mktemp improvements

- add -p dir, -t and -u.
- fix dirname(tmp) check (did not check null terminator).

the semantics of mktemp is now the same as OpenBSD mktemp.

mktemp.c

@@ -2,6 +2,7 @@
 #include <libgen.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include "util.h"
@@ -9,24 +10,34 @@
 static void
 usage(void)
 {
-	eprintf("usage: %s [-dq] [template]\n", argv0);
+	eprintf("usage: %s [-dqtu] [-p directory] [template]\n", argv0);
 }
 
 int
 main(int argc, char *argv[])
 {
-	int dflag = 0, qflag = 0, fd;
-	char *template = "tmp.XXXXXXXXXX",
-	     *tmpdir = "/tmp", *p,
-	      path[PATH_MAX], tmp[PATH_MAX];
+	int dflag = 0, pflag = 0, qflag = 0, tflag = 0, uflag = 0, fd;
+	char *template = "tmp.XXXXXXXXXX", *tmpdir = "", *pdir,
+	     *p, path[PATH_MAX], tmp[PATH_MAX];
+	size_t len;
 
 	ARGBEGIN {
 	case 'd':
 		dflag = 1;
 		break;
+	case 'p':
+		pflag = 1;
+		pdir = EARGF(usage());
+		break;
 	case 'q':
 		qflag = 1;
 		break;
+	case 't':
+		tflag = 1;
+		break;
+	case 'u':
+		uflag = 1;
+		break;
 	default:
 		usage();
 	} ARGEND;
@@ -36,18 +47,26 @@ main(int argc, char *argv[])
 	else if (argc == 1)
 		template = argv[0];
 
-	if ((p = getenv("TMPDIR")))
-		tmpdir = p;
+	if (!argc || pflag || tflag) {
+		if ((p = getenv("TMPDIR")))
+			tmpdir = p;
+		else if (pflag)
+			tmpdir = pdir;
+		else
+			tmpdir = "/tmp";
+	}
+
+	len = estrlcpy(path, tmpdir, sizeof(path));
+	if (path[0] && path[len - 1] != '/')
+		estrlcat(path, "/", sizeof(path));
 
 	estrlcpy(tmp, template, sizeof(tmp));
 	p = dirname(tmp);
-	if (p[0] != '.') {
-		estrlcpy(path, template, sizeof(path));
-	} else {
-		estrlcpy(path, tmpdir, sizeof(path));
-		estrlcat(path, "/", sizeof(path));
-		estrlcat(path, template, sizeof(path));
+	if (!(p[0] == '.' && p[1] == '\0')) {
+		if (tflag && !pflag)
+			eprintf("template must not contain directory separators in -t mode\n");
 	}
+	estrlcat(path, template, sizeof(path));
 
 	if (dflag) {
 		if (!mkdtemp(path)) {
@@ -64,6 +83,8 @@ main(int argc, char *argv[])
 		if (close(fd))
 			eprintf("close %s:", path);
 	}
+	if (uflag)
+		unlink(path);
 	puts(path);
 
 	efshut(stdout, "<stdout>");