util: make interface.c functions consistently return < 0 on error

All of the functions in util/interface.c were returning 0 on success,
but some returned -1 on error, and some returned a positive value
(usually the value of errno, but sometimes just 1). Libvirt's standard
is to return < 0 on error (in the case of functions that need to
return errno, -errno is returned.

This patch modifies all functions in interface.c to consistently
return < 0 on error, and makes changes to callers of those functions
where necessary.

4 files changed, 73 insertions, 72 deletions

diff --git a/src/nwfilter/nwfilter_gentech_driver.c b/src/nwfilter/nwfilter_gentech_driver.c
index bf44fc4ed..7d9871a14 100644
--- a/src/nwfilter/nwfilter_gentech_driver.c
+++ b/src/nwfilter/nwfilter_gentech_driver.c
@@ -715,7 +715,7 @@ virNWFilterInstantiate(virConnectPtr conn,
         if (teardownOld && rc == 0)
             techdriver->tearOldRules(conn, ifname);
 
-        if (rc == 0 && ifaceCheck(false, ifname, NULL, ifindex)) {
+        if (rc == 0 && (ifaceCheck(false, ifname, NULL, ifindex) < 0)) {
             /* interface changed/disppeared */
             techdriver->allTeardown(ifname);
             rc = 1;
@@ -898,7 +898,7 @@ _virNWFilterInstantiateFilter(virConnectPtr conn,
     int ifindex;
     int rc;
 
-    if (ifaceGetIndex(true, net->ifname, &ifindex))
+    if (ifaceGetIndex(true, net->ifname, &ifindex) < 0)
         return 1;
 
     virNWFilterLockFilterUpdates();
@@ -954,8 +954,8 @@ virNWFilterInstantiateFilterLate(virConnectPtr conn,
                                         &foundNewFilter);
     if (rc) {
         /* something went wrong... 'DOWN' the interface */
-        if (ifaceCheck(false, ifname, NULL, ifindex) != 0 ||
-            ifaceDown(ifname)) {
+        if ((ifaceCheck(false, ifname, NULL, ifindex) < 0) ||
+            (ifaceDown(ifname) < 0)) {
             /* assuming interface disappeared... */
             _virNWFilterTeardownFilter(ifname);
         }
diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c
index cf818a212..034eedbee 100644
--- a/src/nwfilter/nwfilter_learnipaddr.c
+++ b/src/nwfilter/nwfilter_learnipaddr.c
@@ -431,7 +431,7 @@ learnIPAddressThread(void *arg)
     req->status = 0;
 
     /* anything change to the VM's interface -- check at least once */
-    if (ifaceCheck(false, req->ifname, NULL, req->ifindex)) {
+    if (ifaceCheck(false, req->ifname, NULL, req->ifindex) < 0) {
         req->status = ENODEV;
         goto done;
     }
@@ -501,7 +501,7 @@ learnIPAddressThread(void *arg)
             }
 
             /* check whether VM's dev is still there */
-            if (ifaceCheck(false, req->ifname, NULL, req->ifindex)) {
+            if (ifaceCheck(false, req->ifname, NULL, req->ifindex) < 0) {
                 req->status = ENODEV;
                 showError = false;
                 break;
diff --git a/src/util/interface.c b/src/util/interface.c
index 7b1a29688..72c7f3d13 100644
--- a/src/util/interface.c
+++ b/src/util/interface.c
@@ -59,10 +59,10 @@ getFlags(int fd, const char *ifname, struct ifreq *ifr) {
 
     if (virStrncpy(ifr->ifr_name,
                    ifname, strlen(ifname), sizeof(ifr->ifr_name)) == NULL)
-        return ENODEV;
+        return -ENODEV;
 
     if (ioctl(fd, SIOCGIFFLAGS, ifr) < 0)
-        return errno;
+        return -errno;
 
     return 0;
 }
@@ -74,7 +74,7 @@ getFlags(int fd, const char *ifname, struct ifreq *ifr) {
  * @ifname : name of the interface
  * @flags : pointer to short holding the flags on success
  *
- * Get the flags of the interface. Returns 0 on success, error code on failure.
+ * Get the flags of the interface. Returns 0 on success, -errno on failure.
  */
 int
 ifaceGetFlags(const char *ifname, short *flags) {
@@ -83,7 +83,7 @@ ifaceGetFlags(const char *ifname, short *flags) {
     int fd = socket(PF_PACKET, SOCK_DGRAM, 0);
 
     if (fd < 0)
-        return errno;
+        return -errno;
 
     rc = getFlags(fd, ifname, &ifr);
 
