Fix #1 (resolve stack-use-after-scope)

* move the code of `send_ioctl` into the `get_ethtool_link_settings`

Cargo.toml

@@ -3,3 +3,4 @@ members = [
     "ethernet-info",
     "xtask",
 ]
+resolver = "2"

ethernet-info/src/internal.rs

@@ -188,10 +188,20 @@ impl CmdContext {
     }
 
     /// Convert the ifreq struct which is filled by kernel to the EthtoolCommnad.
-    pub fn get_ethtool_link_settings(&self) -> EthtoolCommnad {
+    pub fn get_ethtool_link_settings(
+        &mut self,
+        mut ecmd: EthtoolCommnad,
+    ) -> Result<EthtoolCommnad, EthtoolError> {
         unsafe {
-            let ecmd = self.ifr.ifr_ifru.ifru_data as *mut EthtoolCommnad;
-            *ecmd
+            self.ifr = ifreq {
+                ifr_name: str_to_arr(&self.devname),
+                ifr_ifru: libc::__c_anonymous_ifr_ifru {
+                    ifru_data: { transmute(&mut ecmd as *mut _) },
+                },
+            };
+            let ret = ethtool_ioctl(self.fd, &mut self.ifr);
+            ret.map(|_| *(self.ifr.ifr_ifru.ifru_data as *mut EthtoolCommnad))
+                .map_err(|_| EthtoolError::new("Failed to get EthtoolCommnad"))
         }
     }
 
@@ -204,20 +214,4 @@ impl CmdContext {
     pub fn ifname(&self) -> &str {
         &self.devname
     }
-
-    /// Send ioctl command to kernel, which will fill the ifreq struct.
-    pub fn send_ioctl(mut self, mut ecmd: EthtoolCommnad) -> Result<CmdContext, EthtoolError> {
-        self.ifr = ifreq {
-            ifr_name: str_to_arr(&self.devname),
-            ifr_ifru: libc::__c_anonymous_ifr_ifru {
-                ifru_data: unsafe { transmute(&mut ecmd as *mut _) },
-            },
-        };
-        let ret = unsafe { ethtool_ioctl(self.fd, &mut self.ifr) };
-        if ret.is_ok() {
-            Ok(self)
-        } else {
-            Err(EthtoolError::new("Failed to send EthtoolCommnad"))
-        }
-    }
 }

ethernet-info/src/lib.rs

@@ -124,8 +124,7 @@ fn do_ioctl_get_ethernet_info(mut ctx: CmdContext) -> Result<EthernetInfo, Ethto
      * opposite of what it is expecting. We request length 0 below
      * (aka. invalid bitmap length) to get this info.
      */
-    ctx = ctx.send_ioctl(ecmd)?;
-    ecmd = ctx.get_ethtool_link_settings();
+    ecmd = ctx.get_ethtool_link_settings(ecmd)?;
     if ecmd.req.link_mode_masks_nwords >= 0 || ecmd.req.cmd != ETHTOOL_GLINKSETTINGS {
         return Err(EthtoolError::new(
             "Failed to determine number of words for link mode bitmaps",
@@ -137,8 +136,7 @@ fn do_ioctl_get_ethernet_info(mut ctx: CmdContext) -> Result<EthernetInfo, Ethto
      */
     ecmd.req.cmd = ETHTOOL_GLINKSETTINGS;
     ecmd.req.link_mode_masks_nwords = -ecmd.req.link_mode_masks_nwords;
-    ctx = ctx.send_ioctl(ecmd)?;
-    ecmd = ctx.get_ethtool_link_settings();
+    ecmd = ctx.get_ethtool_link_settings(ecmd)?;
 
     /* check the link_mode_masks_nwords again */
     if ecmd.req.link_mode_masks_nwords <= 0 || ecmd.req.cmd != ETHTOOL_GLINKSETTINGS {