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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <LibCore/ArgsParser.h>
28
29#include <stdio.h>
30#include <sys/stat.h>
31#include <unistd.h>
32
33enum TruncateOperation {
34 OP_Set,
35 OP_Grow,
36 OP_Shrink,
37};
38
39int main(int argc, char** argv)
40{
41 const char* resize = nullptr;
42 const char* reference = nullptr;
43 const char* file = nullptr;
44
45 Core::ArgsParser args_parser;
46 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");
47 args_parser.add_option(reference, "Resize the target file to match the size of this one", "reference", 'r', "file");
48 args_parser.add_positional_argument(file, "File path", "file");
49 args_parser.parse(argc, argv);
50
51 if (!resize && !reference) {
52 args_parser.print_usage(stderr, argv[0]);
53 return 1;
54 }
55
56 if (resize && reference) {
57 args_parser.print_usage(stderr, argv[0]);
58 return 1;
59 }
60
61 auto op = OP_Set;
62 int size = 0;
63
64 if (resize) {
65 String str = resize;
66
67 switch (str[0]) {
68 case '+':
69 op = OP_Grow;
70 str = str.substring(1, str.length() - 1);
71 break;
72 case '-':
73 op = OP_Shrink;
74 str = str.substring(1, str.length() - 1);
75 break;
76 }
77
78 bool ok;
79 size = str.to_int(ok);
80 if (!ok) {
81 args_parser.print_usage(stderr, argv[0]);
82 return 1;
83 }
84 }
85
86 if (reference) {
87 struct stat st;
88 int rc = stat(reference, &st);
89 if (rc < 0) {
90 perror("stat");
91 return 1;
92 }
93
94 size = st.st_size;
95 }
96
97 int fd = open(file, O_RDWR | O_CREAT, 0666);
98 if (fd < 0) {
99 perror("open");
100 return 1;
101 }
102
103 struct stat st;
104 if (fstat(fd, &st) < 0) {
105 perror("fstat");
106 return 1;
107 }
108
109 switch (op) {
110 case OP_Set:
111 break;
112 case OP_Grow:
113 size = st.st_size + size;
114 break;
115 case OP_Shrink:
116 size = st.st_size - size;
117 break;
118 }
119
120 if (ftruncate(fd, size) < 0) {
121 perror("ftruncate");
122 return 1;
123 }
124
125 if (close(fd) < 0) {
126 perror("close");
127 return 1;
128 }
129
130 return 0;
131}