1 files changed, 148 insertions, 0 deletions
diff --git a/src/daemon.c b/src/daemon.c
new file mode 100644
index 0000000..9714a65
--- /dev/null
+++ b/src/daemon.c
@@ -0,0 +1,148 @@
+//#include "daemon.h"
+#include "umbrella.h"
+#include "log.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <sys/signalfd.h>
+
+/*
+ * Create a directory and all parents, like mkdir -p.
+ * Returns 0 if the directory exists or was created, -1 on error.
+ */
+static int mkdirp(const char *path, mode_t mode) {
+    char tmp[MAX_PATH];
+    char *p;
+    size_t len;
+
+    snprintf(tmp, sizeof(tmp), "%s", path);
+    len = strlen(tmp);
+    if (tmp[len - 1] == '/')
+        tmp[len - 1] = '\0';
+
+    for (p = tmp + 1; *p; p++) {
+        if (*p == '/') {
+            *p = '\0';
+            if (mkdir(tmp, mode) != 0 && errno != EEXIST)
+                return -1;
+            *p = '/';
+        }
+    }
+    if (mkdir(tmp, mode) != 0 && errno != EEXIST)
+        return -1;
+    return 0;
+}
+
+int daemon_daemonize(int foreground) {
+    if (foreground)
+        return 0;
+
+    pid_t pid = fork();
+    if (pid < 0) {
+        perror("fork");
+        return -1;
+    }
+    if (pid > 0)
+        exit(0); /* parent exits */
+
+    /* Child: become session leader */
+    if (setsid() < 0) {
+        perror("setsid");
+        return -1;
+    }
+
+    /* Fork again so we're not a session leader (can't acquire a tty) */
+    pid = fork();
+    if (pid < 0) {
+        perror("fork");
+        return -1;
+    }
+    if (pid > 0)
+        exit(0);
+
+    /* Redirect stdin/stdout/stderr to /dev/null */
+    int dev_null = open("/dev/null", O_RDWR);
+    if (dev_null >= 0) {
+        dup2(dev_null, STDIN_FILENO);
+        dup2(dev_null, STDOUT_FILENO);
+        dup2(dev_null, STDERR_FILENO);
+        if (dev_null > STDERR_FILENO)
+            close(dev_null);
+    }
+
+    umask(027);
+    return 0;
+}
+
+int daemon_write_pid(void) {
+    /* Ensure the run directory exists */
+    if (mkdirp("/run/umbrella", 0755) != 0 && errno != EEXIST) {
+        log_error("Could not create /run/umbrella: %s", strerror(errno));
+        return -1;
+    }
+
+    FILE *f = fopen(UMBRELLA_PID_FILE, "w");
+    if (!f) {
+        log_error("Could not write pid file %s: %s",
+                  UMBRELLA_PID_FILE, strerror(errno));
+        return -1;
+    }
+    fprintf(f, "%d\n", (int)getpid());
+    fclose(f);
+    return 0;
+}
+
+int daemon_init(void) {
+    /* Ensure runtime and log directories exist */
+    if (mkdirp("/run/umbrella", 0755) != 0 && errno != EEXIST) {
+        log_error("mkdirp /run/umbrella: %s", strerror(errno));
+        return -1;
+    }
+    if (mkdirp("/var/log/umbrella", 0755) != 0 && errno != EEXIST) {
+        log_error("mkdirp /var/log/umbrella: %s", strerror(errno));
+        return -1;
+    }
+
+    if (daemon_write_pid() != 0)
+        return -1;
+
+    /*
+     * Set up a signalfd so signals arrive as readable events on the
+     * epoll loop rather than interrupting syscalls unpredictably.
+     * We block the signals first, then read them via the fd.
+     */
+    sigset_t mask;
+    sigemptyset(&mask);
+    sigaddset(&mask, SIGINT);
+    sigaddset(&mask, SIGTERM);
+    sigaddset(&mask, SIGCHLD);  /* child process state changes */
+    sigaddset(&mask, SIGHUP);   /* reload config */
+    sigaddset(&mask, SIGPIPE);  /* ignore broken pipe */
+
+    if (sigprocmask(SIG_BLOCK, &mask, NULL) != 0) {
+        log_error("sigprocmask: %s", strerror(errno));
+        return -1;
+    }
+
+    int sfd = signalfd(-1, &mask, SFD_NONBLOCK | SFD_CLOEXEC);
+    if (sfd < 0) {
+        log_error("signalfd: %s", strerror(errno));
+        return -1;
+    }
+
+    g.signal_fd = sfd;
+    log_info("Daemon initialized (pid %d)", (int)getpid());
+    return 0;
+}
+
+void daemon_cleanup(void) {
+    log_info("Cleaning up...");
+    unlink(UMBRELLA_PID_FILE);
+    unlink(UMBRELLA_SOCK_PATH);
+}