De-couple ppp from libalias. If libalias isn't there, the

alias commands simply won't work.  Only root may specify the
location of the alias lib (otherwise, it's hard-coded).

Make logprintf silently fail if LogOpen hasn't been called.

Suggested by:	eivind

1 files changed, 88 insertions, 0 deletions

diff --git a/usr.sbin/ppp/loadalias.c b/usr.sbin/ppp/loadalias.c
new file mode 100644
index 0000000..5e26bd4
--- /dev/null
+++ b/usr.sbin/ppp/loadalias.c
@@ -0,0 +1,88 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/param.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <dlfcn.h>
+#include "systems.h"
+#include "mbuf.h"
+#include "log.h"
+#include "loadalias.h"
+#include "vars.h"
+
+#define _PATH_ALIAS "/usr/lib/libalias.so.2.1"
+
+#define off(item) ((int)&(((struct aliasHandlers *)0)->item))
+#define entry(a) { off(a), "_" #a }
+
+static struct {
+    int offset;
+    char *name;
+} map[] = {
+    entry(GetNextFragmentPtr),
+    entry(GetNextFragmentPtr),
+    entry(InitPacketAlias),
+    entry(PacketAliasIn),
+    entry(PacketAliasOut),
+    entry(PacketAliasRedirectAddr),
+    entry(PacketAliasRedirectPort),
+    entry(SaveFragmentPtr),
+    entry(SetPacketAliasAddress),
+    entry(SetPacketAliasMode),
+    entry(FragmentAliasIn),
+    { 0, 0 }
+};
+
+static void *dl;
+
+int loadAliasHandlers(struct aliasHandlers *h)
+{
+    char *path;
+    char *env;
+    char *err;
+    int i;
+
+    path = _PATH_ALIAS;
+    env = getenv("_PATH_ALIAS");
+    if (env)
+        if (OrigUid() == 0)
+            path = env;
+        else {
+            logprintf("Ignoring environment _PATH_ALIAS value (%s)\n", env);
+            printf("Ignoring environment _PATH_ALIAS value (%s)\n", env);
+        }
+
+    dl = dlopen(path, RTLD_LAZY);
+    if (dl == (void *)0) {
+        err = dlerror();
+        logprintf("_PATH_ALIAS (%s): Invalid lib: %s\n", path, err);
+        printf("_PATH_ALIAS (%s): Invalid lib: %s\n", path, err);
+        return -1;
+    }
+
+    for (i = 0; map[i].name; i++) {
+        *(void **)((char *)h + map[i].offset) = dlsym(dl, map[i].name);
+        if (*(void **)((char *)h + map[i].offset) == (void *)0) {
+            err = dlerror();
+            logprintf("_PATH_ALIAS (%s): %s: %s\n", path, map[i].name, err);
+            printf("_PATH_ALIAS (%s): %s: %s\n", path, map[i].name, err);
+            (void)dlclose(dl);
+            dl = (void *)0;
+            return -1;
+        }
+    }
+
+    VarInitPacketAlias();
+
+    return 0;
+}
+
+void unloadAliasHandlers()
+{
+    if (dl) {
+        dlclose(dl);
+        dl = (void *)0;
+    }
+}