From: Christian Brauner <christian.brauner@canonical.com>
Date: Tue, 6 Sep 2016 15:32:47 +0000 (+0200)
Subject: utils: add lxc_safe_uint()
X-Git-Tag: lxc-2.1.0~257^2~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6bc2eafe9094f53fccc1607cab751c1046f83a39;p=thirdparty%2Flxc.git

utils: add lxc_safe_uint()

This function safely parses an unsigned integer. On success it returns 0 and
stores the unsigned integer in @converted. On error it returns a negative
errno.

Signed-off-by: Christian Brauner <christian.brauner@canonical.com>
---

diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 9198340f6..9bf31570d 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1988,3 +1988,23 @@ int lxc_preserve_ns(const int pid, const char *ns)
 
 	return open(path, O_RDONLY | O_CLOEXEC);
 }
+
+int lxc_safe_uint(const char *numstr, unsigned int *converted)
+{
+	char *err = NULL;
+	unsigned long int uli;
+
+	errno = 0;
+	uli = strtoul(numstr, &err, 0);
+	if (errno > 0)
+		return -errno;
+
+	if (!err || err == numstr || *err != '\0')
+		return -EINVAL;
+
+	if (uli > UINT_MAX)
+		return -ERANGE;
+
+	*converted = (unsigned)uli;
+	return 0;
+}
diff --git a/src/lxc/utils.h b/src/lxc/utils.h
index 9b92daf3d..0706125e1 100644
--- a/src/lxc/utils.h
+++ b/src/lxc/utils.h
@@ -316,4 +316,8 @@ int lxc_preserve_ns(const int pid, const char *ns);
 
 /* Check whether a signal is blocked by a process. */
 bool task_blocking_signal(pid_t pid, int signal);
+
+/* Helper functions to parse numbers. */
+int lxc_safe_uint(const char *numstr, unsigned int *converted);
+
 #endif /* __LXC_UTILS_H */