ls.c

minix软件源代码

/*	ls 4.1 - List files.				Author: Kees J. Bot
 *								25 Apr 1989
 *
 * About the amount of bytes for heap + stack under Minix:
 * Ls needs a average amount of 42 bytes per unserviced directory entry, so
 * scanning 10 directory levels deep in an ls -R with 100 entries per directory
 * takes 42000 bytes of heap.  So giving ls 10000 bytes is tight, 20000 is
 * usually enough, 40000 is pessimistic.
 */

/* The array _ifmt[] is used in an 'ls -l' to map the type of a file to a
 * letter.  This is done so that ls can list any future file or device type
 * other than symlinks, without recompilation.  (Yes it's dirty.)
 */
char _ifmt[] = "0pcCd?bB-?l?s???";

#define ifmt(mode)	_ifmt[((mode) >> 12) & 0xF]

#define nil 0
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include <fcntl.h>
#include <termios.h>
#include <sys/ioctl.h>

#ifndef major
#define major(dev)	((int) (((dev) >> 8) & 0xFF))
#define minor(dev)	((int) (((dev) >> 0) & 0xFF))
#endif

#if !__minix
#define SUPER_ID	uid	/* Let -A flag be default for SUPER_ID == 0. */
#else
#define SUPER_ID	gid
#endif

#ifdef S_IFLNK
int (*status)(const char *file, struct stat *stp);
#else
#define status	stat
#endif

/* Basic disk block size is 512 except for one niche O.S. */
#if __minix
#define BLOCK	1024
#else
#define BLOCK	 512
#endif

/* Assume other systems have st_blocks. */
#if !__minix
#define ST_BLOCKS 1
#endif

/* Some terminals ignore more than 80 characters on a line.  Dumb ones wrap
 * when the cursor hits the side.  Nice terminals don't wrap until they have
 * to print the 81st character.  Wether we like it or not, no column 80.
 */
int ncols= 79;

#define NSEP	2	/* # spaces between columns. */

#define MAXCOLS	150	/* Max # of files per line. */

char *arg0;	/* Last component of argv[0]. */
int uid, gid;	/* callers id. */
int ex= 0;	/* Exit status to be. */
int istty;	/* Output is on a terminal. */

/* Safer versions of malloc and realloc: */

void heaperr(void)
{
	fprintf(stderr, "%s: Out of memory\n", arg0);
	exit(-1);
}

void *allocate(size_t n)
/* Deliver or die. */
{
	void *a;

	if ((a= malloc(n)) == nil) heaperr();
	return a;
}

#define reallocate	rllct	/* Same as realloc under some compilers. */

void *reallocate(void *a, size_t n)
{
	if ((a= realloc(a, n)) == nil) heaperr();
	return a;
}

char allowed[] = "acdfgilnqrstu1ACFLMRTX";
char flags[sizeof(allowed)];

char arg0flag[] = "cfmrtx";	/* These in argv[0] go to upper case. */

void setflags(char *flgs)
{
	int c;

	while ((c= *flgs++) != 0) {
		if (strchr(allowed, c) == nil) {
			fprintf(stderr, "Usage: %s -[%s] [file ...]\n",
				arg0, allowed);
			exit(1);
		} else
		if (strchr(flags, c) == nil) {
			flags[strlen(flags)] = c;
		}
	}
}

int present(int f)
{
	return f == 0 || strchr(flags, f) != nil;
}

void report(char *f)
/* Like perror(3), but in the style: "ls: junk: No such file or directory. */
{
	fprintf(stderr, "%s: %s: %s\n", arg0, f, strerror(errno));
	ex= 1;
}

