vmsig: management daemon, runtime endpoint lifecycle, roster, discovery, in-tree drivers, packaging

- core: runtime attach/detach of a per-endpoint adapter trio (runtime-safe add_adapter + vmsig_core_detach_endpoint, deferred reap)
- roster: VMSIG_EV_ROSTER + CAP_ROSTER, retained per-endpoint and replayed to late subscribers
- discovery: inotify trigger dir, vmid/endpoint slot allocator, host probe; vmsigd daemon with config + per-uid admission
- input driver and vgpu perception built in-tree; vgpu perception as a separate library
- memctx: own the supplied ro_fd (closed at detach)
- deb packaging: install rules, systemd unit, tmpfiles, default config

src/si/input/qmp.c

@@ -0,0 +1,113 @@
+/* qmp.c — AF_UNIX QMP client: connect + capability handshake, line-based recv
+ * with a poll timeout, and synchronous command execution. */
+
+#include "qmp.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <poll.h>
+
+#define QMP_TIMEOUT_MS 5000
+#define QMP_BUF_SIZE   4096
+
+struct qmp_conn {
+    int fd;
+};
+
+static int recv_line(int fd, char* buf, size_t cap) {
+    size_t n = 0;
+    while (n + 1 < cap) {
+        struct pollfd pfd = { .fd = fd, .events = POLLIN };
+        if (poll(&pfd, 1, QMP_TIMEOUT_MS) <= 0) return -1;
+        char c;
+        if (read(fd, &c, 1) != 1) return -1;
+        buf[n++] = c;
+        if (c == '\n') break;
+    }
+    buf[n] = '\0';
+    return (int)n;
+}
+
+static int send_all(int fd, const char* s, size_t len) {
+    while (len > 0) {
+        ssize_t w = write(fd, s, len);
+        if (w <= 0) return -1;
+        s += w;
+        len -= (size_t)w;
+    }
+    return 0;
+}
+
+qmp_conn* qmp_connect(const char* sock_path) {
+    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (fd < 0) return NULL;
+
+    struct sockaddr_un addr;
+    memset(&addr, 0, sizeof addr);
+    addr.sun_family = AF_UNIX;
+    strncpy(addr.sun_path, sock_path, sizeof addr.sun_path - 1);
+
+    if (connect(fd, (struct sockaddr*)&addr, sizeof addr) < 0) {
+        close(fd);
+        return NULL;
+    }
+
+    char buf[QMP_BUF_SIZE];
+    if (recv_line(fd, buf, sizeof buf) < 0) {
+        close(fd);
+        return NULL;
+    }
+
+    const char* cap_cmd = "{\"execute\":\"qmp_capabilities\"}\r\n";
+    if (send_all(fd, cap_cmd, strlen(cap_cmd)) < 0) {
+        close(fd);
+        return NULL;
+    }
+
+    if (recv_line(fd, buf, sizeof buf) < 0) {
+        close(fd);
+        return NULL;
+    }
+
+    qmp_conn* c = malloc(sizeof *c);
+    if (!c) {
+        close(fd);
+        return NULL;
+    }
+    c->fd = fd;
+    return c;
+}
+
+void qmp_disconnect(qmp_conn* c) {
+    if (!c) return;
+    close(c->fd);
+    free(c);
+}
+
+int qmp_exec(qmp_conn* c, const char* cmd, char* resp, size_t cap) {
+    size_t cmdlen = strlen(cmd);
+    if (send_all(c->fd, cmd, cmdlen) < 0) return -1;
+    if (send_all(c->fd, "\r\n", 2) < 0) return -1;
+
+    char line[QMP_BUF_SIZE];
+    for (;;) {
+        if (recv_line(c->fd, line, sizeof line) < 0) return -1;
+        if (strstr(line, "\"return\"")) {
+            if (resp && cap > 0) {
+                strncpy(resp, line, cap - 1);
+                resp[cap - 1] = '\0';
+            }
+            return 0;
+        }
+        if (strstr(line, "\"error\"")) {
+            if (resp && cap > 0) {
+                strncpy(resp, line, cap - 1);
+                resp[cap - 1] = '\0';
+            }
+            return -1;
+        }
+    }
+}