toaruos/apps/cat.c

82 lines
1.5 KiB
C

/**
* @brief cat - Concatenate files
*
* Concatenates files together to standard output.
* In a supporting terminal, you can then pipe
* standard out to another file or other useful
* things like that.
*
* @copyright
* This file is part of ToaruOS and is released under the terms
* of the NCSA / University of Illinois License - see LICENSE.md
* Copyright (C) 2013-2018 K. Lange
*/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#define CHUNK_SIZE 4096
static char * _argv_0;
static char * _file;
void doit(int fd) {
while (1) {
char buf[CHUNK_SIZE];
memset(buf, 0, CHUNK_SIZE);
ssize_t r = read(fd, buf, CHUNK_SIZE);
if (!r) return;
if (r < 0) {
fprintf(stderr, "%s: %s: %s\n", _argv_0, _file, strerror(errno));
return;
}
write(STDOUT_FILENO, buf, r);
}
}
int main(int argc, char ** argv) {
int ret = 0;
_argv_0 = argv[0];
if (argc == 1) {
_file = "stdin";
doit(0);
}
for (int i = 1; i < argc; ++i) {
if (!strcmp(argv[i],"-")) {
_file = "stdin";
doit(0);
continue;
}
_file = argv[i];
int fd = open(argv[i], O_RDONLY);
if (fd < 0) {
fprintf(stderr, "%s: %s: %s\n", argv[0], argv[i], strerror(errno));
ret = 1;
continue;
}
struct stat _stat;
fstat(fd, &_stat);
if (S_ISDIR(_stat.st_mode)) {
fprintf(stderr, "%s: %s: Is a directory\n", argv[0], argv[i]);
close(fd);
ret = 1;
continue;
}
doit(fd);
close(fd);
}
return ret;
}