plan9port

sysuse.c (13953B)

---

 /*
  * To understand this code, see Rock Ridge Interchange Protocol
  * standard 1.12 and System Use Sharing Protocol version 1.12
  * (search for rrip112.ps and susp112.ps on the web).
  *
  * Even better, go read something else.
  */
 
 #include <u.h>
 #include <libc.h>
 #include <bio.h>
 #include <libsec.h>
 #include "iso9660.h"
 
 static long mode(Direc*, int);
 static long nlink(Direc*);
 static ulong suspdirflags(Direc*, int);
 static ulong CputsuspCE(Cdimg *cd, ulong offset);
 static int CputsuspER(Cdimg*, int);
 static int CputsuspRR(Cdimg*, int, int);
 static int CputsuspSP(Cdimg*, int);
 /*static int CputsuspST(Cdimg*, int); */
 static int Cputrripname(Cdimg*, char*, int, char*, int);
 static int CputrripSL(Cdimg*, int, int, char*, int);
 static int CputrripPX(Cdimg*, Direc*, int, int);
 static int CputrripTF(Cdimg*, Direc*, int, int);
 
 /*
  * Patch the length field in a CE record.
  */
 static void
 setcelen(Cdimg *cd, ulong woffset, ulong len)
 {
 	ulong o;
 
 	o = Cwoffset(cd);
 	Cwseek(cd, woffset);
 	Cputn(cd, len, 4);
 	Cwseek(cd, o);
 }
 
 /*
  * Rock Ridge data is put into little blockettes, which can be
  * at most 256 bytes including a one-byte length.  Some number
  * of blockettes get packed together into a normal 2048-byte block.
  * Blockettes cannot cross block boundaries.
  *
  * A Cbuf is a blockette buffer.  Len contains
  * the length of the buffer written so far, and we can
  * write up to 254-28.
  *
  * We only have one active Cbuf at a time; cdimg.rrcontin is the byte
  * offset of the beginning of that Cbuf.
  *
  * The blockette can be at most 255 bytes.  The last 28
  * will be (in the worst case) a CE record pointing at
  * a new blockette.  If we do write 255 bytes though,
  * we'll try to pad it out to be even, and overflow.
  * So the maximum is 254-28.
  *
  * Ceoffset contains the offset to be used with setcelen
  * to patch the CE pointing at the Cbuf once we know how
  * long the Cbuf is.
  */
 typedef struct Cbuf Cbuf;
 struct Cbuf {
 	int len;	/* written so far, of 254-28 */
 	ulong ceoffset;
 };
 
 static int
 freespace(Cbuf *cp)
 {
 	return (254-28) - cp->len;
 }
 
 static Cbuf*
 ensurespace(Cdimg *cd, int n, Cbuf *co, Cbuf *cn, int dowrite)
 {
 	ulong end;
 
 	if(co->len+n <= 254-28) {
 		co->len += n;
 		return co;
 	}
 
 	co->len += 28;
 	assert(co->len <= 254);
 
 	if(dowrite == 0) {
 		cn->len = n;
 		return cn;
 	}
 
 	/*
 	 * the current blockette is full; update cd->rrcontin and then
  	 * write a CE record to finish it.  Unfortunately we need to
 	 * figure out which block will be next before we write the CE.
 	 */
 	end = Cwoffset(cd)+28;
 
 	/*
 	 * if we're in a continuation blockette, update rrcontin.
 	 * also, write our length into the field of the CE record
 	 * that points at us.
 	 */
 	if(cd->rrcontin+co->len == end) {
 		assert(cd->rrcontin != 0);
 		assert(co == cn);
 		cd->rrcontin += co->len;
 		setcelen(cd, co->ceoffset, co->len);
 	} else
 		assert(co != cn);
 