@@ -100,7 +100,7 @@ ifaceIsUp(const char *ifname, bool *up) {
     short flags = 0;
     int rc = ifaceGetFlags(ifname, &flags);
 
-    if (rc)
+    if (rc < 0)
         return rc;
 
     *up = ((flags & IFF_UP) == IFF_UP);
@@ -112,11 +112,12 @@ ifaceIsUp(const char *ifname, bool *up) {
 /* Note: Showstopper on cygwin is only missing PF_PACKET */
 
 int
+
 ifaceGetFlags(const char *ifname ATTRIBUTE_UNUSED,
               short *flags ATTRIBUTE_UNUSED) {
     ifaceError(VIR_ERR_INTERNAL_ERROR, "%s",
                _("ifaceGetFlags is not supported on non-linux platforms"));
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 int
@@ -125,7 +126,7 @@ ifaceIsUp(const char *ifname ATTRIBUTE_UNUSED,
 
     ifaceError(VIR_ERR_INTERNAL_ERROR, "%s",
                _("ifaceIsUp is not supported on non-linux platforms"));
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -141,7 +142,7 @@ ifaceIsUp(const char *ifname ATTRIBUTE_UNUSED,
  * flagmask = (~0 ^ flagclear)
  * newflags = (curflags & flagmask) | flagset;
  *
- * Returns 0 on success, errno on failure.
+ * Returns 0 on success, -errno on failure.
  */
 #ifdef __linux__
 static int chgIfaceFlags(const char *ifname, short flagclear, short flagset) {
@@ -152,10 +153,10 @@ static int chgIfaceFlags(const char *ifname, short flagclear, short flagset) {
     int fd = socket(PF_PACKET, SOCK_DGRAM, 0);
 
     if (fd < 0)
-        return errno;
+        return -errno;
 
     rc = getFlags(fd, ifname, &ifr);
-    if (rc != 0)
+    if (rc < 0)
         goto cleanup;
 
     flags = (ifr.ifr_flags & flagmask) | flagset;
@@ -164,7 +165,7 @@ static int chgIfaceFlags(const char *ifname, short flagclear, short flagset) {
         ifr.ifr_flags = flags;
 
         if (ioctl(fd, SIOCSIFFLAGS, &ifr) < 0)
-            rc = errno;
+            rc = -errno;
     }
 
 cleanup:
@@ -180,7 +181,7 @@ cleanup:
  *
  * Function to control if an interface is activated (up, 1) or not (down, 0)
  *
- * Returns 0 in case of success or an errno code in case of failure.
+ * Returns 0 on success, -errno on failure.
  */
 int
 ifaceCtrl(const char *name, bool up)
@@ -195,7 +196,7 @@ ifaceCtrl(const char *name, bool up)
 int
 ifaceCtrl(const char *name ATTRIBUTE_UNUSED, bool up ATTRIBUTE_UNUSED)
 {
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -212,10 +213,10 @@ ifaceCtrl(const char *name ATTRIBUTE_UNUSED, bool up ATTRIBUTE_UNUSED)
  * it must have the given MAC address and if an interface index is
  * passed, it must also match the interface index.
  *
- * Returns 0 on success, an error code on failure.
- *   ENODEV : if interface with given name does not exist or its interface
- *            index is different than the one passed
- *   EINVAL : if interface name is invalid (too long)
+ * Returns 0 on success, -errno on failure.
+ *   -ENODEV : if interface with given name does not exist or its interface
+ *             index is different than the one passed
+ *   -EINVAL : if interface name is invalid (too long)
  */
 #ifdef __linux__
 int
@@ -230,7 +231,7 @@ ifaceCheck(bool reportError, const char *ifname,
     if (macaddr != NULL) {
         fd = socket(PF_PACKET, SOCK_DGRAM, 0);
         if (fd < 0)
-            return errno;
+            return -errno;
 
         memset(&ifr, 0, sizeof(ifr));
 
@@ -240,7 +241,7 @@ ifaceCheck(bool reportError, const char *ifname,
                 ifaceError(VIR_ERR_INTERNAL_ERROR,
                            _("invalid interface name %s"),
                            ifname);
-            rc = EINVAL;
+            rc = -EINVAL;
             goto cleanup;
         }
 
