ls.c

这是 gnu 程序中 ls 程序的源代码程序。

	} else {
		switch (sortkey) {
		case BY_NAME:
			sortfcn = namecmp;
			break;
		case BY_SIZE:
			sortfcn = sizecmp;
			break;
		case BY_TIME:
			if (f_accesstime)
				sortfcn = acccmp;
			else if (f_statustime)
				sortfcn = statcmp;
			else /* Use modification time. */
				sortfcn = modcmp;
			break;
		}
	}

	/* Select a print function. */
	if (f_singlecol)
		printfcn = printscol;
	else if (f_columnacross)
		printfcn = printacol;
	else if (f_longform)
		printfcn = printlong;
	else if (f_stream)
		printfcn = printstream;
	else
		printfcn = printcol;

	if (argc)
		traverse(argc, argv, fts_options);
	else
		traverse(1, dotav, fts_options);
	exit(rval);
	/* NOTREACHED */
}

static int output;			/* If anything output. */

/*
 * Traverse() walks the logical directory structure specified by the argv list
 * in the order specified by the mastercmp() comparison function.  During the
 * traversal it passes linked lists of structures to display() which represent
 * a superset (may be exact set) of the files to be displayed.
 */
static void
traverse(int argc, char *argv[], int options)
{
	FTS *ftsp;
	FTSENT *p, *chp;
	int ch_options;

	if ((ftsp =
	    fts_open(argv, options, f_nosort ? NULL : mastercmp)) == NULL)
		err(EXIT_FAILURE, NULL);

	display(NULL, fts_children(ftsp, 0));
	if (f_listdir)
		return;

	/*
	 * If not recursing down this tree and don't need stat info, just get
	 * the names.
	 */
	ch_options = !f_recursive && options & FTS_NOSTAT ? FTS_NAMEONLY : 0;

	while ((p = fts_read(ftsp)) != NULL)
		switch (p->fts_info) {
		case FTS_DC:
			warnx("%s: directory causes a cycle", p->fts_name);
			break;
		case FTS_DNR:
		case FTS_ERR:
			warnx("%s: %s", p->fts_name, strerror(p->fts_errno));
			rval = EXIT_FAILURE;
			break;
		case FTS_D:
			if (p->fts_level != FTS_ROOTLEVEL &&
			    p->fts_name[0] == '.' && !f_listdot)
				break;

			/*
			 * If already output something, put out a newline as
			 * a separator.  If multiple arguments, precede each
			 * directory with its name.
			 */
			if (output)
				(void)printf("\n%s:\n", p->fts_path);
			else if (argc > 1) {
				(void)printf("%s:\n", p->fts_path);
				output = 1;
			}

			chp = fts_children(ftsp, ch_options);
			display(p, chp);

			if (!f_recursive && chp != NULL)
				(void)fts_set(ftsp, p, FTS_SKIP);
			break;
		}
	if (errno)
		err(EXIT_FAILURE, "fts_read");
}

/*
 * Display() takes a linked list of FTSENT structures and passes the list
 * along with any other necessary information to the print function.  P
 * points to the parent directory of the display list.
 */
static void
display(FTSENT *p, FTSENT *list)
{
	struct stat *sp;
	DISPLAY d;
	FTSENT *cur;
	NAMES *np;
	u_int64_t btotal, stotal, maxblock, maxsize;
	int maxinode, maxnlink, maxmajor, maxminor;
	int bcfile, entries, flen, glen, ulen, maxflags, maxgroup, maxlen;
	int maxuser, needstats;
	const char *user, *group;
	char buf[21];		/* 64 bits == 20 digits, +1 for NUL */
	char nuser[12], ngroup[12];
	char *flags = NULL;

#ifdef __GNUC__
	/* This outrageous construct just to shut up a GCC warning. */
	(void) &maxsize;
#endif

	/*
	 * If list is NULL there are two possibilities: that the parent
	 * directory p has no children, or that fts_children() returned an
	 * error.  We ignore the error case since it will be replicated
	 * on the next call to fts_read() on the post-order visit to the
	 * directory p, and will be signalled in traverse().
	 */
	if (list == NULL)
		return;

	needstats = f_inode || f_longform || f_size;
	flen = 0;
	maxinode = maxnlink = 0;
	bcfile = 0;
	maxuser = maxgroup = maxflags = maxlen = 0;
	btotal = stotal = maxblock = maxsize = 0;
	maxmajor = maxminor = 0;
	for (cur = list, entries = 0; cur; cur = cur->fts_link) {
		if (cur->fts_info == FTS_ERR || cur->fts_info == FTS_NS) {
			warnx("%s: %s",
			    cur->fts_name, strerror(cur->fts_errno));
			cur->fts_number = NO_PRINT;
			rval = EXIT_FAILURE;
			continue;
		}

