/*
* tar - `tape archiver', actually usable on any medium.
* POSIX "ustar" compliant when extracting, and by default when creating.
* this tar attempts to read and write multiple Tblock-byte blocks
* at once to and from the filesystem, and does not copy blocks
* around internally.
*/
#include <u.h>
#include <libc.h>
#include <fcall.h> /* for %M */
#include <String.h>
/*
* modified versions of those in libc.h; scans only the first arg for
* keyletters and options.
*/
#define TARGBEGIN {\
(argv0 || (argv0 = *argv)), argv++, argc--;\
if (argv[0]) {\
char *_args, *_argt;\
Rune _argc;\
_args = &argv[0][0];\
_argc = 0;\
while(*_args && (_args += chartorune(&_argc, _args)))\
switch(_argc)
#define TARGEND SET(_argt); USED(_argt);USED(_argc);USED(_args); \
argc--, argv++; } \
USED(argv); USED(argc); }
#define TARGC() (_argc)
#define ROUNDUP(a, b) (((a) + (b) - 1)/(b))
#define BYTES2TBLKS(bytes) ROUNDUP(bytes, Tblock)
typedef vlong Off;
typedef char *(*Refill)(int ar, char *bufs);
enum { Stdin, Stdout, Stderr };
enum { Rd, Wr }; /* pipe fd-array indices */
enum { Output, Input };
enum { None, Toc, Xtract, Replace };
enum {
Tblock = 512,
Nblock = 40, /* maximum blocksize */
Dblock = 20, /* default blocksize */
Namsiz = 100,
Maxpfx = 155, /* from POSIX */
Maxname = Namsiz + 1 + Maxpfx,
DEBUG = 0,
};
/* POSIX link flags */
enum {
LF_PLAIN1 = '\0',
LF_PLAIN2 = '0',
LF_LINK = '1',
LF_SYMLINK1 = '2',
LF_SYMLINK2 = 's',
LF_CHR = '3',
LF_BLK = '4',
LF_DIR = '5',
LF_FIFO = '6',
LF_CONTIG = '7',
/* 'A' - 'Z' are reserved for custom implementations */
};
#define islink(lf) (isreallink(lf) || issymlink(lf))
#define isreallink(lf) ((lf) == LF_LINK)
#define issymlink(lf) ((lf) == LF_SYMLINK1 || (lf) == LF_SYMLINK2)
typedef union {
uchar data[Tblock];
struct {
char name[Namsiz];
char mode[8];
char uid[8];
char gid[8];
char size[12];
char mtime[12];
char chksum[8];
char linkflag;
char linkname[Namsiz];
/* rest are defined by POSIX's ustar format; see p1003.2b */
char magic[6]; /* "ustar" */
char version[2];
char uname[32];
char gname[32];
char devmajor[8];
char devminor[8];
char prefix[Maxpfx]; /* if non-null, path= prefix "/" name */
};
} Hdr;
typedef struct {
char *comp;
char *decomp;
char *sfx[4];
} Compress;
static Compress comps[] = {
"gzip", "gunzip", { ".tar.gz", ".tgz" }, /* default */
"compress", "uncompress", { ".tar.Z", ".tz" },
"bzip2", "bunzip2", { ".tar.bz", ".tbz",
".tar.bz2",".tbz2" },
};
typedef struct {
int kid;
int fd; /* original fd */
int rfd; /* replacement fd */
int input;
int open;
} Pushstate;
#define OTHER(rdwr) (rdwr == Rd? Wr: Rd)
static int debug;
static int verb;
static int posix = 1;
static int docreate;
static int aruid;
static int argid;
static int relative = 1;
static int settime;
static int verbose;
static int docompress;
static int keepexisting;
static int nblock = Dblock;
static char *usefile;
static char origdir[Maxname*2];
static Hdr *tpblk, *endblk;
static Hdr *curblk;
static void
usage(void)
{
fprint(2, "usage: %s {crtx}[PRTfgkmpuvz] [archive] file1 file2...\n",
argv0);
exits("usage");
}
/* compression */
static Compress *
compmethod(char *name)
{
int i, nmlen = strlen(name), sfxlen;
Compress *cp;
for (cp = comps; cp < comps + nelem(comps); cp++)
for (i = 0; i < nelem(cp->sfx) && cp->sfx[i]; i++) {
sfxlen = strlen(cp->sfx[i]);
if (nmlen > sfxlen &&
strcmp(cp->sfx[i], name + nmlen - sfxlen) == 0)
return cp;
}
return docompress? comps: nil;
}
/*
* push a filter, cmd, onto fd. if input, it's an input descriptor.
