3 files changed, 158 insertions, 195 deletions

diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index 433d98026..5f9b437fe 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -1216,7 +1216,7 @@ static int PerformCommandDiff(CommandParameters& params) {
 
     size_t len;
     if (!android::base::ParseUint(params.tokens[params.cpos++].c_str(), &len)) {
-        fprintf(stderr, "invalid patch offset\n");
+        fprintf(stderr, "invalid patch len\n");
         return -1;
     }
 
@@ -1248,10 +1248,8 @@ static int PerformCommandDiff(CommandParameters& params) {
         if (status == 0) {
             fprintf(stderr, "patching %zu blocks to %zu\n", blocks, tgt.size);
 
-            Value patch_value;
-            patch_value.type = VAL_BLOB;
-            patch_value.size = len;
-            patch_value.data = (char*) (params.patch_start + offset);
+            Value patch_value(VAL_BLOB,
+                    std::string(reinterpret_cast<const char*>(params.patch_start + offset), len));
 
             RangeSinkState rss(tgt);
             rss.fd = params.fd;
@@ -1398,64 +1396,62 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
     Value* patch_data_fn = nullptr;
     if (ReadValueArgs(state, argv, 4, &blockdev_filename, &transfer_list_value,
             &new_data_fn, &patch_data_fn) < 0) {
-        return StringValue(strdup(""));
+        return StringValue("");
     }
-    std::unique_ptr<Value, decltype(&FreeValue)> blockdev_filename_holder(blockdev_filename,
-            FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> transfer_list_value_holder(transfer_list_value,
-            FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> new_data_fn_holder(new_data_fn, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> patch_data_fn_holder(patch_data_fn, FreeValue);
+    std::unique_ptr<Value> blockdev_filename_holder(blockdev_filename);
+    std::unique_ptr<Value> transfer_list_value_holder(transfer_list_value);
+    std::unique_ptr<Value> new_data_fn_holder(new_data_fn);
+    std::unique_ptr<Value> patch_data_fn_holder(patch_data_fn);
 
     if (blockdev_filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string",
                    name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (transfer_list_value->type != VAL_BLOB) {
         ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (new_data_fn->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (patch_data_fn->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string",
                    name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     UpdaterInfo* ui = reinterpret_cast<UpdaterInfo*>(state->cookie);
 
     if (ui == nullptr) {
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     FILE* cmd_pipe = ui->cmd_pipe;
     ZipArchive* za = ui->package_zip;
 
     if (cmd_pipe == nullptr || za == nullptr) {
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    const ZipEntry* patch_entry = mzFindZipEntry(za, patch_data_fn->data);
+    const ZipEntry* patch_entry = mzFindZipEntry(za, patch_data_fn->data.c_str());
     if (patch_entry == nullptr) {
-        fprintf(stderr, "%s(): no file \"%s\" in package", name, patch_data_fn->data);
-        return StringValue(strdup(""));
+        fprintf(stderr, "%s(): no file \"%s\" in package", name, patch_data_fn->data.c_str());
+        return StringValue("");
     }
 
     params.patch_start = ui->package_zip_addr + mzGetZipEntryOffset(patch_entry);
-    const ZipEntry* new_entry = mzFindZipEntry(za, new_data_fn->data);
+    const ZipEntry* new_entry = mzFindZipEntry(za, new_data_fn->data.c_str());
     if (new_entry == nullptr) {
-        fprintf(stderr, "%s(): no file \"%s\" in package", name, new_data_fn->data);
-        return StringValue(strdup(""));
+        fprintf(stderr, "%s(): no file \"%s\" in package", name, new_data_fn->data.c_str());
+        return StringValue("");
     }
 
-    params.fd.reset(TEMP_FAILURE_RETRY(ota_open(blockdev_filename->data, O_RDWR)));
+    params.fd.reset(TEMP_FAILURE_RETRY(ota_open(blockdev_filename->data.c_str(), O_RDWR)));
     if (params.fd == -1) {
-        fprintf(stderr, "open \"%s\" failed: %s\n", blockdev_filename->data, strerror(errno));
-        return StringValue(strdup(""));
+        fprintf(stderr, "open \"%s\" failed: %s\n", blockdev_filename->data.c_str(), strerror(errno));
+        return StringValue("");
     }
 
     if (params.canwrite) {
@@ -1471,24 +1467,21 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
         int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
         if (error != 0) {
             fprintf(stderr, "pthread_create failed: %s\n", strerror(error));
-            return StringValue(strdup(""));
+            return StringValue("");
         }
     }
 