		/*
		 * P is NULL if list is the argv list, to which different rules
		 * apply.
		 */
		if (p == NULL) {
			/* Directories will be displayed later. */
			if (cur->fts_info == FTS_D && !f_listdir) {
				cur->fts_number = NO_PRINT;
				continue;
			}
		} else {
			/* Only display dot file if -a/-A set. */
			if (cur->fts_name[0] == '.' && !f_listdot) {
				cur->fts_number = NO_PRINT;
				continue;
			}
		}
		if (cur->fts_namelen > maxlen)
			maxlen = cur->fts_namelen;
		if (needstats) {
			sp = cur->fts_statp;
			if (sp->st_blocks > maxblock)
				maxblock = sp->st_blocks;
			if (sp->st_ino > maxinode)
				maxinode = sp->st_ino;
			if (sp->st_nlink > maxnlink)
				maxnlink = sp->st_nlink;
			if (sp->st_size > maxsize)
				maxsize = sp->st_size;
			if (S_ISCHR(sp->st_mode) || S_ISBLK(sp->st_mode)) {
				bcfile = 1;
				if (major(sp->st_rdev) > maxmajor)
					maxmajor = major(sp->st_rdev);
				if (minor(sp->st_rdev) > maxminor)
					maxminor = minor(sp->st_rdev);
			}

			btotal += sp->st_blocks;
			stotal += sp->st_size;
			if (f_longform) {
				if (f_numericonly ||
				    (user = user_from_uid(sp->st_uid, 0)) ==
				    NULL) {
					(void)snprintf(nuser, sizeof(nuser),
					    "%u", sp->st_uid);
					user = nuser;
				}
				if (f_numericonly ||
				    (group = group_from_gid(sp->st_gid, 0)) ==
				    NULL) {
					(void)snprintf(ngroup, sizeof(ngroup),
					    "%u", sp->st_gid);
					group = ngroup;
				}
				if ((ulen = strlen(user)) > maxuser)
					maxuser = ulen;
				if ((glen = strlen(group)) > maxgroup)
					maxgroup = glen;
				if (f_flags) {
					flags =
					    flags_to_string(sp->st_flags, "-");
					if ((flen = strlen(flags)) > maxflags)
						maxflags = flen;
				} else
					flen = 0;

				if ((np = malloc(sizeof(NAMES) +
				    ulen + glen + flen + 3)) == NULL)
					err(EXIT_FAILURE, NULL);

				np->user = &np->data[0];
				(void)strcpy(np->user, user);
				np->group = &np->data[ulen + 1];
				(void)strcpy(np->group, group);

				if (f_flags) {
					np->flags = &np->data[ulen + glen + 2];
				  	(void)strcpy(np->flags, flags);
				}
				cur->fts_pointer = np;
			}
		}
		++entries;
	}

	if (!entries)
		return;

	d.list = list;
	d.entries = entries;
	d.maxlen = maxlen;
	if (needstats) {
		d.btotal = btotal;
		d.stotal = stotal;
		if (f_humanize) {
			d.s_block = 4; /* min buf length for humanize_number */
		} else {
			(void)snprintf(buf, sizeof(buf), "%llu",
			    (long long)howmany(maxblock, blocksize));
			d.s_block = strlen(buf);
		}
		d.s_flags = maxflags;
		d.s_group = maxgroup;
		(void)snprintf(buf, sizeof(buf), "%u", maxinode);
		d.s_inode = strlen(buf);
		(void)snprintf(buf, sizeof(buf), "%u", maxnlink);
		d.s_nlink = strlen(buf);
		if (f_humanize) {
			d.s_size = 4; /* min buf length for humanize_number */
		} else {
			(void)snprintf(buf, sizeof(buf), "%llu",
			    (long long)maxsize);
			d.s_size = strlen(buf);
		}
		d.s_user = maxuser;
		if (bcfile) {
			(void)snprintf(buf, sizeof(buf), "%u", maxmajor);
			d.s_major = strlen(buf);
			(void)snprintf(buf, sizeof(buf), "%u", maxminor);
			d.s_minor = strlen(buf);
			if (d.s_major + d.s_minor + 2 > d.s_size)
				d.s_size = d.s_major + d.s_minor + 2;
			else if (d.s_size - d.s_minor - 2 > d.s_major)
				d.s_major = d.s_size - d.s_minor - 2;
		} else {
			d.s_major = 0;
			d.s_minor = 0;
		}
	}

	printfcn(&d);
	output = 1;

	if (f_longform)
		for (cur = list; cur; cur = cur->fts_link)
			free(cur->fts_pointer);
}

/*
 * Ordering for mastercmp:
 * If ordering the argv (fts_level = FTS_ROOTLEVEL) return non-directories
 * as larger than directories.  Within either group, use the sort function.
 * All other levels use the sort function.  Error entries remain unsorted.
 */
static int
mastercmp(const FTSENT **a, const FTSENT **b)
{
	int a_info, b_info;

	a_info = (*a)->fts_info;
	if (a_info == FTS_ERR)
		return (0);
	b_info = (*b)->fts_info;
	if (b_info == FTS_ERR)
		return (0);

	if (a_info == FTS_NS || b_info == FTS_NS) {
		if (b_info != FTS_NS)
			return (1);
		else if (a_info != FTS_NS)
			return (-1);
		else
			return (namecmp(*a, *b));
	}

	if (a_info != b_info && !f_listdir &&
	    (*a)->fts_level == FTS_ROOTLEVEL) {
		if (a_info == FTS_D)
			return (1);
		else if (b_info == FTS_D)
			return (-1);
	}
	return (sortfcn(*a, *b));
}