Fix (mostly false positive) clang static analyzer warnings about potential null pointer dereference

7 files changed, 28 insertions, 14 deletions

diff --git a/src/PJ_pipeline.c b/src/PJ_pipeline.c
index 3f61ad88..2791a4e8 100644
--- a/src/PJ_pipeline.c
+++ b/src/PJ_pipeline.c
@@ -286,7 +286,9 @@ static void set_ellipsoid(PJ *P) {
     /* Break the linked list after the global args */
     attachment = 0;
     for (cur = P->params; cur != 0; cur = cur->next)
-        if (strcmp("step", cur->next->param) == 0) {
+        /* cur->next will always be non 0 given argv_sentinel presence, */
+        /* but this is far from being obvious for a static analyzer */
+        if (cur->next != 0 && strcmp(argv_sentinel, cur->next->param) == 0) {
             attachment = cur->next;
             cur->next = 0;
             break;
@@ -310,7 +312,10 @@ static void set_ellipsoid(PJ *P) {
     geod_init(P->geod, P->a,  (1 - sqrt (1 - P->es)));
 
     /* Re-attach the dangling list */
-    cur->next = attachment;
+    /* Note: cur will always be non 0 given argv_sentinel presence, */
+    /* but this is far from being obvious for a static analyzer */
+    if( cur != 0 )
+        cur->next = attachment;
     proj_errno_restore (P, err);
 }
 
diff --git a/src/geod_set.c b/src/geod_set.c
index 26a86b61..571a7d20 100644
--- a/src/geod_set.c
+++ b/src/geod_set.c
@@ -19,7 +19,7 @@ geod_set(int argc, char **argv) {
 	start = curr = pj_mkparam(argv[0]);
 	if (!curr)
 		emess(1, "memory allocation failed");
-	for (i = 1; i < argc; ++i) {
+	for (i = 1; curr != 0 && i < argc; ++i) {
 		curr->next = pj_mkparam(argv[i]);
 		if (!curr->next)
 			emess(1, "memory allocation failed");
diff --git a/src/geodesic.c b/src/geodesic.c
index 5121ea98..40dffbc1 100644
--- a/src/geodesic.c
+++ b/src/geodesic.c
@@ -658,21 +658,21 @@ real geod_genposition(const struct geod_geodesicline* l,
     S12 = l->c2 * atan2(salp12, calp12) + l->A4 * (B42 - l->B41);
   }
 
-  if (outmask & GEOD_LATITUDE)
+  if ((outmask & GEOD_LATITUDE) && plat2)
     *plat2 = lat2;
-  if (outmask & GEOD_LONGITUDE)
+  if ((outmask & GEOD_LONGITUDE) && plon2)
     *plon2 = lon2;
-  if (outmask & GEOD_AZIMUTH)
+  if ((outmask & GEOD_AZIMUTH) && pazi2)
     *pazi2 = azi2;
-  if (outmask & GEOD_DISTANCE)
+  if ((outmask & GEOD_DISTANCE) && ps12)
     *ps12 = s12;
-  if (outmask & GEOD_REDUCEDLENGTH)
+  if ((outmask & GEOD_REDUCEDLENGTH) && pm12)
     *pm12 = m12;
   if (outmask & GEOD_GEODESICSCALE) {
     if (pM12) *pM12 = M12;
     if (pM21) *pM21 = M21;
   }
-  if (outmask & GEOD_AREA)
+  if ((outmask & GEOD_AREA) && pS12)
     *pS12 = S12;
 
   return (flags & GEOD_ARCMODE) ? s12_a12 : sig12 / degree;
diff --git a/src/pj_datum_set.c b/src/pj_datum_set.c
index 5955ed5e..374beda2 100644
--- a/src/pj_datum_set.c
+++ b/src/pj_datum_set.c
@@ -61,7 +61,10 @@ int pj_datum_set(projCtx ctx, paralist *pl, PJ *projdef)
 
         /* find the end of the list, so we can add to it */
         for (curr = pl; curr && curr->next ; curr = curr->next) {}
-        
+
+        /* cannot happen in practice, but makes static analyzers happy */
+        if( !curr ) return -1;
+
         /* find the datum definition */
         for (i = 0; (s = pj_datums[i].id) && strcmp(name, s) ; ++i) {}
 
diff --git a/src/pj_gridcatalog.c b/src/pj_gridcatalog.c
index c0194146..8777185b 100644
--- a/src/pj_gridcatalog.c
+++ b/src/pj_gridcatalog.c
@@ -260,7 +260,7 @@ PJ_GRIDINFO *pj_gc_findgrid( projCtx ctx, PJ_GridCatalog *catalog, int after,
         break;
     }
 
-    if( iEntry == catalog->entry_count )
+    if( entry == NULL )
     {
         if( grid_date )
             *grid_date = 0.0;
diff --git a/src/pj_init.c b/src/pj_init.c
index 16408ebb..2d549317 100644
--- a/src/pj_init.c
+++ b/src/pj_init.c
@@ -67,6 +67,9 @@ static paralist *string_to_paralist (PJ_CONTEXT *ctx, char *definition) {
             c++;
     }
 
+    if( next == 0 )
+        return 0;
+
     /* Terminate list and return */
     next->next = 0;
     return first;
diff --git a/src/pj_param.c b/src/pj_param.c
index 133f3ea6..b52ac940 100644
--- a/src/pj_param.c
+++ b/src/pj_param.c
@@ -131,17 +131,20 @@ PROJVALUE pj_param (projCtx ctx, paralist *pl, const char *opt) {
 
     /* Not found */
     if (0==pl) {
+        /* Return value after the switch, so that the return path is */
+        /* taken in all cases */
         switch (type) {
         case 'b': case 'i':
             value.i = 0;
-            return value;
+            break;
         case 'd': case 'r':
             value.f = 0.;
-            return value;
+            break;
         case 's':
             value.s = 0;
-            return value;
+            break;
         }
+        return value;
     }
 
     /* Found parameter - now find its value */