commit ba522d3c85e14ed4626a823f0cef8d42aef9d0bc
from: smytht <smytht@users.noreply.github.com>
via: GitHub <noreply@github.com>
date: Mon May 27 14:59:30 2024 UTC

ctl.c fix handling of interrupted edits 



fix handling of <ctrl> + <c> interruption that previously caused lock files to remain and prevent further editing 
The default SIGINT handler does the wrong thing when a file is currently
locked for editing. Please try the diff below. 


ensure that edited files get unlocked if the user types Ctrl-C at prompt

 While editing files, temporarily disable the default SIGINT handler which
 does a long jump to displaying a command prompt. Otherwise we would jump away
 without removing our lock on the file and future attempts to edit the file
 would fail.

 Issue found by Tom Smyth. Fixed by stsp@ 
Thanks

commit - 7b14cfd98d4c0900c1b3d8b95ef388d895a9f363
commit + ba522d3c85e14ed4626a823f0cef8d42aef9d0bc
blob - 700b931c36131a8b0513e60d55ab18b3a8da45d0
blob + d8d9e210e900e38322ae61e42335b5789eae6811
--- ctl.c
+++ ctl.c
@@ -985,14 +985,14 @@ call_editor(char *name, char **args, char *z)
 	edit_file(tmpfile, daemons2->mode, daemons2->propername, args);
 }
 
-static void
+static int
 provide_example_config(char *filename)
 {
 	char *name;
 	char path[PATH_MAX];
 	char tmpprompt[sizeof(prompt)];
 	FILE *f = NULL, *example = NULL;
-	int ret, num;
+	int ret = 0, n, num;
 	struct stat sb;
 	size_t len, remain;
 
@@ -1000,7 +1000,7 @@ provide_example_config(char *filename)
 
 	f = fopen(filename, "a+");
 	if (f == NULL)
-		return;
+		return 0;
 
 	if (fstat(fileno(f), &sb) == -1)
 		goto done;
@@ -1012,8 +1012,8 @@ provide_example_config(char *filename)
 	if (name == NULL)
 		goto done;
 	
-	ret = snprintf(path, sizeof(path), "/etc/examples/%s", name);
-	if (ret < 0 || (size_t)ret >= sizeof(path))
+	n = snprintf(path, sizeof(path), "/etc/examples/%s", name);
+	if (n < 0 || (size_t)n >= sizeof(path))
 		goto done;
 
 	/* Snip off rdomain trailer at end of filename. */
@@ -1104,6 +1104,7 @@ done:
 		restoreprompt();
 	if (example)
 		fclose(example);
+	return ret;
 }
 
 int
@@ -1112,6 +1113,7 @@ edit_file(char *tmpfile, mode_t mode, char *propername
 	char *editor;
 	int fd;
 	int ret = 0;
+	sig_t sigint;
 
 	/* acq lock, call editor, test config with cmd and args, release lock */
 	if ((editor = getenv("VISUAL")) == NULL) {
@@ -1120,8 +1122,17 @@ edit_file(char *tmpfile, mode_t mode, char *propername
 	}
 	if ((fd = acq_lock(tmpfile)) > 0) {
 		char *argv[] = { editor, tmpfile, NULL };
-		provide_example_config(tmpfile);
-		ret = cmdargs(editor, argv);
+
+		/*
+		 * Temporarily disable command.c intr() handler to ensure
+		 * we tidy up the lock file when the user hits Ctrl-C at
+		 * at prompt.
+		 */
+		sigint = signal(SIGINT, SIG_IGN);
+
+		ret = provide_example_config(tmpfile);
+		if (ret == 0)
+			ret = cmdargs(editor, argv);
 		if (ret == 0 && chmod(tmpfile, mode) == -1) {
 			printf("%% chmod %o %s: %s\n",
 			    mode, tmpfile, strerror(errno));
@@ -1130,6 +1141,7 @@ edit_file(char *tmpfile, mode_t mode, char *propername
 		if (ret == 0 && args != NULL)
 			ret = cmdargs(args[0], args);
 		rls_lock(fd);
+		signal(SIGINT, sigint); /* Restore SIGINT handler. */
 	} else {
 		printf ("%% %s configuration is locked for editing\n",
 		    propername);