/ Check-in [1241086f]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Omit the maximum loop count on the random name chooser in the VACUUM command. Add a comment to explain why this is safe and does not result in an infinite loop. Ticket #1009. (CVS 2122)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:1241086f23a2ef7aef85139817f0c1b90140481d
User & Date: drh 2004-11-20 19:18:56
Context
2004-11-20
19:55
Rename source file sqlite.1 as sqlite3.1. Ticket #995. (CVS 2123) check-in: 297559c6 user: drh tags: trunk
19:18
Omit the maximum loop count on the random name chooser in the VACUUM command. Add a comment to explain why this is safe and does not result in an infinite loop. Ticket #1009. (CVS 2122) check-in: 1241086f user: drh tags: trunk
19:18
Rig the sqliteMalloc() routine so that we can make it fail multiple times in a row. Modify the malloc.test procedure to make malloc fail in this way and verify that the failures are still handled correctly. (CVS 2121) check-in: 519bc9d9 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/vacuum.c.

10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
..
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
...
125
126
127
128
129
130
131
132









133
134
135
136
137
138
139
140
141
142
143
**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.33 2004/10/30 20:23:09 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#ifndef SQLITE_OMIT_VACUUM
/*
** Generate a random name of 20 character in length.
................................................................................
*/
int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
  int rc = SQLITE_OK;     /* Return code from service routines */
#ifndef SQLITE_OMIT_VACUUM
  const char *zFilename;  /* full pathname of the database file */
  int nFilename;          /* number of characters  in zFilename[] */
  char *zTemp = 0;        /* a temporary file in same directory as zFilename */
  int i;                  /* Loop counter */
  Btree *pMain;           /* The database being vacuumed */
  Btree *pTemp;
  char *zSql = 0;

  if( !db->autoCommit ){
    sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", 
       (char*)0);
................................................................................
  nFilename = strlen(zFilename);
  zTemp = sqliteMalloc( nFilename+100 );
  if( zTemp==0 ){
    rc = SQLITE_NOMEM;
    goto end_of_vacuum;
  }
  strcpy(zTemp, zFilename);
  i = 0;









  do {
    zTemp[nFilename] = '-';
    randomName((unsigned char*)&zTemp[nFilename+1]);
  } while( i<10 && sqlite3OsFileExists(zTemp) );

  /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
  ** can be set to 'off' for this file, as it is not recovered if a crash
  ** occurs anyway. The integrity of the database is maintained by a
  ** (possibly synchronous) transaction opened on the main database before
  ** sqlite3BtreeCopyFile() is called.
  **







|







 







<







 







<
>
>
>
>
>
>
>
>
>



|







10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
..
93
94
95
96
97
98
99

100
101
102
103
104
105
106
...
124
125
126
127
128
129
130

131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.34 2004/11/20 19:18:56 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#ifndef SQLITE_OMIT_VACUUM
/*
** Generate a random name of 20 character in length.
................................................................................
*/
int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
  int rc = SQLITE_OK;     /* Return code from service routines */
#ifndef SQLITE_OMIT_VACUUM
  const char *zFilename;  /* full pathname of the database file */
  int nFilename;          /* number of characters  in zFilename[] */
  char *zTemp = 0;        /* a temporary file in same directory as zFilename */

  Btree *pMain;           /* The database being vacuumed */
  Btree *pTemp;
  char *zSql = 0;

  if( !db->autoCommit ){
    sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", 
       (char*)0);
................................................................................
  nFilename = strlen(zFilename);
  zTemp = sqliteMalloc( nFilename+100 );
  if( zTemp==0 ){
    rc = SQLITE_NOMEM;
    goto end_of_vacuum;
  }
  strcpy(zTemp, zFilename);


  /* The randomName() procedure in the following loop uses an excellent
  ** source of randomness to generate a name from a space of 1.3e+31 
  ** possibilities.  So unless the directory already contains on the order
  ** of 1.3e+31 files, the probability that the following loop will
  ** run more than once or twice is vanishingly small.  We are certain
  ** enough that this loop will always terminate (and terminate quickly)
  ** that we don't even bother to set a maximum loop count.
  */
  do {
    zTemp[nFilename] = '-';
    randomName((unsigned char*)&zTemp[nFilename+1]);
  } while( sqlite3OsFileExists(zTemp) );

  /* Attach the temporary database as 'vacuum_db'. The synchronous pragma
  ** can be set to 'off' for this file, as it is not recovered if a crash
  ** occurs anyway. The integrity of the database is maintained by a
  ** (possibly synchronous) transaction opened on the main database before
  ** sqlite3BtreeCopyFile() is called.
  **