New -osirrox option sparse= controls extraction into sparse files

xorriso/base_obj.c

@@ -473,6 +473,8 @@ int Xorriso_new(struct XorrisO ** xorriso,char *progname, int flag)
  m->show_hfs_cmd_count= 0;
  m->show_hfs_cmds= NULL;
 
+ m->sparse_min_gap= 0;
+
  m->result_line[0]= 0;
  m->result_line_counter= 0;
  m->result_page_counter= 0;

xorriso/misc_funct.c

@@ -1,7 +1,7 @@
 
 /* xorriso - creates, loads, manipulates and burns ISO 9660 filesystem images.
 
-   Copyright 2007-2019 Thomas Schmitt, <scdbackup@gmx.net>
+   Copyright 2007-2020 Thomas Schmitt, <scdbackup@gmx.net>
 
    Provided under GPL version 2 or later.
 
@@ -1367,3 +1367,18 @@ int Xorriso__format_guid(uint8_t guid[16], char *text, int flag)
  return(1);
 }
 
+
+int Xorriso__parse_size_param(char *cpt, int key_l, int l, double *num)
+{
+ char text[16];
+
+ *num= 0.0;
+ if(l <= key_l || l >= key_l + 16)
+   return(0);
+ strncpy(text, cpt + key_l, l - key_l);
+ text[l - key_l]= 0;
+ *num= Scanf_io_size(text, 0);
+ return(1);
+}
+
+

xorriso/misc_funct.h

@@ -1,11 +1,12 @@
 
 /* xorriso - creates, loads, manipulates and burns ISO 9660 filesystem images.
 
-   Copyright 2007-2019 Thomas Schmitt, <scdbackup@gmx.net>
+   Copyright 2007-2020 Thomas Schmitt, <scdbackup@gmx.net>
 
    Provided under GPL version 2 or later.
 
-   This file contains declarations of cellaneous helper functions of xorriso.
+   This file contains declarations of miscellaneous helper functions of
+   xorriso.
 */
 
 
@@ -114,5 +115,13 @@ int Xorriso__exchange_prefix(char *source_prefix, char *target_prefix,
 */
 int Xorriso__format_guid(uint8_t guid[16], char *text, int flag);
 
+/* @param cpt    start of keyword=value string
+   @param key_l  length from cpt of keyword= string
+   @param l      length from cpt up to end of value string
+   @param num    result
+*/
+int Xorriso__parse_size_param(char *cpt, int key_l, int l, double *num);
+
+
 #endif /* ! Xorriso_pvt_misc_includeD */
 

xorriso/opts_d_h.c

@@ -2308,6 +2308,7 @@ int Xorriso_option_help(struct XorrisO *xorriso, int flag)
 "           [:\"sort_lba_on\"|\"sort_lba_off\"]",
 "           [:\"strict_acl_on\"|\"strict_acl_off\"]",
 "           [:\"check_md5_on\"|\"check_md5_off\"|\"check_md5_force\"]",
+"           [:\"sparse=off\"|\"sparse=\"number]",
 "                 By default \"off\" the inverse operation of xorriso from ISO",
 "                 image to disk filesystem is disabled. \"on\" allows xorriso",
 "                 to create, overwrite, delete files in the disk filesystem.", 

xorriso/opts_i_o.c

@@ -1746,6 +1746,7 @@ int Xorriso_option_osirrox(struct XorrisO *xorriso, char *mode, int flag)
 {
  int l, allow_restore;
  char *npt, *cpt;
+ double num= 0.0;
 
  allow_restore= xorriso->allow_restore;
 
@@ -1799,6 +1800,21 @@ int Xorriso_option_osirrox(struct XorrisO *xorriso, char *mode, int flag)
      xorriso->do_md5|= 3 << 6;
    } else if(strncmp(cpt, "check_md5_off", l)==0 && l >= 13) {
      xorriso->do_md5&= ~(3 << 6);
+   } else if(strncmp(cpt, "sparse=", 7) == 0 && l >= 7) {
+     if(strncmp(cpt + 7, "off", 3) == 0 && l == 10) {
+       num= 0.0;
+     } else {
+       Xorriso__parse_size_param(cpt, 7, l, &num);
+       if(num < 1.0)
+         num= 0.0;
+       if(num > 1.0 * 1024.0 * 1024.0 * 1024.0) {
+         strcpy(xorriso->info_text,
+                "osirrox sparse= too large (allowed: off, 1 to 1g)");
+         Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "FAILURE", 0);
+         return(0);
+       }
+     }
+     xorriso->sparse_min_gap= num;
    } else {
 unknown_mode:;
      sprintf(xorriso->info_text, "-osirrox: unknown mode '%s'", cpt);

xorriso/opts_p_z.c

@@ -147,8 +147,11 @@ int Xorriso_option_paste_in(struct XorrisO *xorriso, char *iso_rr_path,
          (double) startbyte, (double) (startbyte+bytecount));
  Xorriso_msgs_submit(xorriso, 0, xorriso->info_text, 0, "DEBUG", 0);
 
