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/* Copyright (C) 2005 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include "my_global.h"
#include "mysys_priv.h"
#include "m_string.h"
#include <my_dir.h>
#define BUFF_SIZE 1024
#define RESERVE 1024 /* Extend buffer with this extent */
#ifdef __WIN__
#define NEWLINE "\r\n"
#define NEWLINE_LEN 2
#else
#define NEWLINE "\n"
#define NEWLINE_LEN 1
#endif
static char *add_option(char *dst, const char *option_value,
const char *option, int remove_option);
/*
Add/remove option to the option file section.
SYNOPSYS
modify_defaults_file()
file_location The location of configuration file to edit
option option to look for
option value The value of the option we would like to set
section_name the name of the section
remove_option This is true if we want to remove the option.
False otherwise.
IMPLEMENTATION
We open the option file first, then read the file line-by-line,
looking for the section we need. At the same time we put these lines
into a buffer. Then we look for the option within this section and
change/remove it. In the end we get a buffer with modified version of the
file. Then we write it to the file, truncate it if needed and close it.
Note that there is a small time gap, when the file is incomplete,
and this theoretically might introduce a problem.
RETURN
0 - ok
1 - some error has occured. Probably due to the lack of resourses
2 - cannot open the file
*/
int modify_defaults_file(const char *file_location, const char *option,
const char *option_value,
const char *section_name, int remove_option)
{
FILE *cnf_file;
MY_STAT file_stat;
char linebuff[BUFF_SIZE], *src_ptr, *dst_ptr, *file_buffer;
uint opt_len, optval_len, sect_len, nr_newlines= 0, buffer_size;
my_bool in_section= FALSE, opt_applied= 0;
uint reserve_extended;
uint new_opt_len;
int reserve_occupied= 0;
DBUG_ENTER("modify_defaults_file");
if (!(cnf_file= my_fopen(file_location, O_RDWR | O_BINARY, MYF(0))))
DBUG_RETURN(2);
/* my_fstat doesn't use the flag parameter */
if (my_fstat(fileno(cnf_file), &file_stat, MYF(0)))
goto malloc_err;
opt_len= (uint) strlen(option);
optval_len= (uint) strlen(option_value);
new_opt_len= opt_len + 1 + optval_len + NEWLINE_LEN;
/* calculate the size of the buffer we need */
reserve_extended= (opt_len +
1 + /* For '=' char */
optval_len + /* Option value len */
NEWLINE_LEN + /* Space for newline */
RESERVE); /* Some additional space */
buffer_size= (file_stat.st_size +
1); /* The ending zero */
/*
Reserve space to read the contents of the file and some more
for the option we want to add.
*/
if (!(file_buffer= (char*) my_malloc(buffer_size + reserve_extended,
MYF(MY_WME))))
goto malloc_err;
sect_len= (uint) strlen(section_name);
for (dst_ptr= file_buffer; fgets(linebuff, BUFF_SIZE, cnf_file); )
{
/* Skip over whitespaces */
for (src_ptr= linebuff; my_isspace(&my_charset_latin1, *src_ptr);
src_ptr++)
{}
if (!*src_ptr) /* Empty line */
{
nr_newlines++;
continue;
}
/* correct the option */
if (in_section && !strncmp(src_ptr, option, opt_len) &&
(*(src_ptr + opt_len) == '=' ||
my_isspace(&my_charset_latin1, *(src_ptr + opt_len)) ||
*(src_ptr + opt_len) == '\0'))
{
char *old_src_ptr= src_ptr;
src_ptr= strend(src_ptr+ opt_len); /* Find the end of the line */
/* could be negative */
reserve_occupied+= (int) new_opt_len - (int) (src_ptr - old_src_ptr);
if (reserve_occupied >= (int) reserve_extended)
{
reserve_extended= (uint) reserve_occupied + RESERVE;
if (!(file_buffer= (char*) my_realloc(file_buffer, buffer_size +
reserve_extended,
MYF(MY_WME|MY_FREE_ON_ERROR))))
goto malloc_err;
}
opt_applied= 1;
dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
}
else
{
/* If going to new group and we have option to apply, do it now */
if (in_section && !opt_applied && *src_ptr == '[')
{
dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
opt_applied= 1; /* set the flag to do write() later */
reserve_occupied= new_opt_len+ opt_len + 1 + NEWLINE_LEN;
}
for (; nr_newlines; nr_newlines--)
dst_ptr= strmov(dst_ptr, NEWLINE);
dst_ptr= strmov(dst_ptr, linebuff);
}
/* Look for a section */
if (*src_ptr == '[')
{
/* Copy the line to the buffer */
if (!strncmp(++src_ptr, section_name, sect_len))
{
src_ptr+= sect_len;
/* Skip over whitespaces. They are allowed after section name */
for (; my_isspace(&my_charset_latin1, *src_ptr); src_ptr++)
{}
if (*src_ptr != ']')
continue; /* Missing closing parenthesis. Assume this was no group */
in_section= TRUE;
}
else
in_section= FALSE; /* mark that this section is of no interest to us */
}
}
/* File ended. */
if (!opt_applied && !remove_option && in_section)
{
/* New option still remains to apply at the end */
if (*(dst_ptr - 1) != '\n')
dst_ptr= strmov(dst_ptr, NEWLINE);
dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
opt_applied= 1;
}
for (; nr_newlines; nr_newlines--)
dst_ptr= strmov(dst_ptr, NEWLINE);
if (opt_applied)
{
/* Don't write the file if there are no changes to be made */
if (my_chsize(fileno(cnf_file), (my_off_t) (dst_ptr - file_buffer), 0,
MYF(MY_WME)) ||
my_fseek(cnf_file, 0, MY_SEEK_SET, MYF(0)) ||
my_fwrite(cnf_file, file_buffer, (uint) (dst_ptr - file_buffer),
MYF(MY_NABP)))
goto err;
}
if (my_fclose(cnf_file, MYF(MY_WME)))
DBUG_RETURN(1);
my_free(file_buffer, MYF(0));
DBUG_RETURN(0);
err:
my_free(file_buffer, MYF(0));
malloc_err:
my_fclose(cnf_file, MYF(0));
DBUG_RETURN(1); /* out of resources */
}
static char *add_option(char *dst, const char *option_value,
const char *option, int remove_option)
{
if (!remove_option)
{
dst= strmov(dst, option);
if (*option_value)
{
*dst++= '=';
dst= strmov(dst, option_value);
}
/* add a newline */
dst= strmov(dst, NEWLINE);
}
return dst;
}
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