-    // Copy all the lines in transfer_list_value into std::string for
-    // processing.
-    const std::string transfer_list(transfer_list_value->data, transfer_list_value->size);
-    std::vector<std::string> lines = android::base::Split(transfer_list, "\n");
+    std::vector<std::string> lines = android::base::Split(transfer_list_value->data, "\n");
     if (lines.size() < 2) {
         ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zd]\n",
                    lines.size());
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     // First line in transfer list is the version number
     if (!android::base::ParseInt(lines[0].c_str(), &params.version, 1, 4)) {
         fprintf(stderr, "unexpected transfer list version [%s]\n", lines[0].c_str());
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     fprintf(stderr, "blockimg version is %d\n", params.version);
@@ -1497,11 +1490,11 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
     int total_blocks;
     if (!android::base::ParseInt(lines[1].c_str(), &total_blocks, 0)) {
         ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]\n", lines[1].c_str());
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     if (total_blocks == 0) {
-        return StringValue(strdup("t"));
+        return StringValue("t");
     }
 
     size_t start = 2;
@@ -1509,7 +1502,7 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
         if (lines.size() < 4) {
             ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]\n",
                        lines.size());
-            return StringValue(strdup(""));
+            return StringValue("");
         }
 
         // Third line is how many stash entries are needed simultaneously
@@ -1520,12 +1513,12 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
         if (!android::base::ParseInt(lines[3].c_str(), &stash_max_blocks, 0)) {
             ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]\n",
                        lines[3].c_str());
-            return StringValue(strdup(""));
+            return StringValue("");
         }
 
-        int res = CreateStash(state, stash_max_blocks, blockdev_filename->data, params.stashbase);
+        int res = CreateStash(state, stash_max_blocks, blockdev_filename->data.c_str(), params.stashbase);
         if (res == -1) {
-            return StringValue(strdup(""));
+            return StringValue("");
         }
 
         params.createdstash = res;
@@ -1589,7 +1582,7 @@ static Value* PerformBlockImageUpdate(const char* name, State* state, int /* arg
         fprintf(stderr, "stashed %zu blocks\n", params.stashed);
         fprintf(stderr, "max alloc needed was %zu\n", params.buffer.size());
 
-        const char* partition = strrchr(blockdev_filename->data, '/');
+        const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
         if (partition != nullptr && *(partition+1) != 0) {
             fprintf(cmd_pipe, "log bytes_written_%s: %zu\n", partition + 1,
                     params.written * BLOCKSIZE);
@@ -1623,7 +1616,7 @@ pbiudone:
         state->cause_code = failure_type;
     }
 
-    return StringValue(rc == 0 ? strdup("t") : strdup(""));
+    return StringValue(rc == 0 ? "t" : "");
 }
 
 // The transfer list is a text file containing commands to
@@ -1721,27 +1714,26 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
     Value* ranges;
 
     if (ReadValueArgs(state, argv, 2, &blockdev_filename, &ranges) < 0) {
-        return StringValue(strdup(""));
+        return StringValue("");
     }
-    std::unique_ptr<Value, decltype(&FreeValue)> ranges_holder(ranges, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> blockdev_filename_holder(blockdev_filename,
-            FreeValue);
+    std::unique_ptr<Value> ranges_holder(ranges);
+    std::unique_ptr<Value> blockdev_filename_holder(blockdev_filename);
 
     if (blockdev_filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string",
                    name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (ranges->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    android::base::unique_fd fd(ota_open(blockdev_filename->data, O_RDWR));
+    android::base::unique_fd fd(ota_open(blockdev_filename->data.c_str(), O_RDWR));
     if (fd == -1) {
-        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", blockdev_filename->data,
-                   strerror(errno));
-        return StringValue(strdup(""));
+        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s",
+                   blockdev_filename->data.c_str(), strerror(errno));
+        return StringValue("");
     }
 