+ Xorriso_pacifier_reset(xorriso, 0);
  ret= Xorriso_paste_in(xorriso, disk_path, startbyte, bytecount,
                        iso_rr_path, 0); 
+ Xorriso_pacifier_callback(xorriso, "files restored",xorriso->pacifier_count,
+                           xorriso->pacifier_total, "", 1 | 4 | 8 | 32);
  return(ret);
 }
 
@@ -2245,19 +2248,6 @@ int Xorriso_option_xattr(struct XorrisO *xorriso, char *mode, int flag)
 }
 
 
-static int parse_zisofs_param(char *cpt, int key_l, int l, double *num)
-{
- char text[16];
-
- *num= 0.0;
- if(l <= key_l || l >= key_l + 16)
-   return(0);
- strncpy(text, cpt + key_l, l - key_l);
- text[l - key_l]= 0;
- *num= Scanf_io_size(text, 0);
- return(1);
-}
-
 /* Option -zisofs */
 int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
 {
@@ -2307,7 +2297,7 @@ int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
      /* (ignored info from -status) */;
 
    } else if(strncmp(cpt, "block_size=", 11)==0) {
-     parse_zisofs_param(cpt, 11, l, &num);
+     Xorriso__parse_size_param(cpt, 11, l, &num);
      if (num != (1 << 15) && num != (1 << 16) && num != (1 << 17)) {
        sprintf(xorriso->info_text,
                "-zisofs: Unsupported block size (allowed 32k, 64k, 128k)");
@@ -2342,7 +2332,7 @@ int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
      }
 
    } else if(strncmp(cpt, "max_bpt=", 8) == 0) {
-     parse_zisofs_param(cpt, 8, l, &num);
+     Xorriso__parse_size_param(cpt, 8, l, &num);
      if(num < 1024.0 || num > 128.0 * 1024.0 * 1024.0 * 1024.0) {
        sprintf(xorriso->info_text,
          "-zisofs: Unsupported block pointer pool size (allowed: 1k to 128g)");
@@ -2357,7 +2347,7 @@ int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
        xorriso->zisofs_max_file_blocks= xorriso->zisofs_max_total_blocks;
 
    } else if(strncmp(cpt, "max_bpt_f=", 10) == 0) {
-     parse_zisofs_param(cpt, 10, l, &num);
+     Xorriso__parse_size_param(cpt, 10, l, &num);
      if(num < 1024.0 || num > 128.0 * 1024.0 * 1024.0 * 1024.0) {
        sprintf(xorriso->info_text,
          "-zisofs: Unsupported block pointer list size (allowed: 1k to 128g)");
@@ -2368,7 +2358,7 @@ int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
        xorriso->zisofs_max_total_blocks= xorriso->zisofs_max_file_blocks;
 
    } else if(strncmp(cpt, "block_size_v2=", 14) == 0) {
-     parse_zisofs_param(cpt, 14, l, &num);
+     Xorriso__parse_size_param(cpt, 14, l, &num);
      for(i= 15 ; i <= 20; i++)
        if(num == (1 << i))
      break;
@@ -2380,11 +2370,11 @@ int Xorriso_option_zisofs(struct XorrisO *xorriso, char *mode, int flag)
      xorriso->zisofs_v2_block_size= num;
 
    } else if(strncmp(cpt, "bpt_target=", 11) == 0) {
-     parse_zisofs_param(cpt, 11, l, &num);
+     Xorriso__parse_size_param(cpt, 11, l, &num);
      xorriso->zisofs_block_number_target= num;
 
    } else if(strncmp(cpt, "bpt_free_ratio=", 15) == 0) {
-     parse_zisofs_param(cpt, 15, l, &num);
+     Xorriso__parse_size_param(cpt, 15, l, &num);
      /* 0 means to libisofs "do not change" */
      if(num == 0.0)
        num= -1.0;