 	/*
 	 * if the current continuation block can't fit another
 	 * blockette, then start a new continuation block.
 	 * rrcontin = 0 (mod Blocksize) means we just finished
 	 * one, not that we've just started one.
 	 */
 	if(cd->rrcontin%Blocksize == 0
 	|| cd->rrcontin/Blocksize != (cd->rrcontin+256)/Blocksize) {
 		cd->rrcontin = cd->nextblock*Blocksize;
 		cd->nextblock++;
 	}
 
 	cn->ceoffset = CputsuspCE(cd, cd->rrcontin);
 
 	assert(Cwoffset(cd) == end);
 
 	cn->len = n;
 	Cwseek(cd, cd->rrcontin);
 	assert(cd->rrcontin != 0);
 
 	return cn;
 }
 
 /*
  * Put down the name, but we might need to break it
  * into chunks so that each chunk fits in 254-28-5 bytes.
  * What a crock.
  *
  * The new Plan 9 format uses strings of this form too,
  * since they're already there.
  */
 Cbuf*
 Cputstring(Cdimg *cd, Cbuf *cp, Cbuf *cn, char *nm, char *p, int flags, int dowrite)
 {
 	char buf[256], *q;
 	int free;
 
 	for(; p[0] != '\0'; p = q) {
 		cp = ensurespace(cd, 5+1, cp, cn, dowrite);
 		cp->len -= 5+1;
 		free = freespace(cp);
 		assert(5+1 <= free && free < 256);
 
 		strncpy(buf, p, free-5);
 		buf[free-5] = '\0';
 		q = p+strlen(buf);
 		p = buf;
 
 		ensurespace(cd, 5+strlen(p), cp, nil, dowrite);	/* nil: better not use this. */
 		Cputrripname(cd, nm, flags | (q[0] ? NMcontinue : 0), p, dowrite);
 	}
 	return cp;
 }
 
 /*
  * Write a Rock Ridge SUSP set of records for a directory entry.
  */
 int
 Cputsysuse(Cdimg *cd, Direc *d, int dot, int dowrite, int initlen)
 {
 	char buf[256], buf0[256], *nextpath, *p, *path, *q;
 	int flags, free, m, what;
 	ulong o;
 	Cbuf cn, co, *cp;
 
 	assert(cd != nil);
 	assert((initlen&1) == 0);
 
 	if(dot == DTroot)
 		return 0;
 
 	co.len = initlen;
 
 	o = Cwoffset(cd);
 
 	assert(dowrite==0 || Cwoffset(cd) == o+co.len-initlen);
 	cp = &co;
 
 	if (dot == DTrootdot) {
 		m = CputsuspSP(cd, 0);
 		cp = ensurespace(cd, m, cp, &cn, dowrite);
 		CputsuspSP(cd, dowrite);
 
 		m = CputsuspER(cd, 0);
 		cp = ensurespace(cd, m, cp, &cn, dowrite);
 		CputsuspER(cd, dowrite);
 	}
 
 	/*
 	 * In a perfect world, we'd be able to omit the NM
 	 * entries when our name was all lowercase and conformant,
 	 * but OpenBSD insists on uppercasing (really, not lowercasing)
 	 * the ISO9660 names.
 	 */
 	what = RR_PX | RR_TF | RR_NM;
 	if(d != nil && (d->mode & CHLINK))
 		what |= RR_SL;
 
 	m = CputsuspRR(cd, what, 0);
 	cp = ensurespace(cd, m, cp, &cn, dowrite);
 	CputsuspRR(cd, what, dowrite);
 
 	if(what & RR_PX) {
 		m = CputrripPX(cd, d, dot, 0);
 		cp = ensurespace(cd, m, cp, &cn, dowrite);
 		CputrripPX(cd, d, dot, dowrite);
 	}
 
 	if(what & RR_NM) {
 		if(dot == DTiden)
 			p = d->name;
 		else if(dot == DTdotdot)
 			p = "..";
 		else
 			p = ".";
 
 		flags = suspdirflags(d, dot);
 		assert(dowrite==0 || cp != &co || Cwoffset(cd) == o+co.len-initlen);
 		cp = Cputstring(cd, cp, &cn, "NM", p, flags, dowrite);
 	}
 
