pg.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

/*
 * pg  - A clone of the System V CRT paging utility.
 *
 *	Copyright (c) 2000-2001 Gunnar Ritter. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. [deleted]
 * 4. Neither the name of Gunnar Ritter nor the names of his contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY GUNNAR RITTER AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL GUNNAR RITTER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* Sccsid @(#)pg.c 1.44 (gritter) 2/8/02 - modified for util-linux */

/*
 * #define _XOPEN_SOURCE  500L
 *
 * Adding this define gives us the correct prototypes for fseeko, ftello,
 * but (for some glibc versions) conflicting prototype for wcwidth.
 * So, avoid defining _XOPEN_SOURCE, and give prototypes for fseeko, ftello
 * by hand.
 */

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#ifndef	TIOCGWINSZ
#include <sys/ioctl.h>
#endif
#include <sys/termios.h>
#include <fcntl.h>
#include <regex.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <ctype.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <setjmp.h>
#include <locale.h>
#include <nl_types.h>
#include <libgen.h>
#if NCH
#include <ncurses.h>
#else
#include <curses.h>
#endif
#include <term.h>

#include "nls.h"
#include "widechar.h"
#include "../defines.h"		/* for HAVE_fseeko */

#define	READBUF		LINE_MAX	/* size of input buffer */
#define CMDBUF		255		/* size of command buffer */
#define	TABSIZE		8		/* spaces consumed by tab character */

/*
 * Avoid the message "`var' might be clobbered by `longjmp' or `vfork'"
 */
#define	CLOBBGRD(a)	(void)(&(a));

#define	cuc(c)		((c) & 0377)

enum { FORWARD = 1, BACKWARD = 2 };	/* search direction */
enum { TOP, MIDDLE, BOTTOM };		/* position of matching line */

/*
 * States for syntax-aware command line editor.
 */
enum {
	COUNT,
	SIGN,
	CMD_FIN,
	SEARCH,
	SEARCH_FIN,
	ADDON_FIN,
	STRING,
	INVALID
};

/*
 * Current command
 */
struct {
	char cmdline[CMDBUF];
	size_t cmdlen;
	int count;
	int key;
	char pattern[CMDBUF];
	char addon;
} cmd;

/*
 * Position of file arguments on argv[] to main()
 */
struct {
	int first;
	int current;
	int last;
} files;

void		(*oldint)(int);		/* old SIGINT handler */
void		(*oldquit)(int);	/* old SIGQUIT handler */
void		(*oldterm)(int);	/* old SIGTERM handler */
char		*tty;			/* result of ttyname(1) */
char		*progname;		/* program name */
unsigned	ontty;			/* whether running on tty device */
unsigned	exitstatus;		/* exit status */
int		pagelen = 23;		/* lines on a single screen page */
int		ttycols = 79;		/* screen columns (starting at 0) */
struct termios	otio;			/* old termios settings */
int		tinfostat = -1;		/* terminfo routines initialized */
int		searchdisplay = TOP;	/* matching line position */
regex_t		re;			/* regular expression to search for */
int		remembered;		/* have a remembered search string */
int		cflag;			/* clear screen before each page */
int		eflag;			/* suppress (EOF) */
int		fflag;			/* do not split lines */
int		nflag;			/* no newline for commands required */
int		rflag;			/* "restricted" pg */
int		sflag;			/* use standout mode */
char		*pstring = ":";		/* prompt string */
char		*searchfor;		/* search pattern from argv[] */
int		havepagelen;		/* page length is manually defined */
long		startline;		/* start line from argv[] */
int		nextfile = 1;		/* files to advance */
jmp_buf		jmpenv;			/* jump from signal handlers */
int		canjump;		/* jmpenv is valid */
wchar_t		wbuf[READBUF];		/* used in several widechar routines */

const char *copyright =
"@(#)pg 1.44 2/8/02. Copyright (c) 2000-2001 Gunnar Ritter. ";
const char *helpscreen = "All rights reserved.\n\
-------------------------------------------------------\n\
  h                       this screen\n\
  q or Q                  quit program\n\
  <newline>               next page\n\
  f                       skip a page forward\n\
  d or ^D                 next halfpage\n\
  l                       next line\n\
  $                       last page\n\
  /regex/                 search forward for regex\n\
  ?regex? or ^regex^      search backward for regex\n\
  . or ^L                 redraw screen\n\
  w or z                  set page size and go to next page\n\
  s filename              save current file to filename\n\
  !command                shell escape\n\
  p                       go to previous file\n\
  n                       go to next file\n\
\n\
Many commands accept preceding numbers, for example:\n\
+1<newline> (next page); -1<newline> (previous page); 1<newline> (first page).\n\
\n\
See pg(1) for more information.\n\
-------------------------------------------------------\n";

