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Do not use O_APPEND on fd-based operations that do not really want it; have them just lseek instead. 

svn:r17460
This commit is contained in:
Nick Mathewson 2008-12-02 23:49:40 +00:00
parent b2321cfd2f
commit 37bd9181f0
2 changed files with 20 additions and 1 deletions
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2
ChangeLog
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@ -29,6 +29,8 @@ Changes in version 0.2.1.8-alpha - 2008-??-??
- Do not use C's stdio library for writing to log files. This will
improve logging performance by a minute amount, and will stop leaking
fds when our disk is full. Fixes bug 861.
- Stop erroneous use of O_APPEND in cases where we did not in fact
want to re-seek to the end of a file before every last write().
o Minor features:
- Report the case where all signatures in a detached set are rejected

19
src/common/util.c
View File

@ -1577,6 +1577,9 @@ struct open_file_t {
*
* NOTE: When not appending, the flags O_CREAT and O_TRUNC are treated
* as true and the flag O_EXCL is treated as false.
*
* NOTE: Ordinarily, O_APPEND means "seek to the end of the file before each
* write()". We don't do that.
*/
int
start_writing_to_file(const char *fname, int open_flags, int mode,
@ -1585,6 +1588,8 @@ start_writing_to_file(const char *fname, int open_flags, int mode,
size_t tempname_len = strlen(fname)+16;
open_file_t *new_file = tor_malloc_zero(sizeof(open_file_t));
const char *open_name;
int append = 0;
tor_assert(fname);
tor_assert(data_out);
#if (O_BINARY != 0 && O_TEXT != 0)
@ -1596,6 +1601,8 @@ start_writing_to_file(const char *fname, int open_flags, int mode,
if (open_flags & O_APPEND) {
open_name = fname;
new_file->rename_on_close = 0;
append = 1;
open_flags &= ~O_APPEND;
} else {
open_name = new_file->tempname = tor_malloc(tempname_len);
if (tor_snprintf(new_file->tempname, tempname_len, "%s.tmp", fname)<0) {
@ -1613,11 +1620,21 @@ start_writing_to_file(const char *fname, int open_flags, int mode,
open_name, fname, strerror(errno));
goto err;
}
if (append) {
if (tor_fd_seekend(new_file->fd) < 0) {
log_warn(LD_FS, "Couldn't seek to end of file \"%s\": %s", open_name,
strerror(errno));
goto err;
}
}
*data_out = new_file;
return new_file->fd;
err:
if (new_file->fd >= 0)
close(new_file->fd);
*data_out = NULL;
tor_free(new_file->filename);
tor_free(new_file->tempname);
@ -2277,7 +2294,7 @@ finish_daemon(const char *desired_cwd)
exit(1);
}
nullfd = open("/dev/null", O_RDWR | O_APPEND);
nullfd = open("/dev/null", O_RDWR);
if (nullfd < 0) {
log_err(LD_GENERAL,"/dev/null can't be opened. Exiting.");
exit(1);