tnew tar import - plan9port - [fork] Plan 9 from user space
git clone git://src.adamsgaard.dk/plan9port
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---
commit 6019a96c7867a30b6968c9ebe9276b1025e157df
parent c86883cab53a2f0633ea58539fc4d9fbfe2fc1dd
Author: rsc 
Date:   Thu, 30 Mar 2006 19:25:10 +0000

new tar import

Diffstat:
  M src/cmd/tar.c                       |     258 +++++++++++++++++++++++--------

1 file changed, 195 insertions(+), 63 deletions(-)
---
diff --git a/src/cmd/tar.c b/src/cmd/tar.c
t@@ -16,9 +16,7 @@
  * keyletters and options.
  */
 #define        TARGBEGIN {\
-        if (argv0 == nil)\
-                argv0 = *argv;\
-        argv++, argc--;\
+        (argv0 || (argv0 = *argv)), argv++, argc--;\
         if (argv[0]) {\
                 char *_args, *_argt;\
                 Rune _argc;\
t@@ -34,6 +32,12 @@
 #define ROUNDUP(a, b)        (((a) + (b) - 1)/(b))
 #define BYTES2TBLKS(bytes) ROUNDUP(bytes, Tblock)
 
+/* read big-endian binary integers; args must be (uchar *) */
+#define        G2BEBYTE(x)        (((x)[0]<<8)  |  (x)[1])
+#define        G3BEBYTE(x)        (((x)[0]<<16) | ((x)[1]<<8)  |  (x)[2])
+#define        G4BEBYTE(x)        (((x)[0]<<24) | ((x)[1]<<16) | ((x)[2]<<8) | (x)[3])
+#define        G8BEBYTE(x)        (((vlong)G4BEBYTE(x)<<32) | (u32int)G4BEBYTE((x)+4))
+
 typedef vlong Off;
 typedef char *(*Refill)(int ar, char *bufs, int justhdr);
 
t@@ -44,11 +48,14 @@ 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,
+        Binsize = 0x80,                /* flag in size[0], from gnu: positive binary size */
+        Binnegsz = 0xff,        /* flag in size[0]: negative binary size */
+
+        Nblock = 40,                /* maximum blocksize */
+        Dblock = 20,                /* default blocksize */
         DEBUG = 0,
 };
 
t@@ -58,7 +65,7 @@ enum {
         LF_PLAIN2 =        '0',
         LF_LINK =        '1',
         LF_SYMLINK1 =        '2',
-        LF_SYMLINK2 =        's',
+        LF_SYMLINK2 =        's',                /* 4BSD used this */
         LF_CHR =        '3',
         LF_BLK =        '4',
         LF_DIR =        '5',
t@@ -71,25 +78,28 @@ enum {
 #define isreallink(lf)        ((lf) == LF_LINK)
 #define issymlink(lf)        ((lf) == LF_SYMLINK1 || (lf) == LF_SYMLINK2)
 
-typedef 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 */
+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 {
t@@ -247,9 +257,9 @@ refill(int ar, char *bufs, int justhdr)
 
         if (first)
                 seekable = seek(ar, 0, 1) >= 0;
+        blkoff = seek(ar, 0, 1);                /* note position for `tar r' */
         /* 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");
t@@ -317,7 +327,7 @@ getblkz(int ar)
         Hdr *hp = getblke(ar);
 
         if (hp != nil)
-                memset(hp, 0, Tblock);
+                memset(hp->data, 0, Tblock);
         return hp;
 }
 
t@@ -385,12 +395,12 @@ putblkmany(int ar, int blks)
  * modifies hp->chksum but restores it; important for the last block of the
  * old archive when updating with `tar rf archive'
  */
-long
+static long
 chksum(Hdr *hp)
 {
         int n = Tblock;
         long i = 0;
-        uchar *cp = (uchar*)hp;
+        uchar *cp = hp->data;
         char oldsum[sizeof hp->chksum];
 
         memmove(oldsum, hp->chksum, sizeof oldsum);
t@@ -458,14 +468,62 @@ eotar(Hdr *hp)
         return name(hp)[0] == '\0';
 }
 
-Off
+/*
+static uvlong
+getbe(uchar *src, int size)
+{
+        uvlong vl = 0;
+
+        while (size-- > 0) {
+                vl <<= 8;
+                vl |= *src++;
+        }
+        return vl;
+}
+ */
+
+static void
+putbe(uchar *dest, uvlong vl, int size)
+{
+        for (dest += size; size-- > 0; vl >>= 8)
+                *--dest = vl;
+}
+
+/*
+ * return the nominal size from the header block, which is not always the
+ * size in the archive (the archive size may be zero for some file types
+ * regardless of the nominal size).
+ *
+ * gnu and freebsd tars are now recording vlongs as big-endian binary
+ * with a flag in byte 0 to indicate this, which permits file sizes up to
+ * 2^64-1 (actually 2^80-1 but our file sizes are vlongs) rather than 2^33-1.
+ */
+static Off
 hdrsize(Hdr *hp)
 {
-        Off bytes = strtoull(hp->size, nil, 8);
+        uchar *p;
 
