If a scriptlet/hook dies at the wrong moment it can trigger SIGPIPE,
terminating the process. For pipes, there is no way to prevent SIGPIPE
other than ignoring it process-wide. This can have unintended
consequences in a multi-threaded process. Using send(2) with sockets,
however, allows ignoring SIGPIPE on a per-call basis, leaving other
threads able to make use of SIGPIPE.
Signed-off-by: Andrew Gregory
---
lib/libalpm/util.c | 17 ++++-------------
1 file changed, 4 insertions(+), 13 deletions(-)
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
index 58efa5c7..5a7f2c87 100644
--- a/lib/libalpm/util.c
+++ b/lib/libalpm/util.c
@@ -30,6 +30,7 @@
#include
#include
#include
+#include
#include
#include
@@ -463,7 +464,6 @@ static int _alpm_chroot_write_to_child(alpm_handle_t *handle, int fd,
_alpm_cb_io out_cb, void *cb_ctx)
{
ssize_t nwrite;
- struct sigaction newaction, oldaction;
if(*buf_size == 0) {
/* empty buffer, ask the callback for more */
@@ -473,16 +473,7 @@ static int _alpm_chroot_write_to_child(alpm_handle_t *handle, int fd,
}
}
- /* ignore SIGPIPE in case the pipe has been closed */
- newaction.sa_handler = SIG_IGN;
- sigemptyset(&newaction.sa_mask);
- newaction.sa_flags = 0;
- sigaction(SIGPIPE, &newaction, &oldaction);
-
- nwrite = write(fd, buf, *buf_size);
-
- /* restore previous SIGPIPE handler */
- sigaction(SIGPIPE, &oldaction, NULL);
+ nwrite = send(fd, buf, *buf_size, MSG_NOSIGNAL);
if(nwrite != -1) {
/* write was successful, remove the written data from the buffer */
@@ -592,13 +583,13 @@ int _alpm_run_chroot(alpm_handle_t *handle, const char *cmd, char *const argv[],
/* Flush open fds before fork() to avoid cloning buffers */
fflush(NULL);
- if(pipe(child2parent_pipefd) == -1) {
+ if(socketpair(AF_UNIX, SOCK_STREAM, 0, child2parent_pipefd) == -1) {
_alpm_log(handle, ALPM_LOG_ERROR, _("could not create pipe (%s)\n"), strerror(errno));
retval = 1;
goto cleanup;
}
- if(pipe(parent2child_pipefd) == -1) {
+ if(socketpair(AF_UNIX, SOCK_STREAM, 0, parent2child_pipefd) == -1) {
_alpm_log(handle, ALPM_LOG_ERROR, _("could not create pipe (%s)\n"), strerror(errno));
retval = 1;
goto cleanup;
--
2.12.2