rc-env: add new binary

Author: navi-desu

src/meson.build

@@ -23,6 +23,7 @@ subdir('pam_openrc')
 subdir('poweroff')
 subdir('rc-abort')
 subdir('rc-depend')
+subdir('rc-env')
 subdir('rc-service')
 subdir('rc-sstat')
 subdir('rc-status')

src/rc-env/meson.build

@@ -0,0 +1,5 @@
+executable('rc-env', 'rc-env.c',
+  include_directories: incdir,
+  dependencies: [rc, einfo, shared],
+  install: true,
+  install_dir: sbindir)

src/rc-env/rc-env.c

@@ -0,0 +1,111 @@
+#include <rc.h>
+#include <einfo.h>
+
+#include "helpers.h"
+#include "queue.h"
+#include "_usage.h"
+
+const char *applet = NULL;
+const char *extraopts = NULL;
+const char *usagestring = "Usage: rc-env [options] [<NAME=VALUE>...]\n";
+const char getoptstring[] = "s:u" getoptstring_COMMON;
+const struct option longopts[] = {
+	{ "service",  required_argument, NULL, 's' },
+	{ "unset",    no_argument,       NULL, 'u' },
+	longopts_COMMON
+};
+const char * const longopts_help[] = {
+	"Service whose variables to print",
+	"Unset listed varibles",
+	longopts_help_COMMON
+};
+
+static void escape_variable(const char *value) {
+	char ch;
+
+	printf("$'");
+	for (const char *p = value; *p; p++) {
+		switch ((ch = *p)) {
+		case '\a': ch = 'a'; break;
+		case '\b': ch = 'b'; break;
+		case '\f': ch = 'f'; break;
+		case '\n': ch = 'n'; break;
+		case '\r': ch = 'r'; break;
+		case '\t': ch = 't'; break;
+		case '\v': ch = 'v'; break;
+		/* \e is non-standard. */
+		case 0x1b: ch = 'e'; break;
+		case '"':
+		case '\'':
+		case '\\':
+			break;
+		default:
+			putchar(ch);
+			continue;
+		}
+		printf("\\%c", ch);
+	}
+	puts("\'\n");
+}
+
+static void
+print_environment(const char *service)
+{
+	/* from POSIX.2024 Shell Command Language 2.2 */
+	static const char special_chars[] = "|&;<>()$`\\\"' \t\n*?[]^-!#~=%{},";
+	struct rc_environ env;
+
+	if (!rc_environ_open(&env, service))
+		return;
+
+	for (const char *name, *value; rc_environ_get(&env, &name, &value);) {
+		if (strpbrk(value, special_chars))
+			escape_variable(value);
+		else
+			puts(value);
+	}
+
+	rc_environ_close(&env);
+}
+
+int main(int argc, char **argv) {
+	RC_STRINGLIST *services = NULL;
+	RC_STRING *service;
+	bool unset = false;
+	int opt;
+
+	applet = basename_c(argv[0]);
+	while ((opt = getopt_long(argc, argv, getoptstring, longopts, NULL)) != -1) {
+		switch (opt) {
+		case 'u': unset = true; break;
+		case 's':
+			if (!services)
+				services = rc_stringlist_new();
+			rc_stringlist_addu(services, optarg);
+			break;
+		case_RC_COMMON_GETOPT
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (!argc) {
+		if (!services) {
+			services = rc_services_in_state(RC_SERVICE_STARTED);
+			print_environment("rc");
+		}
+		TAILQ_FOREACH(service, services, entries)
+			print_environment(service->value);
+		rc_stringlist_free(services);
+	} else for (int i = 0; i < argc; i++) {
+		char *value = argv[i], *name = strsep(&value, "=");
+
+		if (unset && value)
+			eerror("invalid variable name '%s=%s'", name, value);
+		else if (!unset && !value && !(value = getenv(name)))
+			ewarn("no value found for variable '%s'", name);
+		else
+			rc_service_setenv(NULL, name, value);
+	}
+}