Work around a macOS botch.

Welcome to the club, Apple; Linux makes the same mistake for some
ethtool ioctls, checking for root permission *before* checking whether
the ioctl is valid in the first place, so you get "you don't have
permission" rather than "that's not supported" unless you're running as
root.

Fix another error message while we're at it - remove some debugging
cruft.

diff --git a/pcap-bpf.c b/pcap-bpf.c
index 13c1cf27027c2dbc09773b6b6b1bdab266266b30..3ad7fafb986e6ce9b3534e4bbb69f1c239d6b4cc 100644 (file)
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -2756,12 +2756,21 @@ get_if_flags(const char *name, bpf_u_int32 *flags, char *errbuf)
        strncpy(req.ifm_name, name, sizeof(req.ifm_name));
        if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
                if (errno == EOPNOTSUPP || errno == EINVAL || errno == ENOTTY ||
        strncpy(req.ifm_name, name, sizeof(req.ifm_name));
        if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) {
                if (errno == EOPNOTSUPP || errno == EINVAL || errno == ENOTTY ||

-                   errno == ENODEV) {
+                   errno == ENODEV || errno == EPERM) {

                        /*
                         * Not supported, so we can't provide any
                         * additional information.  Assume that
                         * this means that "connected" vs.
                         * "disconnected" doesn't apply.
                        /*
                         * Not supported, so we can't provide any
                         * additional information.  Assume that
                         * this means that "connected" vs.
                         * "disconnected" doesn't apply.

+                        *
+                        * The ioctl routine for Apple's pktap devices,
+                        * annoyingly, checks for "are you root?" before
+                        * checking whether the ioctl is valid, so it
+                        * returns EPERM, rather than ENOTSUP, for the
+                        * invalid SIOCGIFMEDIA, unless you're root.
+                        * So, just as we do for some ethtool ioctls
+                        * on Linux, which makes the same mistake, we
+                        * also treat EPERM as meaning "not supported".

                         */
                        *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
                        close(sock);
                         */
                        *flags |= PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE;
                        close(sock);


@@ -2898,7 +2907,7 @@ monitor_mode(pcap_t *p, int set)
 
                default:
                        pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 
                default:
                        pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,

-                           errno, "SIOCGIFMEDIA 1");
+                           errno, "SIOCGIFMEDIA");

                        close(sock);
                        return (PCAP_ERROR);
                }
                        close(sock);
                        return (PCAP_ERROR);
                }