/* Two functions, uidname and gidname, translate id's to readable names.
 * All names are remembered to avoid searching the password file.
 */
#define NNAMES	(1 << (sizeof(int) + sizeof(char *)))
enum whatmap { PASSWD, GROUP };

struct idname {		/* Hash list of names. */
	struct idname	*next;
	char		*name;
	uid_t		id;
} *uids[NNAMES], *gids[NNAMES];

char *idname(unsigned id, enum whatmap map)
/* Return name for a given user/group id. */
{
	struct idname *i;
	struct idname **ids= &(map == PASSWD ? uids : gids)[id % NNAMES];

	while ((i= *ids) != nil && id < i->id) ids= &i->next;

	if (i == nil || id != i->id) {
		/* Not found, go look in the password or group map. */
		char *name= nil;
		char noname[3 * sizeof(uid_t)];

		if (!present('n')) {
			if (map == PASSWD) {
				struct passwd *pw= getpwuid(id);

				if (pw != nil) name= pw->pw_name;
			} else {
				struct group *gr= getgrgid(id);

				if (gr != nil) name= gr->gr_name;
			}
		}
		if (name == nil) {
			/* Can't find it, weird.  Use numerical "name." */
			sprintf(noname, "%u", id);
			name= noname;
		}

		/* Add a new id-to-name cell. */
		i= allocate(sizeof(*i));
		i->id= id;
		i->name= allocate(strlen(name) + 1);
		strcpy(i->name, name);
		i->next= *ids;
		*ids= i;
	}
	return i->name;
}

#define uidname(uid)	idname((uid), PASSWD)
#define gidname(gid)	idname((gid), GROUP)

/* Path name construction, addpath adds a component, delpath removes it.
 * The string path is used throughout the program as the file under examination.
 */

char *path;	/* Path name constructed in path[]. */
int plen= 0, pidx= 0;	/* Lenght/index for path[]. */

void addpath(int *didx, char *name)
/* Add a component to path. (name may also be a full path at the first call)
 * The index where the current path ends is stored in *pdi.
 */
{
	if (plen == 0) path= (char *) allocate((plen= 32) * sizeof(path[0]));

	if (pidx == 1 && path[0] == '.') pidx= 0;	/* Remove "." */

	*didx= pidx;	/* Record point to go back to for delpath. */

	if (pidx > 0 && path[pidx-1] != '/') path[pidx++]= '/';

	do {
		if (*name != '/' || pidx == 0 || path[pidx-1] != '/') {
			if (pidx == plen) {
				path= (char *) reallocate((void *) path,
						(plen*= 2) * sizeof(path[0]));
			}
			path[pidx++]= *name;
		}
	} while (*name++ != 0);

	--pidx;		/* Put pidx back at the null.  The path[pidx++]= '/'
			 * statement will overwrite it at the next call.
			 */
}

#define delpath(didx)	(path[pidx= didx]= 0)	/* Remove component. */

int field = 0;	/* (used to be) Fields that must be printed. */
		/* (now) Effects triggered by certain flags. */

#define F_INODE		0x001	/* -i */
#define F_BLOCKS	0x002	/* -s */
#define F_EXTRA		0x004	/* -X */
#define F_MODE		0x008	/* -lMX */
#define F_LONG		0x010	/* -l */
#define F_GROUP		0x020	/* -g */
#define F_BYTIME	0x040	/* -tuc */
#define F_ATIME		0x080	/* -u */
#define F_CTIME		0x100	/* -c */
#define F_MARK		0x200	/* -F */
#define F_TYPE		0x400	/* -T */
#define F_DIR		0x800	/* -d */

struct file {		/* A file plus stat(2) information. */
	struct file	*next;	/* Lists are made of them. */
	char		*name;	/* Null terminated name. */
	ino_t		ino;
	mode_t		mode;
	uid_t		uid;
	gid_t		gid;
	nlink_t		nlink;
	dev_t		rdev;
	off_t		size;
	time_t		mtime;
	time_t		atime;
	time_t		ctime;
#if ST_BLOCKS
	long		blocks;
#endif
};

void setstat(struct file *f, struct stat *stp)
{
	f->ino=		stp->st_ino;
	f->mode=	stp->st_mode;
	f->nlink=	stp->st_nlink;
	f->uid=		stp->st_uid;
	f->gid=		stp->st_gid;
	f->rdev=	stp->st_rdev;
	f->size=	stp->st_size;
	f->mtime=	stp->st_mtime;
	f->atime=	stp->st_atime;
	f->ctime=	stp->st_ctime;
#if ST_BLOCKS
	f->blocks=	stp->st_blocks;
#endif
}