xorriso/read_run.c

@@ -533,6 +533,278 @@ ex:;
 }
 
 
+/* If defined the position accounting will be done by lseek() and used to
+ * verify the position accounting in struct Xorriso_sparse_statE.
+ * # def ine Xorriso_check_sparsE yes
+ */
+
+struct Xorriso_sparse_statE {
+ int use_lseek;
+ off_t cur_pos;
+ off_t after_last_written;
+ int warnings;
+};
+
+
+#ifdef Xorriso_check_sparsE
+
+static int Xorriso_sparse_warn(struct XorrisO *xorriso,
+                               struct Xorriso_sparse_statE *sparse_state,
+                               int occasion, char *msg, int flag)
+{
+ if(sparse_state->warnings & (1 << occasion))
+   return(1);
+ sparse_state->warnings|= 1 << occasion;
+ Xorriso_msgs_submit(xorriso, 0, msg, 0, "SORRY", 0);
+ return(1);
+}
+
+#endif /* Xorriso_check_sparsE */
+
+
+static int Xorriso_sparse_init(struct XorrisO *xorriso,
+                               struct Xorriso_sparse_statE **sparse_state,
+                               int write_fd, int flag)
+{
+ struct Xorriso_sparse_statE *o= NULL;
+ off_t cur_pos;
+ struct stat stbuf;
+ int ret;
+
+ *sparse_state= NULL;
+
+ /* Check whether sparse writing is disabled */
+ if(xorriso->sparse_min_gap <= 0)
+   {ret= 0; goto ex;}
+
+ /* Analyze write_fd */
+ ret= fstat(write_fd, &stbuf);
+ if(ret == -1)
+   {ret= 0; goto ex;}
+ if(!S_ISREG(stbuf.st_mode))
+   {ret= 0; goto ex;}
+ cur_pos= lseek(write_fd, (off_t) 0, SEEK_CUR);
+ if(cur_pos < stbuf.st_size)
+   {ret= 0; goto ex;}
+
+ Xorriso_alloc_meM(o, struct Xorriso_sparse_statE, 1);
+
+ /* Initialize sparse_state */
+ o->use_lseek= 1;
+ o->cur_pos= o->after_last_written= cur_pos;
+ o->warnings= 0;
+
+ ret= 1;
+ex:;
+ if(ret >= 1)
+   *sparse_state= o;
+ else
+   Xorriso_free_meM(o);
+ return(ret);
+}
+
+
+static int Xorriso_sparse_zeroize(struct XorrisO *xorriso,
+                                  struct Xorriso_sparse_statE *sparse_state,
+                                  int write_fd, off_t start, off_t count,
+                                  int flag)
+{
+ int ret, buf_size= 32 * 1024, buf_fill, wret;
+ off_t todo, seek_ret;
+ char *buf= NULL;
+
+ if(count <= 0)
+   {ret= 2; goto ex;}
+ Xorriso_alloc_meM(buf, char, buf_size);
+
+ seek_ret= lseek(write_fd, start, SEEK_SET);
+ if(seek_ret == -1)
+   {ret= -1; goto ex;}
+ sparse_state->cur_pos= seek_ret;
+ for(todo= count; todo > 0; ) {
+   if(buf_size < todo)
+     buf_fill= buf_size;
+   else
+     buf_fill= todo;
+   wret= write(write_fd, buf, buf_fill);
+   if(wret <= 0)
+     {ret= wret; goto ex;}
+   todo-= wret;
+   sparse_state->cur_pos+= wret;
+ }
+ ret= 1;
+ex:;
+ Xorriso_free_meM(buf);
+ return(ret);
+}
+
+
+/* @param flag bit0= this is the last buffer of the stream
+*/
+static int Xorriso_sparse_write(struct XorrisO *xorriso,
+                                struct Xorriso_sparse_statE *sparse_state,
+                                int write_fd, char *buf, int count,
+                                int flag)
+{
+ int wret, i, ret;
+ off_t cur_pos= -1, seek_ret;
+ static char zero[32]= {0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0,
+                        0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0};
+
+ if(sparse_state == NULL)
+   goto do_write;
+ if(!sparse_state->use_lseek)
+   goto do_write;
+ if(flag & 1)
+   goto do_write;
+
+#ifdef Xorriso_check_sparsE
+
+ cur_pos= lseek(write_fd, (off_t) 0, SEEK_CUR);
+ if(cur_pos == -1)
+   goto do_write;
+ if(cur_pos != sparse_state->cur_pos) {
+   Xorriso_sparse_warn(xorriso, sparse_state, 0,
+                       "cur_pos deviation in Xorriso_sparse_write:intro", 0);
+   sparse_state->cur_pos= cur_pos;
+ }
+
+#else
+  
+ cur_pos= sparse_state->cur_pos;
+
+#endif
+
+ /* Check for all zeros */
+ if(count % 32)
+   goto do_write;
+ for(i= 0; i < count; i+= 32)
+   if(memcmp(buf + i, zero, 32))
+ break;
+ if(i < count)
+   goto do_write;
+
+ /* Omit write() until next non-zero buffer or end of writing */
+
+#ifdef Xorriso_check_sparsE
+
+ /* Only for debugging: Do real lseek() instead of write() */
+ seek_ret= lseek(write_fd, cur_pos + count, SEEK_SET);
+ if(seek_ret == -1)
+   return(-1);
+
+#endif
+
+ sparse_state->cur_pos= cur_pos + count;
+ return(count);
+
+do_write:
+ if(sparse_state != NULL) {
+   /* Check whether the gap since after_last_written is too small.
+      If so: fill the whole gap by writing zeros.
+   */
+   if(sparse_state->after_last_written < cur_pos) {
+     if(xorriso->sparse_min_gap > cur_pos - sparse_state->after_last_written) {
+       ret= Xorriso_sparse_zeroize(xorriso, sparse_state, write_fd,
+                                sparse_state->after_last_written,
+                                cur_pos - sparse_state->after_last_written, 0);
+       if(ret < 0)
+         return(ret);
+       if(ret == 0) {
+         seek_ret= lseek(write_fd, cur_pos, SEEK_SET);
+         if(seek_ret == -1)
+           return(-1);
+         sparse_state->cur_pos= seek_ret;
+       }
+     }
+   }
+ }
+
+
+ if(sparse_state != NULL) {
+
+#ifdef Xorriso_check_sparsE
+
+   cur_pos= lseek(write_fd, (off_t) 0, SEEK_CUR);
+   if(cur_pos != sparse_state->cur_pos) {
+     Xorriso_sparse_warn(xorriso, sparse_state, 1,
+                      "cur_pos deviation in Xorriso_sparse_write:do_write", 0);
+     sparse_state->cur_pos= cur_pos;
+   }
+
+#else
+
+   /* lseek() has been delayed until now */
+   if(sparse_state->after_last_written != sparse_state->cur_pos) {
+     seek_ret= lseek(write_fd, sparse_state->cur_pos, SEEK_SET);
+     if(seek_ret == -1)
+       return(-1);
+   }
+
+#endif /* ! Xorriso_check_sparsE */
+
+ }
+ wret= write(write_fd, buf, count);
+ if(sparse_state != NULL && wret > 0 && cur_pos >= 0)
+   sparse_state->cur_pos= sparse_state->after_last_written= cur_pos + wret;
+ return(wret);
+}
+
+
+static int Xorriso_sparse_finish(struct XorrisO *xorriso,
+                                 struct Xorriso_sparse_statE **sparse_state,
+                                 int write_fd, int flag)
+{
+ int ret;
+ off_t cur_pos;
+ struct Xorriso_sparse_statE *o;
+
+ if(sparse_state == NULL)
+   return(0);
+ o= *sparse_state;
+ if(o == NULL)
+   return(1);
+ if(write_fd == -1)
+   {ret= 1; goto ex;}
+
+#ifdef Xorriso_check_sparsE
+
+ cur_pos= lseek(write_fd, (off_t) 0, SEEK_CUR);
+ if(cur_pos == -1)
+   {ret= -1; goto ex;}
+ if(cur_pos != o->cur_pos) {
+   Xorriso_sparse_warn(xorriso, o, 2,
+                       "cur_pos deviation in Xorriso_sparse_finish", 0);
+   o->cur_pos= cur_pos;
+ }
+
+#else
+  
+ cur_pos= o->cur_pos;
+
+#endif /* ! Xorriso_check_sparsE */
+
+ if(o->after_last_written < cur_pos) {
+   /* Check whether the gap since after_last_written is too small.
+      If so: fill the whole gap by writing zeros, else: write a last zero byte.
+   */
+   if(xorriso->sparse_min_gap > cur_pos - o->after_last_written)
+     ret= Xorriso_sparse_zeroize(xorriso, o, write_fd, o->after_last_written,
+                                 cur_pos - o->after_last_written, 0);
+   else
+     ret= Xorriso_sparse_zeroize(xorriso, o, write_fd, cur_pos - 1, (off_t) 1,
+                                 0);
+   if(ret <= 0)
+     goto ex;
+ }
+ ret= 1;
+ex:;
+ Xorriso_free_meM(o);
+ *sparse_state= NULL;
+ return(ret);
+}
+
+
 /* @param flag bit0= Minimal transfer: access permissions only
                bit1= *_offset and bytes are valid for writing to regular file
                bit2= This is not a parameter. Do not report if ignored
@@ -567,7 +839,8 @@ int Xorriso_tree_restore_node(struct XorrisO *xorriso, IsoNode *node,
  off_t catsize;
  char disk_md5[16], iso_md5[16];
  void *ctx= NULL;
- int use_md5= 0, i;
+ int use_md5= 0, i, sparse_ret= 3;
+ struct Xorriso_sparse_statE *sparse_state= NULL;
 
