initial source checkin

.clang-format

@@ -0,0 +1,12 @@
+---
+AlignAfterOpenBracket: AlwaysBreak
+AlignEscapedNewlines: DontAlign
+AlignOperands: DontAlign
+AlwaysBreakAfterReturnType: AllDefinitions
+ContinuationIndentWidth: 8
+IndentWidth: 4
+KeepEmptyLinesAtTheStartOfBlocks: false
+TabWidth: 4
+UseTab: ForContinuationAndIndentation
+AlignTrailingComments: false
+...

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+tab_width = 4
+indent_size = 4

.github/workflows/build.yaml

@@ -0,0 +1,27 @@
+name: Check
+on:
+- push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    container: alpine:3.14
+    steps:
+    - uses: actions/checkout@v2
+    - name: install deps
+      run: |
+        apk add make gcc musl-dev
+    - name: make
+      run: make DEBUG=0 STATIC=1 STRIP=1
+    - name: irc notice
+      uses: Gottox/irc-message-action@v2
+      if: failure()
+      with:
+        channel: "Gottox"
+        nickname: gh-gottox
+        message: "https://github.com/${{ github.repository }} failed on push ${{ github.event.compare }}"
+    - name: release
+      uses: softprops/action-gh-release@v1
+      if: startsWith(github.ref, 'refs/tags/v') && success()
+      with:
+        files: |
+          autohup

.gitignore

@@ -50,3 +50,8 @@ modules.order
 Module.symvers
 Mkfile.old
 dkms.conf
+
+compile_commands.json
+.cache
+autohup
+.gdb_history

Makefile

@@ -0,0 +1,34 @@
+######################################################################
+# @author      : Enno Boland ([email protected])
+# @file        : Makefile
+# @created     : Tuesday Nov 09, 2021 18:51:02 CET
+######################################################################
+
+CFLAGS ?= -Wall -Wpedantic -Werror
+VERSION ?= 0.1
+
+ifeq ($(STATIC),1)
+    LDFLAGS += -static
+endif
+
+ifeq ($(DEBUG),1)
+    LDFLAGS += -g
+endif
+
+ifeq ($(STRIP),1)
+    LDFLAGS += -s
+endif
+
+autohup: main.c
+	$(CC) -o $@ $< $(CFLAGS) $(LDFLAGS) -DVERSION='"$(VERSION)"'
+
+.PHONY: clean release
+clean:
+	rm -f autohup
+
+release: clean
+	test -z "`git status -s`"
+	test "`git branch --show-current`" = main
+	test "`git rev-parse HEAD`" = "`git rev-parse origin/main`"
+	git tag v$(VERSION)
+	git push --tags

README.md

@@ -1,2 +1,37 @@
 # autohup
 automaticly sends SIGHUP to a process when a file changes.
+
+## usage
+
+```
+usage: autohup [-s signal] [-v] [path ...] -- command [argument ...]
+       autohup -l
+```
+
+## exit code
+
+`autohup` always returns 255 if an error occurs internally. If the program
+defined with `command` exits, its error code is used.
+
+## example
+
+This example watches for changes in `/etc/daemon.d` and sends `SIGHUP` when inotify
+registers a change in that directory.
+```
+$ autohup /etc/daemon.d -- daemon
+```
+
+The second example watches multiple directories and sends `SIGTERM` instead
+```
+$ autohup -s term /etc/daemon.d /var/lib/daemon -- daemon
+```
+
+To list all signals autohup can send use this command:
+```
+$ autohup -l
+```
+
+Signals can also be defined as numbers
+```
+$ autohup /etc/daemon.d -s 10 -- daemon # 10 = SIGUSR2
+```

