list.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

    }
    fprintf(msgfile, "%s", name);
    if ((asb->sb_nlink > 1) && (from = islink(name, asb))) {
	fprintf(msgfile, " linked to %s", from->l_name);
    }
#ifdef	S_IFLNK
    if ((asb->sb_mode & S_IFMT) == S_IFLNK) {
	fprintf(msgfile, " symbolic link to %s", asb->sb_link);
    }
#endif	/* S_IFLNK */
    putc('\n', msgfile);
}


/* tar_entry - print a tar verbose mode entry
 *
 * DESCRIPTION
 *
 *	Print_entry prints a single line of tar file information.  The format
 *	of the line is the same as that produced by the traditional tar 
 *	command.  No error checking is done for bad or invalid data.
 *
 * PARAMETERS
 *
 *	char   *name		- pointer to name to print an entry for
 *	Stat   *asb		- pointer to the stat structure for the file
 */

#ifdef __STDC__

static void tar_entry(char *name, Stat *asb)

#else
    
static void tar_entry(name, asb)
char		*name;
Stat            *asb;

#endif
{
    struct tm  	       *atm;
    int			i;
    int			mode;
    char               *symnam = "NULL";
    Link               *link;

    if ((mode = asb->sb_mode & S_IFMT) == S_IFDIR) {
	return;			/* don't print directories */
    }
    if (f_extract) {
	switch (mode) {
#ifdef S_IFLNK
	case S_IFLNK: 	/* This file is a symbolic link */
	    i = readlink(name, symnam, PATH_MAX - 1);
	    if (i < 0) {		/* Could not find symbolic link */
		warn("can't read symbolic link", strerror());
	    } else { 		/* Found symbolic link filename */
		symnam[i] = '\0';
		fprintf(msgfile, "x %s symbolic link to %s\n", name, symnam);
	    }
	    break;
#endif
	case S_IFREG: 	/* It is a link or a file */
	    if ((asb->sb_nlink > 1) && (link = islink(name, asb))) {
		fprintf(msgfile, "%s linked to %s\n", name, link->l_name); 
	    } else {
		fprintf(msgfile, "x %s, %ld bytes, %d tape blocks\n", 
			name, asb->sb_size, ROUNDUP(asb->sb_size, 
			BLOCKSIZE) / BLOCKSIZE);
	    }
	}
    } else if (f_append || f_create) {
	switch (mode) {
#ifdef S_IFLNK
	case S_IFLNK: 	/* This file is a symbolic link */
	    i = readlink(name, symnam, PATH_MAX - 1);
	    if (i < 0) {		/* Could not find symbolic link */
		warn("can't read symbolic link", strerror());
	    } else { 		/* Found symbolic link filename */
		symnam[i] = '\0';
		fprintf(msgfile, "a %s symbolic link to %s\n", name, symnam);
	    }
	    break;
#endif
	case S_IFREG: 	/* It is a link or a file */
	    fprintf(msgfile, "a %s ", name);
	    if ((asb->sb_nlink > 1) && (link = islink(name, asb))) {
		fprintf(msgfile, "link to %s\n", link->l_name); 
	    } else {
		fprintf(msgfile, "%ld Blocks\n", 
			ROUNDUP(asb->sb_size, BLOCKSIZE) / BLOCKSIZE);
	    }
	    break;
	}
    } else if (f_list) {
	if (f_verbose) {
	    atm = localtime(&asb->sb_mtime);
	    print_mode(asb->sb_mode);
	    fprintf(msgfile," %d/%d %6d %3s %2d %02d:%02d %4d %s",
		    asb->sb_uid, asb->sb_gid, asb->sb_size,
		    monnames[atm->tm_mon], atm->tm_mday, atm->tm_hour, 
		    atm->tm_min, atm->tm_year + 1900, name);
	} else {
	    fprintf(msgfile, "%s", name);
	}
	switch (mode) {
#ifdef S_IFLNK
	case S_IFLNK: 	/* This file is a symbolic link */
	    i = readlink(name, symnam, PATH_MAX - 1);
	    if (i < 0) {		/* Could not find symbolic link */
		warn("can't read symbolic link", strerror());
	    } else { 		/* Found symbolic link filename */
		symnam[i] = '\0';
		fprintf(msgfile, " symbolic link to %s", symnam);
	    }
	    break;
#endif
	case S_IFREG: 	/* It is a link or a file */
	    if ((asb->sb_nlink > 1) && (link = islink(name, asb))) {
		fprintf(msgfile, " linked to %s", link->l_name);
	    }
	    break;		/* Do not print out directories */
	}
	fputc('\n', msgfile);
    } else {
	fprintf(msgfile, "? %s %ld blocks\n", name,
		ROUNDUP(asb->sb_size, BLOCKSIZE) / BLOCKSIZE);
    }
}


/* pax_entry - print a verbose cpio-style entry
 *
 * DESCRIPTION
 *
 *	Print_entry prints a single line of file information.  The format
 *	of the line is the same as that used by the LS command.  
 *	No error checking is done for bad or invalid data.
 *
 * PARAMETERS
 *
 *	char   *name		- pointer to name to print an entry for
 *	Stat   *asb		- pointer to the stat structure for the file
 */

#ifdef __STDC__

static void pax_entry(char *name, Stat *asb)

#else
    
static void pax_entry(name, asb)
char	       *name;
Stat	       *asb;

