code cleanup

src/override_file.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <assert.h>
+#include <getopt.h>
+#include <sys/mman.h>
+#include <errno.h>
+#include "common.h"
+
+int override_file(override_file_t *finfo, niarelap_file_t** orig, unsigned int *orig_len, char *filename) {
+	int ret = 0;
+	int fd = open(filename, O_RDONLY);
+	LOG(LOG_VERBOSE5, "override_file() called!");
+	if (fd == -1) {
+		LOG(LOG_ERROR, "Cannot open file %s: %d (%s)", filename, errno, strerror(errno));
+		return errno;
+	}
+	LOG(LOG_VERBOSE5, "override_file: opened %s!", filename);
+	struct stat st;
+	ret = fstat(fd, &st);
+	if (ret) {
+		LOG(LOG_ERROR, "Cannot fstat fd from file %s: %d (%s)", filename, errno, strerror(errno));
+		return errno;
+	}
+	LOG(LOG_VERBOSE5, "override_file: fstat fd %d succeeded!", fd);	
+	void *addr = mmap(NULL, st.st_size, PROT_READ, MAP_FILE | MAP_PRIVATE, fd, 0);
+	if (addr == MAP_FAILED) {
+		LOG(LOG_ERROR, "Failed to map file %s: %d (%s)", filename, errno, strerror(errno));
+		return errno;
+	}
+	LOG(LOG_VERBOSE5, "override_file: Override file mapped successfully");
+	finfo->magic = OVERRIDE_MAGIC;
+	finfo->fd = fd;
+	finfo->len = (unsigned int)st.st_size;;
+	finfo->ptr = *(niarelap_file_t*)addr;
+	finfo->orig_len = *orig_len;
+	finfo->orig_ptr = **orig;
+	*orig = (niarelap_file_t*)addr;
+	*orig_len = (unsigned int)st.st_size;
+	LOG(LOG_VERBOSE5, "override_file() finished!");
+	return 0;
+};