attach: split attach_context into allocation and initialization

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index e69338f0ac700ef9673b9e8b76bf41857daae833..9e4ff43cbad47549a5aef8e3f7d25057190cf3d3 100644 (file)
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -65,11 +65,15 @@ struct attach_context {
        struct lsm_ops *lsm_ops;
 };
 
-static struct attach_context *get_attach_context(pid_t pid)
+static struct attach_context *alloc_attach_context(void)
+{
+       return zalloc(sizeof(struct attach_context));
+}
+
+static int get_attach_context(struct attach_context *ctx, pid_t pid)
 {
        __do_free char *line = NULL;
        __do_fclose FILE *proc_file = NULL;
-       __do_free struct attach_context *info = NULL;
        int ret;
        bool found;
        char proc_fn[LXC_PROC_STATUS_LEN];
@@ -78,20 +82,16 @@ static struct attach_context *get_attach_context(pid_t pid)
        /* Read capabilities. */
        ret = snprintf(proc_fn, LXC_PROC_STATUS_LEN, "/proc/%d/status", pid);
        if (ret < 0 || ret >= LXC_PROC_STATUS_LEN)
-               return NULL;
+               return -EIO;
 
        proc_file = fopen(proc_fn, "re");
        if (!proc_file)
-               return log_error_errno(NULL, errno, "Failed to open %s", proc_fn);
-
-       info = zalloc(sizeof(*info));
-       if (!info)
-               return NULL;
+               return log_error_errno(-errno, errno, "Failed to open %s", proc_fn);
 
        found = false;
 
        while (getline(&line, &line_bufsz, proc_file) != -1) {
-               ret = sscanf(line, "CapBnd: %llx", &info->capability_mask);
+               ret = sscanf(line, "CapBnd: %llx", &ctx->capability_mask);
                if (ret != EOF && ret == 1) {
                        found = true;
                        break;
@@ -99,16 +99,16 @@ static struct attach_context *get_attach_context(pid_t pid)
        }
 
        if (!found)
-               return log_error_errno(NULL, ENOENT, "Failed to read capability bounding set from %s", proc_fn);
+               return log_error_errno(-ENOENT, ENOENT, "Failed to read capability bounding set from %s", proc_fn);
 
-       info->lsm_ops = lsm_init();
+       ctx->lsm_ops = lsm_init();
 
-       info->lsm_label = info->lsm_ops->process_label_get(info->lsm_ops, pid);
-       info->ns_inherited = 0;
+       ctx->lsm_label = ctx->lsm_ops->process_label_get(ctx->lsm_ops, pid);
+       ctx->ns_inherited = 0;
        for (int i = 0; i < LXC_NS_MAX; i++)
-               info->ns_fd[i] = -EBADF;
+               ctx->ns_fd[i] = -EBADF;
 
-       return move_ptr(info);
+       return 0;
 }
 
 static inline void lxc_proc_close_ns_fd(struct attach_context *ctx)
@@ -996,8 +996,14 @@ int lxc_attach(struct lxc_container *container, lxc_attach_exec_t exec_function,
                return log_error(-1, "Failed to get init pid");
        }
 
-       ctx = get_attach_context(init_pid);
+       ctx = alloc_attach_context();
        if (!ctx) {
+               lxc_container_put(container);
+               return log_error_errno(-ENOMEM, ENOMEM, "Failed to allocate attach context");
+       }
+
+       ret = get_attach_context(ctx, init_pid);
+       if (ret) {
                ERROR("Failed to get context of init process: %ld", (long)init_pid);
                lxc_container_put(container);
                return -1;