* returns a descriptor to replace fd, or -1 on error.
*/
static int
push(int fd, char *cmd, int input, Pushstate *ps)
{
int nfd, pifds[2];
String *s;
ps->open = 0;
ps->fd = fd;
ps->input = input;
if (fd < 0 || pipe(pifds) < 0)
return -1;
ps->kid = fork();
switch (ps->kid) {
case -1:
return -1;
case 0:
if (input)
dup(pifds[Wr], Stdout);
else
dup(pifds[Rd], Stdin);
close(pifds[input? Rd: Wr]);
dup(fd, (input? Stdin: Stdout));
s = s_new();
if (cmd[0] != '/')
s_append(s, "/bin/");
s_append(s, cmd);
execl(s_to_c(s), cmd, nil);
sysfatal("can't exec %s: %r", cmd);
default:
nfd = pifds[input? Rd: Wr];
close(pifds[input? Wr: Rd]);
break;
}
ps->rfd = nfd;
ps->open = 1;
return nfd;
}
static char *
pushclose(Pushstate *ps)
{
Waitmsg *wm;
if (ps->fd < 0 || ps->rfd < 0 || !ps->open)
return "not open";
close(ps->rfd);
ps->rfd = -1;
ps->open = 0;
while ((wm = wait()) != nil && wm->pid != ps->kid)
continue;
return wm? wm->msg: nil;
}
/*
* block-buffer management
*/
static void
initblks(void)
{
free(tpblk);
tpblk = malloc(Tblock * nblock);
assert(tpblk != nil);
endblk = tpblk + nblock;
}
/* (re)fill block buffers from archive */
static char *
refill(int ar, char *bufs)
{
int i, n;
unsigned bytes = Tblock * nblock;
static int done, first = 1;
if (done)
return nil;
/* try to size non-pipe input at first read */
if (first && usefile) {
first = 0;
n = read(ar, bufs, bytes);
if (n <= 0)
sysfatal("error reading archive: %r");
i = n;
if (i % Tblock != 0) {
fprint(2, "%s: archive block size (%d) error\n",
argv0, i);
exits("blocksize");
}
i /= Tblock;
if (i != nblock) {
nblock = i;
fprint(2, "%s: blocking = %d\n", argv0, nblock);
endblk = (Hdr *)bufs + nblock;
bytes = n;
}
} else
n = readn(ar, bufs, bytes);
if (n == 0)
sysfatal("unexpected EOF reading archive");
else if (n < 0)
sysfatal("error reading archive: %r");
else if (n%Tblock != 0)
sysfatal("partial block read from archive");
if (n != bytes) {
done = 1;
memset(bufs + n, 0, bytes - n);
}
return bufs;
}
static Hdr *
getblk(int ar, Refill rfp)
{
if (curblk == nil || curblk >= endblk) { /* input block exhausted? */
if (rfp != nil && (*rfp)(ar, (char *)tpblk) == nil)
return nil;
curblk = tpblk;
}
return curblk++;
}
static Hdr *
getblkrd(int ar)
{
return getblk(ar, refill);
}
static Hdr *
getblke(int ar)
{
return getblk(ar, nil);
}
static Hdr *
getblkz(int ar)
{
Hdr *hp = getblke(ar);
if (hp != nil)
memset(hp->data, 0, Tblock);
return hp;
}
/*
* how many block buffers are available, starting at the address
* just returned by getblk*?
*/
static int
gothowmany(int max)
{
int n = endblk - (curblk - 1);
return n > max? max: n;
}
/*
* indicate that one is done with the last block obtained from getblke
* and it is now available to be written into the archive.
