Eliminate hardcoded GPG references from user visible messages

Use the OpenPGP standard name or the configured+parsed signing command
in messages as appropriate. Also detect if we're specifically using
gpg and only set up its environment in that case to avoid bleeding
those messages to innocent bypassers.

Fixes: rpm-software-management#3274

sign/rpmgensig.c

@@ -235,23 +235,29 @@ static int runGPG(sigTarget sigt, const char *sigfile)
     }
 
     if (!(pid = fork())) {
-	const char *tty = ttyname(STDIN_FILENO);
-	const char *gpg_path = NULL;
-
-	if (!getenv("GPG_TTY") && (!tty || setenv("GPG_TTY", tty, 0)))
-	    rpmlog(RPMLOG_WARNING, _("Could not set GPG_TTY to stdin: %m\n"));
-
-	gpg_path = rpmExpand("%{?_gpg_path}", NULL);
-	if (gpg_path && *gpg_path != '\0')
-	    (void) setenv("GNUPGHOME", gpg_path, 1);
+	/* GnuPG needs extra setup, try to see if that's what we're running */
+	char *out = rpmExpand("%(", argv[0], " --version 2> /dev/null)", NULL);
+	int using_gpg = (strstr(out, "GnuPG") != NULL);
+	if (using_gpg) {
+	    const char *tty = ttyname(STDIN_FILENO);
+	    const char *gpg_path = NULL;
+
+	    if (!getenv("GPG_TTY") && (!tty || setenv("GPG_TTY", tty, 0)))
+		rpmlog(RPMLOG_WARNING, _("Could not set GPG_TTY to stdin: %m\n"));
+
+	    gpg_path = rpmExpand("%{?_gpg_path}", NULL);
+	    if (gpg_path && *gpg_path != '\0')
+		(void) setenv("GNUPGHOME", gpg_path, 1);
+	}
+	free(out);
 
 	dup2(pipefd[0], STDIN_FILENO);
 	close(pipefd[1]);
 
 	rc = execve(argv[0], argv+1, environ);
 
-	rpmlog(RPMLOG_ERR, _("Could not exec %s: %s\n"), "gpg",
-			strerror(errno));
+	rpmlog(RPMLOG_ERR, _("Could not exec %s: %s\n"), argv[0],
+		strerror(errno));
 	_exit(EXIT_FAILURE);
     }
 
@@ -298,9 +304,11 @@ static int runGPG(sigTarget sigt, const char *sigfile)
     } while (reaped == -1 && errno == EINTR);
 
     if (reaped == -1) {
-	rpmlog(RPMLOG_ERR, _("gpg waitpid failed (%s)\n"), strerror(errno));
+	rpmlog(RPMLOG_ERR, _("%s waitpid failed (%s)\n"), argv[0],
+		strerror(errno));
     } else if (!WIFEXITED(status) || WEXITSTATUS(status)) {
-	rpmlog(RPMLOG_ERR, _("gpg exec failed (%d)\n"), WEXITSTATUS(status));
+	rpmlog(RPMLOG_ERR, _("%s exec failed (%d)\n"), argv[0],
+		WEXITSTATUS(status));
     } else {
 	rc = 0;
     }
@@ -331,13 +339,13 @@ static rpmtd makeGPGSignature(Header sigh, int ishdr, sigTarget sigt)
 	goto exit;
 
     if (stat(sigfile, &st)) {
-	/* GPG failed to write signature */
-	rpmlog(RPMLOG_ERR, _("gpg failed to write signature\n"));
+	/* External command failed to write signature */
+	rpmlog(RPMLOG_ERR, _("failed to write signature\n"));
 	goto exit;
     }
 
     pktlen = st.st_size;
-    rpmlog(RPMLOG_DEBUG, "GPG sig size: %zd\n", pktlen);
+    rpmlog(RPMLOG_DEBUG, "OpenPGP sig size: %zd\n", pktlen);
     pkt = (uint8_t *)xmalloc(pktlen);
 
     {	FD_t fd;
@@ -354,7 +362,7 @@ static rpmtd makeGPGSignature(Header sigh, int ishdr, sigTarget sigt)
 	}
     }
 
-    rpmlog(RPMLOG_DEBUG, "Got %zd bytes of GPG sig\n", pktlen);
+    rpmlog(RPMLOG_DEBUG, "Got %zd bytes of OpenPGP sig\n", pktlen);
 
     /* Parse the signature, change signature tag as appropriate. */
     sigtd = makeSigTag(sigh, ishdr, pkt, pktlen);

tests/rpmsigdig.at

@@ -1004,6 +1004,15 @@ run rpmsign --define "__gpg_sign_cmd mumble" --key-id 1964C5FC --addsign "${RPMT
 [error: Invalid sign command: mumble
 ])
 
+RPMTEST_CHECK([
+run rpmsign --define "__gpg /gnus/not/here" --key-id 1964C5FC --addsign "${RPMTEST}"/tmp/hello-2.0-1.x86_64.rpm > /dev/null
+],
+[1],
+[],
+[error: Could not exec /gnus/not/here: No such file or directory
+error: /gnus/not/here exec failed (1)
+])
+
 # rpmsign --addsign <signed>
 RPMTEST_CHECK([
 RPMDB_INIT