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.

3 files changed, 46 insertions, 0 deletions

diff --git a/proc/info.c b/proc/info.c
index 3c1bf6d3..6ab9f3fa 100644
--- a/proc/info.c
+++ b/proc/info.c
@@ -24,6 +24,7 @@
 #include <sys/mman.h>
 #include <hurd/hurd_types.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/resource.h>
@@ -1017,3 +1018,43 @@ S_proc_getnports (struct proc *callerp,
 
   return err;
 }
+
+/* Implement proc_set_path as described in <hurd/process.defs>. */
+kern_return_t
+S_proc_set_exe (struct proc *p,
+	        char *path)
+{
+  char *copy;
+
+  if (!p)
+    return EOPNOTSUPP;
+
+  copy = strdup(path);
+  if (! copy)
+    return ENOMEM;
+
+  free(p->exe);
+  p->exe = copy;
+  return 0;
+}
+
+/* Implement proc_get_path as described in <hurd/process.defs>. */
+kern_return_t
+S_proc_get_exe (struct proc *callerp,
+		pid_t pid,
+		char *path)
+{
+  struct proc *p = pid_find (pid);
+
+  /* No need to check CALLERP here; we don't use it. */
+
+  if (!p)
+    return ESRCH;
+
+  if (p->exe)
+    snprintf (path, 1024 /* XXX */, "%s", p->exe);
+  else
+    path[0] = 0;
+  return 0;
+}
+
diff --git a/proc/mgt.c b/proc/mgt.c
index 354f3784..d92bf528 100644
--- a/proc/mgt.c
+++ b/proc/mgt.c
@@ -223,6 +223,8 @@ S_proc_child (struct proc *parentp,
       childp->start_code = parentp->start_code;
       childp->end_code = parentp->end_code;
     }
+  if (! childp->exe && parentp->exe)
+    childp->exe = strdup (parentp->exe);
 
   if (MACH_PORT_VALID (parentp->p_task_namespace))
     {
@@ -860,6 +862,8 @@ process_has_exited (struct proc *p)
 
   if (!--p->p_login->l_refcnt)
     free (p->p_login);
+  free (p->exe);
+  p->exe = NULL;
 
   ids_rele (p->p_id);
 
diff --git a/proc/proc.h b/proc/proc.h
index b33845d9..a974f629 100644
--- a/proc/proc.h
+++ b/proc/proc.h
@@ -68,6 +68,7 @@ struct proc
   pthread_cond_t p_wakeup;
 
   /* Miscellaneous information */
+  char *exe;			/* path to binary executable */
   vm_address_t p_argv, p_envp;
   vm_address_t start_code;	/* all executable segments are in this range */
   vm_address_t end_code;