dirnamedup() - Simpler interface to dirname()

dirnamedup.c

/*
	Simpler interface to dirname() because dirname() has drawbacks:

	  - may modify the argument
	  - may return a pointer to static memory which gets
	    overwritten in subsequent calls

	This function never modifies the argument and returns a pointer
	to freshly allocated memory.

	The caller is responsibly to free() the result,
*/

#define _POSIX_SOURCE
#define _BSD_SOURCE

#include <libgen.h>
#include <stdlib.h>
#include <string.h>

extern char *dirnamedup(const char *path)
{
	char *dircopy = NULL;

	if (!path || !*path)
		return strdup(".");

	char *pathcopy = strdup(path);
	if (!pathcopy)
		goto exit;

	char *dir = dirname(pathcopy);
	if (!dir)
		goto exit;

	dircopy = strdup(dir);

exit:
	free(pathcopy);
	return dircopy;
}

dirnamedup.h

#ifndef DIRNAMEDUP_H
#define DIRNAMEDUP_H

extern char *dirnamedup(const char *path);

#endif