*/
static void
putlastblk(int ar)
{
unsigned bytes = Tblock * nblock;
/* if writing end-of-archive, aid compression (good hygiene too) */
if (curblk < endblk)
memset(curblk, 0, (char *)endblk - (char *)curblk);
if (write(ar, tpblk, bytes) != bytes)
sysfatal("error writing archive: %r");
}
static void
putblk(int ar)
{
if (curblk >= endblk)
putlastblk(ar);
}
static void
putbackblk(int ar)
{
curblk--;
USED(ar);
}
static void
putreadblks(int ar, int blks)
{
curblk += blks - 1;
USED(ar);
}
static void
putblkmany(int ar, int blks)
{
curblk += blks - 1;
putblk(ar);
}
/*
* common routines
*/
/* modifies hp->chksum */
long
chksum(Hdr *hp)
{
int n = Tblock;
long i = 0;
uchar *cp = hp->data;
memset(hp->chksum, ' ', sizeof hp->chksum);
while (n-- > 0)
i += *cp++;
return i;
}
static int
isustar(Hdr *hp)
{
return strcmp(hp->magic, "ustar") == 0;
}
/*
* s is at most n bytes long, but need not be NUL-terminated.
* if shorter than n bytes, all bytes after the first NUL must also
* be NUL.
*/
static int
strnlen(char *s, int n)
{
return s[n - 1] != '\0'? n: strlen(s);
}
/* set fullname from header */
static char *
name(Hdr *hp)
{
int pfxlen, namlen;
static char fullnamebuf[2 + Maxname + 1]; /* 2 at beginning for ./ on relative names */
char *fullname;
fullname = fullnamebuf+2;
namlen = strnlen(hp->name, sizeof hp->name);
if (hp->prefix[0] == '\0' || !isustar(hp)) { /* old-style name? */
memmove(fullname, hp->name, namlen);
fullname[namlen] = '\0';
return fullname;
}
/* name is in two pieces */
pfxlen = strnlen(hp->prefix, sizeof hp->prefix);
memmove(fullname, hp->prefix, pfxlen);
fullname[pfxlen] = '/';
memmove(fullname + pfxlen + 1, hp->name, namlen);
fullname[pfxlen + 1 + namlen] = '\0';
return fullname;
}
static int
isdir(Hdr *hp)
{
/* the mode test is ugly but sometimes necessary */
return hp->linkflag == LF_DIR ||
strrchr(name(hp), '\0')[-1] == '/' ||
(strtoul(hp->mode, nil, 8)&0170000) == 040000;
}
static int
eotar(Hdr *hp)
{
return name(hp)[0] == '\0';
}
static Hdr *
readhdr(int ar)
{
long hdrcksum;
Hdr *hp;
hp = getblkrd(ar);
if (hp == nil)
sysfatal("unexpected EOF instead of archive header");
if (eotar(hp)) /* end-of-archive block? */
return nil;
hdrcksum = strtoul(hp->chksum, nil, 8);
if (chksum(hp) != hdrcksum)
sysfatal("bad archive header checksum: name %.64s...",
hp->name);
return hp;
}
/*
* tar r[c]
*/
/*
* if name is longer than Namsiz bytes, try to split it at a slash and fit the
* pieces into hp->prefix and hp->name.
*/
static int
putfullname(Hdr *hp, char *name)
{
int namlen, pfxlen;
char *sl, *osl;
String *slname = nil;
if (isdir(hp)) {
slname = s_new();
s_append(slname, name);
s_append(slname, "/"); /* posix requires this */
name = s_to_c(slname);
}
namlen = strlen(name);
if (namlen <= Namsiz) {
strncpy(hp->name, name, Namsiz);
hp->prefix[0] = '\0'; /* ustar paranoia */
return 0;
}
if (!posix || namlen > Maxname) {
fprint(2, "%s: name too long for tar header: %s\n",
argv0, name);
return -1;
}
/*
* try various splits until one results in pieces that fit into the
* appropriate fields of the header. look for slashes from right
* to left, in the hopes of putting the largest part of the name into
* hp->prefix, which is larger than hp->name.
