Use inotify to monitor files

jni/Android.mk

@@ -31,6 +31,7 @@ LOCAL_SRC_FILES := \
 	core/daemon.c \
 	core/log_monitor.c \
 	core/bootstages.c \
+	core/socket.c \
 	utils/misc.c \
 	utils/vector.c \
 	utils/xwrap.c \

jni/core/bootstages.c

@@ -575,9 +575,6 @@ void post_fs(int client) {
 	write_int(client, 0);
 	close(client);
 
-	// Allow magiskinit to full patch
-	close(creat(PATCHSTART, 0));
-
 	// Uninstall or core only mode
 	if (access(UNINSTALLER, F_OK) == 0 || access(DISABLEFILE, F_OK) == 0)
 		goto unblock;
@@ -744,9 +741,7 @@ void late_start(int client) {
 	if (buf2 == NULL) buf2 = xmalloc(PATH_MAX);
 
 	// Wait till the full patch is done
-	while (access(PATCHDONE, F_OK) == -1)
+	wait_till_exists(PATCHDONE);
-		usleep(500); /* Wait 0.5ms */
-	unlink(PATCHDONE);
 
 	// Run scripts after full patch, most reliable way to run scripts
 	LOGI("* Running service.d scripts\n");

jni/core/daemon.c

@@ -13,9 +13,6 @@
 #include <signal.h>
 #include <sys/un.h>
 #include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/stat.h>
-#include <sys/mount.h>
 #include <selinux/selinux.h>
 
 #include "magisk.h"
@@ -95,14 +92,6 @@ static void *request_handler(void *args) {
 	return NULL;
 }
 
-/* Setup the address and return socket fd */
-static int setup_socket(struct sockaddr_un *sun) {
-	int fd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
-	memset(sun, 0, sizeof(*sun));
-	sun->sun_family = AF_LOCAL;
-	memcpy(sun->sun_path, REQUESTOR_DAEMON_PATH, sizeof(REQUESTOR_DAEMON_PATH) - 1);
-	return fd;
-}
 
 static void *start_magisk_hide(void *args) {
 	launch_magiskhide(-1);
@@ -199,136 +188,3 @@ int connect_daemon() {
 	}
 	return fd;
 }
-
-/*
- * Receive a file descriptor from a Unix socket.
- * Contributed by @mkasick
- *
- * Returns the file descriptor on success, or -1 if a file
- * descriptor was not actually included in the message
- *
- * On error the function terminates by calling exit(-1)
- */
-int recv_fd(int sockfd) {
-    // Need to receive data from the message, otherwise don't care about it.
-    char iovbuf;
-
-    struct iovec iov = {
-        .iov_base = &iovbuf,
-        .iov_len  = 1,
-    };
-
-    char cmsgbuf[CMSG_SPACE(sizeof(int))];
-
-    struct msghdr msg = {
-        .msg_iov        = &iov,
-        .msg_iovlen     = 1,
-        .msg_control    = cmsgbuf,
-        .msg_controllen = sizeof(cmsgbuf),
-    };
-
-    xrecvmsg(sockfd, &msg, MSG_WAITALL);
-
-    // Was a control message actually sent?
-    switch (msg.msg_controllen) {
-    case 0:
-        // No, so the file descriptor was closed and won't be used.
-        return -1;
-    case sizeof(cmsgbuf):
-        // Yes, grab the file descriptor from it.
-        break;
-    default:
-        goto error;
-    }
-
-    struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
-
-    if (cmsg             == NULL                  ||
-        cmsg->cmsg_len   != CMSG_LEN(sizeof(int)) ||
-        cmsg->cmsg_level != SOL_SOCKET            ||
-        cmsg->cmsg_type  != SCM_RIGHTS) {
-error:
-        LOGE("unable to read fd");
-        exit(-1);
-    }
-
-    return *(int *)CMSG_DATA(cmsg);
-}
-
-/*
- * Send a file descriptor through a Unix socket.
- * Contributed by @mkasick
- *
- * On error the function terminates by calling exit(-1)
- *
- * fd may be -1, in which case the dummy data is sent,
- * but no control message with the FD is sent.
- */
-void send_fd(int sockfd, int fd) {
-    // Need to send some data in the message, this will do.
-    struct iovec iov = {
-        .iov_base = "",
-        .iov_len  = 1,
-    };
-
-    struct msghdr msg = {
-        .msg_iov        = &iov,
-        .msg_iovlen     = 1,
-    };
-
-    char cmsgbuf[CMSG_SPACE(sizeof(int))];
-
-    if (fd != -1) {
-        // Is the file descriptor actually open?
-        if (fcntl(fd, F_GETFD) == -1) {
-            if (errno != EBADF) {
-                PLOGE("unable to send fd");
-            }
-            // It's closed, don't send a control message or sendmsg will EBADF.
-        } else {
-            // It's open, send the file descriptor in a control message.
-            msg.msg_control    = cmsgbuf;
-            msg.msg_controllen = sizeof(cmsgbuf);
-
-            struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
-
-            cmsg->cmsg_len   = CMSG_LEN(sizeof(int));
-            cmsg->cmsg_level = SOL_SOCKET;
-            cmsg->cmsg_type  = SCM_RIGHTS;
-
-            *(int *)CMSG_DATA(cmsg) = fd;
-        }
-    }
-
-    xsendmsg(sockfd, &msg, 0);
-}
-
-int read_int(int fd) {
-    int val;
-    xxread(fd, &val, sizeof(int));
-    return val;
-}
-
-void write_int(int fd, int val) {
-    if (fd < 0) return;
-    xwrite(fd, &val, sizeof(int));
-}
-
-char* read_string(int fd) {
-    int len = read_int(fd);
-    if (len > PATH_MAX || len < 0) {
-        LOGE("invalid string length %d", len);
-        exit(1);
-    }
-    char* val = xmalloc(sizeof(char) * (len + 1));
-    xxread(fd, val, len);
-    val[len] = '\0';
-    return val;
-}
-
-void write_string(int fd, const char* val) {
-    if (fd < 0) return;
-    int len = strlen(val);
-    write_int(fd, len);
-    xwrite(fd, val, len);
-}

