nameserv: check infohints in MPI_Lookup_name

Check info hints "port_name_size" in MPI_Lookup_name and pass the buffer
length to PMI utilities.

This provides a mechanism for users to safely allocate a portname buffer
and accommodate larger portname size than MPI_MAX_PORT_NAME.

src/include/mpir_pmi.h

@@ -90,7 +90,7 @@ int MPIR_pmi_bcast_local(char *val, int val_size);
 
 /* name service functions */
 int MPIR_pmi_publish(const char name[], const char port[]);
-int MPIR_pmi_lookup(const char name[], char port[]);
+int MPIR_pmi_lookup(const char name[], char port[], int portlen);
 int MPIR_pmi_unpublish(const char name[]);
 
 /* Other misc functions */

src/mpi/errhan/errnames.txt

@@ -167,6 +167,8 @@ be in the range 0 to %d
 **namepubnotfound %s:Lookup failed for service name %s
 **namepubnotunpub:Failed to unpublish service name
 **namepubnotunpub %s:Failed to unpublish service name %s
+**namepubtrunc:Lookup returned port_name is truncated
+**namepubtrunc %s:Lookup for service name %s is truncated
 **sendbuf_inplace:sendbuf cannot be MPI_IN_PLACE
 **recvbuf_inplace:recvbuf cannot be MPI_IN_PLACE
 **buf_inplace:buffer cannot be MPI_IN_PLACE

src/nameserv/pmi/pmi_nameserv.c

@@ -41,10 +41,16 @@ int MPID_NS_Publish(MPID_NS_Handle handle, const MPIR_Info * info_ptr,
 int MPID_NS_Lookup(MPID_NS_Handle handle, const MPIR_Info * info_ptr,
                    const char service_name[], char port[])
 {
-    MPL_UNREFERENCED_ARG(info_ptr);
     MPL_UNREFERENCED_ARG(handle);
 
-    return MPIR_pmi_lookup(service_name, port);
+    int port_name_size = MPI_MAX_PORT_NAME;
+    if (info_ptr) {
+        const char *val = MPIR_Info_lookup(info_ptr, "port_name_size");
+        if (val) {
+            port_name_size = atoi(val);
+        }
+    }
+    return MPIR_pmi_lookup(service_name, port, port_name_size);
 }
 
 int MPID_NS_Unpublish(MPID_NS_Handle handle, const MPIR_Info * info_ptr, const char service_name[])

src/util/mpir_pmi.c

@@ -740,11 +740,12 @@ int MPIR_pmi_publish(const char name[], const char port[])
     return mpi_errno;
 }
 
-int MPIR_pmi_lookup(const char name[], char port[])
+int MPIR_pmi_lookup(const char name[], char port[], int port_len)
 {
     int mpi_errno = MPI_SUCCESS;
-    SWITCH_PMI(mpi_errno = pmi1_lookup(name, port),
-               mpi_errno = pmi2_lookup(name, port), mpi_errno = pmix_lookup(name, port));
+    SWITCH_PMI(mpi_errno = pmi1_lookup(name, port, port_len),
+               mpi_errno = pmi2_lookup(name, port, port_len),
+               mpi_errno = pmix_lookup(name, port, port_len));
     return mpi_errno;
 }
 

src/util/mpir_pmi1.inc

@@ -213,15 +213,36 @@ static int pmi1_publish(const char name[], const char port[])
     goto fn_exit;
 }
 
