1 files changed, 40 insertions, 24 deletions
diff --git a/toys/lsb/mktemp.c b/toys/lsb/mktemp.c
index 112f84c4..22c880fa 100644
--- a/toys/lsb/mktemp.c
+++ b/toys/lsb/mktemp.c
@@ -33,37 +33,53 @@ GLOBALS(
 
 void mktemp_main(void)
 {
-  char *template = *toys.optargs;
-  int use_dir = (toys.optflags & (FLAG_p|FLAG_t));
+  char *template = *toys.optargs, *dir = TT.p, *te = getenv("TMPDIR");
+  int len;
 
-  if (!template) {
-    template = "tmp.XXXXXXXXXX";
-    use_dir = 1;
-  }
-
-  // Normally, the precedence is DIR (if set), $TMPDIR (if set), /tmp.
-  // With -t it's $TMPDIR, DIR, /tmp.
-  if (use_dir) {
-    char *tmpdir = getenv("TMPDIR");
-
-    if (toys.optflags & FLAG_t) {
-      if (tmpdir && *tmpdir) TT.p = tmpdir;
-    } else {
-      if (!TT.p || !*TT.p) TT.p = tmpdir;
-    }
-    if (!TT.p || !*TT.p) TT.p = "/tmp";
+  // if template, no prefix unless -pt. if !template, always prefix
+  if (!dir || !*dir || (FLAG(t) && te && *te)) dir = te;
+  if (!dir || !*dir) dir = "/tmp";
+  if (!template) template = "tmp.XXXXXXXXXX";
+  else {
+    if (*template == '/' && TT.p && *TT.p) perror_exit("-p + /template");
+    if (!FLAG(p)&&!FLAG(t)) dir = 0;
   }
 
   // TODO: coreutils cleans paths, so -p /t/// would result in /t/xxx...
-  template = use_dir ? xmprintf("%s/%s", TT.p, template) : xstrdup(template);
+  template = dir ? xmprintf("%s/%s", dir, template) : xstrdup(template);
+  len = strlen(template);
+  if (len<3 || strcmp(template+len-3, "XXX")) perror_exit("need XXX");
 
+  // In theory you just xputs(mktemp(template)) for -u, in practice there's
+  // link-time deprecation warnings if you do that. So we fake up our own:
   if (toys.optflags & FLAG_u) {
-    xputs(mktemp(template));
-  } else if (toys.optflags & FLAG_d ? !mkdtemp(template) : mkstemp(template) == -1) {
-    if (toys.optflags & FLAG_q) toys.exitval = 1;
-    else perror_exit("Failed to create %s %s/%s",
-        toys.optflags & FLAG_d ? "directory" : "file", TT.p, template);
+    long long rr;
+    char *s = template+len;
+
+    // Fall back to random-ish if xgetrandom fails.
+    if (!xgetrandom(&rr, sizeof(rr), WARN_ONLY)) {
+      struct timespec ts;
+
+      clock_gettime(CLOCK_REALTIME, &ts);
+      rr = ts.tv_nsec*65537+(long)template+getpid()+(long)&template;
+    }
+    // Replace X with 64 chars from posix portable character set (all but "_").
+    while (--s>template) {
+      if (*s != 'X') break;
+      *s = '-'+(rr&63);
+      if (*s>'.') ++*s;
+      if (*s>'9') (*s) += 7;
+      if (*s>'Z') (*s) += 6;
+      rr>>=6;
+    }
+  } else if ((toys.optflags & FLAG_d) ? !mkdtemp(template) : mkstemp(template) == -1) {
+    if (toys.optflags & FLAG_q) {
+      toys.exitval = 1;
+      return;
+    } else perror_exit("Failed to create %s %s/%s",
+        (toys.optflags & FLAG_d) ? "directory" : "file", TT.p, template);
   }
 
+  xputs(template);
   if (CFG_TOYBOX_FREE) free(template);
 }