#endif
{
    struct tm	       *atm;
    Link	       *from;
    struct passwd      *pwp;
    struct group       *grp;

    if (f_list && f_verbose) {
	print_mode(asb->sb_mode);
	fprintf(msgfile, " %2d", asb->sb_nlink);
	atm = localtime(&asb->sb_mtime);
	if (pwp = getpwuid((int) USH(asb->sb_uid))) {
	    fprintf(msgfile, " %-8s", pwp->pw_name);
	} else {
	    fprintf(msgfile, " %-8u", USH(asb->sb_uid));
	}
	if (grp = getgrgid((int) USH(asb->sb_gid))) {
	    fprintf(msgfile, " %-8s", grp->gr_name);
	} else {
	    fprintf(msgfile, " %-8u", USH(asb->sb_gid));
	}
	switch (asb->sb_mode & S_IFMT) {
	case S_IFBLK:
	case S_IFCHR:
	    fprintf(msgfile, "\t%3d, %3d",
		           major(asb->sb_rdev), minor(asb->sb_rdev));
	    break;
	case S_IFREG:
	    fprintf(msgfile, "\t%8ld", asb->sb_size);
	    break;
	default:
	    fprintf(msgfile, "\t        ");
	}
	fprintf(msgfile," %3s %2d %02d:%02d ",
	        monnames[atm->tm_mon], atm->tm_mday, 
		atm->tm_hour, atm->tm_min);
    }
    fprintf(msgfile, "%s", name);
    if ((asb->sb_nlink > 1) && (from = islink(name, asb))) {
	fprintf(msgfile, " == %s", from->l_name);
    }
#ifdef	S_IFLNK
    if ((asb->sb_mode & S_IFMT) == S_IFLNK) {
	fprintf(msgfile, " -> %s", asb->sb_link);
    }
#endif	/* S_IFLNK */
    putc('\n', msgfile);
}


/* print_mode - fancy file mode display
 *
 * DESCRIPTION
 *
 *	Print_mode displays a numeric file mode in the standard unix
 *	representation, ala ls (-rwxrwxrwx).  No error checking is done
 *	for bad mode combinations.  FIFOS, sybmbolic links, sticky bits,
 *	block- and character-special devices are supported if supported
 *	by the hosting implementation.
 *
 * PARAMETERS
 *
 *	ushort	mode	- The integer representation of the mode to print.
 */

#ifdef __STDC__

static void print_mode(ushort mode)

#else
    
static void print_mode(mode)
ushort	mode;

#endif
{
    /* Tar does not print the leading identifier... */
    if (ar_interface != TAR) {
	switch (mode & S_IFMT) {
	case S_IFDIR: 
	    putc('d', msgfile); 
	    break;
#ifdef	S_IFLNK
	case S_IFLNK: 
	    putc('l', msgfile); 
	    break;
#endif	/* S_IFLNK */
	case S_IFBLK: 
	    putc('b', msgfile); 
	    break;
	case S_IFCHR: 
	    putc('c', msgfile); 
	    break;
#ifdef	S_IFIFO
	case S_IFIFO: 
	    putc('p', msgfile); 
	    break; 
#endif	/* S_IFIFO */ 
	case S_IFREG: 
	default:
	    putc('-', msgfile); 
	    break;
	}
    }
    putc(mode & 0400 ? 'r' : '-', msgfile);
    putc(mode & 0200 ? 'w' : '-', msgfile);
    putc(mode & 0100
	 ? mode & 04000 ? 's' : 'x'
	 : mode & 04000 ? 'S' : '-', msgfile);
    putc(mode & 0040 ? 'r' : '-', msgfile);
    putc(mode & 0020 ? 'w' : '-', msgfile);
    putc(mode & 0010
	 ? mode & 02000 ? 's' : 'x'
	 : mode & 02000 ? 'S' : '-', msgfile);
    putc(mode & 0004 ? 'r' : '-', msgfile);
    putc(mode & 0002 ? 'w' : '-', msgfile);
    putc(mode & 0001
	 ? mode & 01000 ? 't' : 'x'
	 : mode & 01000 ? 'T' : '-', msgfile);
}


/* from_oct - quick and dirty octal conversion
 *
 * DESCRIPTION
 *
 *	From_oct will convert an ASCII representation of an octal number
 *	to the numeric representation.  The number of characters to convert
 *	is given by the parameter "digs".  If there are less numbers than
 *	specified by "digs", then the routine returns -1.
 *
 * PARAMETERS
 *
 *	int digs	- Number to of digits to convert 
 *	char *where	- Character representation of octal number
 *
 * RETURNS
 *
 *	The value of the octal number represented by the first digs
 *	characters of the string where.  Result is -1 if the field 
 *	is invalid (all blank, or nonoctal). 
 *
 * ERRORS
 *
 *	If the field is all blank, then the value returned is -1.
 *
 */

#ifdef __STDC__

static long from_oct(int digs, char *where)

#else

static long from_oct(digs, where)
int             digs;		/* number of characters to convert */
char           *where;		/* character representation of octal number */

#endif
{
    long            value;

    while (isspace(*where)) {	/* Skip spaces */
	where++;
	if (--digs <= 0) {
	    return(-1);		/* All blank field */
	}
    }
    value = 0;
    while (digs > 0 && ISODIGIT(*where)) {	/* Scan til nonoctal */
	value = (value << 3) | (*where++ - '0');
	--digs;
    }

    if (digs > 0 && *where && !isspace(*where)) {
	return(-1);		/* Ended on non-space/nul */
    }
    return(value);
}