Merge branch 'rs/leave-base-name-in-name-field-of-tar'
authorJunio C Hamano <gitster@pobox.com>
Thu, 10 Jan 2013 21:47:35 +0000 (13:47 -0800)
committerJunio C Hamano <gitster@pobox.com>
Thu, 10 Jan 2013 21:47:35 +0000 (13:47 -0800)
Improve compatibility with implementations of "tar" that do not
like empty name field in header (with the additional prefix field
holding everything).

* rs/leave-base-name-in-name-field-of-tar:
archive-tar: split long paths more carefully

1  2 
archive-tar.c
diff --combined archive-tar.c
index 0ba3f25cf579d6629566a39d4d5ac19b51293ed5,9d4eec2c71ed703fcb5e6df4cfed200b219e1e2e..d1cce46e3310d64af32b231de697449ae90ddccf
@@@ -4,7 -4,6 +4,7 @@@
  #include "cache.h"
  #include "tar.h"
  #include "archive.h"
 +#include "streaming.h"
  #include "run-command.h"
  
  #define RECORDSIZE    (512)
@@@ -31,9 -30,10 +31,9 @@@ static void write_if_needed(void
   * queues up writes, so that all our write(2) calls write exactly one
   * full block; pads writes to RECORDSIZE
   */
 -static void write_blocked(const void *data, unsigned long size)
 +static void do_write_blocked(const void *data, unsigned long size)
  {
        const char *buf = data;
 -      unsigned long tail;
  
        if (offset) {
                unsigned long chunk = BLOCKSIZE - offset;
                memcpy(block + offset, buf, size);
                offset += size;
        }
 +}
 +
 +static void finish_record(void)
 +{
 +      unsigned long tail;
        tail = offset % RECORDSIZE;
        if (tail)  {
                memset(block + offset, 0, RECORDSIZE - tail);
        write_if_needed();
  }
  
 +static void write_blocked(const void *data, unsigned long size)
 +{
 +      do_write_blocked(data, size);
 +      finish_record();
 +}
 +
  /*
   * The end of tar archives is marked by 2*512 nul bytes and after that
   * follows the rest of the block (if any).
@@@ -88,33 -77,6 +88,33 @@@ static void write_trailer(void
        }
  }
  
 +/*
 + * queues up writes, so that all our write(2) calls write exactly one
 + * full block; pads writes to RECORDSIZE
 + */
 +static int stream_blocked(const unsigned char *sha1)
 +{
 +      struct git_istream *st;
 +      enum object_type type;
 +      unsigned long sz;
 +      char buf[BLOCKSIZE];
 +      ssize_t readlen;
 +
 +      st = open_istream(sha1, &type, &sz, NULL);
 +      if (!st)
 +              return error("cannot stream blob %s", sha1_to_hex(sha1));
 +      for (;;) {
 +              readlen = read_istream(st, buf, sizeof(buf));
 +              if (readlen <= 0)
 +                      break;
 +              do_write_blocked(buf, readlen);
 +      }
 +      close_istream(st);
 +      if (!readlen)
 +              finish_record();
 +      return readlen;
 +}
 +
  /*
   * pax extended header records have the format "%u %s=%s\n".  %u contains
   * the size of the whole string (including the %u), the first %s is the
@@@ -139,13 -101,13 +139,13 @@@ static void strbuf_append_ext_header(st
  
  static unsigned int ustar_header_chksum(const struct ustar_header *header)
  {
 -      char *p = (char *)header;
 +      const unsigned char *p = (const unsigned char *)header;
        unsigned int chksum = 0;
 -      while (p < header->chksum)
 +      while (p < (const unsigned char *)header->chksum)
                chksum += *p++;
        chksum += sizeof(header->chksum) * ' ';
        p += sizeof(header->chksum);
 -      while (p < (char *)header + sizeof(struct ustar_header))
 +      while (p < (const unsigned char *)header + sizeof(struct ustar_header))
                chksum += *p++;
        return chksum;
  }
  static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
  {
        size_t i = pathlen;
+       if (i > 1 && path[i - 1] == '/')
+               i--;
        if (i > maxlen)
                i = maxlen;
        do {
        return i;
  }
  
