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[PATCH v3 04/11] {linux,bsd}-user: Pass pid to fork_end()

Ilya Leoshkevich posted 11 patches 8 months, 2 weeks ago
Maintainers: Warner Losh <imp@bsdimp.com>, Kyle Evans <kevans@freebsd.org>, "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Laurent Vivier <laurent@vivier.eu>
There is a newer version of this series
[PATCH v3 04/11] {linux,bsd}-user: Pass pid to fork_end()
Posted by Ilya Leoshkevich 8 months, 2 weeks ago 
The upcoming follow-fork-mode child support requires knowing the child
pid. Pass it down.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 bsd-user/freebsd/os-proc.h  | 6 +++---
 bsd-user/main.c             | 4 +++-
 bsd-user/qemu.h             | 2 +-
 linux-user/main.c           | 4 +++-
 linux-user/syscall.c        | 6 +++---
 linux-user/user-internals.h | 2 +-
 6 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/bsd-user/freebsd/os-proc.h b/bsd-user/freebsd/os-proc.h
index d6418780344..3003c8cb637 100644
--- a/bsd-user/freebsd/os-proc.h
+++ b/bsd-user/freebsd/os-proc.h
@@ -208,7 +208,7 @@ static inline abi_long do_freebsd_fork(void *cpu_env)
      */
     set_second_rval(cpu_env, child_flag);
 
-    fork_end(child_flag);
+    fork_end(ret);
 
     return ret;
 }
@@ -252,7 +252,7 @@ static inline abi_long do_freebsd_rfork(void *cpu_env, abi_long flags)
      * value: 0 for parent process, 1 for child process.
      */
     set_second_rval(cpu_env, child_flag);
-    fork_end(child_flag);
+    fork_end(ret);
 
     return ret;
 
@@ -285,7 +285,7 @@ static inline abi_long do_freebsd_pdfork(void *cpu_env, abi_ulong target_fdp,
      * value: 0 for parent process, 1 for child process.
      */
     set_second_rval(cpu_env, child_flag);
-    fork_end(child_flag);
+    fork_end(ret);
 
     return ret;
 }
diff --git a/bsd-user/main.c b/bsd-user/main.c
index bfe6888ea89..bc233a85cef 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -109,8 +109,10 @@ void fork_start(void)
     gdbserver_fork_start();
 }
 
-void fork_end(int child)
+void fork_end(abi_long pid)
 {
+    int child = pid == 0;
+
     if (child) {
         CPUState *cpu, *next_cpu;
         /*
diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index dc842fffa7d..2414a87559b 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -180,7 +180,7 @@ void cpu_loop(CPUArchState *env);
 char *target_strerror(int err);
 int get_osversion(void);
 void fork_start(void);
-void fork_end(int child);
+void fork_end(abi_long pid);
 
 #include "qemu/log.h"
 
diff --git a/linux-user/main.c b/linux-user/main.c
index 8c7bea1c631..f1a0267816b 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -147,8 +147,10 @@ void fork_start(void)
     gdbserver_fork_start();
 }
 
-void fork_end(int child)
+void fork_end(abi_long pid)
 {
+    int child = pid == 0;
+
     qemu_plugin_user_postfork(child);
     mmap_fork_end(child);
     if (child) {
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e384e142489..572d8e0ed1c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6669,7 +6669,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         if (ret == 0) {
             /* Child Process.  */
             cpu_clone_regs_child(env, newsp, flags);
-            fork_end(1);
+            fork_end(ret);
             /* There is a race condition here.  The parent process could
                theoretically read the TID in the child process before the child
                tid is set.  This would require using either ptrace
@@ -6700,8 +6700,8 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
                 }
 #endif
                 put_user_u32(pid_fd, parent_tidptr);
-                }
-            fork_end(0);
+            }
+            fork_end(ret);
         }
         g_assert(!cpu_in_exclusive_context(cpu));
     }
diff --git a/linux-user/user-internals.h b/linux-user/user-internals.h
index c63ef45fc78..9014014d920 100644
--- a/linux-user/user-internals.h
+++ b/linux-user/user-internals.h
@@ -71,7 +71,7 @@ const char *target_strerror(int err);
 int get_osversion(void);
 void init_qemu_uname_release(void);
 void fork_start(void);
-void fork_end(int child);
+void fork_end(abi_long pid);
 