#ifdef HAVE_fseeko
#if defined (_FILE_OFFSET_BITS) && (_FILE_OFFSET_BITS) == 64
  extern int fseeko64(FILE *f, off_t off, int whence);
  extern off_t ftello64(FILE *f);
  #define      my_fseeko       fseeko64
  #define      my_ftello       ftello64
#else
  extern int fseeko(FILE *f, off_t off, int whence);
  extern off_t ftello(FILE *f);
  #define	my_fseeko	fseeko
  #define	my_ftello	ftello
#endif
#else
  static int my_fseeko(FILE *f, off_t off, int whence) {
	return fseek(f, (long) off, whence);
  }
  static off_t my_ftello(FILE *f) {
	return (off_t) ftell(f);
  }
#endif

#ifdef USE_SIGSET	/* never defined */
/* sigset and sigrelse are obsolete - use when POSIX stuff is unavailable */
#define my_sigset	sigset
#define my_sigrelse	sigrelse
#else
static int my_sigrelse(int sig) {
	sigset_t sigs;

	if (sigemptyset(&sigs) || sigaddset(&sigs, sig))
		return -1;
	return sigprocmask(SIG_UNBLOCK, &sigs, NULL);
}
typedef void (*my_sighandler_t)(int);
static my_sighandler_t my_sigset(int sig, my_sighandler_t disp) {
	struct sigaction act, oact;

	act.sa_handler = disp;
	if (sigemptyset(&act.sa_mask))
		return SIG_ERR;
	act.sa_flags = 0;
	if (sigaction(sig, &act, &oact))
		return SIG_ERR;
	if (my_sigrelse(sig))
		return SIG_ERR;
	return oact.sa_handler;
}
#endif

/*
 * Quit pg.
 */
static void
quit(int status)
{
	exit(status < 0100 ? status : 077);
}

/*
 * Memory allocator including check.
 */
static char *
smalloc(size_t s)
{
        char *m = (char *)malloc(s);
        if (m == NULL) {
                write(2, "Out of memory\n", 14);
                quit(++exitstatus);
        }
        return m;
}

/*
 * Usage message and similar routines.
 */
static void
usage(void)
{
	fprintf(stderr, _("%s: Usage: %s [-number] [-p string] [-cefnrs] "
			  "[+line] [+/pattern/] [files]\n"),
			progname, progname);
	quit(2);
}

static void
needarg(char *s)
{
	fprintf(stderr, _("%s: option requires an argument -- %s\n"),
		progname, s);
	usage();
}

static void
invopt(char *s)
{
	fprintf(stderr, _("%s: illegal option -- %s\n"), progname, s);
	usage();
}

#ifdef ENABLE_WIDECHAR
/*
 * A mbstowcs()-alike function that transparently handles invalid sequences.
 */
static size_t
xmbstowcs(wchar_t *pwcs, const char *s, size_t nwcs)
{
	size_t n = nwcs;
	int c;

	mbtowc(pwcs, NULL, MB_CUR_MAX);
	while (*s && n) {
		if ((c = mbtowc(pwcs, s, MB_CUR_MAX)) < 0) {
			s++;
			*pwcs = L'?';
		} else
			s += c;
		pwcs++;
		n--;
	}
	if (n)
		*pwcs = L'\0';
	mbtowc(pwcs, NULL, MB_CUR_MAX);
	return nwcs - n;
}
#endif

/*
 * Helper function for tputs().
 */
static int
outcap(int i)
{
	char c = i;
	return write(1, &c, 1);
}

/*
 * Write messages to terminal.
 */
static void
mesg(char *message)
{
	if (ontty == 0)
		return;
	if (*message != '\n' && sflag)
		vidputs(A_STANDOUT, outcap);
	write(1, message, strlen(message));
	if (*message != '\n' && sflag)
		vidputs(A_NORMAL, outcap);
}

/*
 * Get the window size.
 */
static void
getwinsize(void)
{
	static int initialized, envlines, envcols, deflines, defcols;
#ifdef	TIOCGWINSZ
	struct winsize winsz;
	int badioctl;
#endif
	char *p;

	if (initialized == 0) {
		if ((p = getenv("LINES")) != NULL && *p != '\0')
			if ((envlines = atoi(p)) < 0)
				envlines = 0;
		if ((p = getenv("COLUMNS")) != NULL && *p != '\0')
			if ((envcols = atoi(p)) < 0)
				envcols = 0;
		/* terminfo values. */
		if (tinfostat != 1 || columns == 0)
			defcols = 24;
		else
			defcols = columns;
		if (tinfostat != 1 || lines == 0)
			deflines = 80;
		else
			deflines = lines;
		initialized = 1;
	}
#ifdef	TIOCGWINSZ
	badioctl = ioctl(1, TIOCGWINSZ, &winsz);
#endif
	if (envcols)
		ttycols = envcols - 1;
#ifdef	TIOCGWINSZ
	else if (!badioctl)
		ttycols = winsz.ws_col - 1;
#endif
	else
		ttycols = defcols - 1;
	if (havepagelen == 0) {
		if (envlines)
			pagelen = envlines - 1;
#ifdef	TIOCGWINSZ
		else if (!badioctl)
			pagelen = winsz.ws_row - 1;
#endif
		else
			pagelen = deflines - 1;
	}
}

