1 files changed, 109 insertions, 0 deletions
diff --git a/spawn/spawn.h b/spawn/spawn.h
new file mode 100644
index 00000000..34b2632e
--- /dev/null
+++ b/spawn/spawn.h
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_SPAWN_H
+#define NETDATA_SPAWN_H 1
+
+#include "../daemon/common.h"
+
+#define SPAWN_SERVER_COMMAND_LINE_ARGUMENT "--special-spawn-server"
+
+typedef enum spawn_protocol {
+    SPAWN_PROT_EXEC_CMD = 0,
+    SPAWN_PROT_SPAWN_RESULT,
+    SPAWN_PROT_CMD_EXIT_STATUS
+} spawn_prot_t;
+
+struct spawn_prot_exec_cmd {
+    uint16_t command_length;
+    char command_to_run[];
+};
+
+struct spawn_prot_spawn_result {
+    pid_t exec_pid; /* 0 if failed to spawn */
+    time_t exec_run_timestamp; /* time of successfully spawning the command */
+};
+
+struct spawn_prot_cmd_exit_status {
+    int exec_exit_status;
+};
+
+struct spawn_prot_header {
+    spawn_prot_t opcode;
+    void *handle;
+};
+
+#undef SPAWN_DEBUG /* define to enable debug prints */
+
+#define SPAWN_MAX_OUTSTANDING (32768)
+
+#define SPAWN_CMD_PROCESSED         0x00000001
+#define SPAWN_CMD_IN_PROGRESS       0x00000002
+#define SPAWN_CMD_FAILED_TO_SPAWN   0x00000004
+#define SPAWN_CMD_DONE              0x00000008
+
+struct spawn_cmd_info {
+    avl avl;
+
+    /* concurrency control per command */
+    uv_mutex_t mutex;
+    uv_cond_t cond; /* users block here until command has finished */
+
+    uint64_t serial;
+    char *command_to_run;
+    int exit_status;
+    pid_t pid;
+    unsigned long flags;
+    time_t exec_run_timestamp; /* time of successfully spawning the command */
+};
+
+/* spawn command queue */
+struct spawn_queue {
+    avl_tree_type cmd_tree;
+
+    /* concurrency control of command queue */
+    uv_mutex_t mutex;
+    uv_cond_t cond;
+
+    volatile unsigned size;
+    uint64_t latest_serial;
+};
+
+struct write_context {
+    uv_write_t write_req;
+    struct spawn_prot_header header;
+    struct spawn_prot_cmd_exit_status exit_status;
+    struct spawn_prot_spawn_result spawn_result;
+    struct spawn_prot_exec_cmd payload;
+};
+
+extern int spawn_thread_error;
+extern int spawn_thread_shutdown;
+extern uv_async_t spawn_async;
+
+void spawn_init(void);
+void spawn_server(void);
+void spawn_client(void *arg);
+void destroy_spawn_cmd(struct spawn_cmd_info *cmdinfo);
+uint64_t spawn_enq_cmd(char *command_to_run);
+void spawn_wait_cmd(uint64_t serial, int *exit_status, time_t *exec_run_timestamp);
+void spawn_deq_cmd(struct spawn_cmd_info *cmdinfo);
+struct spawn_cmd_info *spawn_get_unprocessed_cmd(void);
+int create_spawn_server(uv_loop_t *loop, uv_pipe_t *spawn_channel, uv_process_t *process);
+
+/*
+ * Copies from the source buffer to the protocol buffer. It advances the source buffer by the amount copied. It
+ * subtracts the amount copied from the source length.
+ */
+static inline void copy_to_prot_buffer(char *prot_buffer, unsigned *prot_buffer_len, unsigned max_to_copy,
+                                       char **source, unsigned *source_len)
+{
+    unsigned to_copy;
+
+    to_copy = MIN(max_to_copy, *source_len);
+    memcpy(prot_buffer + *prot_buffer_len, *source, to_copy);
+    *prot_buffer_len += to_copy;
+    *source += to_copy;
+    *source_len -= to_copy;
+}
+
+#endif //NETDATA_SPAWN_H