jni/core/magiskinit.c

@@ -340,6 +340,17 @@ static int dump_magiskrc(const char *path, mode_t mode) {
 	return 0;
 }
 
+static void magisk_init_daemon() {
+	// Fork a new process for full patch
+	setsid();
+	sepol_allow("su", ALL, ALL, ALL);
+	wait_till_exists("/dev/.coldboot_done");
+	dump_policydb(SELINUX_LOAD);
+	close(open(PATCHDONE, O_RDONLY | O_CREAT, 0));
+	destroy_policydb();
+	exit(0);
+}
+
 int main(int argc, char *argv[]) {
 	umask(0);
 
@@ -423,18 +434,8 @@ int main(int argc, char *argv[]) {
 
 	umount("/vendor");
 
-	if (fork() == 0) {
+	if (fork() == 0)
-		// Fork a new process for full patch
+		magisk_init_daemon();
-		setsid();
-		sepol_allow("su", ALL, ALL, ALL);
-		while (access(PATCHSTART, W_OK) == -1)
-			usleep(500); /* Wait 0.5ms */
-		unlink(PATCHSTART);
-		dump_policydb(SELINUX_LOAD);
-		close(open(PATCHDONE, O_RDONLY | O_CREAT, 0));
-		destroy_policydb();
-		return 0;
-	}
 
 	// Finally, give control back!
 	execv("/init", argv);

