Move to modern utility methods from android::base.

Moves away from crufty char* operations to std::string utility
methods, including android::base methods for splitting/parsing.

Rewrite of how Process handles scanning procfs for filesystem
references; now uses fts(3) for more sane traversal.

Replace sscanf() with new FindValue() method, also has unit tests.

Remove some unused methods.  Switch almost everyone over to using
modern logging library.

Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Test: cts-tradefed run commandAndExit cts-dev --abi armeabi-v7a -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.AdoptableHostTest
Bug: 67041047
Change-Id: I70dc512f21459d1e25b187f24289002b2c7bc7af
diff --git a/Loop.cpp b/Loop.cpp
index 1eb9865..3736d6a 100644
--- a/Loop.cpp
+++ b/Loop.cpp
@@ -31,11 +31,8 @@
 
 #include <linux/kdev_t.h>
 
-#define LOG_TAG "Vold"
-
-#include <cutils/log.h>
-
 #include <android-base/logging.h>
+#include <android-base/strings.h>
 #include <android-base/stringprintf.h>
 #include <android-base/unique_fd.h>
 #include <utils/Trace.h>
@@ -49,161 +46,6 @@
 
 static const char* kVoldPrefix = "vold:";
 
-int Loop::lookupActive(const char *id_raw, char *buffer, size_t len) {
-    auto id_string = StringPrintf("%s%s", kVoldPrefix, id_raw);
-    const char* id = id_string.c_str();
-
-    int i;
-    int fd;
-    char filename[256];
-
-    memset(buffer, 0, len);
-
-    for (i = 0; i < LOOP_MAX; i++) {
-        struct loop_info64 li;
-        int rc;
-
-        snprintf(filename, sizeof(filename), "/dev/block/loop%d", i);
-
-        if ((fd = open(filename, O_RDWR | O_CLOEXEC)) < 0) {
-            if (errno != ENOENT) {
-                SLOGE("Unable to open %s (%s)", filename, strerror(errno));
-            } else {
-                continue;
-            }
-            return -1;
-        }
-
-        rc = ioctl(fd, LOOP_GET_STATUS64, &li);
-        if (rc < 0 && errno == ENXIO) {
-            close(fd);
-            continue;
-        }
-        close(fd);
-
-        if (rc < 0) {
-            SLOGE("Unable to get loop status for %s (%s)", filename,
-                 strerror(errno));
-            return -1;
-        }
-        if (!strncmp((const char*) li.lo_crypt_name, id, LO_NAME_SIZE)) {
-            break;
-        }
-    }
-
-    if (i == LOOP_MAX) {
-        errno = ENOENT;
-        return -1;
-    }
-    strlcpy(buffer, filename, len);
-    return 0;
-}
-
-int Loop::create(const char *id_raw, const char *loopFile, char *loopDeviceBuffer, size_t len) {
-    auto id_string = StringPrintf("%s%s", kVoldPrefix, id_raw);
-    const char* id = id_string.c_str();
-
-    int i;
-    int fd;
-    char filename[256];
-
-    for (i = 0; i < LOOP_MAX; i++) {
-        struct loop_info64 li;
-        int rc;
-        char *secontext = NULL;
-
-        snprintf(filename, sizeof(filename), "/dev/block/loop%d", i);
-
-        /*
-         * The kernel starts us off with 8 loop nodes, but more
-         * are created on-demand if needed.
-         */
-        mode_t mode = 0660 | S_IFBLK;
-        unsigned int dev = (0xff & i) | ((i << 12) & 0xfff00000) | (7 << 8);
-
-        if (sehandle) {
-            rc = selabel_lookup(sehandle, &secontext, filename, S_IFBLK);
-            if (rc == 0)
-                setfscreatecon(secontext);
-        }
-
-        if (mknod(filename, mode, dev) < 0) {
-            if (errno != EEXIST) {
-                int sverrno = errno;
-                SLOGE("Error creating loop device node (%s)", strerror(errno));
-                if (secontext) {
-                    freecon(secontext);
-                    setfscreatecon(NULL);
-                }
-                errno = sverrno;
-                return -1;
-            }
-        }
-        if (secontext) {
-            freecon(secontext);
-            setfscreatecon(NULL);
-        }
-
-        if ((fd = open(filename, O_RDWR | O_CLOEXEC)) < 0) {
-            SLOGE("Unable to open %s (%s)", filename, strerror(errno));
-            return -1;
-        }
-
-        rc = ioctl(fd, LOOP_GET_STATUS64, &li);
-        if (rc < 0 && errno == ENXIO)
-            break;
-
-        close(fd);
-
-        if (rc < 0) {
-            SLOGE("Unable to get loop status for %s (%s)", filename,
-                 strerror(errno));
-            return -1;
-        }
-    }
-
-    if (i == LOOP_MAX) {
-        SLOGE("Exhausted all loop devices");
-        errno = ENOSPC;
-        return -1;
-    }
-
-    strlcpy(loopDeviceBuffer, filename, len);
-
-    int file_fd;
-
-    if ((file_fd = open(loopFile, O_RDWR | O_CLOEXEC)) < 0) {
-        SLOGE("Unable to open %s (%s)", loopFile, strerror(errno));
-        close(fd);
-        return -1;
-    }
-
-    if (ioctl(fd, LOOP_SET_FD, file_fd) < 0) {
-        SLOGE("Error setting up loopback interface (%s)", strerror(errno));
-        close(file_fd);
-        close(fd);
-        return -1;
-    }
-
-    struct loop_info64 li;
-
-    memset(&li, 0, sizeof(li));
-    strlcpy((char*) li.lo_crypt_name, id, LO_NAME_SIZE);
-    strlcpy((char*) li.lo_file_name, loopFile, LO_NAME_SIZE);
-
-    if (ioctl(fd, LOOP_SET_STATUS64, &li) < 0) {
-        SLOGE("Error setting loopback status (%s)", strerror(errno));
-        close(file_fd);
-        close(fd);
-        return -1;
-    }
-
-    close(fd);
-    close(file_fd);
-
-    return 0;
-}
-
 int Loop::create(const std::string& target, std::string& out_device) {
     unique_fd ctl_fd(open("/dev/loop-control", O_RDWR | O_CLOEXEC));
     if (ctl_fd.get() == -1) {
@@ -251,12 +93,12 @@
 
