Improve logging code.

- Write to log buffer ourselves instead of calling log, so the printed
  pid is correct
- Reduce debug spam

Change-Id: I9afe7249fc589268ea61419a7cfc724897981e9e

Superuser/jni/su/daemon.c

@@ -192,13 +192,13 @@ static void pump_async(int input, int output) {
 static int daemon_accept(int fd) {
     is_daemon = 1;
     int pid = read_int(fd);
-    LOGD("remote pid: %d", pid);
+    LOGV("remote pid: %d", pid);
     int atty = read_int(fd);
-    LOGD("remote atty: %d", atty);
+    LOGV("remote atty: %d", atty);
     daemon_from_uid = read_int(fd);
-    LOGD("remote uid: %d", daemon_from_uid);
+    LOGV("remote uid: %d", daemon_from_uid);
     daemon_from_pid = read_int(fd);
-    LOGD("remote req pid: %d", daemon_from_pid);
+    LOGV("remote req pid: %d", daemon_from_pid);
 
     struct ucred credentials;
     int ucred_length = sizeof(struct ucred);
@@ -221,7 +221,7 @@ static int daemon_accept(int fd) {
         LOGE("unable to allocate args: %d", argc);
         exit(-1);
     }
-    LOGD("remote args: %d", argc);
+    LOGV("remote args: %d", argc);
     char** argv = (char**)malloc(sizeof(char*) * (argc + 1));
     argv[argc] = NULL;
     int i;
@@ -272,7 +272,7 @@ static int daemon_accept(int fd) {
             close(ptm);
             exit(-1);
         }
-        LOGD("devname: %s", devname);
+        LOGV("devname: %s", devname);
     }
 
     int outfd = open(outfile, O_WRONLY);
@@ -359,7 +359,7 @@ static int daemon_accept(int fd) {
     // wait for the child to exit, and send the exit code
     // across the wire.
     int status;
-    LOGD("waiting for child exit");
+    LOGV("waiting for child exit");
     if (waitpid(child, &status, 0) > 0) {
         code = WEXITSTATUS(status);
     }
@@ -370,7 +370,7 @@ static int daemon_accept(int fd) {
 done:
     write(fd, &code, sizeof(int));
     close(fd);
-    LOGD("child exited");
+    LOGV("child exited");
     return code;
 }
 
@@ -473,7 +473,7 @@ int connect_daemon(int argc, char *argv[]) {
         exit(-1);
     }
 
-    LOGD("connecting client %d", getpid());
+    LOGV("connecting client %d", getpid());
 
     int mount_storage = getenv("MOUNT_EMULATED_STORAGE") != NULL;
 
@@ -516,6 +516,6 @@ int connect_daemon(int argc, char *argv[]) {
     pump(outfd, STDOUT_FILENO);
 
     int code = read_int(socketfd);
-    LOGD("client exited %d", code);
+    LOGV("client exited %d", code);
     return code;
 }

Superuser/jni/su/su.c

@@ -17,6 +17,7 @@
 
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/uio.h>
 #include <sys/un.h>
 #include <sys/wait.h>
 #include <sys/select.h>
@@ -81,48 +82,31 @@ int fork_zero_fucks() {
     }
 }
 
-void exec_log(char *priority, char* logline) {
-  int pid;
-  if ((pid = fork()) == 0) {
-      int null = open("/dev/null", O_WRONLY | O_CLOEXEC);
-      dup2(null, STDIN_FILENO);
-      dup2(null, STDOUT_FILENO);
-      dup2(null, STDERR_FILENO);
-      execl("/system/bin/log", "/system/bin/log", "-p", priority, "-t", LOG_TAG, logline, NULL);
-      _exit(0);
-  }
-  int status;
-  waitpid(pid, &status, 0);
-}
-
-void exec_loge(const char* fmt, ...) {
+void exec_log(int priority, const char* fmt, ...) {
+    static int log_fd = -1;
+    struct iovec vec[3];
     va_list args;
+    char msg[PATH_MAX];
 
-    char logline[PATH_MAX];
-    va_start(args, fmt);
-    vsnprintf(logline, PATH_MAX, fmt, args);
-    va_end(args);
-    exec_log("e", logline);
-}
-
-void exec_logw(const char* fmt, ...) {
-    va_list args;
+    if (log_fd < 0) {
+        log_fd = open("/dev/log/main", O_WRONLY);
+        if (log_fd < 0) {
+            return;
+        }
+    }
 
-    char logline[PATH_MAX];
     va_start(args, fmt);
-    vsnprintf(logline, PATH_MAX, fmt, args);
+    vsnprintf(msg, PATH_MAX, fmt, args);
     va_end(args);
-    exec_log("w", logline);
-}
 
-void exec_logd(const char* fmt, ...) {
-    va_list args;
+    vec[0].iov_base   = (unsigned char *) &priority;
+    vec[0].iov_len    = 1;
+    vec[1].iov_base   = (void *) LOG_TAG;
+    vec[1].iov_len    = strlen(LOG_TAG) + 1;
+    vec[2].iov_base   = (void *) msg;
+    vec[2].iov_len    = strlen(msg) + 1;
 
-    char logline[PATH_MAX];
-    va_start(args, fmt);
-    vsnprintf(logline, PATH_MAX, fmt, args);
-    va_end(args);
-    exec_log("d", logline);
+    writev(log_fd, vec, 3);
 }
 
 static int from_init(struct su_initiator *from) {
@@ -427,7 +411,7 @@ do {                                        \
 static int socket_receive_result(int fd, char *result, ssize_t result_len) {
     ssize_t len;
 
-    LOGD("waiting for user");
+    LOGV("waiting for user");
     len = read(fd, result, result_len-1);
     if (len < 0) {
         PLOGE("read(result)");

Superuser/jni/su/su.h

@@ -168,10 +168,6 @@ static inline char *get_command(const struct su_request *to)
   return DEFAULT_SHELL;
 }
 
-void exec_loge(const char* fmt, ...);
-void exec_logw(const char* fmt, ...);
-void exec_logd(const char* fmt, ...);
-
 int run_daemon();
 int connect_daemon(int argc, char *argv[]);
 int su_main(int argc, char *argv[], int need_client);
@@ -180,16 +176,31 @@ int su_main(int argc, char *argv[], int need_client);
 // deadbeat dad fork.
 int fork_zero_fucks();
 
-// fallback to using /system/bin/log.
-// can't use liblog.so because this is a static binary.
+// can't use liblog.so because this is a static binary, so we need
+// to implement this ourselves
+#include <android/log.h>
+
+void exec_log(int priority, const char* fmt, ...);
+
+#ifndef LOG_NDEBUG
+#define LOG_NDEBUG 1
+#endif
+
 #ifndef LOGE
-#define LOGE exec_loge
+#define LOGE(fmt,args...) exec_log(ANDROID_LOG_ERROR, fmt, ##args)
+#endif
+#ifndef LOGW
+#define LOGW(fmt,args...) exec_log(ANDROID_LOG_WARN, fmt, ##args)
 #endif
 #ifndef LOGD
-#define LOGD exec_logd
+#define LOGD(fmt,args...) exec_log(ANDROID_LOG_DEBUG, fmt, ##args)
+#endif
+#ifndef LOGV
+#if LOG_NDEBUG
+#define LOGV(...)   ((void)0)
+#else
+#define LOGV(fmt,args...) exec_log(ANDROID_LOG_VERBOSE, fmt, ##args)
 #endif
-#ifndef LOGW
-#define LOGW exec_logw
 #endif
 
 #if 0