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/*
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.
RETURN
0 - ok
1 - some error has occured. Probably due to the lack of resourses
2 - cannot open the file
*/
#include "my_global.h"
#include "mysys_priv.h"
#include "m_string.h"
#include <my_dir.h>
#define BUFF_SIZE 1024
#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);
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 optlen, optval_len, sect_len, nr_newlines= 0;
my_bool in_section= FALSE, opt_applied= 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 err;
optlen= strlen(option);
optval_len= strlen(option_value);
/*
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(sizeof(char) *
(file_stat.st_size +
/* option name len */
optlen +
/* reserve space for newline */
NEWLINE_LEN +
/* reserve for '=' char */
1 +
/* option value len */
optval_len +
/* The ending zero plus some safety */
FN_REFLEN), MYF(MY_WME))))
goto malloc_err;
sect_len= 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;
}
if (!opt_applied && in_section && !strncmp(src_ptr, option, optlen) &&
(*(src_ptr + optlen) == '=' ||
my_isspace(&my_charset_latin1, *(src_ptr + optlen)) ||
*(src_ptr + optlen) == '\0'))
{
dst_ptr= add_option(dst_ptr, option_value, option, remove_option);
opt_applied= 1;
}
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);
}
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)))
goto err;
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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