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Code Issues

(svn r15686) -Codechange: make it a bit harder for crashes to trash your config file.

release/0.7
rubidium 2009-03-12 14:22:17 +00:00
parent 3d780608a2
commit bd2e1ac903
1 changed files with 30 additions and 1 deletions
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31
src/ini.cpp
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@ -10,6 +10,12 @@
#include "string_func.h"
#include "fileio_func.h"
#if (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 199309L) || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 500)
# define WITH_FDATASYNC
# include <unistd.h>
#endif
IniItem::IniItem(IniGroup *parent, const char *name, size_t len) : next(NULL), value(NULL), comment(NULL)
{
if (len == 0) len = strlen(name);
@ -253,7 +259,16 @@ void IniFile::LoadFromDisk(const char *filename)
bool IniFile::SaveToDisk(const char *filename)
{
FILE *f = fopen(filename, "w");
/*
* First write the configuration to a (temporary) file and then rename
* that file. This to prevent that when OpenTTD crashes during the save
* you end up with a truncated configuration file.
*/
char file_new[MAX_PATH];
strecpy(file_new, filename, lastof(file_new));
strecat(file_new, ".new", lastof(file_new));
FILE *f = fopen(file_new, "w");
if (f == NULL) return false;
for (const IniGroup *group = this->group; group != NULL; group = group->next) {
@ -275,6 +290,20 @@ bool IniFile::SaveToDisk(const char *filename)
}
if (this->comment) fputs(this->comment, f);
/*
* POSIX (and friends) do not guarantee that when a file is closed it is
* flushed to the disk. So we manually flush it do disk if we have the
* APIs to do so. We only need to flush the data as the metadata itself
* (modification date etc.) is not important to us; only the real data is.
*/
#ifdef WITH_FDATASYNC
int ret = fdatasync(fileno(f));
fclose(f);
if (ret != 0) return false;
#else
fclose(f);
#endif
rename(file_new, filename);
return true;
}