keep track of bg tasks for clean up
This commit is contained in:
parent
1282a75db9
commit
ccbaaad72b
100
src/camera.c
100
src/camera.c
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@ -6,9 +6,11 @@
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#include <stdio.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#define MAX_VIDEO_BUFFERS 20
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#define MAX_BG_TASKS 8
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static const char *pixel_format_names[MP_PIXEL_FMT_MAX] = {
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"unsupported", "BGGR8", "GBRG8", "GRBG8", "RGGB8", "BGGR10P",
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@ -219,6 +221,9 @@ struct _MPCamera {
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struct video_buffer buffers[MAX_VIDEO_BUFFERS];
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uint32_t num_buffers;
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// keeping track of background task child-PIDs for cleanup code
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int child_bg_pids[MAX_BG_TASKS];
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bool use_mplane;
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};
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@ -250,12 +255,15 @@ mp_camera_new(int video_fd, int subdev_fd)
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camera->has_set_mode = false;
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camera->num_buffers = 0;
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camera->use_mplane = use_mplane;
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memset(camera->child_bg_pids, 0, sizeof(camera->child_bg_pids[0]) * MAX_BG_TASKS);
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return camera;
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}
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void
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mp_camera_free(MPCamera *camera)
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{
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mp_camera_wait_bg_tasks(camera);
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g_warn_if_fail(camera->num_buffers == 0);
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if (camera->num_buffers != 0) {
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mp_camera_stop_capture(camera);
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@ -264,6 +272,83 @@ mp_camera_free(MPCamera *camera)
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free(camera);
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}
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void
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mp_camera_add_bg_task(MPCamera *camera, pid_t pid)
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{
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int status;
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while (true) {
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for (size_t i = 0; i < MAX_BG_TASKS; ++i) {
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if (camera->child_bg_pids[i] == 0) {
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camera->child_bg_pids[i] = pid;
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return;
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} else {
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// error == -1, still running == 0
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if (waitpid(camera->child_bg_pids[i], &status, WNOHANG) <= 0)
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continue; // consider errored wait still running
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if (WIFEXITED(status)) {
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// replace exited
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camera->child_bg_pids[i] = pid;
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return;
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}
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}
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}
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// wait for any status change on child processes
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pid_t changed = waitpid(-1, &status, 0);
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if (WIFEXITED(status)) {
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// some child exited
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for (size_t i = 0; i < MAX_BG_TASKS; ++i) {
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if (camera->child_bg_pids[i] == changed) {
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camera->child_bg_pids[i] = pid;
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return;
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}
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}
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}
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// no luck, repeat and check if something exited maybe
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}
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}
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void
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mp_camera_wait_bg_tasks(MPCamera *camera)
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{
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for (size_t i = 0; i < MAX_BG_TASKS; ++i) {
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if (camera->child_bg_pids[i] != 0) {
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// ignore errors
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waitpid(camera->child_bg_pids[i], NULL, 0);
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}
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}
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}
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bool
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mp_camera_check_task_complete(MPCamera *camera, pid_t pid)
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{
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// this method is potentially unsafe because pid could already be reused at
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// this point, but extremely unlikely so we won't implement this.
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int status;
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if (pid == 0)
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return true;
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// ignore errors (-1), no exit == 0
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int pidchange = waitpid(pid, &status, WNOHANG);
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if (pidchange == -1) // error or exists and runs
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return false;
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if (WIFEXITED(status)) {
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for (size_t i = 0; i < MAX_BG_TASKS; ++i) {
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if (camera->child_bg_pids[i] == pid) {
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camera->child_bg_pids[i] = 0;
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break;
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}
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}
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return true;
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} else {
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return false;
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}
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}
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bool
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mp_camera_is_subdev(MPCamera *camera)
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{
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@ -1178,7 +1263,7 @@ control_impl_int32(MPCamera *camera, uint32_t id, int request, int32_t *value)
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return true;
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}
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void
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pid_t
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mp_camera_control_set_int32_bg(MPCamera *camera, uint32_t id, int32_t v)
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{
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struct v4l2_ext_control ctrl = {};
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@ -1195,8 +1280,15 @@ mp_camera_control_set_int32_bg(MPCamera *camera, uint32_t id, int32_t v)
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int fd = control_fd(camera);
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// fork only after all the memory has been read
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if (fork() != 0)
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return; // discard errors, nothing to do in parent process
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pid_t pid = fork();
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if (pid == -1) {
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return 0; // discard errors, nothing to do in parent process
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} else if (pid != 0) {
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// parent process adding pid to wait list (to clear zombie processes)
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mp_camera_add_bg_task(camera, pid);
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return pid;
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}
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// ignore errors
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xioctl(fd, VIDIOC_S_EXT_CTRLS, &ctrls);
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// exit without calling exit handlers
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@ -1247,7 +1339,7 @@ mp_camera_control_get_bool(MPCamera *camera, uint32_t id)
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return v;
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}
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void
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pid_t
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mp_camera_control_set_bool_bg(MPCamera *camera, uint32_t id, bool v)
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{
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int32_t value = v;
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@ -1,6 +1,7 @@
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#pragma once
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#include <linux/v4l2-subdev.h>
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#include <sys/wait.h>
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#include <stdbool.h>
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#include <stdint.h>
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@ -56,6 +57,10 @@ typedef struct _MPCamera MPCamera;
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MPCamera *mp_camera_new(int video_fd, int subdev_fd);
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void mp_camera_free(MPCamera *camera);
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void mp_camera_add_bg_task(MPCamera *camera, pid_t pid);
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void mp_camera_wait_bg_tasks(MPCamera *camera);
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bool mp_camera_check_task_complete(MPCamera *camera, pid_t pid);
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bool mp_camera_is_subdev(MPCamera *camera);
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int mp_camera_get_video_fd(MPCamera *camera);
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int mp_camera_get_subdev_fd(MPCamera *camera);
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@ -112,10 +117,10 @@ bool mp_camera_control_try_int32(MPCamera *camera, uint32_t id, int32_t *v);
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bool mp_camera_control_set_int32(MPCamera *camera, uint32_t id, int32_t v);
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int32_t mp_camera_control_get_int32(MPCamera *camera, uint32_t id);
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// set the value in the background, discards result
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void mp_camera_control_set_int32_bg(MPCamera *camera, uint32_t id, int32_t v);
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pid_t mp_camera_control_set_int32_bg(MPCamera *camera, uint32_t id, int32_t v);
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bool mp_camera_control_try_bool(MPCamera *camera, uint32_t id, bool *v);
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bool mp_camera_control_set_bool(MPCamera *camera, uint32_t id, bool v);
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bool mp_camera_control_get_bool(MPCamera *camera, uint32_t id);
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// set the value in the background, discards result
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void mp_camera_control_set_bool_bg(MPCamera *camera, uint32_t id, bool v);
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pid_t mp_camera_control_set_bool_bg(MPCamera *camera, uint32_t id, bool v);
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