/* yes - output a string repeatedly until killed Copyright (C) 1991-2023 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /* David MacKenzie */ #include #include #include #include "system.h" #include "full-write.h" #include "long-options.h" /* The official name of this program (e.g., no 'g' prefix). */ #define PROGRAM_NAME "yes" #define AUTHORS proper_name ("David MacKenzie") void usage (int status) { if (status != EXIT_SUCCESS) emit_try_help (); else { printf (_("\ Usage: %s [STRING]...\n\ or: %s OPTION\n\ "), program_name, program_name); fputs (_("\ Repeatedly output a line with all specified STRING(s), or 'y'.\n\ \n\ "), stdout); fputs (HELP_OPTION_DESCRIPTION, stdout); fputs (VERSION_OPTION_DESCRIPTION, stdout); emit_ancillary_info (PROGRAM_NAME); } exit (status); } int main (int argc, char **argv) { initialize_main (&argc, &argv); set_program_name (argv[0]); setlocale (LC_ALL, ""); bindtextdomain (PACKAGE, LOCALEDIR); textdomain (PACKAGE); atexit (close_stdout); parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version, true, usage, AUTHORS, (char const *) nullptr); char **operands = argv + optind; char **operand_lim = argv + argc; if (optind == argc) *operand_lim++ = bad_cast ("y"); /* Buffer data locally once, rather than having the large overhead of stdio buffering each item. */ size_t bufalloc = 0; bool reuse_operand_strings = true; char **operandp = operands; do { size_t operand_len = strlen (*operandp); bufalloc += operand_len + 1; if (operandp + 1 < operand_lim && *operandp + operand_len + 1 != operandp[1]) reuse_operand_strings = false; } while (++operandp < operand_lim); /* Improve performance by using a buffer size greater than BUFSIZ / 2. */ if (bufalloc <= BUFSIZ / 2) { bufalloc = BUFSIZ; reuse_operand_strings = false; } /* Fill the buffer with one copy of the output. If possible, reuse the operands strings; this wins when the buffer would be large. */ char *buf = reuse_operand_strings ? *operands : xmalloc (bufalloc); size_t bufused = 0; operandp = operands; do { size_t operand_len = strlen (*operandp); if (! reuse_operand_strings) memcpy (buf + bufused, *operandp, operand_len); bufused += operand_len; buf[bufused++] = ' '; } while (++operandp < operand_lim); buf[bufused - 1] = '\n'; /* If a larger buffer was allocated, fill it by repeating the buffer contents. */ size_t copysize = bufused; for (size_t copies = bufalloc / copysize; --copies; ) { memcpy (buf + bufused, buf, copysize); bufused += copysize; } /* Repeatedly output the buffer until there is a write error; then fail. */ while (full_write (STDOUT_FILENO, buf, bufused) == bufused) continue; error (0, errno, _("standard output")); main_exit (EXIT_FAILURE); }