  Xorriso_alloc_meM(buf, char, buf_size);
  Xorriso_alloc_meM(temp_path, char, SfileadrL);
@@ -679,6 +952,9 @@ int Xorriso_tree_restore_node(struct XorrisO *xorriso, IsoNode *node,
        goto cannot_restore;
      }
    }
+   if(ISO_NODE_IS_FILE(node))
+     Xorriso_sparse_init(xorriso, &sparse_state, write_fd, 0);
+
    while(todo>0) {
      wanted= buf_size;
      if(wanted>todo)
@@ -731,7 +1007,11 @@ int Xorriso_tree_restore_node(struct XorrisO *xorriso, IsoNode *node,
        ret= read_count - img_offset;
      }
 
-     wret= write(write_fd, buf_pt, ret);
+     if(sparse_state == NULL)
+       wret= write(write_fd, buf_pt, ret);
+     else
+       wret= Xorriso_sparse_write(xorriso, sparse_state, write_fd, buf_pt, ret,
+                                  0);
      if(wret>=0) {
        todo-= wret;
        xorriso->pacifier_byte_count+= wret;
@@ -774,8 +1054,11 @@ bad_md5:;
        }
      }
    }
-   if(write_fd != -1)
+
+   if(write_fd != -1) {
+     sparse_ret= Xorriso_sparse_finish(xorriso, &sparse_state, write_fd, 0);
      close(write_fd);
+   }
    write_fd= -1;
    if(todo > 0 && xorriso->extract_error_mode == 2) {
      unlink(open_path_pt);
@@ -798,6 +1081,12 @@ bad_md5:;
    }
    ret= -(todo > 0);
    l_errno= 0;
+   if(sparse_ret <= 0) {
+     strcpy(xorriso->info_text, "Could not finalize sparse extraction of ");
+     Text_shellsafe(disk_path, xorriso->info_text, 1 | 2);
+     Xorriso_msgs_submit(xorriso, 0, xorriso->info_text,
+                         sparse_ret < 0 ? errno : 0, "FAILURE", 0);
+   }
 
  } else if(LIBISO_ISLNK(node)) {
    what= "symbolic link";
@@ -898,6 +1187,8 @@ ex:;
    Xorriso_iso_file_close(xorriso, &data_stream, 0);
  if(ctx != NULL)
    Xorriso_md5_end(xorriso, &ctx, disk_md5, 0);
+ if(sparse_state != NULL)
+   Xorriso_sparse_finish(xorriso, &sparse_state, -1, 0);
  Xorriso_process_msg_queues(xorriso,0);
  return(ret);
 }

xorriso/text_io.c

@@ -2990,18 +2990,29 @@ int Xorriso_status(struct XorrisO *xorriso, char *filter, FILE *fp, int flag)
  if(xorriso->allow_restore == -1)
    sprintf(line,"-osirrox %s\n", mode_pt);
  else
-   sprintf(line,"-osirrox %s:%s:%s:%s:%s:%s:%s\n", mode_pt,
+   sprintf(line,"-osirrox %s:%s:%s:%s:%s\n", mode_pt,
          xorriso->do_concat_split ? "concat_split_on" : "concat_split_off",
          xorriso->do_auto_chmod ? "auto_chmod_on" : "auto_chmod_off",
          xorriso->do_restore_sort_lba ? "sort_lba_on" : "sort_lba_off",
-         xorriso->drives_exclusive ? "o_excl_on" : "o_excl_off",
+         xorriso->drives_exclusive ? "o_excl_on" : "o_excl_off");
+ if(!(is_default && no_defaults))
+   Xorriso_status_result(xorriso,filter,fp,flag&2);
+
+ is_default = ((xorriso->do_strict_acl & 1) == 0 &&
+               (xorriso->do_md5 & (64 | 128)) == 0 &&
+               xorriso->sparse_min_gap == 0);
+ sprintf(line,"-osirrox %s:%s:sparse=",
          (xorriso->do_strict_acl & 1) ? "strict_acl_on" : "strict_acl_off",
          (xorriso->do_md5 & 64) ? 
                    (xorriso->do_md5 & 128) ? "check_md5_force" : "check_md5_on"
-                                : "check_md5_off"
+                                : "check_md5_off");
-        );
+ if(xorriso->sparse_min_gap <= 0)
+   strcat(line, "off");
+ else
+   Sfile_off_t_text(line  + strlen(line), xorriso->sparse_min_gap, 0);
+ strcat(line, "\n");
  if(!(is_default && no_defaults))
-   Xorriso_status_result(xorriso,filter,fp,flag&2);
+   Xorriso_status_result(xorriso, filter, fp, flag & 2);
 
