Implement /proc/<pid>/exe

by adding proc_set/get_exe to the proc server, making
exec call proc_set_exe, and libps call proc_get_exe. procfs can then just
retrieve the information to make the "exe" symlink.

* hurd/process.defs (proc_set_exe, proc_get_exe): New RPCs.
* hurd/process_request.defs: Likewise.
* hurd/process_reply.defs: Add skips for proc_set_exe and proc_get_exe RPCs.
* proc/proc.h (struct proc): Add `exe' field.
* proc/info.c (S_proc_set_exe, S_proc_get_exe): New functions.
* proc/mgt.c (process_has_exited): Free p->exe.
(S_proc_child): Duplicate parent `exe' into child's `exe'.
* exec/exec.c (do_exec): Call proc_set_exe when a filename is available.
* libps/ps.h (struct proc_stat): Add `exe_vm_alloced', `exe', and `exe_len'
field.
(PSTAT_EXE): New macro.
(PSTAT_USER_BASE): Change value to make room.
(proc_stat_exe, proc_stat_exe_len): New macros.
* libps/procstat.c (proc_stat_set_flags): Handle PSTAT_EXE case by calling
proc_get_exe.
* libps/spec.c (ps_get_exe): New function.
(ps_exe_getter): New structure.
(ps_fmt_spec): Add "Exe" specification.
* procfs/process.c (process_file_symlink_make_node, process_file_gc_exe): New
functions.
(procfs_dir_entry): Add "exe" entry.
* startup/startup.c (launch_core_servers): Set exe paths for startup, auth,
proc, and fs servers.
(frob_kernel_process): Set exe path for kernel task.
(S_startup_essential_task): Set exe path for exec server.

1 files changed, 10 insertions, 0 deletions

diff --git a/libps/spec.c b/libps/spec.c
index 5e540f87..4760c431 100644
--- a/libps/spec.c
+++ b/libps/spec.c
@@ -358,6 +358,14 @@ ps_get_num_ports (struct proc_stat *ps)
 const struct ps_getter ps_num_ports_getter =
 {"num_ports", PSTAT_NUM_PORTS, (vf) ps_get_num_ports};
 
+static void
+ps_get_exe (struct proc_stat *ps, char **exe_p, int *exe_len_p)
+{
+  *exe_p = proc_stat_exe (ps);
+  *exe_len_p = proc_stat_exe_len (ps);
+}
+const struct ps_getter ps_exe_getter =
+{"exe", PSTAT_EXE, ps_get_exe};
 /* ---------------------------------------------------------------- */
 /* some printing functions */
 
@@ -1166,6 +1174,8 @@ static const struct ps_fmt_spec specs[] =
    &ps_zero_fills_getter,  ps_emit_int,	    ps_cmp_ints,   ps_nominal_zint},
   {"Ports",	0,	-5, -1, 0,
    &ps_num_ports_getter,       ps_emit_int,	    ps_cmp_ints,   0},
+  {"Exe",	0,	 0, -1, 0,
+   &ps_exe_getter,	   ps_emit_string,  ps_cmp_strings,ps_nominal_string},
   {0}
 };