main.c

@@ -0,0 +1,183 @@
+/**
+ * @author      : Enno Boland ([email protected])
+ * @file        : main
+ * @created     : Tuesday Nov 09, 2021 18:54:40 CET
+ */
+
+#include <limits.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/inotify.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+#define EXIT_ERROR_CODE 255
+#define MAX_EVENTS 1
+#define EVENT_SIZE (sizeof(struct inotify_event))
+#define BUF_LEN (MAX_EVENTS * (EVENT_SIZE + NAME_MAX))
+
+#define SIG(x) \
+	{ .number = SIG##x, .name = #x }
+const struct {
+	int number;
+	char name[7];
+} signals[] = {SIG(ALRM), SIG(HUP),  SIG(INT),  SIG(QUIT),  SIG(TERM),
+			   SIG(URG),  SIG(USR1), SIG(USR2), SIG(WINCH), {0}};
+#undef SIG
+
+pid_t child = 0;
+int trigger_signal = SIGHUP;
+int verbose = 0;
+
+static const char *
+get_sig_name(const int signal) {
+	int i;
+
+	for (i = 0; signals[i].number != 0; i++) {
+		if (signal == signals[i].number) {
+			return signals[i].name;
+		}
+	}
+
+	return NULL;
+}
+
+static int
+get_sig_number(const char *signal) {
+	int i;
+	if (strncasecmp("SIG", signal, 3) == 0) {
+		signal += 3;
+	}
+
+	for (i = 0; signals[i].number != 0; i++) {
+		if (strcasecmp(signals[i].name, signal) == 0) {
+			return signals[i].number;
+		}
+	}
+
+	return -1;
+}
+
+void
+sig_handler_forward(int sig) {
+	if (child == 0) {
+		return;
+	}
+
+	kill(child, sig);
+}
+
+static void
+sig_handler_child(int sig) {
+	int status;
+
+	while (waitpid(-1, &status, WNOHANG) > 0) {
+	}
+
+	exit(status);
+}
+
+int
+list_signals() {
+	int i;
+	for (i = 0; signals[i].number != 0; i++) {
+		fputs("SIG", stdout);
+		puts(signals[i].name);
+	}
+
+	return EXIT_SUCCESS;
+}
+
+int
+usage(char *arg0) {
+	fprintf(stderr,
+			"usage: %s [-s signal] [-v] [path ...] -- command [argument ...]\n",
+			arg0);
+	fprintf(stderr, "       %s -l\n", arg0);
+	return EXIT_ERROR_CODE;
+}
+
+int
+main(int argc, char **argv) {
+	int rv;
+	int inotify_fd;
+	char buffer[BUF_LEN];
+	const char *observed = argv[1];
+	int opt;
+
+	inotify_fd = inotify_init();
+
+	while ((opt = getopt(argc, argv, "-s:lvV")) != -1) {
+		switch (opt) {
+		case 'l':
+			return list_signals();
+		case 's':
+			rv = atoi(optarg);
+			if (rv == 0) {
+				rv = get_sig_number(optarg);
+			}
+			if (rv < 0) {
+				fprintf(stderr, "%s: Signal cannot be found\n", optarg);
+				return usage(argv[0]);
+			}
+			trigger_signal = rv;
+			break;
+		case 'V':
+			fputs("autohup-" VERSION "\n", stderr);
+			return EXIT_ERROR_CODE;
+		case 'v':
+			verbose++;
+			break;
+		case 1:
+			rv = inotify_add_watch(inotify_fd, optarg, IN_ALL_EVENTS);
+			if (rv < 0) {
+				perror(observed);
+				return EXIT_ERROR_CODE;
+			}
+			break;
+		default:
+			return EXIT_ERROR_CODE;
+		}
+	}
+	if (optind == argc) {
+		return usage(argv[0]);
+	}
+
+	signal(SIGCHLD, sig_handler_child);
+
+	child = fork();
+	if (child < 0) {
+		perror(argv[2]);
+	} else if (child == 0) {
+		argv += optind;
+		execvp(argv[0], argv);
+		perror(argv[0]);
+
+		return EXIT_ERROR_CODE;
+	} else {
+		signal(SIGHUP, sig_handler_forward);
+		signal(SIGINT, sig_handler_forward);
+		signal(SIGQUIT, sig_handler_forward);
+		signal(SIGUSR1, sig_handler_forward);
+		signal(SIGUSR2, sig_handler_forward);
+		signal(SIGTERM, sig_handler_forward);
+		signal(SIGCONT, sig_handler_forward);
+		for (;;) {
+			rv = read(inotify_fd, buffer, BUF_LEN);
+			if (rv < 0) {
+				perror("inotify");
+				return EXIT_ERROR_CODE;
+			}
+
+			if (verbose) {
+				fprintf(stderr, "DEBUG: sending signal %s to child process\n",
+						get_sig_name(trigger_signal));
+			}
+			sig_handler_forward(trigger_signal);
+		}
+		return EXIT_ERROR_CODE;
+	}
+}