  is_default= (xorriso->mount_opts_flag == 0);
   sprintf(line,"-mount_opts %s\n",

xorriso/xorriso.1

@@ -9,7 +9,7 @@
 .\" First parameter, NAME, should be all caps
 .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 .\" other parameters are allowed: see man(7), man(1)
-.TH XORRISO 1 "Version 1.5.3, Oct 27, 2020"
+.TH XORRISO 1 "Version 1.5.3, Nov 02, 2020"
 .\" Please adjust this date whenever revising the manpage.
 .\"
 .\" Some roff macros, for reference:
@@ -5004,6 +5004,21 @@ MD5 of the copied content gets computed and compared with the recorded MD5.
 A mismatch causes an error message of severity SORRY.
 Option \fBcheck_md5_force\fR causes an error message if  \-md5 is "on"
 but no MD5 is recorded for the data file. 
+.br
+Option \fBsparse=\fR controls production of sparse files during
+extraction of files from the ISO filesystem.
+Default is \fBsparse=off\fR.
+.br
+A positive number like in \fBsparse=1m\fR sets the minimum requirement
+for the length of a sequence of 0\-bytes which shall be represented by a gap.
+This saves disk space if the disk filesystem supports sparse files.
+A gap gets created by help of lseek(2) if a sequence of read buffers, which
+contain only 0\-bytes, bears at least the minimum amount of bytes. Expect
+read buffers to be in the size range of 32k or 64k.
+.br
+Command \-paste_in creates gaps only if the writing begins at or after the end
+of the existing disk file. So the sequence of \-paste_in commands matters.
+Command \-concat does not create sparse files.
 .TP
 \fB\-extract\fR iso_rr_path disk_path
 Copy the file objects at and underneath iso_rr_path to their corresponding