/*
 * Message if skipping parts of files.
 */
static void
skip(int direction)
{
	if (direction > 0)
		mesg(_("...skipping forward\n"));
	else
		mesg(_("...skipping backward\n"));
}

/*
 * Signal handler while reading from input file.
 */
static void
sighandler(int signum)
{
	if (canjump && (signum == SIGINT || signum == SIGQUIT))
		longjmp(jmpenv, signum);
	tcsetattr(1, TCSADRAIN, &otio);
	quit(exitstatus);
}

/*
 * Check whether the requested file was specified on the command line.
 */
static int
checkf(void)
{
	if (files.current + nextfile >= files.last) {
		mesg(_("No next file"));
		return 1;
	}
	if (files.current + nextfile < files.first) {
		mesg(_("No previous file"));
		return 1;
	}
	return 0;
}

#ifdef ENABLE_WIDECHAR
/*
 * Return the last character that will fit on the line at col columns
 * in case MB_CUR_MAX > 1.
 */
static char *
endline_for_mb(unsigned col, char *s)
{
	unsigned pos = 0;
	wchar_t *p = wbuf;
	wchar_t *end;
	size_t wl;
	char *t = s;

	if ((wl = xmbstowcs(wbuf, t, sizeof wbuf - 1)) == (size_t)-1)
		return s + 1;
	wbuf[wl] = L'\0';
	while (*p != L'\0') {
		switch (*p) {
			/*
			 * Cursor left.
			 */
		case L'\b':
			if (pos > 0)
				pos--;
			break;
			/*
			 * No cursor movement.
			 */
		case L'\a':
			break;
			/*
			 * Special.
			 */
		case L'\r':
			pos = 0;
			break;
		case L'\n':
			end = p + 1;
			goto ended;
			/*
			 * Cursor right.
			 */
		case L'\t':
			pos += TABSIZE - (pos % TABSIZE);
			break;
		default:
			pos += wcwidth(*p);
		}
		if (pos > col) {
			if (*p == L'\t')
				p++;
			else if (pos > col + 1)
				/*
				 * wcwidth() found a character that
				 * has multiple columns. What happens
				 * now? Assume the terminal will print
				 * the entire character onto the next
				 * row.
				 */
				p--;
			if (*++p == L'\n')
				p++;
			end = p;
			goto ended;
		}
		p++;
	}
	end = p;
 ended:
	*end = L'\0';
	p = wbuf;
	if ((pos = wcstombs(NULL, p, READBUF)) == -1)
		return s + 1;
	return s + pos;
}
#endif

/*
 * Return the last character that will fit on the line at col columns.
 */
static char *
endline(unsigned col, char *s)
{
	unsigned pos = 0;
	char *t = s;

#ifdef ENABLE_WIDECHAR
	if (MB_CUR_MAX > 1)
		return endline_for_mb(col, s);
#endif

	while (*s != '\0') {
		switch (*s) {
			/*
			 * Cursor left.
			 */
		case '\b':
			if (pos > 0)
				pos--;
			break;
			/*
			 * No cursor movement.
			 */
		case '\a':
			break;
			/*
			 * Special.
			 */
		case '\r':
			pos = 0;
			break;
		case '\n':
			t = s + 1;
			goto cend;
			/*
			 * Cursor right.
			 */
		case '\t':
			pos += TABSIZE - (pos % TABSIZE);
			break;
		default:
			pos++;
		}
		if (pos > col) {
			if (*s == '\t')
				s++;
			if (*++s == '\n')
				s++;
			t = s;
			goto cend;
		}
		s++;
	}
	t = s;
 cend:
	return t;
}

/*
 * Clear the current line on the terminal's screen.
 */
static void
cline(void)
{
	char *buf = (char *)smalloc(ttycols + 2);
	memset(buf, ' ', ttycols + 2);
	buf[0] = '\r';
	buf[ttycols + 1] = '\r';
	write(1, buf, ttycols + 2);
	free(buf);
}

/*
 * Evaluate a command character's semantics.
 */
static int
getstate(int c)
{
	switch (c) {
	case '1': case '2': case '3': case '4': case '5':
	case '6': case '7': case '8': case '9': case '0':
	case '\0':
		return COUNT;
	case '-': case '+':
		return SIGN;
	case 'l': case 'd': case '\004': case 'f': case 'z':
	case '.': case '\014': case '$': case 'n': case 'p':
	case 'w': case 'h': case 'q': case 'Q':
		return CMD_FIN;
	case '/': case '?': case '^':
		return SEARCH;