 +static void prepare_header(struct archiver_args *args,
 +                         struct ustar_header *header,
 +                         unsigned int mode, unsigned long size)
 +{
 +      sprintf(header->mode, "%07o", mode & 07777);
 +      sprintf(header->size, "%011lo", S_ISREG(mode) ? size : 0);
 +      sprintf(header->mtime, "%011lo", (unsigned long) args->time);
 +
 +      sprintf(header->uid, "%07o", 0);
 +      sprintf(header->gid, "%07o", 0);
 +      strlcpy(header->uname, "root", sizeof(header->uname));
 +      strlcpy(header->gname, "root", sizeof(header->gname));
 +      sprintf(header->devmajor, "%07o", 0);
 +      sprintf(header->devminor, "%07o", 0);
 +
 +      memcpy(header->magic, "ustar", 6);
 +      memcpy(header->version, "00", 2);
 +
 +      sprintf(header->chksum, "%07o", ustar_header_chksum(header));
 +}
 +
 +static int write_extended_header(struct archiver_args *args,
 +                               const unsigned char *sha1,
 +                               const void *buffer, unsigned long size)
 +{
 +      struct ustar_header header;
 +      unsigned int mode;
 +      memset(&header, 0, sizeof(header));
 +      *header.typeflag = TYPEFLAG_EXT_HEADER;
 +      mode = 0100666;
 +      sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 +      prepare_header(args, &header, mode, size);
 +      write_blocked(&header, sizeof(header));
 +      write_blocked(buffer, size);
 +      return 0;
 +}
 +
  static int write_tar_entry(struct archiver_args *args,
 -              const unsigned char *sha1, const char *path, size_t pathlen,
 -              unsigned int mode, void *buffer, unsigned long size)
 +                         const unsigned char *sha1,
 +                         const char *path, size_t pathlen,
 +                         unsigned int mode)
  {
        struct ustar_header header;
        struct strbuf ext_header = STRBUF_INIT;
 +      unsigned int old_mode = mode;
 +      unsigned long size;
 +      void *buffer;
        int err = 0;
  
        memset(&header, 0, sizeof(header));
  
 -      if (!sha1) {
 -              *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 -              mode = 0100666;
 -              strcpy(header.name, "pax_global_header");
 -      } else if (!path) {
 -              *header.typeflag = TYPEFLAG_EXT_HEADER;
 -              mode = 0100666;
 -              sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 +      if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 +              *header.typeflag = TYPEFLAG_DIR;
 +              mode = (mode | 0777) & ~tar_umask;
 +      } else if (S_ISLNK(mode)) {
 +              *header.typeflag = TYPEFLAG_LNK;
 +              mode |= 0777;
 +      } else if (S_ISREG(mode)) {
 +              *header.typeflag = TYPEFLAG_REG;
 +              mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
        } else {
 -              if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 -                      *header.typeflag = TYPEFLAG_DIR;
 -                      mode = (mode | 0777) & ~tar_umask;
 -              } else if (S_ISLNK(mode)) {
 -                      *header.typeflag = TYPEFLAG_LNK;
 -                      mode |= 0777;
 -              } else if (S_ISREG(mode)) {
 -                      *header.typeflag = TYPEFLAG_REG;
 -                      mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
 +              return error("unsupported file mode: 0%o (SHA1: %s)",
 +                           mode, sha1_to_hex(sha1));
 +      }
 +      if (pathlen > sizeof(header.name)) {
 +              size_t plen = get_path_prefix(path, pathlen,
 +                                            sizeof(header.prefix));
 +              size_t rest = pathlen - plen - 1;
 +              if (plen > 0 && rest <= sizeof(header.name)) {
 +                      memcpy(header.prefix, path, plen);
 +                              memcpy(header.name, path + plen + 1, rest);
                } else {
 -                      return error("unsupported file mode: 0%o (SHA1: %s)",
 -                                      mode, sha1_to_hex(sha1));
 +                      sprintf(header.name, "%s.data",
 +                              sha1_to_hex(sha1));
 +                      strbuf_append_ext_header(&ext_header, "path",
 +                                               path, pathlen);
                }
 -              if (pathlen > sizeof(header.name)) {
 -                      size_t plen = get_path_prefix(path, pathlen,
 -                                      sizeof(header.prefix));
 -                      size_t rest = pathlen - plen - 1;
 -                      if (plen > 0 && rest <= sizeof(header.name)) {
 -                              memcpy(header.prefix, path, plen);
 -                              memcpy(header.name, path + plen + 1, rest);
 -                      } else {
 -                              sprintf(header.name, "%s.data",
 -                                      sha1_to_hex(sha1));
 -                              strbuf_append_ext_header(&ext_header, "path",
 -                                              path, pathlen);
 -                      }
 -              } else
 -                      memcpy(header.name, path, pathlen);
 +      } else
 +              memcpy(header.name, path, pathlen);
 +
 +      if (S_ISREG(mode) && !args->convert &&
 +          sha1_object_info(sha1, &size) == OBJ_BLOB &&
 +          size > big_file_threshold)
 +              buffer = NULL;
 +      else if (S_ISLNK(mode) || S_ISREG(mode)) {
 +              enum object_type type;
 +              buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
 +              if (!buffer)
 +                      return error("cannot read %s", sha1_to_hex(sha1));
 +      } else {
 +              buffer = NULL;
 +              size = 0;
        }
  