@@ -249,12 +250,12 @@ ifaceCheck(bool reportError, const char *ifname,
                 ifaceError(VIR_ERR_INTERNAL_ERROR,
                            _("coud not get MAC address of interface %s"),
                            ifname);
-            rc = errno;
+            rc = -errno;
             goto cleanup;
         }
 
         if (memcmp(&ifr.ifr_hwaddr.sa_data, macaddr, VIR_MAC_BUFLEN) != 0) {
-            rc = ENODEV;
+            rc = -ENODEV;
             goto cleanup;
         }
     }
@@ -262,7 +263,7 @@ ifaceCheck(bool reportError, const char *ifname,
     if (ifindex != -1) {
         rc = ifaceGetIndex(reportError, ifname, &idx);
         if (rc == 0 && idx != ifindex)
-            rc = ENODEV;
+            rc = -ENODEV;
     }
 
  cleanup:
@@ -279,7 +280,7 @@ ifaceCheck(bool reportError ATTRIBUTE_UNUSED,
            const unsigned char *macaddr ATTRIBUTE_UNUSED,
            int ifindex ATTRIBUTE_UNUSED)
 {
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -294,9 +295,9 @@ ifaceCheck(bool reportError ATTRIBUTE_UNUSED,
  *
  * Get the index of an interface given its name.
  *
- * Returns 0 on success, an error code on failure.
- *   ENODEV : if interface with given name does not exist
- *   EINVAL : if interface name is invalid (too long)
+ * Returns 0 on success, -errno on failure.
+ *   -ENODEV : if interface with given name does not exist
+ *   -EINVAL : if interface name is invalid (too long)
  */
 #ifdef __linux__
 int
@@ -307,7 +308,7 @@ ifaceGetIndex(bool reportError, const char *ifname, int *ifindex)
     int fd = socket(PF_PACKET, SOCK_DGRAM, 0);
 
     if (fd < 0)
-        return errno;
+        return -errno;
 
     memset(&ifreq, 0, sizeof(ifreq));
 
@@ -317,7 +318,7 @@ ifaceGetIndex(bool reportError, const char *ifname, int *ifindex)
             ifaceError(VIR_ERR_INTERNAL_ERROR,
                        _("invalid interface name %s"),
                        ifname);
-        rc = EINVAL;
+        rc = -EINVAL;
         goto cleanup;
     }
 
@@ -328,7 +329,7 @@ ifaceGetIndex(bool reportError, const char *ifname, int *ifindex)
             ifaceError(VIR_ERR_INTERNAL_ERROR,
                        _("interface %s does not exist"),
                        ifname);
-        rc = ENODEV;
+        rc = -ENODEV;
     }
 
 cleanup:
@@ -349,7 +350,7 @@ ifaceGetIndex(bool reportError,
                    _("ifaceGetIndex is not supported on non-linux platforms"));
     }
 
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -364,15 +365,15 @@ ifaceGetVlanID(const char *vlanifname, int *vlanid) {
     int fd = socket(PF_PACKET, SOCK_DGRAM, 0);
 
     if (fd < 0)
-        return errno;
+        return -errno;
 
     if (virStrcpyStatic(vlanargs.device1, vlanifname) == NULL) {
-        rc = EINVAL;
+        rc = -EINVAL;
         goto cleanup;
     }
 
     if (ioctl(fd, SIOCGIFVLAN, &vlanargs) != 0) {
-        rc = errno;
+        rc = -errno;
         goto cleanup;
     }
 
@@ -393,7 +394,7 @@ ifaceGetVlanID(const char *vlanifname ATTRIBUTE_UNUSED,
     ifaceError(VIR_ERR_INTERNAL_ERROR, "%s",
                _("ifaceGetVlanID is not supported on non-linux platforms"));
 
-    return ENOSYS;
+    return -ENOSYS;
 }
 #endif /* __linux__ */
 
@@ -404,7 +405,7 @@ ifaceGetVlanID(const char *vlanifname ATTRIBUTE_UNUSED,
  *
  * This function gets the @macaddr for a given interface @ifname.
  *
- * Returns 0 in case of success or an errno code in case of failure.
+ * Returns 0 on success, -errno on failure.
  */
 #ifdef __linux__
 int
@@ -416,20 +417,20 @@ ifaceGetMacAddress(const char *ifname,
     int rc = 0;
 
     if (!ifname)
-        return EINVAL;
+        return -EINVAL;
 
     fd = socket(AF_INET, SOCK_STREAM, 0);
     if (fd < 0)
-        return errno;
+        return -errno;
 
     memset(&ifr, 0, sizeof(struct ifreq));
     if (virStrcpyStatic(ifr.ifr_name, ifname) == NULL) {
-        rc = EINVAL;
+        rc = -EINVAL;
         goto cleanup;
     }
 
     if (ioctl(fd, SIOCGIFHWADDR, (char *)&ifr) != 0) {
-        rc = errno;
+        rc = -errno;
         goto cleanup;
     }
 