*/
sl = strrchr(name, '/');
while (sl != nil) {
pfxlen = sl - name;
if (pfxlen <= sizeof hp->prefix && namlen-1 - pfxlen <= Namsiz)
break;
osl = sl;
*osl = '\0';
sl = strrchr(name, '/');
*osl = '/';
}
if (sl == nil) {
fprint(2, "%s: name can't be split to fit tar header: %s\n",
argv0, name);
return -1;
}
*sl = '\0';
strncpy(hp->prefix, name, sizeof hp->prefix);
*sl++ = '/';
strncpy(hp->name, sl, sizeof hp->name);
if (slname)
s_free(slname);
return 0;
}
static int
mkhdr(Hdr *hp, Dir *dir, char *file)
{
/*
* these fields run together, so we format them in order and don't use
* snprint.
*/
sprint(hp->mode, "%6lo ", dir->mode & 0777);
sprint(hp->uid, "%6o ", aruid);
sprint(hp->gid, "%6o ", argid);
/*
* files > 2 bytes can't be described
* (unless we resort to xustar or exustar formats).
*/
if (dir->length >= (Off)1<<33) {
fprint(2, "%s: %s: too large for tar header format\n",
argv0, file);
return -1;
}
sprint(hp->size, "%11lluo ", dir->length);
sprint(hp->mtime, "%11luo ", dir->mtime);
hp->linkflag = (dir->mode&DMDIR? LF_DIR: LF_PLAIN1);
putfullname(hp, file);
if (posix) {
strncpy(hp->magic, "ustar", sizeof hp->magic);
strncpy(hp->version, "00", sizeof hp->version);
strncpy(hp->uname, dir->uid, sizeof hp->uname);
strncpy(hp->gname, dir->gid, sizeof hp->gname);
}
sprint(hp->chksum, "%6luo", chksum(hp));
return 0;
}
static void addtoar(int ar, char *file, char *shortf);
static void
addtreetoar(int ar, char *file, char *shortf, int fd)
{
int n;
Dir *dent, *dirents;
String *name = s_new();
n = dirreadall(fd, &dirents);
close(fd);
if (n == 0)
return;
if (chdir(shortf) < 0)
sysfatal("chdir %s: %r", file);
if (DEBUG)
fprint(2, "chdir %s\t# %s\n", shortf, file);
for (dent = dirents; dent < dirents + n; dent++) {
s_reset(name);
s_append(name, file);
s_append(name, "/");
s_append(name, dent->name);
addtoar(ar, s_to_c(name), dent->name);
}
s_free(name);
free(dirents);
if (chdir("..") < 0)
sysfatal("chdir %s/..: %r", file);
if (DEBUG)
fprint(2, "chdir ..\n");
}
static void
addtoar(int ar, char *file, char *shortf)
{
int n, fd, isdir;
long bytes;
ulong blksleft, blksread;
Hdr *hbp;
Dir *dir;
fd = open(shortf, OREAD);
if (fd < 0) {
fprint(2, "%s: can't open %s: %r\n", argv0, file);
return;
}
dir = dirfstat(fd);
if (dir == nil)
sysfatal("can't fstat %s: %r", file);
hbp = getblkz(ar);
isdir = !!(dir->qid.type&QTDIR);
if (mkhdr(hbp, dir, file) < 0) {
putbackblk(ar);
free(dir);
close(fd);
return;
}
putblk(ar);
blksleft = BYTES2TBLKS(dir->length);
free(dir);
if (isdir)
addtreetoar(ar, file, shortf, fd);
else {
for (; blksleft > 0; blksleft -= blksread) {
hbp = getblke(ar);
blksread = gothowmany(blksleft);
bytes = blksread * Tblock;
n = readn(fd, hbp->data, bytes);
if (n < 0)
sysfatal("error reading %s: %r", file);
/*
* ignore EOF. zero any partial block to aid
* compression and emergency recovery of data.