 /**
  * probe_guest_base:
-- 
2.43.0
Re: [PATCH v3 04/11] {linux,bsd}-user: Pass pid to fork_end()
Posted by Richard Henderson 8 months, 2 weeks ago 
On 2/16/24 03:05, Ilya Leoshkevich wrote:
> diff --git a/linux-user/user-internals.h b/linux-user/user-internals.h
> index c63ef45fc78..9014014d920 100644
> --- a/linux-user/user-internals.h
> +++ b/linux-user/user-internals.h
> @@ -71,7 +71,7 @@ const char *target_strerror(int err);
>   int get_osversion(void);
>   void init_qemu_uname_release(void);
>   void fork_start(void);
> -void fork_end(int child);
> +void fork_end(abi_long pid);

Use pid_t.  There's nothing guest specific about the value here.

Otherwise,
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~
Re: [PATCH v3 04/11] {linux,bsd}-user: Pass pid to fork_end()
Posted by Alex Bennée 8 months, 2 weeks ago 
Ilya Leoshkevich <iii@linux.ibm.com> writes:

> The upcoming follow-fork-mode child support requires knowing the child
> pid. Pass it down.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  bsd-user/freebsd/os-proc.h  | 6 +++---
>  bsd-user/main.c             | 4 +++-
>  bsd-user/qemu.h             | 2 +-
>  linux-user/main.c           | 4 +++-
>  linux-user/syscall.c        | 6 +++---
>  linux-user/user-internals.h | 2 +-
>  6 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/bsd-user/freebsd/os-proc.h b/bsd-user/freebsd/os-proc.h
> index d6418780344..3003c8cb637 100644
> --- a/bsd-user/freebsd/os-proc.h
> +++ b/bsd-user/freebsd/os-proc.h
> @@ -208,7 +208,7 @@ static inline abi_long do_freebsd_fork(void *cpu_env)
>       */
>      set_second_rval(cpu_env, child_flag);
>  
> -    fork_end(child_flag);
> +    fork_end(ret);
>  
>      return ret;
>  }
> @@ -252,7 +252,7 @@ static inline abi_long do_freebsd_rfork(void *cpu_env, abi_long flags)
>       * value: 0 for parent process, 1 for child process.
>       */
>      set_second_rval(cpu_env, child_flag);
> -    fork_end(child_flag);
> +    fork_end(ret);
>  
>      return ret;
>  
> @@ -285,7 +285,7 @@ static inline abi_long do_freebsd_pdfork(void *cpu_env, abi_ulong target_fdp,
>       * value: 0 for parent process, 1 for child process.
>       */
>      set_second_rval(cpu_env, child_flag);
> -    fork_end(child_flag);
> +    fork_end(ret);
>  
>      return ret;
>  }
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index bfe6888ea89..bc233a85cef 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -109,8 +109,10 @@ void fork_start(void)
>      gdbserver_fork_start();
>  }
>  
> -void fork_end(int child)
> +void fork_end(abi_long pid)
>  {
> +    int child = pid == 0;
> +
>      if (child) {
>          CPUState *cpu, *next_cpu;
>          /*
> diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
> index dc842fffa7d..2414a87559b 100644
> --- a/bsd-user/qemu.h
> +++ b/bsd-user/qemu.h
> @@ -180,7 +180,7 @@ void cpu_loop(CPUArchState *env);
>  char *target_strerror(int err);
>  int get_osversion(void);
>  void fork_start(void);
> -void fork_end(int child);
> +void fork_end(abi_long pid);
>  
>  #include "qemu/log.h"
>  
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 8c7bea1c631..f1a0267816b 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -147,8 +147,10 @@ void fork_start(void)
>      gdbserver_fork_start();
>  }
>  
> -void fork_end(int child)
> +void fork_end(abi_long pid)
>  {
> +    int child = pid == 0;
> +

The intent is clearer if we make it a bool:

  bool child = pid == 0;

Otherwise:

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Patchew 2.1-devel-b67e4c2

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