xorriso/xorriso.info

@@ -4221,6 +4221,20 @@ The directory permissions on disk have to allow rwx.
      compared with the recorded MD5.  A mismatch causes an error message
      of severity SORRY. Option *check_md5_force* causes an error message
      if -md5 is "on" but no MD5 is recorded for the data file.
+     Option *sparse=* controls production of sparse files during
+     extraction of files from the ISO filesystem.  Default is
+     *sparse=off*.
+     A positive number like in *sparse=1m* sets the minimum requirement
+     for the length of a sequence of 0-bytes which shall be represented
+     by a gap.  This saves disk space if the disk filesystem supports
+     sparse files.  A gap gets created by help of lseek(2) if a sequence
+     of read buffers, which contain only 0-bytes, bears at least the
+     minimum amount of bytes.  Expect read buffers to be in the size
+     range of 32k or 64k.
+     Command -paste_in creates gaps only if the writing begins at or
+     after the end of the existing disk file.  So the sequence of
+     -paste_in commands matters.  Command -concat does not create sparse
+     files.
 -extract iso_rr_path disk_path
      Copy the file objects at and underneath iso_rr_path to their
      corresponding addresses at and underneath disk_path.  This is the
@@ -5519,14 +5533,14 @@ File: xorriso.info,  Node: CommandIdx,  Next: ConceptIdx,  Prev: Legal,  Up: Top
 * -compare_l reports ISO/disk differences: Navigate.          (line 147)
 * -compare_r reports ISO/disk differences: Navigate.          (line 143)
 * -compliance controls standard compliance: SetWrite.         (line  62)
-* -concat copies ISO file content:       Restore.             (line 125)
+* -concat copies ISO file content:       Restore.             (line 139)
 * -copyright_file sets copyright file name: SetWrite.         (line 245)
-* -cpax copies files to disk:            Restore.             (line 107)
+* -cpax copies files to disk:            Restore.             (line 121)
 * -cpr inserts like with cp -r:          Insert.              (line 164)
-* -cpx copies files to disk:             Restore.             (line  96)
+* -cpx copies files to disk:             Restore.             (line 110)
 * -cp_clone copies ISO directory tree:   Insert.              (line 196)
-* -cp_rx copies file trees to disk:      Restore.             (line 110)
+* -cp_rx copies file trees to disk:      Restore.             (line 124)
-* -cp_rx copies file trees to disk <1>:  Restore.             (line 118)
+* -cp_rx copies file trees to disk <1>:  Restore.             (line 132)
 * -cut_out inserts piece of data file:   Insert.              (line 139)
 * -data_cache_size adjusts read cache size: Loading.          (line 353)
 * -dev acquires one drive for input and output: AqDrive.      (line  12)
@@ -5553,10 +5567,10 @@ File: xorriso.info,  Node: CommandIdx,  Next: ConceptIdx,  Prev: Legal,  Up: Top
 * -error_behavior controls error workarounds: Exception.      (line  92)
 * -external_filter registers data filter: Filter.             (line  20)
 * -external_filter unregisters data filter: Filter.           (line  47)
-* -extract copies file tree to disk:     Restore.             (line  69)
+* -extract copies file tree to disk:     Restore.             (line  83)
-* -extract_cut copies file piece to disk: Restore.            (line  87)
+* -extract_cut copies file piece to disk: Restore.            (line 101)
-* -extract_l copies files to disk:       Restore.             (line  83)
+* -extract_l copies files to disk:       Restore.             (line  97)
-* -extract_single copies file to disk:   Restore.             (line  80)
+* -extract_single copies file to disk:   Restore.             (line  94)
 * -file_name_limit curbs length of file names: Loading.       (line 267)
 * -file_size_limit limits data file size: SetInsert.          (line   7)
 * -find traverses and alters ISO tree:   CmdFind.             (line   7)
@@ -5610,7 +5624,7 @@ File: xorriso.info,  Node: CommandIdx,  Next: ConceptIdx,  Prev: Legal,  Up: Top
 * -md5 controls handling of MD5 sums:    Loading.             (line 184)
 * -mkdir creates ISO directory:          Insert.              (line 177)
 * -modesty_on_drive keep drive buffer hungry: SetWrite.       (line 406)
-* -mount issues mount command for ISO session: Restore.       (line 153)
+* -mount issues mount command for ISO session: Restore.       (line 167)
 * -mount_cmd composes mount command line: Inquiry.            (line  49)
 * -mount_cmd controls mount command:     Inquiry.             (line  65)
 * -msg_op perform operations on program messages: Frontend.   (line  27)
@@ -5630,7 +5644,7 @@ File: xorriso.info,  Node: CommandIdx,  Next: ConceptIdx,  Prev: Legal,  Up: Top
 * -pacifier controls pacifier text form: Emulation.           (line 166)
 * -padding sets amount or mode of image padding: SetWrite.    (line 494)