*/
if (n < Tblock)
memset(hbp->data + n, 0, bytes - n);
putblkmany(ar, blksread);
}
close(fd);
if (verbose)
fprint(2, "%s\n", file);
}
}
static char *
replace(char **argv)
{
int i, ar;
ulong blksleft, blksread;
Off bytes;
Hdr *hp;
Compress *comp = nil;
Pushstate ps;
if (usefile && docreate) {
ar = create(usefile, OWRITE, 0666);
if (docompress)
comp = compmethod(usefile);
} else if (usefile)
ar = open(usefile, ORDWR);
else
ar = Stdout;
if (comp)
ar = push(ar, comp->comp, Output, &ps);
if (ar < 0)
sysfatal("can't open archive %s: %r", usefile);
if (usefile && !docreate) {
/* skip quickly to the end */
while ((hp = readhdr(ar)) != nil) {
bytes = strtoull(hp->size, nil, 8);
if(isdir(hp))
bytes = 0;
for (blksleft = BYTES2TBLKS(bytes);
blksleft > 0 && getblkrd(ar) != nil;
blksleft -= blksread) {
blksread = gothowmany(blksleft);
putreadblks(ar, blksread);
}
}
/*
* we have just read the end-of-archive Tblock.
* now seek back over the (big) archive block containing it,
* and back up curblk ptr over end-of-archive Tblock in memory.
*/
if (seek(ar, -Tblock*nblock, 1) < 0)
sysfatal("can't seek back over end-of-archive: %r");
curblk--;
}
for (i = 0; argv[i] != nil; i++)
addtoar(ar, argv[i], argv[i]);
/* write end-of-archive marker */
getblkz(ar);
putblk(ar);
getblkz(ar);
putlastblk(ar);
if (comp)
return pushclose(&ps);
if (ar > Stderr)
close(ar);
return nil;
}
/*
* tar [xt]
*/
/* is pfx a file-name prefix of name? */
static int
prefix(char *name, char *pfx)
{
int pfxlen = strlen(pfx);
char clpfx[Maxname+1];
if (pfxlen > Maxname)
return 0;
strcpy(clpfx, pfx);
cleanname(clpfx);
return strncmp(pfx, name, pfxlen) == 0 &&
(name[pfxlen] == '\0' || name[pfxlen] == '/');
}
static int
match(char *name, char **argv)
{
int i;
char clname[Maxname+1];
if (argv[0] == nil)
return 1;
strcpy(clname, name);
cleanname(clname);
for (i = 0; argv[i] != nil; i++)
if (prefix(clname, argv[i]))
return 1;
return 0;
}
static int
makedir(char *s)
{
int f;
if (access(s, AEXIST) == 0)
return -1;
f = create(s, OREAD, DMDIR | 0777);
if (f >= 0)
close(f);
return f;
}
static void
mkpdirs(char *s)
{
int done = 0;
char *p = s;
while (!done && (p = strchr(p + 1, '/')) != nil) {
*p = '\0';
done = (access(s, AEXIST) < 0 && makedir(s) < 0);
*p = '/';
}
}
/* copy a file from the archive into the filesystem */
/* fname is result of name(), so has two extra bytes at beginning */
static void
extract1(int ar, Hdr *hp, char *fname)
{
int wrbytes, fd = -1, dir = 0;
long mtime = strtol(hp->mtime, nil, 8);
ulong mode = strtoul(hp->mode, nil, 8) & 0777;
Off bytes = strtoll(hp->size, nil, 8);
ulong blksread, blksleft = BYTES2TBLKS(bytes);
Hdr *hbp;
if (isdir(hp)) {
mode |= DMDIR|0700;
blksleft = 0;
dir = 1;
}
switch (hp->linkflag) {
case LF_LINK:
case LF_SYMLINK1:
case LF_SYMLINK2:
case LF_FIFO:
blksleft = 0;
break;
}
if (relative) {
if(fname[0] == '/')
*--fname = '.';
else if(fname[0] == '#'){
*--fname = '/';
*--fname = '.';
}
}
if (verb == Xtract) {
cleanname(fname);
switch (hp->linkflag) {
case LF_LINK:
case LF_SYMLINK1:
case LF_SYMLINK2:
fprint(2, "%s: can't make (sym)link %s\n",
argv0, fname);
break;
case LF_FIFO:
fprint(2, "%s: can't make fifo %s\n", argv0, fname);
break;
default:
if (!keepexisting || access(fname, AEXIST) < 0) {
int rw = (dir? OREAD: OWRITE);
fd = create(fname, rw, mode);
if (fd < 0) {
mkpdirs(fname);
fd = create(fname, rw, mode);
}
if (fd < 0 &&
(!dir || access(fname, AEXIST) < 0))
fprint(2, "%s: can't create %s: %r\n",
argv0, fname);
}
if (fd >= 0 && verbose)
fprint(2, "%s\n", fname);
break;
}
} else if (verbose) {
char *cp = ctime(mtime);
print("%M %8lld %-12.12s %-4.4s %s\n",
mode, bytes, cp+4, cp+24, fname);
} else
print("%s\n", fname);
for (; blksleft > 0; blksleft -= blksread) {
hbp = getblkrd(ar);
if (hbp == nil)
sysfatal("unexpected EOF on archive extracting %s",
fname);
blksread = gothowmany(blksleft);
wrbytes = Tblock*blksread;
if(wrbytes > bytes)
wrbytes = bytes;
if (fd >= 0 && write(fd, hbp->data, wrbytes) != wrbytes)
sysfatal("write error on %s: %r", fname);
putreadblks(ar, blksread);
bytes -= wrbytes;
}
if (fd >= 0) {
/*
* directories should be wstated after we're done
* creating files in them.
