Use safer allocation macros

Use of these macros, apart from the benefits mentioned in the commit
that adds the macros, has some other good side effects:

-  Consistency in getting the size of the object from sizeof(type),
   instead of a mix of sizeof(type) sometimes and sizeof(*p) other
   times.

-  More readable code: no casts, and no sizeof(), so also shorter lines
   that we don't need to cut.

-  Consistency in using array allocation calls for allocations of arrays
   of objects, even when the object size is 1.

Cc: Valentin V. Bartenev <vbartenev@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

libmisc/idmapping.c

@@ -11,6 +11,8 @@
 #include <limits.h>
 #include <stdlib.h>
 #include <stdio.h>
+
+#include "alloc.h"
 #include "prototypes.h"
 #include "stpeprintf.h"
 #include "idmapping.h"
@@ -44,7 +46,7 @@ struct map_range *get_map_ranges(int ranges, int argc, char **argv)
 		return NULL;
 	}
 
-	mappings = calloc(ranges, sizeof(*mappings));
+	mappings = CALLOC(ranges, struct map_range);
 	if (!mappings) {
 		fprintf(log_get_logfd(), _( "%s: Memory allocation failure\n"),
 			log_get_progname());
@@ -189,7 +191,7 @@ void write_mapping(int proc_dir_fd, int ranges, const struct map_range *mappings
 #endif
 
 	bufsize = ranges * ((ULONG_DIGITS + 1) * 3);
-	pos = buf = xmalloc(bufsize);
+	pos = buf = XMALLOCARRAY(bufsize, char);
 	end = buf + bufsize;
 
 	/* Build the mapping command */