-        if(isdir(hp))
-                bytes = 0;
-        return bytes;
+        if((uchar)hp->size[0] == Binnegsz) {
+                fprint(2, "%s: %s: negative length, which is insane\n",
+                        argv0, name(hp));
+                return 0;
+        } else if((uchar)hp->size[0] == Binsize) {
+                p = (uchar *)hp->size + sizeof hp->size - 1 -
+                        sizeof(vlong);                /* -1 for terminating space */
+                return G8BEBYTE(p);
+        } else
+                return strtoull(hp->size, nil, 8);
+}
+
+/*
+ * return the number of bytes recorded in the archive.
+ */
+static Off
+arsize(Hdr *hp)
+{
+        if(isdir(hp) || islink(hp->linkflag))
+                return 0;
+        return hdrsize(hp);
 }
 
 static Hdr *
t@@ -483,7 +541,7 @@ readhdr(int ar)
         if (chksum(hp) != hdrcksum)
                 sysfatal("bad archive header checksum: name %.64s...",
                         hp->name);
-        nexthdr += Tblock*(1 + BYTES2TBLKS(hdrsize(hp)));
+        nexthdr += Tblock*(1 + BYTES2TBLKS(arsize(hp)));
         return hp;
 }
 
t@@ -561,16 +619,19 @@ mkhdr(Hdr *hp, Dir *dir, char *file)
         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);
+        if (dir->length >= (Off)1<<32) {
+                static int printed;
+
+                if (!printed) {
+                        printed = 1;
+                        fprint(2, "%s: storing large sizes in \"base 256\"\n", argv0);
+                }
+                hp->size[0] = Binsize;
+                /* emit so-called `base 256' representation of size */
+                putbe((uchar *)hp->size+1, dir->length, sizeof hp->size - 2);
+                hp->size[sizeof hp->size - 1] = ' ';
+        } else
+                sprint(hp->size, "%11lluo ", dir->length);
         sprint(hp->mtime, "%11luo ", dir->mtime);
         hp->linkflag = (dir->mode&DMDIR? LF_DIR: LF_PLAIN1);
         putfullname(hp, file);
t@@ -633,10 +694,20 @@ addtoar(int ar, char *file, char *shortf)
         ulong blksleft, blksread;
         Hdr *hbp;
         Dir *dir;
+        String *name = nil;
+
+        if (shortf[0] == '#') {
+                name = s_new();
+                s_append(name, "./");
+                s_append(name, shortf);
+                shortf = s_to_c(name);
+        }
 
         fd = open(shortf, OREAD);
         if (fd < 0) {
                 fprint(2, "%s: can't open %s: %r\n", argv0, file);
+                if (name)
+                        s_free(name);
                 return;
         }
         dir = dirfstat(fd);
t@@ -649,6 +720,8 @@ addtoar(int ar, char *file, char *shortf)
                 putbackblk(ar);
                 free(dir);
                 close(fd);
+                if (name)
+                        s_free(name);
                 return;
         }
         putblk(ar);
t@@ -663,7 +736,7 @@ addtoar(int ar, char *file, char *shortf)
                         hbp = getblke(ar);
                         blksread = gothowmany(blksleft);
                         bytes = blksread * Tblock;
-                        n = readn(fd, hbp, bytes);
+                        n = readn(fd, hbp->data, bytes);
                         if (n < 0)
                                 sysfatal("error reading %s: %r", file);
                         /*
t@@ -671,13 +744,15 @@ addtoar(int ar, char *file, char *shortf)
                          * compression and emergency recovery of data.
                          */
                         if (n < Tblock)
-                                memset((uchar*)hbp + n, 0, bytes - n);
+                                memset(hbp->data + n, 0, bytes - n);
                         putblkmany(ar, blksread);
                 }
                 close(fd);
                 if (verbose)
                         fprint(2, "%s\n", file);
         }
+        if (name)
+                s_free(name);
 }
 
 static char *
t@@ -706,7 +781,7 @@ replace(char **argv)
         if (usefile && !docreate) {
                 /* skip quickly to the end */
                 while ((hp = readhdr(ar)) != nil) {
-                        bytes = hdrsize(hp);
+                        bytes = arsize(hp);
                         for (blksleft = BYTES2TBLKS(bytes);
                              blksleft > 0 && getblkrd(ar, Justnxthdr) != nil;
                              blksleft -= blksread) {
t@@ -777,6 +852,34 @@ match(char *name, char **argv)
         return 0;
 }
 