#define	PAST	(26*7*24*3600L)	/* Half a year ago. */
/* Between PAST and FUTURE from now a time is printed, otherwise a year. */
#define FUTURE	(15*60L)	/* Fifteen minutes. */

static char *timestamp(struct file *f)
/* Transform the right time field into something readable. */
{
	struct tm *tm;
	time_t t;
	static time_t now;
	static int drift= 0;
	static char date[] = "Jan 19  2038";
	static char month[] = "JanFebMarAprMayJunJulAugSepOctNovDec";

	t= f->mtime;
	if (field & F_ATIME) t= f->atime;
	if (field & F_CTIME) t= f->ctime;

	tm= localtime(&t);
	if (--drift < 0) { time(&now); drift= 50; }	/* limit time() calls */

	if (t < now - PAST || t > now + FUTURE) {
		sprintf(date, "%.3s %2d  %4d",
			month + 3*tm->tm_mon,
			tm->tm_mday,
			1900 + tm->tm_year);
	} else {
		sprintf(date, "%.3s %2d %02d:%02d",
			month + 3*tm->tm_mon,
			tm->tm_mday,
			tm->tm_hour, tm->tm_min);
	}
	return date;
}

char *permissions(struct file *f)
/* Compute long or short rwx bits. */
{
	static char rwx[] = "drwxr-x--x";

	rwx[0] = ifmt(f->mode);
	/* Note that rwx[0] is a guess for the more alien file types.  It is
	 * correct for BSD4.3 and derived systems.  I just don't know how
	 * "standardized" these numbers are.
	 */

	if (field & F_EXTRA) {		/* Short style */
		int mode = f->mode, ucase= 0;

		if (uid == f->uid) {	/* What group of bits to use. */
			/* mode<<= 0, */
			ucase= (mode<<3) | (mode<<6);
			/* Remember if group or others have permissions. */
		} else
		if (gid == f->gid) {
			mode<<= 3;
		} else {
			mode<<= 6;
		}
		rwx[1]= mode&S_IRUSR ? (ucase&S_IRUSR ? 'R' : 'r') : '-';
		rwx[2]= mode&S_IWUSR ? (ucase&S_IWUSR ? 'W' : 'w') : '-';

		if (mode&S_IXUSR) {
			static char sbit[]= { 'x', 'g', 'u', 's' };

			rwx[3]= sbit[(f->mode&(S_ISUID|S_ISGID))>>10];
			if (ucase&S_IXUSR) rwx[3] += 'A'-'a';
		} else {
			rwx[3]= f->mode&(S_ISUID|S_ISGID) ? '=' : '-';
		}
		rwx[4]= 0;
	} else {		/* Long form. */
		char *p= rwx+1;
		int mode= f->mode;

		do {
			p[0] = (mode & S_IRUSR) ? 'r' : '-';
			p[1] = (mode & S_IWUSR) ? 'w' : '-';
			p[2] = (mode & S_IXUSR) ? 'x' : '-';
			mode<<= 3;
		} while ((p+=3) <= rwx+7);

		if (f->mode&S_ISUID) rwx[3]= f->mode&(S_IXUSR>>0) ? 's' : '=';
		if (f->mode&S_ISGID) rwx[6]= f->mode&(S_IXUSR>>3) ? 's' : '=';
		if (f->mode&S_ISVTX) rwx[9]= f->mode&(S_IXUSR>>6) ? 't' : '=';
	}
	return rwx;
}

void numeral(int i, char **pp)
{
	char itoa[3*sizeof(int)], *a=itoa;

	do *a++ = i%10 + '0'; while ((i/=10) > 0);

	do *(*pp)++ = *--a; while (a>itoa);
}

#define K	1024L		/* A kilobyte counts in multiples of K */
#define T	1000L		/* A megabyte in T*K, a gigabyte in T*T*K */

char *cxsize(struct file *f)
/* Try and fail to turn a 32 bit size into 4 readable characters. */
{
	static char siz[] = "1.2m";
	char *p= siz;
	off_t z;

