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-rw-r--r--unix-socket.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/unix-socket.c b/unix-socket.c
new file mode 100644
index 0000000000..01f119f970
--- /dev/null
+++ b/unix-socket.c
@@ -0,0 +1,122 @@
+#include "cache.h"
+#include "unix-socket.h"
+
+static int unix_stream_socket(void)
+{
+ int fd = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (fd < 0)
+ die_errno("unable to create socket");
+ return fd;
+}
+
+static int chdir_len(const char *orig, int len)
+{
+ char *path = xmemdupz(orig, len);
+ int r = chdir(path);
+ free(path);
+ return r;
+}
+
+struct unix_sockaddr_context {
+ char orig_dir[PATH_MAX];
+};
+
+static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx)
+{
+ if (!ctx->orig_dir[0])
+ return;
+ /*
+ * If we fail, we can't just return an error, since we have
+ * moved the cwd of the whole process, which could confuse calling
+ * code. We are better off to just die.
+ */
+ if (chdir(ctx->orig_dir) < 0)
+ die("unable to restore original working directory");
+}
+
+static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path,
+ struct unix_sockaddr_context *ctx)
+{
+ int size = strlen(path) + 1;
+
+ ctx->orig_dir[0] = '\0';
+ if (size > sizeof(sa->sun_path)) {
+ const char *slash = find_last_dir_sep(path);
+ const char *dir;
+
+ if (!slash) {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+
+ dir = path;
+ path = slash + 1;
+ size = strlen(path) + 1;
+ if (size > sizeof(sa->sun_path)) {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+
+ if (!getcwd(ctx->orig_dir, sizeof(ctx->orig_dir))) {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ if (chdir_len(dir, slash - dir) < 0)
+ return -1;
+ }
+
+ memset(sa, 0, sizeof(*sa));
+ sa->sun_family = AF_UNIX;
+ memcpy(sa->sun_path, path, size);
+ return 0;
+}
+
+int unix_stream_connect(const char *path)
+{
+ int fd, saved_errno;
+ struct sockaddr_un sa;
+ struct unix_sockaddr_context ctx;
+
+ if (unix_sockaddr_init(&sa, path, &ctx) < 0)
+ return -1;
+ fd = unix_stream_socket();
+ if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
+ goto fail;
+ unix_sockaddr_cleanup(&ctx);
+ return fd;
+
+fail:
+ saved_errno = errno;
+ unix_sockaddr_cleanup(&ctx);
+ close(fd);
+ errno = saved_errno;
+ return -1;
+}
+
+int unix_stream_listen(const char *path)
+{
+ int fd, saved_errno;
+ struct sockaddr_un sa;
+ struct unix_sockaddr_context ctx;
+
+ if (unix_sockaddr_init(&sa, path, &ctx) < 0)
+ return -1;
+ fd = unix_stream_socket();
+
+ unlink(path);
+ if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
+ goto fail;
+
+ if (listen(fd, 5) < 0)
+ goto fail;
+
+ unix_sockaddr_cleanup(&ctx);
+ return fd;
+
+fail:
+ saved_errno = errno;
+ unix_sockaddr_cleanup(&ctx);
+ close(fd);
+ errno = saved_errno;
+ return -1;
+}