From 76c469910eef3574dd2235684533ba68a541e1e3 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sat, 14 Sep 2024 09:13:37 -0700
Subject: [PATCH] Added SDL_PROP_PROCESS_CREATE_BACKGROUND_BOOLEAN
---
include/SDL3/SDL_process.h | 12 ++-
src/misc/unix/SDL_sysurl.c | 85 ++++++++++-----------
src/process/SDL_process.c | 5 ++
src/process/SDL_sysprocess.h | 1 +
src/process/posix/SDL_posixprocess.c | 97 +++++++++++++++++++-----
src/process/windows/SDL_windowsprocess.c | 14 ++++
6 files changed, 145 insertions(+), 69 deletions(-)
diff --git a/include/SDL3/SDL_process.h b/include/SDL3/SDL_process.h
index 609c4c4df4ad9..2af0bdcc91ad4 100644
--- a/include/SDL3/SDL_process.h
+++ b/include/SDL3/SDL_process.h
@@ -175,6 +175,7 @@ typedef enum SDL_ProcessIO
* output of the process should be redirected into the standard output of
* the process. This property has no effect if
* `SDL_PROP_PROCESS_CREATE_STDERR_NUMBER` is set.
+ * - `SDL_PROP_PROCESS_CREATE_BACKGROUND_BOOLEAN`: true if the process should run in the background. In this case the default input and output is `SDL_PROCESS_STDIO_NULL` and the exitcode of the process is not available, and will always be 0.
*
* On POSIX platforms, wait() and waitpid(-1, ...) should not be called, and
* SIGCHLD should not be ignored or handled because those would prevent SDL
@@ -208,6 +209,7 @@ extern SDL_DECLSPEC SDL_Process *SDLCALL SDL_CreateProcessWithProperties(SDL_Pro
#define SDL_PROP_PROCESS_CREATE_STDERR_NUMBER "SDL.process.create.stderr_option"
#define SDL_PROP_PROCESS_CREATE_STDERR_POINTER "SDL.process.create.stderr_source"
#define SDL_PROP_PROCESS_CREATE_STDERR_TO_STDOUT_BOOLEAN "SDL.process.create.stderr_to_stdout"
+#define SDL_PROP_PROCESS_CREATE_BACKGROUND_BOOLEAN "SDL.process.create.background"
/**
* Get the properties associated with a process.
@@ -218,6 +220,7 @@ extern SDL_DECLSPEC SDL_Process *SDLCALL SDL_CreateProcessWithProperties(SDL_Pro
* - `SDL_PROP_PROCESS_STDIN_POINTER`: an SDL_IOStream that can be used to write input to the process, if it was created with `SDL_PROP_PROCESS_CREATE_STDIN_NUMBER` set to `SDL_PROCESS_STDIO_APP`.
* - `SDL_PROP_PROCESS_STDOUT_POINTER`: a non-blocking SDL_IOStream that can be used to read output from the process, if it was created with `SDL_PROP_PROCESS_CREATE_STDOUT_NUMBER` set to `SDL_PROCESS_STDIO_APP`.
* - `SDL_PROP_PROCESS_STDERR_POINTER`: a non-blocking SDL_IOStream that can be used to read error output from the process, if it was created with `SDL_PROP_PROCESS_CREATE_STDERR_NUMBER` set to `SDL_PROCESS_STDIO_APP`.
+ * - `SDL_PROP_PROCESS_BACKGROUND_BOOLEAN`: true if the process is running in the background.
*
* \param process the process to query.
* \returns a valid property ID on success or 0 on failure; call
@@ -232,10 +235,11 @@ extern SDL_DECLSPEC SDL_Process *SDLCALL SDL_CreateProcessWithProperties(SDL_Pro
*/
extern SDL_DECLSPEC SDL_PropertiesID SDL_GetProcessProperties(SDL_Process *process);
-#define SDL_PROP_PROCESS_PID_NUMBER "SDL.process.pid"
-#define SDL_PROP_PROCESS_STDIN_POINTER "SDL.process.stdin"
-#define SDL_PROP_PROCESS_STDOUT_POINTER "SDL.process.stdout"
-#define SDL_PROP_PROCESS_STDERR_POINTER "SDL.process.stderr"
+#define SDL_PROP_PROCESS_PID_NUMBER "SDL.process.pid"
+#define SDL_PROP_PROCESS_STDIN_POINTER "SDL.process.stdin"
+#define SDL_PROP_PROCESS_STDOUT_POINTER "SDL.process.stdout"
+#define SDL_PROP_PROCESS_STDERR_POINTER "SDL.process.stderr"
+#define SDL_PROP_PROCESS_BACKGROUND_BOOLEAN "SDL.process.background"
/**
* Read all the output from a process.