	siz[1]= siz[2]= siz[3]= 0;

	if (f->size <= 5*K) {	/* <= 5K prints as is. */
		numeral((int) f->size, &p);
		return siz;
	}
	z= (f->size + K-1) / K;

	if (z <= 999) {		/* Print as 123k. */
		numeral((int) z, &p);
		*p = 'k';	/* Can't use 'K', looks bad */
	} else
	if (z*10 <= 99*T) {	/* 1.2m (Try ls -X /dev/at0) */
		z= (z*10 + T-1) / T;	/* Force roundup */
		numeral((int) z / 10, &p);
		*p++ = '.';
		numeral((int) z % 10, &p);
		*p = 'm';
	} else
	if (z <= 999*T) {	/* 123m */
		numeral((int) ((z + T-1) / T), &p);
		*p = 'm';
	} else {		/* 1.2g */
		z= (z*10 + T*T-1) / (T*T);
		numeral((int) z / 10, &p);
		*p++ = '.';
		numeral((int) z % 10, &p);
		*p = 'g';
	}
	return siz;
}

/* Transform size of file to number of blocks.  This was once a function that
 * guessed the number of indirect blocks, but that nonsense has been removed.
 */
#if ST_BLOCKS
#define nblocks(f)	((f)->blocks)
#else
#define nblocks(f)	(((f)->size + BLOCK-1) / BLOCK)
#endif

/* From number of blocks to kilobytes. */
#if BLOCK < 1024
#define nblk2k(nb)	(((nb) + (1024 / BLOCK - 1)) / (1024 / BLOCK))
#else
#define nblk2k(nb)	((nb) * (BLOCK / 1024))
#endif

static int (*CMP)(struct file *f1, struct file *f2);
static int (*rCMP)(struct file *f1, struct file *f2);

static void mergesort(struct file **al)
/* This is either a stable mergesort, or thermal noise, I'm no longer sure.
 * It must be called like this: if (L != nil && L->next != nil) mergesort(&L);
 */
{
	/* static */ struct file *l1, **mid;  /* Need not be local */
	struct file *l2;

	l1= *(mid= &(*al)->next);
	do {
		if ((l1= l1->next) == nil) break;
		mid= &(*mid)->next;
	} while ((l1= l1->next) != nil);

	l2= *mid;
	*mid= nil;

	if ((*al)->next != nil) mergesort(al);
	if (l2->next != nil) mergesort(&l2);

	l1= *al;
	for (;;) {
		if ((*CMP)(l1, l2) <= 0) {
			if ((l1= *(al= &l1->next)) == nil) {
				*al= l2;
				break;
			}
		} else {
			*al= l2;
			l2= *(al= &l2->next);
			*al= l1;
			if (l2 == nil) break;
		}
	}
}

int namecmp(struct file *f1, struct file *f2)
{
	return strcmp(f1->name, f2->name);
}

int mtimecmp(struct file *f1, struct file *f2)
{
	return f1->mtime == f2->mtime ? 0 : f1->mtime > f2->mtime ? -1 : 1;
}

int atimecmp(struct file *f1, struct file *f2)
{
	return f1->atime == f2->atime ? 0 : f1->atime > f2->atime ? -1 : 1;
}

int ctimecmp(struct file *f1, struct file *f2)
{
	return f1->ctime == f2->ctime ? 0 : f1->ctime > f2->ctime ? -1 : 1;
}

int typecmp(struct file *f1, struct file *f2)
{
	return ifmt(f1->mode) - ifmt(f2->mode);
}

int revcmp(struct file *f1, struct file *f2) { return (*rCMP)(f2, f1); }

static void sort(struct file **al)
/* Sort the files according to the flags. */
{
	if (!present('f') && *al != nil && (*al)->next != nil) {
		CMP= namecmp;

		if (!(field & F_BYTIME)) {
			/* Sort on name */

			if (present('r')) { rCMP= CMP; CMP= revcmp; }
			mergesort(al);
		} else {
			/* Sort on name first, then sort on time. */

			mergesort(al);
			if (field & F_CTIME) {
				CMP= ctimecmp;
			} else