 -      if (S_ISLNK(mode) && buffer) {
 +      if (S_ISLNK(mode)) {
                if (size > sizeof(header.linkname)) {
                        sprintf(header.linkname, "see %s.paxheader",
                                sha1_to_hex(sha1));
                        memcpy(header.linkname, buffer, size);
        }
  
 -      sprintf(header.mode, "%07o", mode & 07777);
 -      sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
 -      sprintf(header.mtime, "%011lo", (unsigned long) args->time);
 -
 -      sprintf(header.uid, "%07o", 0);
 -      sprintf(header.gid, "%07o", 0);
 -      strlcpy(header.uname, "root", sizeof(header.uname));
 -      strlcpy(header.gname, "root", sizeof(header.gname));
 -      sprintf(header.devmajor, "%07o", 0);
 -      sprintf(header.devminor, "%07o", 0);
 -
 -      memcpy(header.magic, "ustar", 6);
 -      memcpy(header.version, "00", 2);
 -
 -      sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 +      prepare_header(args, &header, mode, size);
  
        if (ext_header.len > 0) {
 -              err = write_tar_entry(args, sha1, NULL, 0, 0, ext_header.buf,
 -                              ext_header.len);
 -              if (err)
 +              err = write_extended_header(args, sha1, ext_header.buf,
 +                                          ext_header.len);
 +              if (err) {
 +                      free(buffer);
                        return err;
 +              }
        }
        strbuf_release(&ext_header);
        write_blocked(&header, sizeof(header));
 -      if (S_ISREG(mode) && buffer && size > 0)
 -              write_blocked(buffer, size);
 +      if (S_ISREG(mode) && size > 0) {
 +              if (buffer)
 +                      write_blocked(buffer, size);
 +              else
 +                      err = stream_blocked(sha1);
 +      }
 +      free(buffer);
        return err;
  }
  
@@@ -291,18 -217,11 +293,18 @@@ static int write_global_extended_header
  {
        const unsigned char *sha1 = args->commit_sha1;
        struct strbuf ext_header = STRBUF_INIT;
 -      int err;
 +      struct ustar_header header;
 +      unsigned int mode;
 +      int err = 0;
  
        strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
 -      err = write_tar_entry(args, NULL, NULL, 0, 0, ext_header.buf,
 -                      ext_header.len);
 +      memset(&header, 0, sizeof(header));
 +      *header.typeflag = TYPEFLAG_GLOBAL_HEADER;
 +      mode = 0100666;
 +      strcpy(header.name, "pax_global_header");
 +      prepare_header(args, &header, mode, ext_header.len);
 +      write_blocked(&header, sizeof(header));
 +      write_blocked(ext_header.buf, ext_header.len);
        strbuf_release(&ext_header);
        return err;
  }