auto import from //depot/cupcake/@135843

1 files changed, 181 insertions, 0 deletions

diff --git a/logwrapper/logwrapper.c b/logwrapper/logwrapper.c
new file mode 100644
index 0000000..f00bfbf
--- /dev/null
+++ b/logwrapper/logwrapper.c
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "private/android_filesystem_config.h"
+#include "cutils/log.h"
+
+void fatal(const char *msg) {
+    fprintf(stderr, msg);
+    LOG(LOG_ERROR, "logwrapper", msg);
+    exit(-1);
+}
+
+void usage() {
+    fatal(
+        "Usage: logwrapper [-x] BINARY [ARGS ...]\n"
+        "\n"
+        "Forks and executes BINARY ARGS, redirecting stdout and stderr to\n"
+        "the Android logging system. Tag is set to BINARY, priority is\n"
+        "always LOG_INFO.\n"
+        "\n"
+        "-x: Causes logwrapper to SIGSEGV when BINARY terminates\n"
+        "    fault address is set to the status of wait()\n");
+}
+
+void parent(const char *tag, int seg_fault_on_exit, int parent_read) {
+    int status;
+    char buffer[4096];
+
+    int a = 0;  // start index of unprocessed data
+    int b = 0;  // end index of unprocessed data
+    int sz;
+    while ((sz = read(parent_read, &buffer[b], sizeof(buffer) - 1 - b)) > 0) {
+
+        sz += b;
+        // Log one line at a time
+        for (b = 0; b < sz; b++) {
+            if (buffer[b] == '\r') {
+                buffer[b] = '\0';
+            } else if (buffer[b] == '\n') {
+                buffer[b] = '\0';
+                LOG(LOG_INFO, tag, &buffer[a]);
+                a = b + 1;
+            }
+        }
+
+        if (a == 0 && b == sizeof(buffer) - 1) {
+            // buffer is full, flush
+            buffer[b] = '\0';
+            LOG(LOG_INFO, tag, &buffer[a]);
+            b = 0;
+        } else if (a != b) {
+            // Keep left-overs
+            b -= a;
+            memmove(buffer, &buffer[a], b);
+            a = 0;
+        } else {
+            a = 0;
+            b = 0;
+        }
+
+    }
+    // Flush remaining data
+    if (a != b) {
+        buffer[b] = '\0';
+        LOG(LOG_INFO, tag, &buffer[a]);
+    }
+    status = 0xAAAA;
+    if (wait(&status) != -1) {  // Wait for child
+        if (WIFEXITED(status))
+            LOG(LOG_INFO, "logwrapper", "%s terminated by exit(%d)", tag,
+                    WEXITSTATUS(status));
+        else if (WIFSIGNALED(status))
+            LOG(LOG_INFO, "logwrapper", "%s terminated by signal %d", tag,
+                    WTERMSIG(status));
+        else if (WIFSTOPPED(status))
+            LOG(LOG_INFO, "logwrapper", "%s stopped by signal %d", tag,
+                    WSTOPSIG(status));
+    } else
+        LOG(LOG_INFO, "logwrapper", "%s wait() failed: %s (%d)", tag,
+                strerror(errno), errno);
+    if (seg_fault_on_exit)
+        *(int *)status = 0;  // causes SIGSEGV with fault_address = status
+}
+
+void child(int argc, char* argv[]) {
+    // create null terminated argv_child array
+    char* argv_child[argc + 1];
+    memcpy(argv_child, argv, argc * sizeof(char *));
+    argv_child[argc] = NULL;
+
+    if (execvp(argv_child[0], argv_child)) {
+        LOG(LOG_ERROR, "logwrapper",
+            "executing %s failed: %s\n", argv_child[0], strerror(errno));
+        exit(-1);
+    }
+}
+
+int main(int argc, char* argv[]) {
+    pid_t pid;
+    int seg_fault_on_exit = 0;
+
+    int parent_ptty;
+    int child_ptty;
+    char *child_devname = NULL;
+
+    if (argc < 2) {
+        usage();
+    }
+
+    if (strncmp(argv[1], "-d", 2) == 0) {
+        seg_fault_on_exit = 1;
+        argc--;
+        argv++;
+    }
+
+    if (argc < 2) {
+        usage();
+    }
+
+    /* Use ptty instead of socketpair so that STDOUT is not buffered */
+    parent_ptty = open("/dev/ptmx", O_RDWR);
+    if (parent_ptty < 0) {
+        fatal("Cannot create parent ptty\n");
+    }
+
+    if (grantpt(parent_ptty) || unlockpt(parent_ptty) ||
+            ((child_devname = (char*)ptsname(parent_ptty)) == 0)) {
+        fatal("Problem with /dev/ptmx\n");
+    }
+
+    pid = fork();
+    if (pid < 0) {
+        fatal("Failed to fork\n");
+    } else if (pid == 0) {
+        child_ptty = open(child_devname, O_RDWR);
+        if (child_ptty < 0) {
+            fatal("Problem with child ptty\n");
+        }
+
+        // redirect stdout and stderr
+        close(parent_ptty);
+        dup2(child_ptty, 1);
+        dup2(child_ptty, 2);
+        close(child_ptty);
+
+        child(argc - 1, &argv[1]);
+
+    } else {
+        // switch user and group to "log"
+        // this may fail if we are not root, 
+        // but in that case switching user/group is unnecessary 
+        setgid(AID_LOG);
+        setuid(AID_LOG);
+
+        parent(argv[1], seg_fault_on_exit, parent_ptty);
+    }
+
+    return 0;
+}