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Diffstat (limited to 'src/xz/main.c')
| -rw-r--r-- | src/xz/main.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/src/xz/main.c b/src/xz/main.c new file mode 100644 index 00000000..4e24b98d --- /dev/null +++ b/src/xz/main.c @@ -0,0 +1,402 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file main.c +/// \brief main() +// +// Copyright (C) 2007 Lasse Collin +// +// This program is free software; you can redistribute it and/or +// modify it under the terms of the GNU Lesser General Public +// License as published by the Free Software Foundation; either +// version 2.1 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 +// Lesser General Public License for more details. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "private.h" +#include "open_stdxxx.h" +#include <ctype.h> + + +volatile sig_atomic_t user_abort = false; + +/// Exit status to use. This can be changed with set_exit_status(). +static enum exit_status_type exit_status = E_SUCCESS; + +/// If we were interrupted by a signal, we store the signal number so that +/// we can raise that signal to kill the program when all cleanups have +/// been done. +static volatile sig_atomic_t exit_signal = 0; + +/// Mask of signals for which have have established a signal handler to set +/// user_abort to true. +static sigset_t hooked_signals; + +/// signals_block() and signals_unblock() can be called recursively. +static size_t signals_block_count = 0; + + +static void +signal_handler(int sig) +{ + exit_signal = sig; + user_abort = true; + return; +} + + +static void +establish_signal_handlers(void) +{ + // List of signals for which we establish the signal handler. + static const int sigs[] = { + SIGINT, + SIGTERM, +#ifdef SIGHUP + SIGHUP, +#endif +#ifdef SIGPIPE + SIGPIPE, +#endif +#ifdef SIGXCPU + SIGXCPU, +#endif +#ifdef SIGXFSZ + SIGXFSZ, +#endif + }; + + // Mask of the signals for which we have established a signal handler. + sigemptyset(&hooked_signals); + for (size_t i = 0; i < ARRAY_SIZE(sigs); ++i) + sigaddset(&hooked_signals, sigs[i]); + + struct sigaction sa; + + // All the signals that we handle we also blocked while the signal + // handler runs. + sa.sa_mask = hooked_signals; + + // Don't set SA_RESTART, because we want EINTR so that we can check + // for user_abort and cleanup before exiting. We block the signals + // for which we have established a handler when we don't want EINTR. + sa.sa_flags = 0; + sa.sa_handler = &signal_handler; + + for (size_t i = 0; i < ARRAY_SIZE(sigs); ++i) { + // If the parent process has left some signals ignored, + // we don't unignore them. + struct sigaction old; + if (sigaction(sigs[i], NULL, &old) == 0 + && old.sa_handler == SIG_IGN) + continue; + + // Establish the signal handler. + if (sigaction(sigs[i], &sa, NULL)) + message_signal_handler(); + } + + return; +} + + +extern void +signals_block(void) +{ + if (signals_block_count++ == 0) { + const int saved_errno = errno; + sigprocmask(SIG_BLOCK, &hooked_signals, NULL); + errno = saved_errno; + } + + return; +} + + +extern void +signals_unblock(void) +{ + assert(signals_block_count > 0); + + if (--signals_block_count == 0) { + const int saved_errno = errno; + sigprocmask(SIG_UNBLOCK, &hooked_signals, NULL); + errno = saved_errno; + } + + return; +} + + +extern void +set_exit_status(enum exit_status_type new_status) +{ + assert(new_status == E_WARNING || new_status == E_ERROR); + + if (exit_status != E_ERROR) + exit_status = new_status; + + return; +} + + +extern void +my_exit(enum exit_status_type status) +{ + // Close stdout. If something goes wrong, print an error message + // to stderr. + { + const int ferror_err = ferror(stdout); + const int fclose_err = fclose(stdout); + if (ferror_err || fclose_err) { + // If it was fclose() that failed, we have the reason + // in errno. If only ferror() indicated an error, + // we have no idea what the reason was. + message(V_ERROR, _("Writing to standard output " + "failed: %s"), + fclose_err ? strerror(errno) + : _("Unknown error")); + status = E_ERROR; + } + } + + // Close stderr. If something goes wrong, there's nothing where we + // could print an error message. Just set the exit status. + { + const int ferror_err = ferror(stderr); + const int fclose_err = fclose(stderr); + if (fclose_err || ferror_err) + status = E_ERROR; + } + + // If we have got a signal, raise it to kill the program. + const int sig = exit_signal; + if (sig != 0) { + struct sigaction sa; + sa.sa_handler = SIG_DFL; + sigfillset(&sa.sa_mask); + sa.sa_flags = 0; + sigaction(sig, &sa, NULL); + raise(exit_signal); + + // If, for some weird reason, the signal doesn't kill us, + // we safely fall to the exit below. + } + + exit(status); +} + + +static const char * +read_name(const args_info *args) +{ + // FIXME: Maybe we should have some kind of memory usage limit here + // like the tool has for the actual compression and uncompression. + // Giving some huge text file with --files0 makes us to read the + // whole file in RAM. + static char *name = NULL; + static size_t size = 256; + + // Allocate the initial buffer. This is never freed, since after it + // is no longer needed, the program exits very soon. It is safe to + // use xmalloc() and xrealloc() in this function, because while + // executing this function, no files are open for writing, and thus + // there's no need to cleanup anything before exiting. + if (name == NULL) + name = xmalloc(size); + + // Write position in name + size_t pos = 0; + + // Read one character at a time into name. + while (!user_abort) { + const int c = fgetc(args->files_file); + + if (ferror(args->files_file)) { + // Take care of EINTR since we have established + // the signal handlers already. + if (errno == EINTR) + continue; + + message_error(_("%s: Error reading filenames: %s"), + args->files_name, strerror(errno)); + return NULL; + } + + if (feof(args->files_file)) { + if (pos != 0) + message_error(_("%s: Unexpected end of input " + "when reading filenames"), + args->files_name); + + return NULL; + } + + if (c == args->files_delim) { + // We allow consecutive newline (--files) or '\0' + // characters (--files0), and ignore such empty + // filenames. + if (pos == 0) + continue; + + // A non-empty name was read. Terminate it with '\0' + // and return it. + name[pos] = '\0'; + return name; + } + + if (c == '\0') { + // A null character was found when using --files, + // which expects plain text input separated with + // newlines. + message_error(_("%s: Null character found when " + "reading filenames; maybe you meant " + "to use `--files0' instead " + "of `--files'?"), args->files_name); + return NULL; + } + + name[pos++] = c; + + // Allocate more memory if needed. There must always be space + // at least for one character to allow terminating the string + // with '\0'. + if (pos == size) { + size *= 2; + name = xrealloc(name, size); + } + } + + return NULL; +} + + +int +main(int argc, char **argv) +{ + // Make sure that stdin, stdout, and and stderr are connected to + // a valid file descriptor. Exit immediatelly with exit code ERROR + // if we cannot make the file descriptors valid. Maybe we should + // print an error message, but our stderr could be screwed anyway. + open_stdxxx(E_ERROR); + + // This has to be done before calling any liblzma functions. + lzma_init(); + + // Set up the locale. + setlocale(LC_ALL, ""); + +#ifdef ENABLE_NLS + // Set up the message translations too. + bindtextdomain(PACKAGE, LOCALEDIR); + textdomain(PACKAGE); +#endif + + // Set the program invocation name used in various messages, and + // do other message handling related initializations. + message_init(argv[0]); + + // Set hardware-dependent default values. These can be overriden + // on the command line, thus this must be done before parse_args(). + hardware_init(); + + // Parse the command line arguments and get an array of filenames. + // This doesn't return if something is wrong with the command line + // arguments. If there are no arguments, one filename ("-") is still + // returned to indicate stdin. + args_info args; + args_parse(&args, argc, argv); + + // Tell the message handling code how many input files there are if + // we know it. This way the progress indicator can show it. + if (args.files_name != NULL) + message_set_files(0); + else + message_set_files(args.arg_count); + + // Refuse to write compressed data to standard output if it is + // a terminal and --force wasn't used. + if (opt_mode == MODE_COMPRESS) { + if (opt_stdout || (args.arg_count == 1 + && strcmp(args.arg_names[0], "-") == 0)) { + if (is_tty_stdout()) { + message_try_help(); + my_exit(E_ERROR); + } + } + } + + if (opt_mode == MODE_LIST) { + message_fatal("--list is not implemented yet."); + } + + // Hook the signal handlers. We don't need these before we start + // the actual action, so this is done after parsing the command + // line arguments. + establish_signal_handlers(); + + // Process the files given on the command line. Note that if no names + // were given, parse_args() gave us a fake "-" filename. + for (size_t i = 0; i < args.arg_count && !user_abort; ++i) { + if (strcmp("-", args.arg_names[i]) == 0) { + // Processing from stdin to stdout. Unless --force + // was used, check that we aren't writing compressed + // data to a terminal or reading it from terminal. + if (!opt_force) { + if (opt_mode == MODE_COMPRESS) { + if (is_tty_stdout()) + continue; + } else if (is_tty_stdin()) { + continue; + } + } + + // It doesn't make sense to compress data from stdin + // if we are supposed to read filenames from stdin + // too (enabled with --files or --files0). + if (args.files_name == stdin_filename) { + message_error(_("Cannot read data from " + "standard input when " + "reading filenames " + "from standard input")); + continue; + } + + // Replace the "-" with a special pointer, which is + // recognized by process_file() and other things. + // This way error messages get a proper filename + // string and the code still knows that it is + // handling the special case of stdin. + args.arg_names[i] = (char *)stdin_filename; + } + + // Do the actual compression or uncompression. + process_file(args.arg_names[i]); + } + + // If --files or --files0 was used, process the filenames from the + // given file or stdin. Note that here we don't consider "-" to + // indicate stdin like we do with the command line arguments. + if (args.files_name != NULL) { + // read_name() checks for user_abort so we don't need to + // check it as loop termination condition. + while (true) { + const char *name = read_name(&args); + if (name == NULL) + break; + + // read_name() doesn't return empty names. + assert(name[0] != '\0'); + process_file(name); + } + + if (args.files_name != stdin_filename) + (void)fclose(args.files_file); + } + + my_exit(exit_status); +} |