jni/core/socket.c

@@ -0,0 +1,152 @@
+/* socket.c - All socket related operations
+ */
+
+#include <fcntl.h>
+
+#include "daemon.h"
+#include "logging.h"
+#include "utils.h"
+#include "magisk.h"
+
+/* Setup the address and return socket fd */
+int setup_socket(struct sockaddr_un *sun) {
+    int fd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
+    memset(sun, 0, sizeof(*sun));
+    sun->sun_family = AF_LOCAL;
+    memcpy(sun->sun_path, REQUESTOR_DAEMON_PATH, sizeof(REQUESTOR_DAEMON_PATH) - 1);
+    return fd;
+}
+
+
+/*
+ * Receive a file descriptor from a Unix socket.
+ * Contributed by @mkasick
+ *
+ * Returns the file descriptor on success, or -1 if a file
+ * descriptor was not actually included in the message
+ *
+ * On error the function terminates by calling exit(-1)
+ */
+int recv_fd(int sockfd) {
+    // Need to receive data from the message, otherwise don't care about it.
+    char iovbuf;
+
+    struct iovec iov = {
+        .iov_base = &iovbuf,
+        .iov_len  = 1,
+    };
+
+    char cmsgbuf[CMSG_SPACE(sizeof(int))];
+
+    struct msghdr msg = {
+        .msg_iov        = &iov,
+        .msg_iovlen     = 1,
+        .msg_control    = cmsgbuf,
+        .msg_controllen = sizeof(cmsgbuf),
+    };
+
+    xrecvmsg(sockfd, &msg, MSG_WAITALL);
+
+    // Was a control message actually sent?
+    switch (msg.msg_controllen) {
+    case 0:
+        // No, so the file descriptor was closed and won't be used.
+        return -1;
+    case sizeof(cmsgbuf):
+        // Yes, grab the file descriptor from it.
+        break;
+    default:
+        goto error;
+    }
+
+    struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+
+    if (cmsg             == NULL                  ||
+        cmsg->cmsg_len   != CMSG_LEN(sizeof(int)) ||
+        cmsg->cmsg_level != SOL_SOCKET            ||
+        cmsg->cmsg_type  != SCM_RIGHTS) {
+error:
+        LOGE("unable to read fd");
+        exit(-1);
+    }
+
+    return *(int *)CMSG_DATA(cmsg);
+}
+
+/*
+ * Send a file descriptor through a Unix socket.
+ * Contributed by @mkasick
+ *
+ * On error the function terminates by calling exit(-1)
+ *
+ * fd may be -1, in which case the dummy data is sent,
+ * but no control message with the FD is sent.
+ */
+void send_fd(int sockfd, int fd) {
+    // Need to send some data in the message, this will do.
+    struct iovec iov = {
+        .iov_base = "",
+        .iov_len  = 1,
+    };
+
+    struct msghdr msg = {
+        .msg_iov        = &iov,
+        .msg_iovlen     = 1,
+    };
+
+    char cmsgbuf[CMSG_SPACE(sizeof(int))];
+
+    if (fd != -1) {
+        // Is the file descriptor actually open?
+        if (fcntl(fd, F_GETFD) == -1) {
+            if (errno != EBADF) {
+                PLOGE("unable to send fd");
+            }
+            // It's closed, don't send a control message or sendmsg will EBADF.
+        } else {
+            // It's open, send the file descriptor in a control message.
+            msg.msg_control    = cmsgbuf;
+            msg.msg_controllen = sizeof(cmsgbuf);
+
+            struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+
+            cmsg->cmsg_len   = CMSG_LEN(sizeof(int));
+            cmsg->cmsg_level = SOL_SOCKET;
+            cmsg->cmsg_type  = SCM_RIGHTS;
+
+            *(int *)CMSG_DATA(cmsg) = fd;
+        }
+    }
+
+    xsendmsg(sockfd, &msg, 0);
+}
+
+int read_int(int fd) {
+    int val;
+    xxread(fd, &val, sizeof(int));
+    return val;
+}
+
+void write_int(int fd, int val) {
+    if (fd < 0) return;
+    xwrite(fd, &val, sizeof(int));
+}
+
+char* read_string(int fd) {
+    int len = read_int(fd);
+    if (len > PATH_MAX || len < 0) {
+        LOGE("invalid string length %d", len);
+        exit(1);
+    }
+    char* val = xmalloc(sizeof(char) * (len + 1));
+    xxread(fd, val, len);
+    val[len] = '\0';
+    return val;
+}
+
+void write_string(int fd, const char* val) {
+    if (fd < 0) return;
+    int len = strlen(val);
+    write_int(fd, len);
+    xwrite(fd, val, len);
+}

jni/include/daemon.h

@@ -5,6 +5,7 @@
 #define _DAEMON_H_
 
 #include <pthread.h>
+#include <sys/un.h>
 
 extern pthread_t sepol_patch;
 extern int is_restart;
@@ -42,6 +43,10 @@ typedef enum {
 void start_daemon();
 int connect_daemon();
 void auto_start_magiskhide();
+
+// socket.c
+
+int setup_socket(struct sockaddr_un *sun);
 int recv_fd(int sockfd);
 void send_fd(int sockfd, int fd);
 int read_int(int fd);

jni/include/magisk.h

@@ -17,7 +17,6 @@
 #define LASTLOG         "/cache/last_magisk.log"
 #define DEBUG_LOG       "/data/magisk_debug.log"
 #define UNBLOCKFILE     "/dev/.magisk.unblock"
-#define PATCHSTART      "/dev/.magisk.patch.start"
 #define PATCHDONE       "/dev/.magisk.patch.done"
 #define DISABLEFILE     "/cache/.disable_magisk"
 #define UNINSTALLER     "/cache/magisk_uninstaller.sh"

jni/include/utils.h

@@ -89,6 +89,7 @@ int bind_mount(const char *from, const char *to);
 void get_client_cred(int fd, struct ucred *cred);
 int switch_mnt_ns(int pid);
 int fork_dont_care();
+void wait_till_exists(const char *target);
 
 // file.c
 

jni/utils/file.c

@@ -6,8 +6,10 @@
 #include <unistd.h>
 #include <errno.h>
 #include <string.h>
+#include <libgen.h>
 #include <sys/sendfile.h>
 #include <sys/mman.h>
+#include <sys/inotify.h>
 #include <linux/fs.h>
 
 #ifndef NO_SELINUX
@@ -216,6 +218,23 @@ void clone_dir(int src, int dest) {
 	}
 }
 
+void wait_till_exists(const char *target) {
+	if (access(target, F_OK) == 0)
+		return;
+	int fd = inotify_init();
+	char *dir = dirname(target);
+	char crap[PATH_MAX];
+	inotify_add_watch(fd, dir, IN_CREATE);
+	while (1) {
+		struct inotify_event event;
+		read(fd, &event, sizeof(event));
+		read(fd, crap, event.len);
+		if (access(target, F_OK) == 0)
+			break;
+	}
+	close(fd);
+}
+
 int getattr(const char *path, struct file_attr *a) {
 	if (xlstat(path, &a->st) == -1)
 		return -1;