ioops: Add mkostemp_or_die() wrapper for mkostemp(3)

Add a panic()ing wrapper for mkostemp(3). This will be used to safely
create unique temporary files.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

ioops.c

@@ -1,6 +1,7 @@
 #ifndef _GNU_SOURCE
 # define _GNU_SOURCE
 #endif
+#include <stdlib.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -53,6 +54,15 @@ void create_or_die(const char *file, mode_t mode)
 	close(fd);
 }
 
+int mkostemp_or_die(char *templ, int flags)
+{
+	/* mode is 0600 (S_IRUSR | S_IWUSR) by default */
+	int fd = mkostemp(templ, flags);
+	if (unlikely(fd < 0))
+		panic("Cannot create unique temporary file! %s\n", strerror(errno));
+	return fd;
+}
+
 void pipe_or_die(int pipefd[2], int flags)
 {
 	int ret = pipe2(pipefd, flags);

ioops.h

@@ -8,6 +8,7 @@ extern int open_or_die_m(const char *file, int flags, mode_t mode);
 extern int dup_or_die(int oldfd);
 extern void dup2_or_die(int oldfd, int newfd);
 extern void create_or_die(const char *file, mode_t mode);
+extern int mkostemp_or_die(char *templ, int flags);
 extern int tun_open_or_die(const char *name, int type);
 extern void pipe_or_die(int pipefd[2], int flags);
 extern ssize_t read_or_die(int fd, void *buf, size_t count);