 	/*
 	 * Put down the symbolic link.  This is even more of a crock.
 	 * Not only are the individual elements potentially split,
 	 * but the whole path itself can be split across SL blocks.
 	 * To keep the code simple as possible (really), we write
 	 * only one element per SL block, wasting 6 bytes per element.
 	 */
 	if(what & RR_SL) {
 		for(path=d->symlink; path[0] != '\0'; path=nextpath) {
 			/* break off one component */
 			if((nextpath = strchr(path, '/')) == nil)
 				nextpath = path+strlen(path);
 			strncpy(buf0, path, nextpath-path);
 			buf0[nextpath-path] = '\0';
 			if(nextpath[0] == '/')
 				nextpath++;
 			p = buf0;
 
 			/* write the name, perhaps broken into pieces */
 			if(strcmp(p, "") == 0)
 				flags = NMroot;
 			else if(strcmp(p, ".") == 0)
 				flags = NMcurrent;
 			else if(strcmp(p, "..") == 0)
 				flags = NMparent;
 			else
 				flags = 0;
 
 			/* the do-while handles the empty string properly */
 			do {
 				/* must have room for at least 1 byte of name */
 				cp = ensurespace(cd, 7+1, cp, &cn, dowrite);
 				cp->len -= 7+1;
 				free = freespace(cp);
 				assert(7+1 <= free && free < 256);
 
 				strncpy(buf, p, free-7);
 				buf[free-7] = '\0';
 				q = p+strlen(buf);
 				p = buf;
 
 				/* nil: better not need to expand */
 				assert(7+strlen(p) <= free);
 				ensurespace(cd, 7+strlen(p), cp, nil, dowrite);
 				CputrripSL(cd, nextpath[0], flags | (q[0] ? NMcontinue : 0), p, dowrite);
 				p = q;
 			} while(p[0] != '\0');
 		}
 	}
 
 	assert(dowrite==0 || cp != &co || Cwoffset(cd) == o+co.len-initlen);
 
 	if(what & RR_TF) {
 		m = CputrripTF(cd, d, TFcreation|TFmodify|TFaccess|TFattributes, 0);
 		cp = ensurespace(cd, m, cp, &cn, dowrite);
 		CputrripTF(cd, d, TFcreation|TFmodify|TFaccess|TFattributes, dowrite);
 	}
 	assert(dowrite==0 || cp != &co || Cwoffset(cd) == o+co.len-initlen);
 
 	if(cp == &cn && dowrite) {
 		/* seek out of continuation, but mark our place */
 		cd->rrcontin = Cwoffset(cd);
 		setcelen(cd, cn.ceoffset, cn.len);
 		Cwseek(cd, o+co.len-initlen);
 	}
 
 	if(co.len & 1) {
 		co.len++;
 		if(dowrite)
 			Cputc(cd, 0);
 	}
 
 	if(dowrite) {
 		if(Cwoffset(cd) != o+co.len-initlen)
 			fprint(2, "offset %lud o+co.len-initlen %lud\n", Cwoffset(cd), o+co.len-initlen);
 		assert(Cwoffset(cd) == o+co.len-initlen);
 	} else
 		assert(Cwoffset(cd) == o);
 
 	assert(co.len <= 255);
 	return co.len - initlen;
 }
 
 static char SUSPrrip[10] = "RRIP_1991A";
 static char SUSPdesc[84] = "RRIP <more garbage here>";
 static char SUSPsrc[135] = "RRIP <more garbage here>";
 
 static ulong
 CputsuspCE(Cdimg *cd, ulong offset)
 {
 	ulong o, x;
 
 	chat("writing SUSP CE record pointing to %ld, %ld\n", offset/Blocksize, offset%Blocksize);
 	o = Cwoffset(cd);
 	Cputc(cd, 'C');
 	Cputc(cd, 'E');
 	Cputc(cd, 28);
 	Cputc(cd, 1);
 	Cputn(cd, offset/Blocksize, 4);
 	Cputn(cd, offset%Blocksize, 4);
 	x = Cwoffset(cd);
 	Cputn(cd, 0, 4);
 	assert(Cwoffset(cd) == o+28);
 
 	return x;
 }
 
 static int
 CputsuspER(Cdimg *cd, int dowrite)
 {
 	assert(cd != nil);
 
