Fix memory leak in ncdump (#591)

ncdump is flagged by the gcc address sanitizer as having a small memory
leak due to memory not being cleaned up before exiting.

It's been fixed to quiet the sanitizer output, but the ncdump program
immediately exits after the ideal free location, so this isn't a
problem for users.

Also quiets misc ncdump.c warnings.

mfhdf/ncdump/ncdump.c

@@ -17,9 +17,9 @@
 
 static const char *type_name(nc_type type);
 
-char        *progname;
-struct ncdim dims[H4_MAX_NC_DIMS];  /* dimensions */
-long         vdims[H4_MAX_NC_DIMS]; /* dimension sizes for a single variable */
+char         *progname;
+struct ncdim *dims  = NULL; /* dimensions */
+long         *vdims = NULL; /* dimension sizes for a single variable */
 
 static void
 usage()
@@ -141,14 +141,14 @@ pr_att_vals(nc_type type, int len, void *vals)
     char         *sp;
     unsigned char uc;
     char          gps[30]; /* for ascii of a float or double precision */
-    char         *f_fmt = "%#.8g";
-    char         *d_fmt = "%#.16g";
+    const char   *f_fmt = "%#.8g";
+    const char   *d_fmt = "%#.16g";
 
     switch (type) {
         case NC_BYTE:
             gp.cp = (char *)vals;
             for (iel = 0; iel < len; iel++)
-                if (isprint(uc = *gp.cp++ & 0377))
+                if (isprint(uc = (unsigned char)(*gp.cp++ & 0377)))
                     printf("'%c'%s", uc, iel < len - 1 ? ", " : "");
                 else
                     printf("'\\%o'%s", uc, iel < len - 1 ? ", " : "");
@@ -161,7 +161,7 @@ pr_att_vals(nc_type type, int len, void *vals)
             while (*sp-- == '\0' && len > 0)
                 len--;
             for (iel = 0; iel < len; iel++)
-                switch (uc = *gp.cp++ & 0377) {
+                switch (uc = (unsigned char)(*gp.cp++ & 0377)) {
                     case '\b':
                         printf("\\b");
                         break;
@@ -208,7 +208,7 @@ pr_att_vals(nc_type type, int len, void *vals)
         case NC_FLOAT:
             gp.fp = (float *)vals;
             for (iel = 0; iel < len; iel++) {
-                int ll;
+                size_t ll;
                 (void)sprintf(gps, f_fmt, (double)*gp.fp++);
                 /* append a trailing "f" for floating-point attributes */
                 ll          = strlen(gps);
@@ -388,7 +388,7 @@ do_ncdump(char *path, struct fspec *specp)
 
             printf("\t\t%s:%s = ", fixed_var, fixed_att);
             (void)ncattinq(ncid, varid, att.name, &att.type, &att.len);
-            att.val = (void *)malloc((unsigned)att.len * nctypelen(att.type));
+            att.val = (void *)malloc((size_t)(att.len * nctypelen(att.type)));
 
             if (!att.val) {
                 error("Out of memory!");
@@ -525,6 +525,8 @@ do_ncdump(char *path, struct fspec *specp)
         }
     }
 
+    free(vlist);
+
     printf("}\n");
     (void)ncclose(ncid);
 }
@@ -542,7 +544,7 @@ make_lvars(char *arg, struct fspec *fspecp)
         if (*cp == ',')
             nvars++;
 
-    fspecp->lvars = (char **)malloc(nvars * sizeof(char *));
+    fspecp->lvars = (char **)malloc((size_t)nvars * sizeof(char *));
     if (!fspecp->lvars) {
         error("out of memory");
         exit(EXIT_FAILURE);
@@ -574,8 +576,8 @@ set_sigdigs(char *arg)
     char *ptr2       = 0;
     long  flt_digits = 7;  /* default floating-point digits */
     long  dbl_digits = 15; /* default double-precision digits */
-    char  flt_fmt[6];
-    char  dbl_fmt[6];
+    char  flt_fmt[16];
+    char  dbl_fmt[16];
 
     if (arg != 0 && strlen(arg) > 0 && arg[0] != ',')
         flt_digits = strtol(arg, &ptr, 10);
@@ -620,6 +622,14 @@ main(int argc, char *argv[])
     if (1 == argc) /* if no arguments given, print help and exit */
         usage();
 
+    dims  = (struct ncdim *)calloc(H4_MAX_NC_DIMS, sizeof(struct ncdim)); /* dimensions */
+    vdims = (long *)calloc(H4_MAX_NC_DIMS, sizeof(long)); /* dimension sizes for a single variable */
+
+    if ((dims == NULL) || (vdims == NULL)) {
+        error("Unable to allocate memory!\n");
+        exit(EXIT_FAILURE);
+    }
+
     while ((c = h4getopt(argc, argv, "b:cf:hul:n:v:d:V")) != EOF)
         switch (c) {
             case 'V': /* display version of the library */
@@ -669,7 +679,7 @@ main(int argc, char *argv[])
                 }
                 break;
             case 'l': /* maximum line length */
-                max_len = strtol(h4optarg, 0, 0);
+                max_len = (int)strtol(h4optarg, 0, 0);
                 if (max_len < 10) {
                     error("unreasonably small line length specified: %d", max_len);
                     exit(EXIT_FAILURE);
@@ -698,5 +708,8 @@ main(int argc, char *argv[])
             do_ncdump(argv[i], &fspec);
     } while (++i < argc);
 
+    free(dims);
+    free(vdims);
+
     return EXIT_SUCCESS;
 }