     RangeSet rs;
@@ -1753,16 +1745,16 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
     std::vector<uint8_t> buffer(BLOCKSIZE);
     for (size_t i = 0; i < rs.count; ++i) {
         if (!check_lseek(fd, (off64_t)rs.pos[i*2] * BLOCKSIZE, SEEK_SET)) {
-            ErrorAbort(state, kLseekFailure, "failed to seek %s: %s", blockdev_filename->data,
-                       strerror(errno));
-            return StringValue(strdup(""));
+            ErrorAbort(state, kLseekFailure, "failed to seek %s: %s",
+                       blockdev_filename->data.c_str(), strerror(errno));
+            return StringValue("");
         }
 
         for (size_t j = rs.pos[i*2]; j < rs.pos[i*2+1]; ++j) {
             if (read_all(fd, buffer, BLOCKSIZE) == -1) {
-                ErrorAbort(state, kFreadFailure, "failed to read %s: %s", blockdev_filename->data,
-                        strerror(errno));
-                return StringValue(strdup(""));
+                ErrorAbort(state, kFreadFailure, "failed to read %s: %s",
+                           blockdev_filename->data.c_str(), strerror(errno));
+                return StringValue("");
             }
 
             SHA1_Update(&ctx, buffer.data(), BLOCKSIZE);
@@ -1771,7 +1763,7 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
     uint8_t digest[SHA_DIGEST_LENGTH];
     SHA1_Final(digest, &ctx);
 
-    return StringValue(strdup(print_sha1(digest).c_str()));
+    return StringValue(print_sha1(digest));
 }
 
 // This function checks if a device has been remounted R/W prior to an incremental
@@ -1785,27 +1777,27 @@ Value* CheckFirstBlockFn(const char* name, State* state, int argc, Expr* argv[])
     if (ReadValueArgs(state, argv, 1, &arg_filename) < 0) {
         return nullptr;
     }
-    std::unique_ptr<Value, decltype(&FreeValue)> filename(arg_filename, FreeValue);
+    std::unique_ptr<Value> filename(arg_filename);
 
     if (filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    android::base::unique_fd fd(ota_open(arg_filename->data, O_RDONLY));
+    android::base::unique_fd fd(ota_open(arg_filename->data.c_str(), O_RDONLY));
     if (fd == -1) {
-        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", arg_filename->data,
+        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", arg_filename->data.c_str(),
                    strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     RangeSet blk0 {1 /*count*/, 1/*size*/, std::vector<size_t> {0, 1}/*position*/};
     std::vector<uint8_t> block0_buffer(BLOCKSIZE);
 
     if (ReadBlocks(blk0, block0_buffer, fd) == -1) {
-        ErrorAbort(state, kFreadFailure, "failed to read %s: %s", arg_filename->data,
+        ErrorAbort(state, kFreadFailure, "failed to read %s: %s", arg_filename->data.c_str(),
                 strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     // https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout
@@ -1823,7 +1815,7 @@ Value* CheckFirstBlockFn(const char* name, State* state, int argc, Expr* argv[])
         uiPrintf(state, "Last remount happened on %s", ctime(&mount_time));
     }
 
-    return StringValue(strdup("t"));
+    return StringValue("t");
 }
 
 
@@ -1835,40 +1827,40 @@ Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[
         return NULL;
     }
 
-    std::unique_ptr<Value, decltype(&FreeValue)> filename(arg_filename, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> ranges(arg_ranges, FreeValue);
+    std::unique_ptr<Value> filename(arg_filename);
+    std::unique_ptr<Value> ranges(arg_ranges);
 
     if (filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (ranges->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     // Output notice to log when recover is attempted
-    fprintf(stderr, "%s image corrupted, attempting to recover...\n", filename->data);
+    fprintf(stderr, "%s image corrupted, attempting to recover...\n", filename->data.c_str());
 
