Re: [PATCH 2/5] Assume KERN_PROC_PATHNAME is present on FreeBSD hosts.

[Simon Marchi <simark@simark.ca>]

On 2020-07-20 1:31 p.m., John Baldwin wrote:
> FreeBSD kernels have included this sysctl since 6.0 release.  The most
> recent release without support is 5.5 which was released in May of
> 2006.
> 
> gdb/ChangeLog:
> 
> 	* fbsd-nat.c (fbsd_nat_target::pid_to_exec_file): Always use
> 	sysctl and remove procfs fallback.
> ---
>  gdb/ChangeLog  |  5 +++++
>  gdb/fbsd-nat.c | 13 -------------
>  2 files changed, 5 insertions(+), 13 deletions(-)
> 
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index 687d9aede5..0339083f1a 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,8 @@
> +2020-07-20  John Baldwin  <jhb@FreeBSD.org>
> +
> +	* fbsd-nat.c (fbsd_nat_target::pid_to_exec_file): Always use
> +	sysctl and remove procfs fallback.
> +
>  2020-07-20  John Baldwin  <jhb@FreeBSD.org>
>  
>  	* fbsd-nat.c: Assume PT_LWPINFO is always defined.
> diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
> index fc7136a97c..6193e0fbde 100644
> --- a/gdb/fbsd-nat.c
> +++ b/gdb/fbsd-nat.c
> @@ -53,11 +53,7 @@
>  char *
>  fbsd_nat_target::pid_to_exec_file (int pid)
>  {
> -  ssize_t len;
>    static char buf[PATH_MAX];
> -  char name[PATH_MAX];
> -
> -#ifdef KERN_PROC_PATHNAME
>    size_t buflen;
>    int mib[4];
>  
> @@ -71,15 +67,6 @@ fbsd_nat_target::pid_to_exec_file (int pid)
>         for processes without an associated executable such as kernel
>         processes.  */
>      return buflen == 0 ? NULL : buf;
> -#endif
> -
> -  xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
> -  len = readlink (name, buf, PATH_MAX - 1);
> -  if (len != -1)
> -    {
> -      buf[len] = '\0';
> -      return buf;
> -    }
>  
>    return NULL;
>  }
> -- 
> 2.25.1
> 

Note that the way the code is currently written allows the readlink method to be used
if the sysctl method fails at runtime.  We probably don't care, but I thought I'd raise
it just in case.

Simon