/* 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; version 2 of the License. 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 #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; }