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| author | Denys Vlasenko | 2010-10-20 15:14:32 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2010-10-20 15:14:32 +0200 |
| commit | ff19d525a98418915e5e10e0e0bb6e40f7259b76 (patch) | |
| tree | 0df2deb1b3aa79ddd2e6002606dc28aa3322259a | |
| parent | 5be79ff27a5852567a9bdec80d67b061ad828290 (diff) | |
| download | busybox-ff19d525a98418915e5e10e0e0bb6e40f7259b76.zip busybox-ff19d525a98418915e5e10e0e0bb6e40f7259b76.tar.gz | |
add/remove-shell: use O_TRUNC instead of O_EXCL
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
| -rw-r--r-- | loginutils/add-remove-shell.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/loginutils/add-remove-shell.c b/loginutils/add-remove-shell.c index 986fe57..757e505 100644 --- a/loginutils/add-remove-shell.c +++ b/loginutils/add-remove-shell.c @@ -63,11 +63,19 @@ int add_remove_shell_main(int argc UNUSED_PARAM, char **argv) orig_fp = fopen_for_read(orig_fn); new_fn = xasprintf("%s.tmp", orig_fn); - xmove_fd(xopen(new_fn, O_WRONLY | O_CREAT | O_EXCL), STDOUT_FILENO); + /* + * O_TRUNC or O_EXCL? At the first glance, O_EXCL looks better, + * since it prevents races. But: (1) it requires a retry loop, + * (2) if /etc/shells.tmp is *stale*, then retry loop + * with O_EXCL will never succeed - it should have a timeout, + * after which it should revert to O_TRUNC. + * For now, I settle for O_TRUNC instead. + */ + xmove_fd(xopen(new_fn, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO); /* TODO: struct stat sb; - fstat(fileno(orig_fp), &sb); + xfstat(fileno(orig_fp), &sb); xfchown(STDOUT_FILENO, sb.st_uid, sb.st_gid); xfchmod(STDOUT_FILENO, sb.st_mode); */ |