Index: b/lib/routines.c
===================================================================
--- a/lib/routines.c
+++ b/lib/routines.c
@@ -242,3 +242,50 @@
   /* Don't complain if you can't unlink.  Who cares of a tmp file? */
   unlink (filename);
 }
+
+/*
+ * Securely generate a temp file, and make sure it gets
+ * deleted upon exit.
+ */
+static char **	tempfiles;
+static unsigned	ntempfiles;
+
+static void
+cleanup_tempfiles()
+{
+	while (ntempfiles--)
+		unlink(tempfiles[ntempfiles]);
+}
+
+char *
+safe_tempnam(const char *pfx)
+{
+	char	*dirname, *filename;
+	int	fd;
+
+	if (!(dirname = getenv("TMPDIR")))
+		dirname = "/tmp";
+
+	tempfiles = (char **) realloc(tempfiles,
+			(ntempfiles+1) * sizeof(char *));
+	if (tempfiles == NULL)
+		return NULL;
+
+	filename = malloc(strlen(dirname) + strlen(pfx) + sizeof("/XXXXXX"));
+	if (!filename)
+		return NULL;
+
+	sprintf(filename, "%s/%sXXXXXX", dirname, pfx);
+
+	if ((fd = mkstemp(filename)) < 0) {
+		free(filename);
+		return NULL;
+	}
+	close(fd);
+
+	if (ntempfiles == 0)
+		atexit(cleanup_tempfiles);
+	tempfiles[ntempfiles++] = filename;
+
+	return filename;
+}
Index: b/lib/routines.h
===================================================================
--- a/lib/routines.h
+++ b/lib/routines.h
@@ -255,7 +255,8 @@
 /* If _STR_ is not defined, give it a tempname in _TMPDIR_ */
 #define tempname_ensure(Str)				\
 do {							\
-  (Str) = (Str) ? (Str) : tempnam (NULL, "a2_");	\
+  (Str) = (Str) ? (Str) : safe_tempnam("a2_");	\
 } while (0)
+char * safe_tempnam(const char *);
 
 #endif
4f0527e56f32dd209709181eafb9e52d7d'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/substitutes/ci.guix.gnu.org.pub'>
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<div class='path'>path: <a href='/guix/log/?id=80c3374f0527e56f32dd209709181eafb9e52d7d'>root</a>/<a href='/guix/log/etc?id=80c3374f0527e56f32dd209709181eafb9e52d7d'>etc</a>/<a href='/guix/log/etc/substitutes?id=80c3374f0527e56f32dd209709181eafb9e52d7d'>substitutes</a>/<a href='/guix/log/etc/substitutes/ci.guix.gnu.org.pub?id=80c3374f0527e56f32dd209709181eafb9e52d7d'>ci.guix.gnu.org.pub</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/substitutes/ci.guix.gnu.org.pub?id=80c3374f0527e56f32dd209709181eafb9e52d7d&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-07-10 00:11:00 +0200'>2020-07-10</span></td><td><a href='/guix/commit/etc/substitutes/ci.guix.gnu.org.pub?id=d283bb960f927dd5f7bb8b96bc697221e4e8ad39'>maint: Remove traces of "berlin.guixsd.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>The guixsd.org domain is no longer advertised since before in 1.0.0
release in May 2019.

* etc/substitutes/berlin.guixsd.org.pub: Rename to...
* etc/substitutes/berlin.guix.gnu.org.pub: ... this.
* etc/substitutes/ci.guix.gnu.org.pub,
etc/substitutes/ci.guix.info.pub: Adjust accordingly.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
* guix/build/download-nar.scm (urls-for-item): Likewise.
* guix/self.scm (miscellaneous-files): Likewise.
* Makefile.am (dist_pkgdata_DATA): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-01 11:05:47 +0200'>2019-05-01</span></td><td><a href='/guix/commit/etc/substitutes/ci.guix.gnu.org.pub?id=757e633d57a7b994759d69e41dd759a39f1a34ae'>build: Change default substitute server to "ci.guix.gnu.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>* config-daemon.ac: Replace "ci.guix.info" with "ci.guix.gnu.org".
* doc/guix.texi (SUBSTITUTE-SERVER): Likewise.
* etc/substitutes/ci.guix.gnu.org.pub: New file.
* Makefile.am (dist_pkgdata_DATA): Add it.
* guix/scripts/build.scm (%default-log-urls): Update.
* guix/scripts/substitute.scm (%default-substitute-urls): Likewise.
* guix/store.scm (%default-substitute-urls): Likewise.
* guix/self.scm (miscellaneous-files): Add "ci.guix.gnu.org".
</span></span></td><td>Ludovic Courtès</td></tr>