@@ -446,7 +447,7 @@ int
 ifaceGetMacAddress(const char *ifname ATTRIBUTE_UNUSED,
                    unsigned char *macaddr ATTRIBUTE_UNUSED)
 {
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -459,7 +460,7 @@ ifaceGetMacAddress(const char *ifname ATTRIBUTE_UNUSED,
  * This function sets the @macaddr for a given interface @ifname. This
  * gets rid of the kernel's automatically assigned random MAC.
  *
- * Returns 0 in case of success or an errno code in case of failure.
+ * Returns 0 on success, -errno on failure.
  */
 #ifdef __linux__
 int
@@ -471,27 +472,27 @@ ifaceSetMacAddress(const char *ifname,
     int rc = 0;
 
     if (!ifname)
-        return EINVAL;
+        return -EINVAL;
 
     fd = socket(AF_INET, SOCK_STREAM, 0);
     if (fd < 0)
-        return errno;
+        return -errno;
 
     memset(&ifr, 0, sizeof(struct ifreq));
     if (virStrcpyStatic(ifr.ifr_name, ifname) == NULL) {
-        rc = EINVAL;
+        rc = -EINVAL;
         goto cleanup;
     }
 
     /* To fill ifr.ifr_hdaddr.sa_family field */
     if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0) {
-        rc = errno;
+        rc = -errno;
         goto cleanup;
     }
 
     memcpy(ifr.ifr_hwaddr.sa_data, macaddr, VIR_MAC_BUFLEN);
 
-    rc = ioctl(fd, SIOCSIFHWADDR, &ifr) == 0 ? 0 : errno;
+    rc = ioctl(fd, SIOCSIFHWADDR, &ifr) == 0 ? 0 : -errno;
 
 cleanup:
     VIR_FORCE_CLOSE(fd);
@@ -504,7 +505,7 @@ int
 ifaceSetMacAddress(const char *ifname ATTRIBUTE_UNUSED,
                    const unsigned char *macaddr ATTRIBUTE_UNUSED)
 {
-    return ENOSYS;
+    return -ENOSYS;
 }
 
 #endif /* __linux__ */
@@ -546,7 +547,7 @@ ifaceMacvtapLinkAdd(const char *type,
     struct nl_msg *nl_msg;
     struct nlattr *linkinfo, *info_data;
 
-    if (ifaceGetIndex(true, srcdev, &ifindex) != 0)
+    if (ifaceGetIndex(true, srcdev, &ifindex) < 0)
         return -1;
 
     *retry = 0;
@@ -969,8 +970,8 @@ ifaceGetNthParent(int ifindex, const char *ifname, unsigned int nthParent,
 
     *nth = 0;
 
-    if (ifindex <= 0 && ifaceGetIndex(true, ifname, &ifindex) != 0)
-        return 1;
+    if (ifindex <= 0 && ifaceGetIndex(true, ifname, &ifindex) < 0)
+        return -1;
 
     while (!end && i <= nthParent) {
         rc = ifaceMacvtapLinkDump(true, ifname, ifindex, tb, &recvbuf, NULL);
@@ -983,7 +984,7 @@ ifaceGetNthParent(int ifindex, const char *ifname, unsigned int nthParent,
                 ifaceError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("buffer for root interface name is too small"));
                 VIR_FREE(recvbuf);
-                return 1;
+                return -1;
             }
             *parent_ifindex = ifindex;
         }
@@ -1033,7 +1034,7 @@ ifaceGetNthParent(int ifindex ATTRIBUTE_UNUSED,
  * @linkdev: name of interface
  * @stateDir: directory to store old MAC address
  *
- * Returns 0 on success, -1 in case of fatal error, error code otherwise.
+ * Returns 0 on success, -errno on failure.
  *
  */
 int
@@ -1046,7 +1047,7 @@ ifaceReplaceMacAddress(const unsigned char *macaddress,
 
     rc = ifaceGetMacAddress(linkdev, oldmac);
 