+static void
+cantcreate(char *s, int mode)
+{
+        int len;
+        static char *last;
+
+        /*
+         * Always print about files.  Only print about directories
+         * we haven't printed about.  (Assumes archive is ordered
+         * nicely.)
+         */
+        if(mode&DMDIR){
+                if(last){
+                        /* already printed this directory */
+                        if(strcmp(s, last) == 0)
+                                return;
+                        /* printed a higher directory, so printed this one */
+                        len = strlen(s);
+                        if(memcmp(s, last, len) == 0 && last[len] == '/')
+                                return;
+                }
+                /* save */
+                free(last);
+                last = strdup(s);
+        }
+        fprint(2, "%s: can't create %s: %r\n", argv0, s);
+}
+
 static int
 makedir(char *s)
 {
t@@ -787,20 +890,39 @@ makedir(char *s)
         f = create(s, OREAD, DMDIR | 0777);
         if (f >= 0)
                 close(f);
+        else
+                cantcreate(s, DMDIR);
         return f;
 }
 
-static void
+static int
 mkpdirs(char *s)
 {
-        int done = 0;
-        char *p = s;
+        int err;
+        char *p;
 
-        while (!done && (p = strchr(p + 1, '/')) != nil) {
+        p = s;
+        err = 0;
+        while (!err && (p = strchr(p+1, '/')) != nil) {
                 *p = '\0';
-                done = (access(s, AEXIST) < 0 && makedir(s) < 0);
+                err = (access(s, AEXIST) < 0 && makedir(s) < 0);
                 *p = '/';
         }
+        return -err;
+}
+
+/* Call access but preserve the error string. */
+static int
+xaccess(char *name, int mode)
+{
+        char err[ERRMAX];
+        int rv;
+
+        err[0] = 0;
+        errstr(err, sizeof err);
+        rv = access(name, mode);
+        errstr(err, sizeof err);
+        return rv;
 }
 
 /* copy a file from the archive into the filesystem */
t@@ -811,8 +933,8 @@ 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));
+        Off bytes = hdrsize(hp);                /* for printing */
+        ulong blksread, blksleft = BYTES2TBLKS(arsize(hp));
         Hdr *hbp;
 
         if (isdir(hp)) {
t@@ -857,9 +979,8 @@ extract1(int ar, Hdr *hp, char *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);
+                                    (!dir || xaccess(fname, AEXIST) < 0))
+                                            cantcreate(fname, mode);
                         }
                         if (fd >= 0 && verbose)
                                 fprint(2, "%s\n", fname);
t@@ -873,20 +994,29 @@ extract1(int ar, Hdr *hp, char *fname)
         } else
                 print("%s\n", fname);
 
+        if (blksleft == 0)
+                bytes = 0;
         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);
+                if (blksread <= 0)
+                        fprint(2, "%s: got %ld blocks reading %s!\n",
+                                argv0, blksread, fname);
                 wrbytes = Tblock*blksread;
                 if(wrbytes > bytes)
                         wrbytes = bytes;
-                if (fd >= 0 && write(fd, hbp, wrbytes) != wrbytes)
+                if (fd >= 0 && write(fd, hbp->data, wrbytes) != wrbytes)
                         sysfatal("write error on %s: %r", fname);
                 putreadblks(ar, blksread);
                 bytes -= wrbytes;
         }
+        if (bytes > 0)
+                fprint(2,
+                    "%s: %lld bytes uncopied at eof; %s not fully extracted\n",
+                        argv0, bytes, fname);
         if (fd >= 0) {
                 /*
                  * directories should be wstated after we're done
t@@ -897,9 +1027,12 @@ extract1(int ar, Hdr *hp, char *fname)
 
                         nulldir(&nd);
                         nd.mtime = mtime;
-                        if (isustar(hp))
-                                nd.gid = hp->gname;
                         dirfwstat(fd, &nd);
+                        if (isustar(hp)) {
+                                nulldir(&nd);
+                                nd.gid = hp->gname;
+                                dirfwstat(fd, &nd);
+                        }
                 }
                 close(fd);
         }
t@@ -911,7 +1044,7 @@ skip(int ar, Hdr *hp, char *fname)
         ulong blksleft, blksread;
         Hdr *hbp;
 
-        for (blksleft = BYTES2TBLKS(hdrsize(hp)); blksleft > 0;
+        for (blksleft = BYTES2TBLKS(arsize(hp)); blksleft > 0;
              blksleft -= blksread) {
                 hbp = getblkrd(ar, Justnxthdr);
                 if (hbp == nil)
t@@ -962,7 +1095,6 @@ main(int argc, char *argv[])
         int errflg = 0;
         char *ret = nil;
 
-        quotefmtinstall();
         fmtinstall('M', dirmodefmt);
 
         TARGBEGIN {