*/
if (settime) {
Dir nd;
nulldir(&nd);
nd.mtime = mtime;
if (isustar(hp))
nd.gid = hp->gname;
dirfwstat(fd, &nd);
}
close(fd);
}
}
static void
skip(int ar, Hdr *hp, char *fname)
{
Off bytes;
ulong blksleft, blksread;
Hdr *hbp;
if (isdir(hp))
return;
bytes = strtoull(hp->size, nil, 8);
blksleft = BYTES2TBLKS(bytes);
for (; blksleft > 0; blksleft -= blksread) {
hbp = getblkrd(ar);
if (hbp == nil)
sysfatal("unexpected EOF on archive extracting %s",
fname);
blksread = gothowmany(blksleft);
putreadblks(ar, blksread);
}
}
static char *
extract(char **argv)
{
int ar;
char *longname;
Hdr *hp;
Compress *comp = nil;
Pushstate ps;
if (usefile) {
ar = open(usefile, OREAD);
comp = compmethod(usefile);
} else
ar = Stdin;
if (comp)
ar = push(ar, comp->decomp, Input, &ps);
if (ar < 0)
sysfatal("can't open archive %s: %r", usefile);
while ((hp = readhdr(ar)) != nil) {
longname = name(hp);
if (match(longname, argv))
extract1(ar, hp, longname);
else
skip(ar, hp, longname);
}
if (comp)
return pushclose(&ps);
if (ar > Stderr)
close(ar);
return nil;
}
void
main(int argc, char *argv[])
{
int errflg = 0;
char *ret = nil;
quotefmtinstall();
fmtinstall('M', dirmodefmt);
TARGBEGIN {
case 'c':
docreate++;
verb = Replace;
break;
case 'f':
usefile = EARGF(usage());
break;
case 'g':
argid = strtoul(EARGF(usage()), 0, 0);
break;
case 'k':
keepexisting++;
break;
case 'm': /* compatibility */
settime = 0;
break;
case 'p':
posix++;
break;
case 'P':
posix = 0;
break;
case 'r':
verb = Replace;
break;
case 'R':
relative = 0;
break;
case 't':
verb = Toc;
break;
case 'T':
settime++;
break;
case 'u':
aruid = strtoul(EARGF(usage()), 0, 0);
break;
case 'v':
verbose++;
break;
case 'x':
verb = Xtract;
break;
case 'z':
docompress++;
break;
case '-':
break;
default:
fprint(2, "tar: unknown letter %C\n", TARGC());
errflg++;
break;
} TARGEND
if (argc < 0 || errflg)
usage();
initblks();
switch (verb) {
case Toc:
case Xtract:
ret = extract(argv);
break;
case Replace:
if (getwd(origdir, sizeof origdir) == nil)
strcpy(origdir, "/tmp");
ret = replace(argv);
chdir(origdir); /* for profiling */
break;
default:
usage();
break;
}
exits(ret);
}
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