1) XP_UNIX should use getenv("LOGNAME") instead of getpwuid(geteuid())

since the same UID may be shared by multiple logins (yes, really!).
2) fix bug in ipcmMessageClientInfo::NextTarget().

modules/ipc/common/ipcm.cpp

@@ -197,10 +197,9 @@ ipcmMessageClientInfo::NextTarget(const nsID *target) const
     ipcmClientInfoHeader *hdr = (ipcmClientInfoHeader *) Data();
 
     if (!target)
-        return (const nsID *) hdr + hdr->mTargetStart;
+        return (const nsID *) (Data() + hdr->mTargetStart);
 
-    target += sizeof(nsID);
-    if (target == (const nsID *) MsgBuf() + MsgLen())
+    if (++target == (const nsID *) (MsgBuf() + MsgLen()))
         target = NULL;
     return target;
 }

modules/ipc/src/ipcService.cpp

@@ -161,14 +161,14 @@ ipcService::OnIPCMClientInfo(const ipcmMessageClientInfo *msg)
     PRUint32 targetCount = msg->TargetCount();
     PRUint32 i;
 
-    const char **names = (const char **) calloc(nameCount + 1, sizeof(const char *));
+    const char **names = (const char **) calloc(nameCount, sizeof(char *));
     const char *lastName = NULL;
     for (i = 0; i < nameCount; ++i) {
         lastName = msg->NextName(lastName);
         names[i] = lastName;
     }
 
-    const nsID **targets = (const nsID **) calloc(targetCount + 1, sizeof(const nsID *));
+    const nsID **targets = (const nsID **) calloc(targetCount, sizeof(nsID *));
     const nsID *lastTarget = NULL;
     for (i = 0; i < targetCount; ++i) {
         lastTarget = msg->NextTarget(lastTarget);

modules/ipc/src/ipcTransportUnix.cpp

@@ -35,9 +35,7 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
-#include <pwd.h>
-#include <unistd.h>
-#include <sys/types.h>
+#include "prenv.h"
 
 #include "nsIFile.h"
 #include "nsIServiceManager.h"
@@ -200,13 +198,19 @@ ipcTransport::GetSocketPath(nsACString &socketPath)
     NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(file));
     if (!file)
         return NS_ERROR_FAILURE;
-    // XXX may want to use getpwuid_r when available
-    struct passwd *pw = getpwuid(geteuid());
-    if (!pw)
-        return NS_ERROR_UNEXPECTED;
+
+    const char *logName = PR_GetEnv("LOGNAME");
+    if (!(logName && *logName)) {
+        logName = PR_GetEnv("USER");
+        if (!(logName && *logName)) {
+            LOG(("could not determine username from environment\n"));
+            return NS_ERROR_FAILURE;
+        }
+    }
+
     nsCAutoString leaf;
     leaf = NS_LITERAL_CSTRING(".mozilla-ipc-")
-         + nsDependentCString(pw->pw_name);
+         + nsDependentCString(logName);
     file->AppendNative(leaf);
     file->AppendNative(NS_LITERAL_CSTRING("ipcd"));
     file->GetNativePath(socketPath);

modules/ipc/test/Makefile.in

@@ -48,8 +48,4 @@ LIBS		= \
 		$(NSPR_LIBS) \
 		$(NULL)
 
-LOCAL_INCLUDES = \
-        -I$(srcdir)/../util \
-        $(NULL)
-
 include $(topsrcdir)/config/rules.mk

modules/ipc/test/TestIPC.cpp

@@ -44,6 +44,14 @@
 #include "nsString.h"
 #include "prmem.h"
 
+static const nsID kIPCMTargetID =
+{ /* 753ca8ff-c8c2-4601-b115-8c2944da1150 */
+    0x753ca8ff,
+    0xc8c2,
+    0x4601,
+    {0xb1, 0x15, 0x8c, 0x29, 0x44, 0xda, 0x11, 0x50}
+};
+
 static const nsID kTestTargetID =
 { /* e628fc6e-a6a7-48c7-adba-f241d1128fb8 */
     0xe628fc6e,
@@ -144,8 +152,15 @@ myIpcClientObserver::OnClientInfo(PRUint32 aReqToken,
         printf("***    %d={%s}\n", i, aNames[i]);
     printf("***  targets:\n");
     for (i = 0; i < aTargetCount; ++i) {
+        const char *trailer;
+        if (aTargets[i]->Equals(kTestTargetID))
+            trailer = " (TEST_TARGET_ID)";
+        else if (aTargets[i]->Equals(kIPCMTargetID))
+            trailer = " (IPCM_TARGET_ID)";
+        else
+            trailer = " (unknown)";
         char *str = aTargets[i]->ToString();
-        printf("***    %d=%s\n", i, str);
+        printf("***    %d=%s%s\n", i, str, trailer);
         PR_Free(str);
     }