Add fm_realpath(): a malloc()ating realpath() wrapper.

1 files changed, 62 insertions, 0 deletions

diff --git a/fm_realpath.c b/fm_realpath.c
new file mode 100644
index 00000000..5ae8ca08
--- /dev/null
+++ b/fm_realpath.c
@@ -0,0 +1,62 @@
+#include "config.h"
+#include "fetchmail.h"
+#include "i18n.h"
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/* similar to realpath(file_name, NULL) - on systems that do not natively 
+ * support the resolved file name to be passed as NULL, malloc() the buffer of 
+ * PATH_MAX + 1 bytes, or abort if the system does not define PATH_MAX
+ */
+char *fm_realpath(const char *restrict file_name)
+{
+	char *rv;
+
+	if (NULL == file_name) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	rv = realpath(file_name, NULL);
+		/* FreeBSD, recent GNU libc, and all SUSv4
+		 * compliant systems auto-allocate => done */
+	if (NULL == rv && errno == EINVAL) {
+		/* Implementation does not auto-allocate, but
+		 * PATH_MAX is provided (Solaris 10, f.i.) */
+#if HAVE_DECL_PATH_MAX
+		char *b = (char *)xmalloc(PATH_MAX + 1);
+		rv = realpath(file_name, b);
+#else
+		/* unsupported */
+		report(stderr, GT_("Your operating system neither defines PATH_MAX nor will it accept realpath(f, NULL). Aborting.\n"));
+		abort();
+#endif
+	}
+	return rv;
+}
+
+#ifdef TEST
+#include <string.h>
+const char *program_name= __FILE__;
+
+int main(int argc, char **argv)
+{
+	int i;
+	int e = EXIT_SUCCESS;
+	for (i = 1; i < argc; ++i) {
+		char *p = fm_realpath(argv[i]);
+		if (p) {
+			printf("%s -> %s\n", argv[i], p);
+			free(p);
+		} else {
+			fprintf(stderr, "%s: error: %s\n", argv[i], strerror(errno));
+			e = EXIT_FAILURE;
+		}
+	}
+	exit(e);
+}
+#endif