Merge branch 'master' of git+ssh://bpf.tcpdump.org/tcpdump/master/git/tcpdump

[tcpdump] / tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index 1ae612acd869b9c4fcbfcf8927a2e74cf689fec5..19318047f33f0c3169f850a2df10515e50f0329d 100644 (file)
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -154,7 +154,6 @@ static struct printer printers[] = {
 #ifdef DLT_ARCNET_LINUX
        { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 #endif
-       { ether_if_print,       DLT_EN10MB },
        { token_if_print,       DLT_IEEE802 },
 #ifdef DLT_LANE8023
        { lane_if_print,        DLT_LANE8023 },
@@ -306,6 +305,7 @@ static struct printer printers[] = {
 };
 
 static struct ndo_printer ndo_printers[] = {
+       { ether_if_print,       DLT_EN10MB },
 #ifdef DLT_IPNET
        { ipnet_if_print,       DLT_IPNET },
 #endif
@@ -1250,14 +1250,40 @@ main(int argc, char **argv)
        (void)setsignal(SIGPIPE, cleanup);
        (void)setsignal(SIGTERM, cleanup);
        (void)setsignal(SIGINT, cleanup);
-       (void)setsignal(SIGCHLD, child_cleanup);
 #endif /* WIN32 */
+#if defined(HAVE_FORK) || defined(HAVE_VFORK)
+       (void)setsignal(SIGCHLD, child_cleanup);
+#endif
        /* Cooperate with nohup(1) */
 #ifndef WIN32  
        if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
                (void)setsignal(SIGHUP, oldhandler);
 #endif /* WIN32 */
 
+#ifndef WIN32
+       /*
+        * If a user name was specified with "-Z", attempt to switch to
+        * that user's UID.  This would probably be used with sudo,
+        * to allow tcpdump to be run in a special restricted
+        * account (if you just want to allow users to open capture
+        * devices, and can't just give users that permission,
+        * you'd make tcpdump set-UID or set-GID).
+        *
+        * Tcpdump doesn't necessarily write only to one savefile;
+        * the general only way to allow a -Z instance to write to
+        * savefiles as the user under whose UID it's run, rather
+        * than as the user specified with -Z, would thus be to switch
+        * to the original user ID before opening a capture file and
+        * then switch back to the -Z user ID after opening the savefile.
+        * Switching to the -Z user ID only after opening the first
+        * savefile doesn't handle the general case.
+        */
+       if (getuid() == 0 || geteuid() == 0) {
+               if (username || chroot_dir)
+                       droproot(username, chroot_dir);
+       }
+#endif /* WIN32 */
+
        if (pcap_setfilter(pd, &fcode) < 0)
                error("%s", pcap_geterr(pd));
        if (WFileName) {
@@ -1311,16 +1337,7 @@ main(int argc, char **argv)
                callback = print_packet;
                pcap_userdata = (u_char *)&printinfo;
        }
-#ifndef WIN32
-       /*
-        * We cannot do this earlier, because we want to be able to open
-        * the file (if done) for writing before giving up permissions.
-        */
-       if (getuid() == 0 || geteuid() == 0) {
-               if (username || chroot_dir)
-                       droproot(username, chroot_dir);
-       }
-#endif /* WIN32 */
+
 #ifdef SIGINFO
        /*
         * We can't get statistics when reading from a file rather
@@ -1449,13 +1466,13 @@ cleanup(int signo _U_)
   On windows, we do not use a fork, so we do not care less about
   waiting a child processes to die
  */
-#ifndef WIN32
+#if defined(HAVE_FORK) || defined(HAVE_VFORK)
 static RETSIGTYPE
 child_cleanup(int signo _U_)
 {
   wait(NULL);
 }
-#endif /* WIN32 */
+#endif /* HAVE_FORK && HAVE_VFORK */
 
 static void
 info(register int verbose)
@@ -1499,11 +1516,15 @@ info(register int verbose)
        infoprint = 0;
 }
 
-#ifndef WIN32
+#if defined(HAVE_FORK) || defined(HAVE_VFORK)
 static void
 compress_savefile(const char *filename)
 {
+# ifdef HAVE_FORK
        if (fork())
+# else
+       if (vfork())
+# endif
                return;
        /*
         * Set to lowest priority so that this doesn't disturb the capture
@@ -1519,15 +1540,20 @@ compress_savefile(const char *filename)
                        zflag,
                        filename,
                        strerror(errno));
+# ifdef HAVE_FORK
+       exit(1);
+# else
+       _exit(1);
+# endif
 }
-#else  /* WIN32 */
+#else  /* HAVE_FORK && HAVE_VFORK */
 static void
 compress_savefile(const char *filename)
 {
        fprintf(stderr,
-               "compress_savefile failed. Functionality not implemented under windows\n");
+               "compress_savefile failed. Functionality not implemented under your system\n");
 }
-#endif /* WIN32 */
+#endif /* HAVE_FORK && HAVE_VFORK */
 
 static void
 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)