diff --git a/src/misc/unix/SDL_sysurl.c b/src/misc/unix/SDL_sysurl.c
index 681c0deccc12a..69517f1627208 100644
--- a/src/misc/unix/SDL_sysurl.c
+++ b/src/misc/unix/SDL_sysurl.c
@@ -35,51 +35,44 @@ extern char **environ;
bool SDL_SYS_OpenURL(const char *url)
{
- const pid_t pid1 = fork();
- if (pid1 == 0) { // child process
-#ifdef USE_POSIX_SPAWN
- pid_t pid2;
- const char *args[] = { "xdg-open", url, NULL };
- // Clear LD_PRELOAD so Chrome opens correctly when this application is launched by Steam
- SDL_unsetenv_unsafe("LD_PRELOAD");
- if (posix_spawnp(&pid2, args[0], NULL, NULL, (char **)args, environ) == 0) {
- // Child process doesn't wait for possibly-blocking grandchild.
- _exit(EXIT_SUCCESS);
- } else {
- _exit(EXIT_FAILURE);
- }
-#else
- pid_t pid2;
- // Clear LD_PRELOAD so Chrome opens correctly when this application is launched by Steam
- SDL_unsetenv_unsafe("LD_PRELOAD");
- // Notice this is vfork and not fork!
- pid2 = vfork();
- if (pid2 == 0) { // Grandchild process will try to launch the url
- execlp("xdg-open", "xdg-open", url, NULL);
- _exit(EXIT_FAILURE);
- } else if (pid2 < 0) { // There was an error forking
- _exit(EXIT_FAILURE);
- } else {
- // Child process doesn't wait for possibly-blocking grandchild.
- _exit(EXIT_SUCCESS);
- }
-#endif // USE_POSIX_SPAWN
- } else if (pid1 < 0) {
- return SDL_SetError("fork() failed: %s", strerror(errno));
- } else {
- int status;
- if (waitpid(pid1, &status, 0) == pid1) {
- if (WIFEXITED(status)) {
- if (WEXITSTATUS(status) == 0) {
- return true; // success!
- } else {
- return SDL_SetError("xdg-open reported error or failed to launch: %d", WEXITSTATUS(status));
- }
- } else {
- return SDL_SetError("xdg-open failed for some reason");
- }
- } else {
- return SDL_SetError("Waiting on xdg-open failed: %s", strerror(errno));
- }
+ SDL_Environment *env = NULL;
+ char **process_env = NULL;
+ const char *process_args[] = { "xdg-open", url, NULL };
+ SDL_Process *process = NULL;
+ bool result = false;
+
+ env = SDL_CreateEnvironment(SDL_FALSE);
+ if (!env) {
+ goto done;
+ }
+
+ // Clear LD_PRELOAD so Chrome opens correctly when this application is launched by Steam
+ SDL_UnsetEnvironmentVariable(env, "LD_PRELOAD");
+
+ process_env = SDL_GetEnvironmentVariables(env);
+ if (!process_env) {
+ goto done;
}
+
+ SDL_PropertiesID props = SDL_CreateProperties();
+ if (!props) {
+ goto done;
+ }
+ SDL_SetPointerProperty(props, SDL_PROP_PROCESS_CREATE_ARGS_POINTER, process_args);
+ SDL_SetPointerProperty(props, SDL_PROP_PROCESS_CREATE_ENVIRONMENT_POINTER, process_env);
+ SDL_SetBooleanProperty(props, SDL_PROP_PROCESS_CREATE_BACKGROUND_BOOLEAN, true);
+ process = SDL_CreateProcessWithProperties(props);
+ SDL_DestroyProperties(props);
+ if (!process) {
+ goto done;
+ }
+
+ result = true;
+
+done:
+ SDL_free(process_env);
+ SDL_DestroyEnvironment(env);
+ SDL_DestroyProcess(process);
+
+ return result;
}