     // When opened with O_RDWR, libfec rewrites corrupted blocks when they are read
-    fec::io fh(filename->data, O_RDWR);
+    fec::io fh(filename->data.c_str(), O_RDWR);
 
     if (!fh) {
-        ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data,
+        ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data.c_str(),
                    strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     if (!fh.has_ecc() || !fh.has_verity()) {
         ErrorAbort(state, kLibfecFailure, "unable to use metadata to correct errors");
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     fec_status status;
 
     if (!fh.get_status(status)) {
         ErrorAbort(state, kLibfecFailure, "failed to read FEC status");
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     RangeSet rs;
@@ -1885,8 +1877,8 @@ Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[
 
             if (fh.pread(buffer, BLOCKSIZE, (off64_t)j * BLOCKSIZE) != BLOCKSIZE) {
                 ErrorAbort(state, kLibfecFailure, "failed to recover %s (block %zu): %s",
-                           filename->data, j, strerror(errno));
-                return StringValue(strdup(""));
+                           filename->data.c_str(), j, strerror(errno));
+                return StringValue("");
             }
 
             // If we want to be able to recover from a situation where rewriting a corrected
@@ -1901,8 +1893,8 @@ Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[
             //     read and check if the errors field value has increased.
         }
     }
-    fprintf(stderr, "...%s image recovered successfully.\n", filename->data);
-    return StringValue(strdup("t"));
+    fprintf(stderr, "...%s image recovered successfully.\n", filename->data.c_str());
+    return StringValue("t");
 }
 
 void RegisterBlockImageFunctions() {
diff --git a/updater/install.cpp b/updater/install.cpp
index 3546968d7..d723b3880 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -116,7 +116,7 @@ static int make_parents(char* name) {
 //
 //    fs_type="ext4"   partition_type="EMMC"    location=device
 Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char* result = NULL;
+    char* result = nullptr;
     if (argc != 4 && argc != 5) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 4-5 args, got %d", name, argc);
     }
@@ -197,7 +197,7 @@ done:
 
 // is_mounted(mount_point)
 Value* IsMountedFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char* result = NULL;
+    char* result = nullptr;
     if (argc != 1) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 1 arg, got %d", name, argc);
     }
@@ -227,7 +227,7 @@ done:
 
 
 Value* UnmountFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char* result = NULL;
+    char* result = nullptr;
     if (argc != 1) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 1 arg, got %d", name, argc);
     }
@@ -284,7 +284,7 @@ static int exec_cmd(const char* path, char* const argv[]) {
 //    if fs_size > 0, that is the size to use
 //    if fs_size < 0, then reserve that many bytes at the end of the partition (not for "f2fs")
 Value* FormatFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char* result = NULL;
+    char* result = nullptr;
     if (argc != 5) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 5 args, got %d", name, argc);
     }
@@ -358,7 +358,7 @@ done:
 }
 
 Value* RenameFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char* result = NULL;
+    char* result = nullptr;
     if (argc != 2) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 2 args, got %d", name, argc);
     }
@@ -397,15 +397,10 @@ done:
 }
 
 Value* DeleteFn(const char* name, State* state, int argc, Expr* argv[]) {
-    char** paths = reinterpret_cast<char**>(malloc(argc * sizeof(char*)));
+    std::vector<std::string> paths;
     for (int i = 0; i < argc; ++i) {
-        paths[i] = Evaluate(state, argv[i]);
-        if (paths[i] == NULL) {
-            for (int j = 0; j < i; ++j) {
-                free(paths[j]);
-            }
-            free(paths);
-            return NULL;
+        if (!Evaluate(state, argv[i], &paths[i])) {
+            return nullptr;
         }
     }
 
@@ -413,15 +408,12 @@ Value* DeleteFn(const char* name, State* state, int argc, Expr* argv[]) {
 
     int success = 0;
     for (int i = 0; i < argc; ++i) {
-        if ((recursive ? dirUnlinkHierarchy(paths[i]) : unlink(paths[i])) == 0)
+        if ((recursive ? dirUnlinkHierarchy(paths[i].c_str()) : unlink(paths[i].c_str())) == 0) {
             ++success;
-        free(paths[i]);
+        }
     }
-    free(paths);
 
-    char buffer[10];
-    sprintf(buffer, "%d", success);
-    return StringValue(strdup(buffer));
+    return StringValue(android::base::StringPrintf("%d", success));
 }
 
 
@@ -483,7 +475,7 @@ Value* PackageExtractDirFn(const char* name, State* state,
                                       NULL, NULL, sehandle);
     free(zip_path);
     free(dest_path);
-    return StringValue(strdup(success ? "t" : ""));
+    return StringValue(success ? "t" : "");
 }
 
