From 4e09bca9e34c226b6d7e34b4fa11248405fd988e Mon Sep 17 00:00:00 2001 From: Anton Kling Date: Sun, 22 Oct 2023 19:50:38 +0200 Subject: Move everything into a new repo. --- userland/minibox/utilities/cat.c | 54 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 userland/minibox/utilities/cat.c (limited to 'userland/minibox/utilities/cat.c') diff --git a/userland/minibox/utilities/cat.c b/userland/minibox/utilities/cat.c new file mode 100644 index 0000000..c528d49 --- /dev/null +++ b/userland/minibox/utilities/cat.c @@ -0,0 +1,54 @@ +// cat - concatenate and print files +// https://pubs.opengroup.org/onlinepubs/9699919799/ +// +// TODO: Add -u flag "Write bytes from the input file to the standard +// output without delay as each is read." +#include "include.h" +#include +#include +#include +#include +#include + +int fd_to_stdout(int fd) { + int rc; + for (char buffer[CAT_BUFFER]; (rc = read(fd, &buffer, sizeof(buffer)));) { + if (-1 == rc) + return 0; + if (-1 == write(fd_stdout, buffer, rc)) + return 0; + } + return 1; +} + +int cat_main(int argc, char **argv) { + int fd = fd_stdin; + + // If no file operands are specified, the standard input shall be + // used. + if (argc < 2) { + return (fd_to_stdout(0)) ? 0 : 1; + } + + argv++; + for (; *argv; argv++) { + // If a file is '-', the cat utility shall read from the standard + // input at that point in the sequence. + if (0 == strcmp(*argv, "-")) { + if (!fd_to_stdout(0)) + return 1; + continue; + } + + if (-1 == (fd = open(*argv, O_RDONLY, 0))) { + printf("cat: "); + // fflush(stdout); + perror(*argv); + return 1; + } + if (!fd_to_stdout(fd)) + return 1; + close(fd); + } + return 0; +} -- cgit v1.2.3