ *
+ * Second parameter is the format for the number ("%lle", "%lG", etc.)
+ *
+ * Returns -1 on error, size of the string otherwise.
+ */
+static int
+virNumberToStr(char **strp, const char *fmt, ...)
+ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_FMT_PRINTF(2, 3);
+
+static int
+virNumberToStr(char **strp, const char *fmt, ...)
+{
+    int ret = -1;
+    va_list ap;
+
+#if HAVE_NEWLOCALE
+    locale_t old_loc;
+    if (virLocaleInitialize() < 0)
+        goto error;
+    old_loc = uselocale(virLocale);
+#else /* HAVE_NEWLOCALE */
+    char *radix, *tmp;
+    struct lconv *lc;
+#endif /* HAVE_NEWLOCALE */
+
+    va_start(ap, fmt);
+    ret = virVasprintf(strp, fmt, ap);
+    va_end(ap);
+
+#if HAVE_NEWLOCALE
+    uselocale(old_loc);
+#else /* HAVE_NEWLOCALE */
+    if (ret < 0)
+        goto error;
+
+    lc = localeconv();
+    radix = lc->decimal_point;
+    tmp = strstr(*strp, radix);
+    if (tmp) {
+        *tmp = '.';
+        if (strlen(radix) > 1)
+            memmove(tmp + 1, tmp + strlen(radix), strlen(*strp) - (tmp - str));
+    }
+#endif /* HAVE_NEWLOCALE */
+
+ error:
+    return ret;
+}
+
+/**
+ * virFloatToStr
+ *
+ * the same as virDoubleToStr, but for floats. The function virDoubleToStr is
+ * called because float gets promoted to double with vararg functions anyway.
+ */
+int
+virFloatToStr(char **strp, char fmt, float number)
+{
+    return virDoubleToStr(strp, fmt, (double)number);
+}
+
+/**
+ * virDoubleToStr
+ *
+ * converts double to string with C locale (thread-safe)
+ *
+ * Second parameter may be one of the floating point format characters
+ * used with *printf functions (e, E, f, g, G).
+ *
+ * Returns -1 on error, size of the string otherwise.
+ */
+int
+virDoubleToStr(char **strp, char fmt, double number)
+{
+    char f[] = "%lf";
+    int ret = -1;
+
+    if (strchr("eEfgG", fmt) == NULL)
+        goto error;
+    f[2] = fmt;
+
+    ret = virNumberToStr(strp, f, number);
+
+ error:
+    return ret;
+}
+
+/**
+ * virLongDoubleToStr
+ *
+ * converts long double to string with C locale (thread-safe)
+ *
+ * Second parameter may be one of the floating point format characters
+ * used with *printf functions (e, E, f, g, G).
+ *
+ * Returns -1 on error, size of the string otherwise.
+ */
+int
+virLongDoubleToStr(char **strp, char fmt, long double number)
+{
+    char f[] = "%llf";
+    int ret = -1;
+
+    if (strchr("eEfgG", fmt) == NULL)
+        goto error;
+    f[3] = fmt;
+
+    ret = virNumberToStr(strp, f, number);
+
+ error:
+    return ret;
+}
+
 const char *virEnumToString(const char *const*types,
                             unsigned int ntypes,
                             int type)
diff --git a/src/util/util.h b/src/util/util.h
index d151c27..3db8b8e 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -209,6 +209,13 @@ char *virStrcpy(char *dest, const char *src, size_t destbytes)
     ATTRIBUTE_RETURN_CHECK;
 # define virStrcpyStatic(dest, src) virStrcpy((dest), (src), sizeof(dest))

+int virFloatToStr(char **strp, char fmt, float number)
+    ATTRIBUTE_NONNULL(1);
+int virDoubleToStr(char **strp, char fmt, double number)
+    ATTRIBUTE_NONNULL(1);
+int virLongDoubleToStr(char **strp, char fmt, long double number)
+    ATTRIBUTE_NONNULL(1);
+
 int virDiskNameToIndex(const char* str);
 char *virIndexToDiskName(int idx, const char *prefix);

--
1.7.8.6




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