tupdate from geoff - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 031ddeb2f66c668ebd57bd0407720e41bf403b9d
(DIR) parent 10ae53543743c57fbd4db917b162a688fa19df80
(HTM) Author: rsc <devnull@localhost>
Date: Fri, 22 Jul 2005 11:47:57 +0000
update from geoff
Diffstat:
A src/cmd/tar.c | 1043 +++++++++++++++++++++++++++++++
1 file changed, 1043 insertions(+), 0 deletions(-)
---
(DIR) diff --git a/src/cmd/tar.c b/src/cmd/tar.c
t@@ -0,0 +1,1043 @@
+/*
+ * 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, int justhdr);
+
+enum { Stdin, Stdout, Stderr };
+enum { Rd, Wr }; /* pipe fd-array indices */
+enum { Output, Input };
+enum { None, Toc, Xtract, Replace };
+enum { Alldata, Justnxthdr };
+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 Off blkoff; /* offset of the current archive block (not Tblock) */
+static Off nexthdr;
+
+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. `justhdr' means we don't care
+ * about the data before the next header block.
+ */
+static char *
+refill(int ar, char *bufs, int justhdr)
+{
+ int i, n;
+ unsigned bytes = Tblock * nblock;
+ static int done, first = 1, seekable;
+
+ if (done)
+ return nil;
+
+ if (first)
+ seekable = seek(ar, 0, 1) >= 0;
+ /* try to size non-pipe input at first read */
+ if (first && usefile) {
+ blkoff = seek(ar, 0, 1); /* note position */
+ 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 if (justhdr && seekable && nexthdr - seek(ar, 0, 1) >= bytes) {
+ /* optimisation for huge archive members on seekable media */
+ if (seek(ar, bytes, 1) < 0)
+ sysfatal("can't seek on archive: %r");
+ n = bytes;
+ } else
+ n = readn(ar, bufs, bytes);
+ first = 0;
+
+ 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, int justhdr)
+{
+ if (curblk == nil || curblk >= endblk) { /* input block exhausted? */
+ if (rfp != nil && (*rfp)(ar, (char *)tpblk, justhdr) == nil)
+ return nil;
+ curblk = tpblk;
+ }
+ return curblk++;
+}
+
+static Hdr *
+getblkrd(int ar, int justhdr)
+{
+ return getblk(ar, refill, justhdr);
+}
+
+static Hdr *
+getblke(int ar)
+{
+ return getblk(ar, nil, Alldata);
+}
+
+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 but restores it; important for the last block of the
+ * old archive when updating with `tar rf archive'
+ */
+long
+chksum(Hdr *hp)
+{
+ int n = Tblock;
+ long i = 0;
+ uchar *cp = hp->data;
+ char oldsum[sizeof hp->chksum];
+
+ memmove(oldsum, hp->chksum, sizeof oldsum);
+ memset(hp->chksum, ' ', sizeof hp->chksum);
+ while (n-- > 0)
+ i += *cp++;
+ memmove(hp->chksum, oldsum, sizeof oldsum);
+ 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';
+}
+
+Off
+hdrsize(Hdr *hp)
+{
+ Off bytes = strtoull(hp->size, nil, 8);
+
+ if(isdir(hp))
+ bytes = 0;
+ return bytes;
+}
+
+static Hdr *
+readhdr(int ar)
+{
+ long hdrcksum;
+ Hdr *hp;
+
+ hp = getblkrd(ar, Alldata);
+ 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);
+ nexthdr += Tblock*(1 + BYTES2TBLKS(hdrsize(hp)));
+ 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);
+
+ /*
+ * this assumes that shortf is just one component, which is true
+ * during directory descent, but not necessarily true of command-line
+ * arguments. Our caller (or addtoar's) must reset the working
+ * directory if necessary.
+ */
+ 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 = hdrsize(hp);
+ for (blksleft = BYTES2TBLKS(bytes);
+ blksleft > 0 && getblkrd(ar, Justnxthdr) != 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, blkoff, 0) < 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]);
+ chdir(origdir); /* for correctness & profiling */
+ }
+
+ /* 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); /* for printing */
+ ulong blksread, blksleft = BYTES2TBLKS(hdrsize(hp));
+ Hdr *hbp;
+
+ if (isdir(hp)) {
+ mode |= DMDIR|0700;
+ 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, (fd >= 0? Alldata: Justnxthdr));
+ 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)
+{
+ ulong blksleft, blksread;
+ Hdr *hbp;
+
+ for (blksleft = BYTES2TBLKS(hdrsize(hp)); blksleft > 0;
+ blksleft -= blksread) {
+ hbp = getblkrd(ar, Justnxthdr);
+ 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);
+ break;
+ default:
+ usage();
+ break;
+ }
+ exits(ret);
+}