 	if(dowrite) {
 		chat("writing SUSP ER record\n");
 		Cputc(cd, 'E');           /* ER field marker */
 		Cputc(cd, 'R');
 		Cputc(cd, 26);            /* Length          */
 		Cputc(cd, 1);             /* Version         */
 		Cputc(cd, 10);            /* LEN_ID          */
 		Cputc(cd, 4);             /* LEN_DESC        */
 		Cputc(cd, 4);             /* LEN_SRC         */
 		Cputc(cd, 1);             /* EXT_VER         */
 		Cputs(cd, SUSPrrip, 10);  /* EXT_ID          */
 		Cputs(cd, SUSPdesc, 4);   /* EXT_DESC        */
 		Cputs(cd, SUSPsrc, 4);    /* EXT_SRC         */
 	}
 	return 8+10+4+4;
 }
 
 static int
 CputsuspRR(Cdimg *cd, int what, int dowrite)
 {
 	assert(cd != nil);
 
 	if(dowrite) {
 		Cputc(cd, 'R');           /* RR field marker */
 		Cputc(cd, 'R');
 		Cputc(cd, 5);             /* Length          */
 		Cputc(cd, 1);		  /* Version number  */
 		Cputc(cd, what);          /* Flags           */
 	}
 	return 5;
 }
 
 static int
 CputsuspSP(Cdimg *cd, int dowrite)
 {
 	assert(cd!=0);
 
 	if(dowrite) {
 chat("writing SUSP SP record\n");
 		Cputc(cd, 'S');           /* SP field marker */
 		Cputc(cd, 'P');
 		Cputc(cd, 7);             /* Length          */
 		Cputc(cd, 1);             /* Version         */
 		Cputc(cd, 0xBE);          /* Magic           */
 		Cputc(cd, 0xEF);
 		Cputc(cd, 0);
 	}
 
 	return 7;
 }
 
 #ifdef NOTUSED
 static int
 CputsuspST(Cdimg *cd, int dowrite)
 {
 	assert(cd!=0);
 
 	if(dowrite) {
 		Cputc(cd, 'S');           /* ST field marker */
 		Cputc(cd, 'T');
 		Cputc(cd, 4);             /* Length          */
 		Cputc(cd, 1);             /* Version         */
 	}
 	return 4;
 }
 #endif
 
 static ulong
 suspdirflags(Direc *d, int dot)
 {
 	uchar flags;
 
 	USED(d);
 	flags = 0;
 	switch(dot) {
 	default:
 		assert(0);
 	case DTdot:
 	case DTrootdot:
 		flags |= NMcurrent;
 		break;
 	case DTdotdot:
 		flags |= NMparent;
 		break;
 	case DTroot:
 		flags |= NMvolroot;
 		break;
 	case DTiden:
 		break;
 	}
 	return flags;
 }
 
 static int
 Cputrripname(Cdimg *cd, char *nm, int flags, char *name, int dowrite)
 {
 	int l;
 
 	l = strlen(name);
 	if(dowrite) {
 		Cputc(cd, nm[0]);                   /* NM field marker */
 		Cputc(cd, nm[1]);
 		Cputc(cd, l+5);        /* Length          */
 		Cputc(cd, 1);                     /* Version         */
 		Cputc(cd, flags);                 /* Flags           */
 		Cputs(cd, name, l);    /* Alternate name  */
 	}
 	return 5+l;
 }
 
 static int
 CputrripSL(Cdimg *cd, int contin, int flags, char *name, int dowrite)
 {
 	int l;
 
 	l = strlen(name);
 	if(dowrite) {
 		Cputc(cd, 'S');
 		Cputc(cd, 'L');
 		Cputc(cd, l+7);
 		Cputc(cd, 1);
 		Cputc(cd, contin ? 1 : 0);
 		Cputc(cd, flags);
 		Cputc(cd, l);
 		Cputs(cd, name, l);
 	}
 	return 7+l;
 }
 
 static int
 CputrripPX(Cdimg *cd, Direc *d, int dot, int dowrite)
 {
 	assert(cd!=0);
 
 	if(dowrite) {
 		Cputc(cd, 'P');             /* PX field marker */
 		Cputc(cd, 'X');
 		Cputc(cd, 36);              /* Length          */
 		Cputc(cd, 1);               /* Version         */
 