-static int pmi1_lookup(const char name[], char port[])
+static int pmi1_lookup(const char name[], char port[], int port_len)
 {
     int mpi_errno = MPI_SUCCESS;
     int pmi_errno;
-    pmi_errno = PMI_Lookup_name(name, port);
+#ifdef PMI_MAX_PORT_NAME
+    int maxlen = PMI_MAX_PORT_NAME;
+#else
+    int maxlen = MPI_MAX_PORT_NAME;
+#endif
+    char *tmpbuf = NULL;
+
+    if (port_len >= maxlen) {
+        pmi_errno = PMI_Lookup_name(name, port);
+    } else {
+        /* allocate a temporary buffer for safety */
+        tmpbuf = MPL_malloc(maxlen, MPL_MEM_OTHER);
+        pmi_errno = PMI_Lookup_name(name, tmpbuf);
+        if (pmi_errno == PMI_SUCCESS) {
+            int mpl_err = MPL_strncpy(port, tmpbuf, port_len);
+            MPIR_ERR_CHKANDJUMP1(mpl_err, mpi_errno, MPI_ERR_NAME, "**namepubtrunc",
+                                 "**namepubtrunc %s", name);
+        }
+    }
     MPIR_ERR_CHKANDJUMP1(pmi_errno, mpi_errno, MPI_ERR_NAME, "**namepubnotfound",
                          "**namepubnotfound %s", name);
 
   fn_exit:
+    if (tmpbuf) {
+        MPL_free(tmpbuf);
+    }
     return mpi_errno;
   fn_fail:
     goto fn_exit;
@@ -320,7 +341,7 @@ static int pmi1_publish(const char name[], const char port[])
     return MPI_ERR_INTERN;
 }
 
-static int pmi1_lookup(const char name[], char port[])
+static int pmi1_lookup(const char name[], char port[], int port_len)
 {
     return MPI_ERR_INTERN;
 }

src/util/mpir_pmi2.inc

@@ -261,13 +261,13 @@ static int pmi2_publish(const char name[], const char port[])
     goto fn_exit;
 }
 
-static int pmi2_lookup(const char name[], char port[])
+static int pmi2_lookup(const char name[], char port[], int port_len)
 {
     int mpi_errno = MPI_SUCCESS;
     int pmi_errno;
     /* release the global CS for PMI calls */
     MPID_THREAD_CS_EXIT(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
-    pmi_errno = PMI2_Nameserv_lookup(name, NULL, port, MPI_MAX_PORT_NAME);
+    pmi_errno = PMI2_Nameserv_lookup(name, NULL, port, port_len);
     MPID_THREAD_CS_ENTER(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
     MPIR_ERR_CHKANDJUMP1(pmi_errno, mpi_errno, MPI_ERR_NAME, "**namepubnotfound",
                          "**namepubnotfound %s", name);
@@ -374,7 +374,7 @@ static int pmi2_publish(const char name[], const char port[])
     return MPI_ERR_INTERN;
 }
 
-static int pmi2_lookup(const char name[], char port[])
+static int pmi2_lookup(const char name[], char port[], int port_len)
 {
     return MPI_ERR_INTERN;
 }

src/util/mpir_pmix.inc

@@ -481,7 +481,7 @@ static int pmix_publish(const char name[], const char port[])
     goto fn_exit;
 }
 
-static int pmix_lookup(const char name[], char port[])
+static int pmix_lookup(const char name[], char port[], int port_len)
 {
     int mpi_errno = MPI_SUCCESS;
     int pmi_errno;
@@ -490,7 +490,7 @@ static int pmix_lookup(const char name[], char port[])
     MPL_strncpy(pdata[0].key, name, PMIX_MAX_KEYLEN);
     pmi_errno = PMIx_Lookup(pdata, 1, NULL, 0);
     if (pmi_errno == PMIX_SUCCESS) {
-        MPL_strncpy(port, pdata[0].value.data.string, MPI_MAX_PORT_NAME);
+        MPL_strncpy(port, pdata[0].value.data.string, port_len);
     }
     PMIX_PDATA_FREE(pdata, 1);
     MPIR_ERR_CHKANDJUMP1(pmi_errno, mpi_errno, MPI_ERR_NAME, "**namepubnotfound",
@@ -970,7 +970,7 @@ static int pmix_publish(const char name[], const char port[])
     return MPI_ERR_INTERN;
 }
 
-static int pmix_lookup(const char name[], char port[])
+static int pmix_lookup(const char name[], char port[], int port_len)
 {
     return MPI_ERR_INTERN;
 }