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authorAndrew Gregory <andrew.gregory.8@gmail.com>2017-04-15 18:22:51 -0400
committerAndrew Gregory <andrew.gregory.8@gmail.com>2017-04-16 19:41:35 -0400
commit6a4c6a02de9b45abe4c0f78c4f5d14d92d3359d6 (patch)
treea04920b212b8552602d48a978a9ae44441474a7c
parent6d1dcf7937ba3739d17eda614591d1f59ac0bf3a (diff)
use sockets for scriptlet/hook communication
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 <andrew.gregory.8@gmail.com>
-rw-r--r--lib/libalpm/util.c17
1 files 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 <errno.h>
#include <limits.h>
#include <sys/wait.h>
+#include <sys/socket.h>
#include <fnmatch.h>
#include <poll.h>
@@ -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;