 * -page set terminal geometry:           DialogCtl.           (line  18)
-* -paste_in copies file into disk file:  Restore.             (line 121)
+* -paste_in copies file into disk file:  Restore.             (line 135)
 * -pathspecs sets meaning of = with -add: SetInsert.          (line 115)
 * -path_list inserts paths from disk file: Insert.            (line  81)
 * -pkt_output consolidates text output:  Frontend.            (line   7)
@@ -5803,7 +5817,7 @@ File: xorriso.info,  Node: ConceptIdx,  Prev: CommandIdx,  Up: Top
 * Emulation, pacifier form, -pacifier:   Emulation.           (line 166)
 * Examples:                              Examples.            (line   6)
 * extattr, _definition:                  Extras.              (line  66)
-* File content, copy, -concat:           Restore.             (line 125)
+* File content, copy, -concat:           Restore.             (line 139)
 * File names, curb length, -file_name_limit: Loading.         (line 267)
 * File names, if neither Rock Ridge nor Joliet: Loading.      (line 229)
 * Filter, apply to file tree, -set_filter_r: Filter.          (line  84)
@@ -5966,22 +5980,22 @@ File: xorriso.info,  Node: ConceptIdx,  Prev: CommandIdx,  Up: Top
 * Relocation directory, set name, -rr_reloc_dir: SetWrite.    (line 150)
 * Rename, in ISO image, -move:           Manip.               (line  31)
 * Rename, in ISO image, -mv:             Manip.               (line  37)
-* Restore, copy file into disk file, -paste_in: Restore.      (line 121)
+* Restore, copy file into disk file, -paste_in: Restore.      (line 135)
-* Restore, copy file piece to disk, -extract_cut: Restore.    (line  87)
+* Restore, copy file piece to disk, -extract_cut: Restore.    (line 101)
-* Restore, copy file to disk, -extract_single: Restore.       (line  80)
+* Restore, copy file to disk, -extract_single: Restore.       (line  94)
-* Restore, copy file tree to disk, -extract: Restore.         (line  69)
+* Restore, copy file tree to disk, -extract: Restore.         (line  83)
-* Restore, copy file trees to disk, -cp_rx: Restore.          (line 110)
+* Restore, copy file trees to disk, -cp_rx: Restore.          (line 124)
-* Restore, copy file trees to disk, -cp_rx <1>: Restore.      (line 118)
+* Restore, copy file trees to disk, -cp_rx <1>: Restore.      (line 132)
-* Restore, copy files to disk, -cpax:    Restore.             (line 107)
+* Restore, copy files to disk, -cpax:    Restore.             (line 121)
-* Restore, copy files to disk, -cpx:     Restore.             (line  96)
+* Restore, copy files to disk, -cpx:     Restore.             (line 110)
-* Restore, copy files to disk, -extract_l: Restore.           (line  83)
+* Restore, copy files to disk, -extract_l: Restore.           (line  97)
 * Restore, enable ISO-to-disk, -osirrox: Restore.             (line  18)
 * Result layout, more shell-like, -sh_style_result: Scripting.
                                                               (line  61)
 * Rock Ridge, _definition:               Extras.              (line   6)
 * Session, altered start address, -displacement: Loading.     (line  78)
 * Session, info string, -session_string: Inquiry.             (line  74)
-* Session, issue mount command, -mount:  Restore.             (line 153)
+* Session, issue mount command, -mount:  Restore.             (line 167)
 * Session, log when written, -session_log: Scripting.         (line 134)
 * Session, mount command line, -mount_cmd: Inquiry.           (line  49)
 * Session, mount parameters, -mount_opts: Inquiry.            (line  65)
@@ -6066,32 +6080,32 @@ Node: Inquiry197292
 Node: Navigate206174
 Node: Verify214881
 Node: Restore226030
-Node: Emulation235196
+Node: Emulation236013
-Node: Scripting245652
+Node: Scripting246469
-Node: Frontend253435
+Node: Frontend254252
-Node: Examples263061
+Node: Examples263878
-Node: ExDevices264239
+Node: ExDevices265056
-Node: ExCreate264900
+Node: ExCreate265717
-Node: ExDialog266200
+Node: ExDialog267017
-Node: ExGrowing267471
+Node: ExGrowing268288
-Node: ExModifying268280
+Node: ExModifying269097
-Node: ExBootable268790
+Node: ExBootable269607
-Node: ExCharset269345
+Node: ExCharset270162
-Node: ExPseudo270241
+Node: ExPseudo271058
-Node: ExCdrecord271168
+Node: ExCdrecord271985
-Node: ExMkisofs271488
+Node: ExMkisofs272305
-Node: ExGrowisofs273385
+Node: ExGrowisofs274202
-Node: ExException274538
+Node: ExException275355
-Node: ExTime274996
+Node: ExTime275813
-Node: ExIncBackup275454
+Node: ExIncBackup276271
-Node: ExRestore279480
+Node: ExRestore280297
-Node: ExRecovery280426
+Node: ExRecovery281243
-Node: Files280998
+Node: Files281815
-Node: Environ282332
+Node: Environ283149
-Node: Seealso283080
+Node: Seealso283897
-Node: Bugreport283797
+Node: Bugreport284614
-Node: Legal284388
+Node: Legal285205
-Node: CommandIdx285400
+Node: CommandIdx286217
-Node: ConceptIdx303016
+Node: ConceptIdx303833
 