 
@@ -536,7 +528,7 @@ Value* PackageExtractFileFn(const char* name, State* state,
       done2:
         free(zip_path);
         free(dest_path);
-        return StringValue(strdup(success ? "t" : ""));
+        return StringValue(success ? "t" : "");
     } else {
         // The one-argument version returns the contents of the file
         // as the result.
@@ -544,10 +536,7 @@ Value* PackageExtractFileFn(const char* name, State* state,
         char* zip_path;
         if (ReadArgs(state, argv, 1, &zip_path) < 0) return NULL;
 
-        Value* v = reinterpret_cast<Value*>(malloc(sizeof(Value)));
-        v->type = VAL_BLOB;
-        v->size = -1;
-        v->data = NULL;
+        Value* v = new Value(VAL_INVALID, "");
 
         ZipArchive* za = ((UpdaterInfo*)(state->cookie))->package_zip;
         const ZipEntry* entry = mzFindZipEntry(za, zip_path);
@@ -556,23 +545,16 @@ Value* PackageExtractFileFn(const char* name, State* state,
             goto done1;
         }
 
-        v->size = mzGetZipEntryUncompLen(entry);
-        v->data = reinterpret_cast<char*>(malloc(v->size));
-        if (v->data == NULL) {
-            printf("%s: failed to allocate %zd bytes for %s\n",
-                    name, v->size, zip_path);
-            goto done1;
-        }
-
+        v->data.resize(mzGetZipEntryUncompLen(entry));
         success = mzExtractZipEntryToBuffer(za, entry,
-                                            (unsigned char *)v->data);
+                reinterpret_cast<unsigned char *>(&v->data[0]));
 
       done1:
         free(zip_path);
         if (!success) {
-            free(v->data);
-            v->data = NULL;
-            v->size = -1;
+            v->data.clear();
+        } else {
+            v->type = VAL_BLOB;
         }
         return v;
     }
@@ -584,13 +566,13 @@ Value* SymlinkFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (argc == 0) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 1+ args, got %d", name, argc);
     }
-    char* target;
-    target = Evaluate(state, argv[0]);
-    if (target == NULL) return NULL;
+    std::string target;
+    if (!Evaluate(state, argv[0], &target)) {
+        return nullptr;
+    }
 
     char** srcs = ReadVarArgs(state, argc-1, argv+1);
     if (srcs == NULL) {
-        free(target);
         return NULL;
     }
 
@@ -606,12 +588,12 @@ Value* SymlinkFn(const char* name, State* state, int argc, Expr* argv[]) {
         }
         if (make_parents(srcs[i])) {
             printf("%s: failed to symlink %s to %s: making parents failed\n",
-                    name, srcs[i], target);
+                    name, srcs[i], target.c_str());
             ++bad;
         }
-        if (symlink(target, srcs[i]) < 0) {
+        if (symlink(target.c_str(), srcs[i]) < 0) {
             printf("%s: failed to symlink %s to %s: %s\n",
-                    name, srcs[i], target, strerror(errno));
+                    name, srcs[i], target.c_str(), strerror(errno));
             ++bad;
         }
         free(srcs[i]);
@@ -620,7 +602,7 @@ Value* SymlinkFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (bad) {
         return ErrorAbort(state, kSymlinkFailure, "%s: some symlinks failed", name);
     }
-    return StringValue(strdup(""));
+    return StringValue("");
 }
 
 struct perm_parsed_args {
@@ -883,20 +865,20 @@ done:
         return ErrorAbort(state, kSetMetadataFailure, "%s: some changes failed", name);
     }
 
-    return StringValue(strdup(""));
+    return StringValue("");
 }
 
 Value* GetPropFn(const char* name, State* state, int argc, Expr* argv[]) {
     if (argc != 1) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects 1 arg, got %d", name, argc);
     }
-    char* key = Evaluate(state, argv[0]);
-    if (key == NULL) return NULL;
-
+    std::string key;
+    if (!Evaluate(state, argv[0], &key)) {
+        return nullptr;
+    }
     std::string value = android::base::GetProperty(key, "");
-    free(key);
 
-    return StringValue(strdup(value.c_str()));
+    return StringValue(value);
 }
 
 
@@ -1015,7 +997,7 @@ Value* ApplyPatchSpaceFn(const char* name, State* state,
         return nullptr;
     }
 
