Fix #186: allow continuation character in .conf files

This change makes it possible to use the standard continuation character
in .conf files.  For example:

    service [23456]     \
         log:stderr     \
         <!pid/foo>     \
         bar            \
         -- This is the bar service, it depends on foo # comment that's dropped

Notice the additional support for comments on .conf lines.  If you use
the comment character today you must change to escape it.  Like this:

    service :2 foo -- Foo \#2

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

ChangeLog.md

@@ -4,6 +4,24 @@ Change Log
 All relevant changes are documented in this file.
 
 
+[4.4][UNRELEASED]
+-----------------
+
+> **Note:** this release contains changes to the `.conf` parser.  If you
+> have .conf file statements with comment character (`#`) in the command
+> options or description, you must now escape them (`\#`).
+
+### Changes
+* Support for line continuation character `\` in .conf files, issue #186
+
+        service name:sysklogd [S123456789]   \
+            env:-/etc/default/sysklogd       \
+            syslogd -F $SYSLOGD_ARGS         \
+            -- System log daemon
+
+### Fixes
+
+
 [4.3][] - 2022-05-15
 --------------------
 
@@ -1152,7 +1170,7 @@ Major bug fix release.
 
 * Initial release
 
-[UNRELEASED]: https://github.com/troglobit/finit/compare/4.2...HEAD
+[UNRELEASED]: https://github.com/troglobit/finit/compare/4.3...HEAD
 [4.3]: https://github.com/troglobit/finit/compare/4.2...4.3
 [4.2]: https://github.com/troglobit/finit/compare/4.1...4.2
 [4.1]: https://github.com/troglobit/finit/compare/4.0...4.1

README.md

@@ -74,6 +74,12 @@ files in `/etc/finit.d`.  Available, but not yet enabled, services can
 be placed in `/etc/finit.d/available` and enabled by an operator using
 the [initctl](#commands--status) tool.
 
