Userland: Move command-line utilities to Userland/Utilities/

Userland/Utilities/truncate.cpp

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibCore/ArgsParser.h>
+
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+enum TruncateOperation {
+    OP_Set,
+    OP_Grow,
+    OP_Shrink,
+};
+
+int main(int argc, char** argv)
+{
+    const char* resize = nullptr;
+    const char* reference = nullptr;
+    const char* file = nullptr;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(resize, "Resize the target file to (or by) this size. Prefix with + or - to expand or shrink the file, or a bare number to set the size exactly", "size", 's', "size");
+    args_parser.add_option(reference, "Resize the target file to match the size of this one", "reference", 'r', "file");
+    args_parser.add_positional_argument(file, "File path", "file");
+    args_parser.parse(argc, argv);
+
+    if (!resize && !reference) {
+        args_parser.print_usage(stderr, argv[0]);
+        return 1;
+    }
+
+    if (resize && reference) {
+        args_parser.print_usage(stderr, argv[0]);
+        return 1;
+    }
+
+    auto op = OP_Set;
+    int size = 0;
+
+    if (resize) {
+        String str = resize;
+
+        switch (str[0]) {
+        case '+':
+            op = OP_Grow;
+            str = str.substring(1, str.length() - 1);
+            break;
+        case '-':
+            op = OP_Shrink;
+            str = str.substring(1, str.length() - 1);
+            break;
+        }
+
+        auto size_opt = str.to_int();
+        if (!size_opt.has_value()) {
+            args_parser.print_usage(stderr, argv[0]);
+            return 1;
+        }
+        size = size_opt.value();
+    }
+
+    if (reference) {
+        struct stat st;
+        int rc = stat(reference, &st);
+        if (rc < 0) {
+            perror("stat");
+            return 1;
+        }
+
+        size = st.st_size;
+    }
+
+    int fd = open(file, O_RDWR | O_CREAT, 0666);
+    if (fd < 0) {
+        perror("open");
+        return 1;
+    }
+
+    struct stat st;
+    if (fstat(fd, &st) < 0) {
+        perror("fstat");
+        return 1;
+    }
+
+    switch (op) {
+    case OP_Set:
+        break;
+    case OP_Grow:
+        size = st.st_size + size;
+        break;
+    case OP_Shrink:
+        size = st.st_size - size;
+        break;
+    }
+
+    if (ftruncate(fd, size) < 0) {
+        perror("ftruncate");
+        return 1;
+    }
+
+    if (close(fd) < 0) {
+        perror("close");
+        return 1;
+    }
+
+    return 0;
+}