From 0d706ae72ceefd74053ad6cb0900ecce6cf1f085 Mon Sep 17 00:00:00 2001
From: auric <auric@japegames.com>
Date: Sat, 21 Feb 2026 11:08:36 -0600
Subject: Add Umbrella 0.1.5

---
 src/log_tail.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 src/log_tail.c

(limited to 'src/log_tail.c')

diff --git a/src/log_tail.c b/src/log_tail.c
new file mode 100644
index 0000000..d352f8f
--- /dev/null
+++ b/src/log_tail.c
@@ -0,0 +1,118 @@
+#include "log_tail.h"
+#include "client.h"
+#include "unit.h"
+#include "log.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/epoll.h>
+#include <sys/inotify.h>
+
+#define MAX_LOG_WATCHES (MAX_UNITS * 4)
+
+typedef struct {
+    int inotify_fd;
+    int watch_wd;
+    int log_fd;
+    Unit *unit;
+    char path[MAX_PATH];
+} LogWatch;
+
+static LogWatch watches[MAX_LOG_WATCHES];
+static int watch_count = 0;
+
+void log_tail_init(void) {
+    watch_count = 0;
+    log_info("log_tail_init: checking %d unit(s) for log paths", g.unit_count);
+    for (int i = 0; i < g.unit_count; i++) {
+        Unit *u = &g.units[i];
+        log_info("log_tail_init: unit '%s' has %d log path(s)",
+                 u->name, u->log_count);
+        for (int j = 0; j < u->log_count; j++) {
+            const char *path = u->log_paths[j];
+            if (!path[0]) continue;
+            int log_fd = open(path, O_RDONLY | O_NONBLOCK | O_CLOEXEC);
+            if (log_fd < 0) {
+                log_warn("log_tail: cannot open %s: %s", path, strerror(errno));
+                continue;
+            }
+            lseek(log_fd, 0, SEEK_END);
+            int ifd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
+            if (ifd < 0) {
+                log_error("inotify_init1: %s", strerror(errno));
+                close(log_fd);
+                continue;
+            }
+            int wd = inotify_add_watch(ifd, path, IN_MODIFY);
+            if (wd < 0) {
+                log_warn("log_tail: inotify_add_watch %s: %s",
+                         path, strerror(errno));
+                close(ifd);
+                close(log_fd);
+                continue;
+            }
+            if (watch_count >= MAX_LOG_WATCHES) {
+                log_warn("log_tail: max watches reached, skipping %s", path);
+                close(ifd);
+                close(log_fd);
+                continue;
+            }
+            watches[watch_count].inotify_fd = ifd;
+            watches[watch_count].watch_wd   = wd;
+            watches[watch_count].log_fd     = log_fd;
+            watches[watch_count].unit       = u;
+            strncpy(watches[watch_count].path, path, MAX_PATH - 1);
+            watch_count++;
+            struct epoll_event ev;
+            ev.events  = EPOLLIN;
+            ev.data.fd = ifd;
+            epoll_ctl(g.epoll_fd, EPOLL_CTL_ADD, ifd, &ev);
+            log_info("log_tail: watching %s for unit %s", path, u->name);
+        }
+    }
+}
+
+Unit *log_tail_fd_to_unit(int fd) {
+    for (int i = 0; i < watch_count; i++) {
+        if (watches[i].inotify_fd == fd)
+            return watches[i].unit;
+    }
+    return NULL;
+}
+
+static LogWatch *watch_for_inotify_fd(int fd) {
+    for (int i = 0; i < watch_count; i++) {
+        if (watches[i].inotify_fd == fd)
+            return &watches[i];
+    }
+    return NULL;
+}
+
+void log_tail_handle(int inotify_fd) {
+    LogWatch *w = watch_for_inotify_fd(inotify_fd);
+    if (!w) return;
+    char evbuf[4096];
+    while (read(inotify_fd, evbuf, sizeof(evbuf)) > 0)
+        ;
+    char buf[RING_BUF_LINE_MAX];
+    ssize_t n;
+    while ((n = read(w->log_fd, buf, sizeof(buf) - 1)) > 0) {
+        buf[n] = '\0';
+        ring_push(w->unit->output, buf, (int)n);
+        client_broadcast_output(w->unit->name, buf, 0);
+    }
+}
+
+void log_tail_cleanup(void) {
+    for (int i = 0; i < watch_count; i++) {
+        epoll_ctl(g.epoll_fd, EPOLL_CTL_DEL, watches[i].inotify_fd, NULL);
+        inotify_rm_watch(watches[i].inotify_fd, watches[i].watch_wd);
+        close(watches[i].inotify_fd);
+        close(watches[i].log_fd);
+    }
+    watch_count = 0;
+}
-- 
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