-    return StringValue(strdup(CacheSizeCheck(bytes) ? "" : "t"));
+    return StringValue(CacheSizeCheck(bytes) ? "" : "t");
 }
 
 // apply_patch(file, size, init_sha1, tgt_sha1, patch)
@@ -1047,17 +1029,16 @@ Value* ApplyPatchFn(const char* name, State* state, int argc, Expr* argv[]) {
     }
 
     int patchcount = (argc-4) / 2;
-    std::unique_ptr<Value*, decltype(&free)> arg_values(ReadValueVarArgs(state, argc-4, argv+4),
-                                                        free);
+    std::unique_ptr<Value*> arg_values(ReadValueVarArgs(state, argc-4, argv+4));
     if (!arg_values) {
         return nullptr;
     }
-    std::vector<std::unique_ptr<Value, decltype(&FreeValue)>> patch_shas;
-    std::vector<std::unique_ptr<Value, decltype(&FreeValue)>> patches;
+    std::vector<std::unique_ptr<Value>> patch_shas;
+    std::vector<std::unique_ptr<Value>> patches;
     // Protect values by unique_ptrs first to get rid of memory leak.
     for (int i = 0; i < patchcount * 2; i += 2) {
-        patch_shas.emplace_back(arg_values.get()[i], FreeValue);
-        patches.emplace_back(arg_values.get()[i+1], FreeValue);
+        patch_shas.emplace_back(arg_values.get()[i]);
+        patches.emplace_back(arg_values.get()[i+1]);
     }
 
     for (int i = 0; i < patchcount; ++i) {
@@ -1071,7 +1052,7 @@ Value* ApplyPatchFn(const char* name, State* state, int argc, Expr* argv[]) {
         }
     }
 
-    std::vector<char*> patch_sha_str;
+    std::vector<std::string> patch_sha_str;
     std::vector<Value*> patch_ptrs;
     for (int i = 0; i < patchcount; ++i) {
         patch_sha_str.push_back(patch_shas[i]->data);
@@ -1080,9 +1061,9 @@ Value* ApplyPatchFn(const char* name, State* state, int argc, Expr* argv[]) {
 
     int result = applypatch(source_filename, target_filename,
                             target_sha1, target_size,
-                            patchcount, patch_sha_str.data(), patch_ptrs.data(), NULL);
+                            patch_sha_str, patch_ptrs.data(), NULL);
 
-    return StringValue(strdup(result == 0 ? "t" : ""));
+    return StringValue(result == 0 ? "t" : "");
 }
 
 // apply_patch_check(file, [sha1_1, ...])
@@ -1095,21 +1076,17 @@ Value* ApplyPatchCheckFn(const char* name, State* state,
 
     char* filename;
     if (ReadArgs(state, argv, 1, &filename) < 0) {
-        return NULL;
+        return nullptr;
     }
 
-    int patchcount = argc-1;
-    char** sha1s = ReadVarArgs(state, argc-1, argv+1);
-
-    int result = applypatch_check(filename, patchcount, sha1s);
-
-    int i;
-    for (i = 0; i < patchcount; ++i) {
-        free(sha1s[i]);
+    std::vector<std::string> sha1s;
+    if (!ReadArgs(state, argc-1, argv+1, &sha1s)) {
+        return nullptr;
     }
-    free(sha1s);
 
-    return StringValue(strdup(result == 0 ? "t" : ""));
+    int result = applypatch_check(filename, sha1s);
+
+    return StringValue(result == 0 ? "t" : "");
 }
 
 // This is the updater side handler for ui_print() in edify script. Contents
@@ -1129,7 +1106,7 @@ Value* UIPrintFn(const char* name, State* state, int argc, Expr* argv[]) {
 
     buffer += "\n";
     uiPrint(state, buffer);
-    return StringValue(strdup(buffer.c_str()));
+    return StringValue(buffer);
 }
 
 Value* WipeCacheFn(const char* name, State* state, int argc, Expr* argv[]) {
@@ -1137,7 +1114,7 @@ Value* WipeCacheFn(const char* name, State* state, int argc, Expr* argv[]) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects no args, got %d", name, argc);
     }
     fprintf(((UpdaterInfo*)(state->cookie))->cmd_pipe, "wipe_cache\n");
-    return StringValue(strdup("t"));
+    return StringValue("t");
 }
 
