151 lines
3.7 KiB
C
151 lines
3.7 KiB
C
/*
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* Copyright (c) 2013, 2021 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* cat.c
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* Concatenate and print files to the standard output.
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*/
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#include <sys/stat.h>
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#include <errno.h>
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#include <error.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static bool cat_fd(int fd, const char* path)
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{
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const size_t BUFFER_SIZE = 16 * 1024;
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uint8_t buffer[BUFFER_SIZE];
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ssize_t buffer_used;
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while ( 0 < (buffer_used = read(fd, buffer, BUFFER_SIZE)) )
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{
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size_t so_far = 0;
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while ( so_far < (size_t) buffer_used )
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{
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ssize_t amount = write(1, buffer + so_far, buffer_used - so_far);
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if ( amount <= 0 )
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return error(0, errno, "`%s'", "<stdout>"), false;
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so_far += amount;
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}
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}
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if ( buffer_used < 0 )
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return error(0, errno, "`%s'", path), false;
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return true;
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}
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static bool cat_path(const char* path)
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{
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if ( !strcmp("-", path) )
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return cat_fd(0, "<stdin>");
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int fd = open(path, O_RDONLY);
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if ( fd < 0 )
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{
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error(0, errno, "`%s'", path);
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return false;
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}
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bool result = cat_fd(fd, path);
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close(fd);
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return result;
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}
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static bool cat_arguments(int argc, char* argv[])
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{
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if ( argc <= 1 )
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return cat_path("-");
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bool success = true;
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for ( int i = 1; i < argc; i++ )
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if ( !cat_path(argv[i]) )
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success = false;
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return success;
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}
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static void compact_arguments(int* argc, char*** argv)
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{
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for ( int i = 0; i < *argc; i++ )
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{
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while ( i < *argc && !(*argv)[i] )
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{
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for ( int n = i; n < *argc; n++ )
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(*argv)[n] = (*argv)[n+1];
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(*argc)--;
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}
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}
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}
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static void help(FILE* fp, const char* argv0)
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{
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fprintf(fp, "Usage: %s [OPTION]... [FILE]...\n", argv0);
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fprintf(fp, "Concatenate FILE(s), or standard input, to standard output.\n");
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fprintf(fp, "\n");
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fprintf(fp, " -u (ignored)\n");
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fprintf(fp, " --help display this help and exit\n");
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fprintf(fp, " --version output version information and exit\n");
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fprintf(fp, "\n");
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fprintf(fp, "With no FILE, or when FILE is -, read standard input.\n");
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}
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static void version(FILE* fp, const char* argv0)
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{
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fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
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}
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int main(int argc, char* argv[])
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{
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const char* argv0 = argv[0];
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for ( int i = 1; i < argc; i++ )
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{
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const char* arg = argv[i];
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if ( arg[0] != '-' || !arg[1] )
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continue;
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argv[i] = NULL;
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if ( !strcmp(arg, "--") )
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break;
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if ( arg[1] != '-' )
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{
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char c;
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while ( (c = *++arg) ) switch ( c )
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{
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case 'u': /* Ignored, POSIX compatibility. */ break;
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default:
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fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
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help(stderr, argv0);
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exit(1);
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}
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}
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else if ( !strcmp(arg, "--help") )
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help(stdout, argv0), exit(0);
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else if ( !strcmp(arg, "--version") )
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version(stdout, argv0), exit(0);
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else
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{
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fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
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help(stderr, argv0);
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exit(1);
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}
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}
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compact_arguments(&argc, &argv);
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return cat_arguments(argc, argv) ? 0 : 1;
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}
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