 		Cputn(cd, mode(d, dot), 4); /* POSIX File mode */
 		Cputn(cd, nlink(d), 4);     /* POSIX st_nlink  */
 		Cputn(cd, d?d->uidno:0, 4);  /* POSIX st_uid    */
 		Cputn(cd, d?d->gidno:0, 4);  /* POSIX st_gid    */
 	}
 
 	return 36;
 }
 
 static int
 CputrripTF(Cdimg *cd, Direc *d, int type, int dowrite)
 {
 	int i, length;
 
 	assert(cd!=0);
 	assert(!(type & TFlongform));
 
 	length = 0;
 	for(i=0; i<7; i++)
 		if (type & (1<<i))
 			length++;
 	assert(length == 4);
 
 	if(dowrite) {
 		Cputc(cd, 'T');				/* TF field marker */
 		Cputc(cd, 'F');
 		Cputc(cd, 5+7*length);		/* Length		 */
 		Cputc(cd, 1);				/* Version		 */
 		Cputc(cd, type);					/* Flags (types)	 */
 
 		if (type & TFcreation)
 			Cputdate(cd, d?d->ctime:0);
 		if (type & TFmodify)
 			Cputdate(cd, d?d->mtime:0);
 		if (type & TFaccess)
 			Cputdate(cd, d?d->atime:0);
 		if (type & TFattributes)
 			Cputdate(cd, d?d->ctime:0);
 
 	/*	if (type & TFbackup) */
 	/*		Cputdate(cd, 0); */
 	/*	if (type & TFexpiration) */
 	/*		Cputdate(cd, 0); */
 	/*	if (type & TFeffective) */
 	/*		Cputdate(cd, 0); */
 	}
 	return 5+7*length;
 }
 
 
 #define NONPXMODES  (DMDIR & DMAPPEND & DMEXCL & DMMOUNT)
 #define POSIXMODEMASK (0177777)
 #ifndef S_IFMT
 #define S_IFMT  (0170000)
 #endif
 #ifndef S_IFDIR
 #define S_IFDIR (0040000)
 #endif
 #ifndef S_IFREG
 #define S_IFREG (0100000)
 #endif
 #ifndef S_IFLNK
 #define S_IFLNK (0120000)
 #endif
 #undef  ISTYPE
 #define ISTYPE(mode, mask)  (((mode) & S_IFMT) == (mask))
 #ifndef S_ISDIR
 #define S_ISDIR(mode) ISTYPE(mode, S_IFDIR)
 #endif
 #ifndef S_ISREG
 #define S_ISREG(mode) ISTYPE(mode, S_IREG)
 #endif
 #ifndef S_ISLNK
 #define S_ISLNK(mode) ISTYPE(mode, S_ILNK)
 #endif
 
 
 static long
 mode(Direc *d, int dot)
 {
 	long mode;
 
 	if (!d)
 		return 0;
 
 	if ((dot != DTroot) && (dot != DTrootdot)) {
 		mode = (d->mode & ~(NONPXMODES));
 		if (d->mode & DMDIR)
 			mode |= S_IFDIR;
 		else if (d->mode & CHLINK)
 			mode |= S_IFLNK;
 		else
 			mode |= S_IFREG;
 	} else
 		mode = S_IFDIR | (0755);
 
 	mode &= POSIXMODEMASK;
 
 	/* Botch: not all POSIX types supported yet */
 	assert(mode & (S_IFDIR|S_IFREG));
 
 chat("writing PX record mode field %ulo with dot %d and name \"%s\"\n", mode, dot, d->name);
 
 	return mode;
 }
 
 static long
 nlink(Direc *d)   /* Trump up the nlink field for POSIX compliance */
 {
 	int i;
 	long n;
 
 	if (!d)
 		return 0;
 
 	n = 1;
 	if (d->mode & DMDIR)   /* One for "." and one more for ".." */
 		n++;
 
 	for(i=0; i<d->nchild; i++)
 		if (d->child[i].mode & DMDIR)
 			n++;
 
 	return n;
 }