 Value* RunProgramFn(const char* name, State* state, int argc, Expr* argv[]) {
@@ -1180,10 +1157,7 @@ Value* RunProgramFn(const char* name, State* state, int argc, Expr* argv[]) {
     free(args);
     free(args2);
 
-    char buffer[20];
-    sprintf(buffer, "%d", status);
-
-    return StringValue(strdup(buffer));
+    return StringValue(android::base::StringPrintf("%d", status));
 }
 
 // sha1_check(data)
@@ -1199,32 +1173,32 @@ Value* Sha1CheckFn(const char* name, State* state, int argc, Expr* argv[]) {
         return ErrorAbort(state, kArgsParsingFailure, "%s() expects at least 1 arg", name);
     }
 
-    std::unique_ptr<Value*, decltype(&free)> arg_values(ReadValueVarArgs(state, argc, argv), free);
+    std::unique_ptr<Value*> arg_values(ReadValueVarArgs(state, argc, argv));
     if (arg_values == nullptr) {
         return nullptr;
     }
-    std::vector<std::unique_ptr<Value, decltype(&FreeValue)>> args;
+    std::vector<std::unique_ptr<Value>> args;
     for (int i = 0; i < argc; ++i) {
-        args.emplace_back(arg_values.get()[i], FreeValue);
+        args.emplace_back(arg_values.get()[i]);
     }
 
-    if (args[0]->size < 0) {
-        return StringValue(strdup(""));
+    if (args[0]->type == VAL_INVALID) {
+        return StringValue("");
     }
     uint8_t digest[SHA_DIGEST_LENGTH];
-    SHA1(reinterpret_cast<uint8_t*>(args[0]->data), args[0]->size, digest);
+    SHA1(reinterpret_cast<const uint8_t*>(args[0]->data.c_str()), args[0]->data.size(), digest);
 
     if (argc == 1) {
-        return StringValue(strdup(print_sha1(digest).c_str()));
+        return StringValue(print_sha1(digest));
     }
 
     for (int i = 1; i < argc; ++i) {
         uint8_t arg_digest[SHA_DIGEST_LENGTH];
         if (args[i]->type != VAL_STRING) {
             printf("%s(): arg %d is not a string; skipping", name, i);
-        } else if (ParseSha1(args[i]->data, arg_digest) != 0) {
+        } else if (ParseSha1(args[i]->data.c_str(), arg_digest) != 0) {
             // Warn about bad args and skip them.
-            printf("%s(): error parsing \"%s\" as sha-1; skipping", name, args[i]->data);
+            printf("%s(): error parsing \"%s\" as sha-1; skipping", name, args[i]->data.c_str());
         } else if (memcmp(digest, arg_digest, SHA_DIGEST_LENGTH) == 0) {
             // Found a match.
             return args[i].release();
@@ -1232,7 +1206,7 @@ Value* Sha1CheckFn(const char* name, State* state, int argc, Expr* argv[]) {
     }
 
     // Didn't match any of the hex strings; return false.
-    return StringValue(strdup(""));
+    return StringValue("");
 }
 
 // Read a local file and return its contents (the Value* returned
@@ -1244,21 +1218,12 @@ Value* ReadFileFn(const char* name, State* state, int argc, Expr* argv[]) {
     char* filename;
     if (ReadArgs(state, argv, 1, &filename) < 0) return NULL;
 
-    Value* v = static_cast<Value*>(malloc(sizeof(Value)));
-    if (v == nullptr) {
-        return nullptr;
-    }
-    v->type = VAL_BLOB;
-    v->size = -1;
-    v->data = nullptr;
+    Value* v = new Value(VAL_INVALID, "");
 
