diff options
| -rw-r--r-- | src/ini.cpp | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/src/ini.cpp b/src/ini.cpp index 87897b9a4..fda62950f 100644 --- a/src/ini.cpp +++ b/src/ini.cpp @@ -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; } |