+> **Note:** as of Finit v4.4, .conf lines can be broken up using the
+> standard UNIX continuation character (`\`), also trailing comments are
+> now supported.  The latter means you need to escape any hashes used in
+> directives and descriptions (`\#`).  For more on this and examples,
+> see the finit.conf(5) manual or [doc/config.md](doc/config.md).
+
 ```ApacheConf
 # Fallback if /etc/hostname is missing
 host default

doc/config.md

@@ -1,5 +1,5 @@
-Configuration
+Finit Configuration
-=============
+===================
 
 * [Introduction](#introduction)
   * [Environment Variables](#environment-variables)
@@ -297,6 +297,25 @@ Linux kernel, or the name is misspelled.
 Configuration File Syntax
 -------------------------
 
+The file format is line based, empty lines and comments, lines starting
+with `#`, are ignored.  A configuration directive starts with a keyword
+followed by a space and the rest of the line is treated as the value.
+
+As of Finit v4.4, configuration directives can be broken up in multiple
+lines using the continuation character `\`, and trailing comments are
+also allowed.  Example:
+
+```aconf
+# Escape \# chars if you want them literal in, e.g., descriptions
+service name:sysklogd [S123456789]   \
+    env:-/etc/default/sysklogd       \
+    syslogd -F $SYSLOGD_ARGS         \
+    -- System log daemon \# 1   # Comments allowed now
+```
+
+The .conf files `/etc/finit.conf` and `/etc/finit.d/*` support the
+following directives:
+
 ### Hostname
 
 **Syntax:** `host <NAME>`, or `hostname <NAME>`

man/finit.conf.5

@@ -47,13 +47,20 @@ Available services
 Enabled services, symlinks from available
 .El
 .Sh FILE FORMAT
-Lines starting with `#' are ignored. Note that end-of-line comments are
+The file format is line based, empty lines and comments, lines starting
-NOT supported, comments must be on a line of their own.
+with `#', are ignored.  A configuration directive starts with a keyword
+followed by a space and the rest of the line is treated as the value.
 .Pp
-A configuration stanza must be on a single (long) line and
+As of Finit v4.4, configuration directives can be broken up in multiple
-.Em cannot
+lines using the continuation character `\\', and trailing comments are
-be broken up in multiple lines by use of a backslash as the last
+also allowed.  Example:
-character.
+.Bd -unfilled -offset indent
+# Escape \\# chars if you want them literal in, e.g., descriptions
+service name:sysklogd [S123456789]   \\
+    env:-/etc/default/sysklogd       \\
+    syslogd -F $SYSLOGD_ARGS         \\
+    -- System log daemon \\# 1   # Comments allowed now
+.Ed
 .Sh DIRECTIVES
 This section lists all supported configuration directives.  There also exist
 deprecated directives, see the Markdown documentation for details on these.

src/conf.c

@@ -841,7 +841,6 @@ static int parse_dynamic(char *line, struct rlimit rlimit[], char *file)
 static int parse_conf(char *file, int is_rcsd)
 {
 	struct rlimit rlimit[RLIMIT_NLIMITS];
-	char line[LINE_SIZE] = "";
 	FILE *fp;
 
 	fp = fopen(file, "r");
@@ -856,26 +855,25 @@ static int parse_conf(char *file, int is_rcsd)
 
 	dbg("*** Parsing %s", file);
 	while (!feof(fp)) {
-		char *x;
+		char *line;
 
-		if (!fgets(line, sizeof(line), fp))
+		line = fparseln(fp, NULL, NULL, NULL, FPARSELN_UNESCCOMM);
+		if (!line) {
+			warn("Reading %s", file);
 			continue;
+		}
 
-		chomp(line);
 		tabstospaces(line);
-//DEV		dbg("%s", line);
+		dbg("%s", line);
-
-		/* Skip comments, i.e. lines beginning with # */
-		if (MATCH_CMD(line, "#", x))
-			continue;
 
 		if (!parse_static(line, is_rcsd))
-			continue;
+			;
-		if (!parse_dynamic(line, is_rcsd ? rlimit : global_rlimit, file))
+		else if (!parse_dynamic(line, is_rcsd ? rlimit : global_rlimit, file))
-			continue;
+			;
+		else
+			parse_env(line);
 
-		/* Not static or dynamic conf, check if it is a global env. */
+		free(line);
-		parse_env(line);
 	}
 
 	fclose(fp);

test/initctl-status-subset.sh

@@ -37,9 +37,9 @@ test_add_one()
 
 test_init
 
-test_add_one "task manual:yes name:foo :1 serv -- Foo #1"
+test_add_one "task manual:yes name:foo :1 serv -- Foo \#1"
-test_add_one "task manual:yes name:foo :2 serv -- Foo #2"
+test_add_one "task manual:yes name:foo :2 serv -- Foo \#2"
-test_add_one "task manual:yes name:foo :3 serv -- Foo #3"
+test_add_one "task manual:yes name:foo :3 serv -- Foo \#3"
 test_add_one "task manual:yes name:foobar serv -- Foobar"
 
 say 'Reload Finit'

test/signal-service.sh

@@ -19,16 +19,23 @@ test_teardown()
 say "Test start $(date)"
 
 say 'Ensure file system is cleared'
-texec rm -f /tmp/usr1.log
+run "rm -f /tmp/usr1.log"
 
+# Verifies line continuation as well
 say "Add service stanza in $FINIT_CONF"
-texec sh -c "echo 'service [2345] kill:20 log service.sh -- Test service' > $FINIT_CONF"
+run "echo 'service [2345] kill:20 \\
+  log service.sh \\
+   -- Test service' > $FINIT_CONF"
+run "cat $FINIT_CONF"
+#run "initctl debug"
 
 say 'Reload Finit'
-texec sh -c "initctl reload"
+run "initctl reload"
+
+#run "initctl status service.sh"
 
 say 'Send SIGUSR1 to service...'
-texec sh -c "initctl signal service.sh SIGUSR1"
+run "initctl signal service.sh SIGUSR1"
 
 # shellcheck disable=SC2016
 retry 'assert "service.sh received SIGUSR" "$(texec cat /tmp/usr1.log)" = "USR1"' 10 1