Merge pull request #3362 from BsAtHome/fix_cppchecks

Fix near last cppcheck problems

src/emc/usr_intf/emcsh.cc

@@ -3203,6 +3203,7 @@ static int emc_pendant(ClientData /*clientdata*/,
 		if (strcmp(port, "/dev/psaux")) {	// For Serial mice
 		    inBytes[1] = fgetc(inFile);	// read the first Byte
 		    if (inBytes[1] != 77) {	// If first byte not "M"
+			fseek(inFile, 0, SEEK_CUR); // C standard: write-after-read needs this
 			fputc(77, inFile);	// Request data resent
 			fflush(inFile);
 			inBytes[1] = fgetc(inFile);	// and hope it is

src/hal/drivers/mesa-hostmot2/hm2_eth.c

@@ -63,6 +63,8 @@ static int *kvlist_lookup(struct rtapi_list_head *head, const char *name) {
         if(strncmp(name, ent->key, sizeof(ent->key)) == 0) return &ent->value;
     }
     struct kvlist *ent = rtapi_kzalloc(sizeof(struct kvlist), RTAPI_GPF_KERNEL);
+    if(!ent)
+        return NULL;
     strncpy(ent->key, name, sizeof(ent->key)-1);
     rtapi_list_add(&ent->list, head);
     return &ent->value;
@@ -1047,6 +1049,8 @@ static int hm2_eth_set_force_enqueue(hm2_lowlevel_io_t *this, int do_enqueue) {
 
 static int llio_idx(const char *llio_name) {
     int *idx = kvlist_lookup(&board_num, llio_name);
+    if(!idx)
+        return -1;
     return (*idx)++;
 }
 
@@ -1439,7 +1443,10 @@ static int hm2_eth_probe(hm2_eth_t *board) {
 
     LL_PRINT("discovered %.*s\n", 16, board_name);
 
-    rtapi_snprintf(board->llio.name, sizeof(board->llio.name), "hm2_%.*s.%d", (int)strlen(llio_name), llio_name, llio_idx(llio_name));
+    int llidx = llio_idx(llio_name);
+    if(llidx < 0)
+        return -ENOMEM;
+    rtapi_snprintf(board->llio.name, sizeof(board->llio.name), "hm2_%.*s.%d", (int)strlen(llio_name), llio_name, llidx);
 
     board->llio.comp_id = comp_id;
 
@@ -1585,6 +1592,8 @@ int rtapi_app_main(void) {
         } 
         boards[i].read_cnt = boards[i].write_cnt = 0;
         int *added = kvlist_lookup(&ifnames, ifptr);
+        if(!added)
+            goto error;
         if(*added) continue;
         install_iptables_perinterface(ifptr);
         *added = 1;

src/hal/drivers/mesa-hostmot2/hm2_spix.c

@@ -572,11 +572,18 @@ static int spix_setup(void)
 
 	// Decompose the device-tree buffer into a string-list with the pointers to
 	// each string in dtcs. Don't go beyond the buffer's size.
+	// Note on cppcheck: it thinks that cptr can be NULL, but it cannot. It is
+	// initialized at the start of the buffer and moves inside it. The cptr is
+	// set to NULL when the double NUL character is detected at the end of the
+	// buffer. The loop terminates if cptr becomes NULL and cannot cause
+	// strlen() to be fed a NULL-pointer.
 	memset(dtcs, 0, sizeof(dtcs));
 	cptr = buf;
 	for(unsigned i = 0; i < DTC_MAX && cptr; i++) {
 		dtcs[i] = cptr;
+		// cppcheck-suppress nullPointer
 		int j = strlen(cptr);
+		// cppcheck-suppress nullPointerArithmetic
 		if((cptr - buf) + j + 1 < buflen)
 			cptr += j + 1;
 		else

src/rtapi/uspace_rtapi_app.cc

@@ -523,9 +523,12 @@ int main(int argc, char **argv) {
         int fallback_uid = fallback_uid_str ? atoi(fallback_uid_str) : 0;
         if(fallback_uid == 0)
         {
+	    // Cppcheck cannot see EMC2_BIN_DIR when RTAPI is defined, but that
+	    // doesn't happen in uspace.
             fprintf(stderr,
                 "Refusing to run as root without fallback UID specified\n"
                 "To run under a debugger with I/O, use e.g.,\n"
+                // cppcheck-suppress unknownMacro
                 "    sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb " EMC2_BIN_DIR "/rtapi_app\n");
             exit(1);
         }