Enrico Fraccaroli (Galfurian)
133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
/// @file more.c
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/// @brief `more` program.
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/// @copyright (c) 2014-2024 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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#include "stdbool.h"
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#include "stddef.h"
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/unistd.h>
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#include <strerror.h>
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#include <sys/stat.h>
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#include <termios.h>
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#include <limits.h>
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// Video dimensions defined in mentos/src/io/video.c
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#define HEIGHT 25
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#define WIDTH 80
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#define LAST_LINE (HEIGHT - 1)
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static void erase_backwards(int n)
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{
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for (int i = 0; i < n; i++) {
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putchar('\b');
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}
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}
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static void page_content(int fd)
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{
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int lines = 0;
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char line[WIDTH + 2];
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char *lineend;
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while ((lineend = fgets(line, WIDTH, fd))) {
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if (lineend - line == WIDTH && line[WIDTH - 1] != '\n') {
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line[WIDTH - 1] = '+';
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line[WIDTH] = '\n';
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line[WIDTH + 1] = 0;
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}
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printf("%s", line);
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lines++;
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if (lines == LAST_LINE) {
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int prompt = printf("--more--");
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int c;
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bool_t quit = false;
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do {
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c = getchar();
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if (c == 'q') {
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quit = true;
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} else if (c == '\n') {
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lines = LAST_LINE - 1;
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} else if (c == ' ') {
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lines = 0;
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} else {
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continue;
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}
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break;
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} while (1);
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erase_backwards(prompt);
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if (quit)
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exit(EXIT_SUCCESS);
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}
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}
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}
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int main(int argc, char **argv)
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{
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// Check if `--help` is provided.
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for (int i = 1; i < argc; ++i) {
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if ((strcmp(argv[i], "--help") == 0) || (strcmp(argv[i], "-h") == 0)) {
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printf("Display the content of a file.\n");
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printf("Usage:\n");
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printf(" more [FILE]\n");
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return 0;
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}
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}
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char buffer[PATH_MAX];
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char *filepath = argv[1];
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struct termios _termios;
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tcgetattr(STDIN_FILENO, &_termios);
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_termios.c_lflag &= ~(ICANON | ECHO);
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tcsetattr(STDIN_FILENO, 0, &_termios);
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int fd = STDOUT_FILENO;
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if (argc > 1) {
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// State the file.
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stat_t statbuf;
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if (stat(filepath, &statbuf) == -1) {
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printf("more: %s: %s\n", filepath, strerror(errno));
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exit(EXIT_FAILURE);
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}
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// Check if it is a link.
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if (S_ISLNK(statbuf.st_mode)) {
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// Read the content of the link.
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if (readlink(filepath, buffer, BUFSIZ) < 0) {
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printf("more: %s: %s\n\n", filepath, strerror(errno));
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exit(EXIT_FAILURE);
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}
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// Change the filepath.
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filepath = buffer;
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// Run the stat again, with the real file.
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if (stat(filepath, &statbuf) == -1) {
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printf("more: %s: %s\n", filepath, strerror(errno));
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exit(EXIT_FAILURE);
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}
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}
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// Check if it is a directory.
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if (S_ISDIR(statbuf.st_mode)) {
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printf("more: %s: Is a directory\n", filepath);
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exit(EXIT_FAILURE);
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}
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// If it is a regular file, open the file in read-only.
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if (S_ISREG(statbuf.st_mode)) {
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fd = open(filepath, O_RDONLY, 0);
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}
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if (fd < 0) {
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printf("more: %s: %s\n", filepath, strerror(errno));
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exit(EXIT_FAILURE);
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}
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}
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page_content(fd);
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return 0;
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}
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