 End Tag Table

xorriso/xorriso.texi

@@ -50,7 +50,7 @@
 @c man .\" First parameter, NAME, should be all caps
 @c man .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 @c man .\" other parameters are allowed: see man(7), man(1)
-@c man .TH XORRISO 1 "Version 1.5.3, Oct 27, 2020"
+@c man .TH XORRISO 1 "Version 1.5.3, Nov 02, 2020"
 @c man .\" Please adjust this date whenever revising the manpage.
 @c man .\"
 @c man .\" Some roff macros, for reference:
@@ -5739,6 +5739,21 @@ MD5 of the copied content gets computed and compared with the recorded MD5.
 A mismatch causes an error message of severity SORRY.
 Option @strong{check_md5_force} causes an error message if  -md5 is "on"
 but no MD5 is recorded for the data file. 
+@*
+Option @strong{sparse=} controls production of sparse files during
+extraction of files from the ISO filesystem.
+Default is @strong{sparse=off}.
+@*
+A positive number like in @strong{sparse=1m} sets the minimum requirement
+for the length of a sequence of 0-bytes which shall be represented by a gap.
+This saves disk space if the disk filesystem supports sparse files.
+A gap gets created by help of lseek(2) if a sequence of read buffers, which
+contain only 0-bytes, bears at least the minimum amount of bytes. Expect
+read buffers to be in the size range of 32k or 64k.
+@*
+Command -paste_in creates gaps only if the writing begins at or after the end
+of the existing disk file. So the sequence of -paste_in commands matters.
+Command -concat does not create sparse files.
 @c man .TP
 @item -extract iso_rr_path disk_path
 @kindex -extract   copies file tree to disk

xorriso/xorriso_private.h

@@ -864,6 +864,9 @@ struct XorrisO { /* the global context of xorriso */
  int show_hfs_cmd_count;
  char **show_hfs_cmds;
 
+ /* Extraction to sparse files */
+ off_t sparse_min_gap;
+
  /* result (stdout, R: ) */
  char result_line[10*SfileadrL];
  int result_line_counter;

xorriso/xorriso_timestamp.h

@@ -1 +1 @@
-#define Xorriso_timestamP "2020.10.31.195038"
+#define Xorriso_timestamP "2020.11.03.082729"