diff --git a/src/process/SDL_process.c b/src/process/SDL_process.c
index 10187e4aa934b..4f0ca27120f60 100644
--- a/src/process/SDL_process.c
+++ b/src/process/SDL_process.c
@@ -54,12 +54,14 @@ SDL_Process *SDL_CreateProcessWithProperties(SDL_PropertiesID props)
if (!process) {
return NULL;
}
+ process->background = SDL_GetBooleanProperty(props, SDL_PROP_PROCESS_CREATE_BACKGROUND_BOOLEAN, false);
process->props = SDL_CreateProperties();
if (!process->props) {
SDL_DestroyProcess(process);
return NULL;
}
+ SDL_SetBooleanProperty(process->props, SDL_PROP_PROCESS_BACKGROUND_BOOLEAN, process->background);
if (!SDL_SYS_CreateProcessWithProperties(process, props)) {
SDL_DestroyProcess(process);
@@ -180,6 +182,9 @@ SDL_bool SDL_WaitProcess(SDL_Process *process, SDL_bool block, int *exitcode)
if (SDL_SYS_WaitProcess(process, block, &process->exitcode)) {
process->alive = false;
if (exitcode) {
+ if (process->background) {
+ process->exitcode = 0;
+ }
*exitcode = process->exitcode;
}
return true;
diff --git a/src/process/SDL_sysprocess.h b/src/process/SDL_sysprocess.h
index bcc8be4dcec9e..fbea4a679f6e2 100644
--- a/src/process/SDL_sysprocess.h
+++ b/src/process/SDL_sysprocess.h
@@ -25,6 +25,7 @@ typedef struct SDL_ProcessData SDL_ProcessData;
struct SDL_Process
{
bool alive;
+ bool background;
int exitcode;
SDL_PropertiesID props;
SDL_ProcessData *internal;
diff --git a/src/process/posix/SDL_posixprocess.c b/src/process/posix/SDL_posixprocess.c
index 35cc6a5dbd4fa..3aaef3cef27e8 100644
--- a/src/process/posix/SDL_posixprocess.c
+++ b/src/process/posix/SDL_posixprocess.c
@@ -137,6 +137,19 @@ bool SDL_SYS_CreateProcessWithProperties(SDL_Process *process, SDL_PropertiesID
goto posix_spawn_fail_attr;
}
+ // Background processes don't have access to the terminal
+ if (process->background) {
+ if (stdin_option == SDL_PROCESS_STDIO_INHERITED) {
+ stdin_option = SDL_PROCESS_STDIO_NULL;
+ }
+ if (stdout_option == SDL_PROCESS_STDIO_INHERITED) {
+ stdout_option = SDL_PROCESS_STDIO_NULL;
+ }
+ if (stderr_option == SDL_PROCESS_STDIO_INHERITED) {
+ stderr_option = SDL_PROCESS_STDIO_NULL;
+ }
+ }
+
switch (stdin_option) {
case SDL_PROCESS_STDIO_REDIRECT:
if (!GetStreamFD(props, SDL_PROP_PROCESS_CREATE_STDIN_POINTER, &fd)) {
@@ -276,9 +289,38 @@ bool SDL_SYS_CreateProcessWithProperties(SDL_Process *process, SDL_PropertiesID
}
// Spawn the new process
- if (posix_spawnp(&data->pid, args[0], &fa, &attr, args, env) != 0) {
- SDL_SetError("posix_spawn failed: %s", strerror(errno));
- goto posix_spawn_fail_all;
+ if (process->background) {
+ int status = -1;
+ pid_t pid = vfork();
+ switch (pid) {
+ case -1:
+ SDL_SetError("vfork() failed: %s", strerror(errno));
+ goto posix_spawn_fail_all;
+
+ case 0:
+ // Detach from the terminal and launch the process
+ setsid();
+ if (posix_spawnp(&data->pid, args[0], &fa, &attr, args, env) != 0) {
+ _exit(errno);
+ }
+ _exit(0);
+
+ default:
