Don't test for capture devices, test for header files.

[libpcap] / pcap-bpf.c

diff --git a/pcap-bpf.c b/pcap-bpf.c
index a6403780a81817b837e38b96b907f88a4cd22117..e821ff05105c73de22236327d517f41ba9341de7 100644 (file)
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -477,12 +477,10 @@ static int
 bpf_open(char *errbuf)
 {
        int fd;
-#ifdef HAVE_CLONING_BPF
-       static const char device[] = "/dev/bpf";
-#else
+       static const char cloning_device[] = "/dev/bpf";
        int n = 0;
        char device[sizeof "/dev/bpf0000000000"];
-#endif
+       static int no_cloning_bpf = 0;
 
 #ifdef _AIX
        /*
@@ -494,19 +492,32 @@ bpf_open(char *errbuf)
                return (PCAP_ERROR);
 #endif
 
-#ifdef HAVE_CLONING_BPF
-       if ((fd = open(device, O_RDWR)) == -1 &&
-           (errno != EACCES || (fd = open(device, O_RDONLY)) == -1)) {
-               if (errno == EACCES)
-                       fd = PCAP_ERROR_PERM_DENIED;
-               else
-                       fd = PCAP_ERROR;
-               pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
-                 "(cannot open device) %s: %s", device, pcap_strerror(errno));
+       /*
+        * First, unless we've already tried opening /dev/bpf and
+        * gotten ENOENT, try opening /dev/bpf.
+        * If it fails with ENOENT, remember that, so we don't try
+        * again, and try /dev/bpfN.
+        */
+       if (!no_cloning_bpf &&
+           (fd = open(cloning_device, O_RDWR)) == -1 &&
+           ((errno != EACCES && errno != ENOENT) ||
+            (fd = open(cloning_device, O_RDONLY)) == -1)) {
+               if (errno != ENOENT) {
+                       if (errno == EACCES)
+                               fd = PCAP_ERROR_PERM_DENIED;
+                       else
+                               fd = PCAP_ERROR;
+                       pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
+                         "(cannot open device) %s: %s", device,
+                         pcap_strerror(errno));
+                       return (fd);
+               }
+               no_cloning_bpf = 1;
        }
-#else
+
        /*
-        * Go through all the minors and find one that isn't in use.
+        * Go through all the /dev/bpfN minors and find one that isn't
+        * in use.
         */
        do {
                (void)pcap_snprintf(device, sizeof(device), "/dev/bpf%d", n++);
@@ -580,7 +591,6 @@ bpf_open(char *errbuf)
                        break;
                }
        }
-#endif
 
        return (fd);
 }