-    if (rc) {
+    if (rc < 0) {
         virReportSystemError(rc,
                              _("Getting MAC address from '%s' "
                                "to '%02x:%02x:%02x:%02x:%02x:%02x' failed."),
@@ -1061,18 +1062,18 @@ ifaceReplaceMacAddress(const unsigned char *macaddress,
                         stateDir,
                         linkdev) < 0) {
             virReportOOMError();
-            return errno;
+            return -errno;
         }
         virFormatMacAddr(oldmac, macstr);
         if (virFileWriteStr(path, macstr, O_CREAT|O_TRUNC|O_WRONLY) < 0) {
             virReportSystemError(errno, _("Unable to preserve mac for %s"),
                                  linkdev);
-            return errno;
+            return -errno;
         }
     }
 
     rc = ifaceSetMacAddress(linkdev, macaddress);
-    if (rc) {
+    if (rc < 0) {
         virReportSystemError(rc,
                              _("Setting MAC address on  '%s' to "
                                "'%02x:%02x:%02x:%02x:%02x:%02x' failed."),
@@ -1089,7 +1090,7 @@ ifaceReplaceMacAddress(const unsigned char *macaddress,
  * @linkdev: name of interface
  * @stateDir: directory containing old MAC address
  *
- * Returns 0 on success, -1 in case of fatal error, error code otherwise.
+ * Returns 0 on success, -errno on failure.
  *
  */
 int
@@ -1106,11 +1107,11 @@ ifaceRestoreMacAddress(const char *linkdev,
                     stateDir,
                     linkdev) < 0) {
         virReportOOMError();
-        return -1;
+        return -errno;
     }
 
     if (virFileReadAll(path, VIR_MAC_STRING_BUFLEN, &macstr) < 0) {
-        return errno;
+        return -errno;
     }
 
     if (virParseMacAddr(macstr, &oldmac[0]) != 0) {
@@ -1118,12 +1119,12 @@ ifaceRestoreMacAddress(const char *linkdev,
                    _("Cannot parse MAC address from '%s'"),
                    oldmacname);
         VIR_FREE(macstr);
-        return -1;
+        return -EINVAL;
     }
 
     /*reset mac and remove file-ignore results*/
     rc = ifaceSetMacAddress(linkdev, oldmac);
-    if (rc) {
+    if (rc < 0) {
         virReportSystemError(rc,
                              _("Setting MAC address on  '%s' to "
                                "'%02x:%02x:%02x:%02x:%02x:%02x' failed."),
diff --git a/src/util/macvtap.c b/src/util/macvtap.c
index 7b97c6af0..86e52fa26 100644
--- a/src/util/macvtap.c
+++ b/src/util/macvtap.c
@@ -309,14 +309,14 @@ openMacvtapTap(const char *tgifname,
         cr_ifname = tgifname;
         rc = ifaceMacvtapLinkAdd(type, macaddress, 6, tgifname, linkdev,
                                  macvtapMode, &do_retry);
-        if (rc)
+        if (rc < 0)
             return -1;
     } else {
 create_name:
         retries = 5;
         for (c = 0; c < 8192; c++) {
             snprintf(ifname, sizeof(ifname), MACVTAP_NAME_PATTERN, c);
-            if (ifaceGetIndex(false, ifname, &ifindex) == ENODEV) {
+            if (ifaceGetIndex(false, ifname, &ifindex) == -ENODEV) {
                 rc = ifaceMacvtapLinkAdd(type, macaddress, 6, ifname, linkdev,
                                          macvtapMode, &do_retry);
                 if (rc == 0)
@@ -340,7 +340,7 @@ create_name:
     }
 
     rc = ifaceUp(cr_ifname);
-    if (rc != 0) {
+    if (rc < 0) {
         virReportSystemError(errno,
                              _("cannot 'up' interface %s -- another "
                              "macvtap device may be 'up' and have the same "
@@ -838,7 +838,7 @@ getPhysdevAndVlan(const char *ifname, int *root_ifindex, char *root_ifname,
         if (nth == 0)
             break;
         if (*vlanid == -1) {
-            if (ifaceGetVlanID(root_ifname, vlanid))
+            if (ifaceGetVlanID(root_ifname, vlanid) < 0)
                 *vlanid = -1;
         }
 
@@ -997,7 +997,7 @@ doPortProfileOp8021Qbh(const char *ifname,
     if (rc)
         goto err_exit;
 
-    if (ifaceGetIndex(true, physfndev, &ifindex) != 0) {
+    if (ifaceGetIndex(true, physfndev, &ifindex) < 0) {
         rc = 1;
         goto err_exit;
     }