+ if (waitpid(pid, &status, 0) < 0) {
+ SDL_SetError("waitpid() failed: %s", strerror(errno));
+ goto posix_spawn_fail_all;
+ }
+ if (status != 0) {
+ SDL_SetError("posix_spawn() failed: %s", strerror(status));
+ goto posix_spawn_fail_all;
+ }
+ break;
+ }
+ } else {
+ if (posix_spawnp(&data->pid, args[0], &fa, &attr, args, env) != 0) {
+ SDL_SetError("posix_spawn() failed: %s", strerror(errno));
+ goto posix_spawn_fail_all;
+ }
}
SDL_SetNumberProperty(process->props, SDL_PROP_PROCESS_PID_NUMBER, data->pid);
@@ -353,26 +395,43 @@ bool SDL_SYS_KillProcess(SDL_Process *process, SDL_bool force)
bool SDL_SYS_WaitProcess(SDL_Process *process, SDL_bool block, int *exitcode)
{
int wstatus = 0;
- int ret = waitpid(process->internal->pid, &wstatus, block ? 0 : WNOHANG);
+ int ret;
+ pid_t pid = process->internal->pid;
+
+ if (process->background) {
+ // We can't wait on the status, so we'll poll to see if it's alive
+ if (block) {
+ while (kill(pid, 0) == 0) {
+ SDL_Delay(10);
+ }
+ } else {
+ if (kill(pid, 0) == 0) {
+ return false;
+ }
+ }
+ *exitcode = 0;
+ return true;
+ } else {
+ ret = waitpid(pid, &wstatus, block ? 0 : WNOHANG);
+ if (ret < 0) {
+ return SDL_SetError("Could not waitpid(): %s", strerror(errno));
+ }
- if (ret < 0) {
- return SDL_SetError("Could not waitpid(): %s", strerror(errno));
- }
+ if (ret == 0) {
+ SDL_ClearError();
+ return false;
+ }
- if (ret == 0) {
- SDL_ClearError();
- return false;
- }
+ if (WIFEXITED(wstatus)) {
+ *exitcode = WEXITSTATUS(wstatus);
+ } else if (WIFSIGNALED(wstatus)) {
+ *exitcode = -WTERMSIG(wstatus);
+ } else {
+ *exitcode = -255;
+ }
- if (WIFEXITED(wstatus)) {
- *exitcode = WEXITSTATUS(wstatus);
- } else if (WIFSIGNALED(wstatus)) {
- *exitcode = -WTERMSIG(wstatus);
- } else {
- *exitcode = -255;
+ return true;
}
-
- return true;
}
void SDL_SYS_DestroyProcess(SDL_Process *process)
diff --git a/src/process/windows/SDL_windowsprocess.c b/src/process/windows/SDL_windowsprocess.c
index 75293346253da..3820a578cb068 100644
--- a/src/process/windows/SDL_windowsprocess.c
+++ b/src/process/windows/SDL_windowsprocess.c
@@ -232,6 +232,20 @@ bool SDL_SYS_CreateProcessWithProperties(SDL_Process *process, SDL_PropertiesID
security_attributes.bInheritHandle = TRUE;
security_attributes.lpSecurityDescriptor = NULL;
+ // Background processes don't have access to the terminal
+ // This isn't necessary on Windows, but we keep the same behavior as the POSIX implementation.
+ if (process->background) {
+ if (stdin_option == SDL_PROCESS_STDIO_INHERITED) {
+ stdin_option = SDL_PROCESS_STDIO_NULL;
+ }
+ if (stdout_option == SDL_PROCESS_STDIO_INHERITED) {
+ stdout_option = SDL_PROCESS_STDIO_NULL;
+ }
+ if (stderr_option == SDL_PROCESS_STDIO_INHERITED) {
+ stderr_option = SDL_PROCESS_STDIO_NULL;
+ }
+ }
+
switch (stdin_option) {
case SDL_PROCESS_STDIO_REDIRECT:
if (!SetupRedirect(props, SDL_PROP_PROCESS_CREATE_STDIN_POINTER, &startup_info.hStdInput)) {