     FileContents fc;
     if (LoadFileContents(filename, &fc) == 0) {
-        v->data = static_cast<char*>(malloc(fc.data.size()));
-        if (v->data != nullptr) {
-            memcpy(v->data, fc.data.data(), fc.data.size());
-            v->size = fc.data.size();
-        }
+        v->type = VAL_BLOB;
+        v->data = std::string(fc.data.begin(), fc.data.end());
     }
     free(filename);
     return v;
@@ -1326,16 +1291,19 @@ Value* SetStageFn(const char* name, State* state, int argc, Expr* argv[]) {
     // package installation.
     FILE* f = ota_fopen(filename, "r+b");
     fseek(f, offsetof(struct bootloader_message, stage), SEEK_SET);
-    int to_write = strlen(stagestr)+1;
-    int max_size = sizeof(((struct bootloader_message*)0)->stage);
+    size_t to_write = strlen(stagestr) + 1;
+    size_t max_size = sizeof(((struct bootloader_message*)0)->stage);
     if (to_write > max_size) {
         to_write = max_size;
-        stagestr[max_size-1] = 0;
+        stagestr[max_size - 1] = 0;
     }
-    ota_fwrite(stagestr, to_write, 1, f);
+    size_t status = ota_fwrite(stagestr, to_write, 1, f);
     ota_fclose(f);
 
     free(stagestr);
+    if (status != to_write) {
+        return StringValue("");
+    }
     return StringValue(filename);
 }
 
@@ -1352,11 +1320,14 @@ Value* GetStageFn(const char* name, State* state, int argc, Expr* argv[]) {
     char buffer[sizeof(((struct bootloader_message*)0)->stage)];
     FILE* f = ota_fopen(filename, "rb");
     fseek(f, offsetof(struct bootloader_message, stage), SEEK_SET);
-    ota_fread(buffer, sizeof(buffer), 1, f);
+    size_t status = ota_fread(buffer, sizeof(buffer), 1, f);
     ota_fclose(f);
-    buffer[sizeof(buffer)-1] = '\0';
+    if (status != sizeof(buffer)) {
+        return StringValue("");
+    }
 
-    return StringValue(strdup(buffer));
+    buffer[sizeof(buffer)-1] = '\0';
+    return StringValue(buffer);
 }
 
 Value* WipeBlockDeviceFn(const char* name, State* state, int argc, Expr* argv[]) {
@@ -1378,7 +1349,7 @@ Value* WipeBlockDeviceFn(const char* name, State* state, int argc, Expr* argv[])
 
     ota_close(fd);
 
-    return StringValue(strdup(success ? "t" : ""));
+    return StringValue(success ? "t" : "");
 }
 
 Value* EnableRebootFn(const char* name, State* state, int argc, Expr* argv[]) {
@@ -1387,7 +1358,7 @@ Value* EnableRebootFn(const char* name, State* state, int argc, Expr* argv[]) {
     }
     UpdaterInfo* ui = (UpdaterInfo*)(state->cookie);
     fprintf(ui->cmd_pipe, "enable_reboot\n");
-    return StringValue(strdup("t"));
+    return StringValue("t");
 }
 
 Value* Tune2FsFn(const char* name, State* state, int argc, Expr* argv[]) {
@@ -1418,7 +1389,7 @@ Value* Tune2FsFn(const char* name, State* state, int argc, Expr* argv[]) {
         return ErrorAbort(state, kTune2FsFailure, "%s() returned error code %d",
                           name, result);
     }
-    return StringValue(strdup("t"));
+    return StringValue("t");
 }
 
 void RegisterInstallFunctions() {
diff --git a/updater/updater.cpp b/updater/updater.cpp
index f65fb2b20..0d19e53c4 100644
--- a/updater/updater.cpp
+++ b/updater/updater.cpp
@@ -152,13 +152,14 @@ int main(int argc, char** argv) {
         }
     }
 
-    char* result = Evaluate(&state, root);
+    std::string result;
+    bool status = Evaluate(&state, root, &result);
 
     if (have_eio_error) {
         fprintf(cmd_pipe, "retry_update\n");
     }
 
-    if (result == NULL) {
+    if (!status) {
         if (state.errmsg.empty()) {
             printf("script aborted (no error message)\n");
             fprintf(cmd_pipe, "ui_print script aborted (no error message)\n");
@@ -189,8 +190,7 @@ int main(int argc, char** argv) {
 
         return 7;
     } else {
-        fprintf(cmd_pipe, "ui_print script succeeded: result was [%s]\n", result);
-        free(result);
+        fprintf(cmd_pipe, "ui_print script succeeded: result was [%s]\n", result.c_str());
     }
 
     if (updater_info.package_zip) {