     device_fd = open(loopDevice, O_RDONLY | O_CLOEXEC);
     if (device_fd < 0) {
-        SLOGE("Failed to open loop (%d)", errno);
+        PLOG(ERROR) << "Failed to open " << loopDevice;
         return -1;
     }
 
     if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
-        SLOGE("Failed to destroy loop (%d)", errno);
+        PLOG(ERROR) << "Failed to destroy " << loopDevice;
         close(device_fd);
         return -1;
     }
@@ -279,7 +121,8 @@
 
     // Poke through all devices looking for loops
     while ((de = readdir(dir))) {
-        if (strncmp(de->d_name, "loop", 4) != 0) continue;
+        auto test = std::string(de->d_name);
+        if (!android::base::StartsWith(test, "loop")) continue;
 
         auto path = root + de->d_name;
         unique_fd fd(open(path.c_str(), O_RDWR | O_CLOEXEC));
@@ -296,8 +139,8 @@
             continue;
         }
 
-        char* id = (char*) li.lo_crypt_name;
-        if (strncmp(id, kVoldPrefix, strlen(kVoldPrefix)) == 0) {
+        auto id = std::string((char*) li.lo_crypt_name);
+        if (android::base::StartsWith(id, kVoldPrefix)) {
             LOG(DEBUG) << "Tearing down stale loop device at " << path << " named " << id;
 
             if (ioctl(fd.get(), LOOP_CLR_FD, 0) < 0) {
@@ -332,22 +175,22 @@
     int fd;
 
     if ((fd = open(file, O_RDWR | O_CLOEXEC)) < 0) {
-        SLOGE("Error opening imagefile (%s)", strerror(errno));
+        PLOG(ERROR) << "Failed to open " << file;
         return -1;
     }
 
-    SLOGD("Attempting to increase size of %s to %lu sectors.", file, numSectors);
+    LOG(DEBUG) << "Attempting to increase " << file << " to " << numSectors;
 
     if (fallocate(fd, 0, 0, numSectors * 512)) {
         if (errno == ENOSYS || errno == ENOTSUP) {
-            SLOGW("fallocate not found. Falling back to ftruncate.");
+            PLOG(WARNING) << "fallocate not found. Falling back to ftruncate.";
             if (ftruncate(fd, numSectors * 512) < 0) {
-                SLOGE("Error truncating imagefile (%s)", strerror(errno));
+                PLOG(ERROR) << "Failed to ftruncate";
                 close(fd);
                 return -1;
             }
         } else {
-            SLOGE("Error allocating space (%s)", strerror(errno));
+            PLOG(ERROR) << "Failed to fallocate";
             close(fd);
             return -1;
         }