A toy operating system written in C.
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freywaros/src/user/app/cat/cat.c

47 lines
944 B

#include "src/lib/util.h"
#include "src/user/syscall.h"
#define BLOCK_SIZE 65536
#define PRINT_S(s) write(1, s, sizeof(s) - 1);
#define PRINT_D(s) write(1, s, string_length(s));
exit_code_t cat(const char *path) {
uint64_t fd = open(path);
if (fd == (uint64_t)-1) {
PRINT_S("cat: path does not exist\n");
return EXIT_CODE_GENERAL_FAILURE;
}
static char buffer[BLOCK_SIZE];
uint64_t bytes;
while ((bytes = read(fd, BLOCK_SIZE, buffer))) {
if (bytes == (uint64_t)-1) {
PRINT_S("cat: could not read file\n");
close(fd);
return EXIT_CODE_GENERAL_FAILURE;
}
write(1, buffer, bytes);
}
close(fd);
return 0;
}
exit_code_t main(uint64_t argc, const char **argv) {
if (argc == 1) {
return cat(".");
}
uint64_t code = EXIT_CODE_OK;
for (uint64_t i = 1; i < argc; i++) {
exit_code_t c = cat(argv[i]);
if (c != EXIT_CODE_OK) {
code = c;
}
}
return code;
}