emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

add/remove-shell: use O_TRUNC instead of O_EXCL

Browse Source 
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko 2010-10-20 15:14:32 +02:00
parent 5be79ff27a
commit ff19d525a9
1 changed files with 10 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
loginutils/add-remove-shell.c
View File

@ -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);
*/