Add --stat-mode to override the perms for [pid]/stat

* main.c (argp_parser, main): Add the --stat-mode option.
* process.c (process_lookup_pid): Use it.

3 files changed, 20 insertions, 0 deletions

diff --git a/main.c b/main.c
index a59ab47..09cffc7 100644
--- a/main.c
+++ b/main.c
@@ -12,6 +12,7 @@
 
 /* Command-line options */
 int opt_clk_tck;
+mode_t opt_stat_mode;
 
 static error_t
 argp_parser (int key, char *arg, struct argp_state *state)
@@ -25,6 +26,12 @@ argp_parser (int key, char *arg, struct argp_state *state)
       if (*endp || ! *arg || opt_clk_tck <= 0)
 	error (1, 0, "--clk-tck: HZ should be a positive integer");
       break;
+
+    case 's':
+      opt_stat_mode = strtol (arg, &endp, 8);
+      if (*endp || ! *arg || opt_stat_mode & ~07777)
+	error (1, 0, "--stat-mode: MODE should be an octal mode");
+      break;
   }
 
   return 0;
@@ -35,6 +42,12 @@ struct argp argp = {
     { "clk-tck", 'h', "HZ", 0,
 	"Unit used for the values expressed in system clock ticks "
 	"(default: sysconf(_SC_CLK_TCK))" },
+    { "stat-mode", 's', "MODE", 0,
+	"The [pid]/stat file publishes information which on Hurd is only "
+	"available to the process owner.  "
+	"You can use this option to override its mode to be more permissive "
+	"for compatibility purposes.  "
+	"(default: 0400)" },
     {}
   },
   .parser = argp_parser,
@@ -81,6 +94,7 @@ int main (int argc, char **argv)
   mach_port_t bootstrap;
 
   opt_clk_tck = sysconf(_SC_CLK_TCK);
+  opt_stat_mode = 0400;
   argp_parse (&argp, argc, argv, 0, 0, 0);
 
   task_get_bootstrap_port (mach_task_self (), &bootstrap);
diff --git a/main.h b/main.h
index 4b2ef9a..6669d32 100644
--- a/main.h
+++ b/main.h
@@ -1,2 +1,3 @@
 /* Startup options */
 extern int opt_clk_tck;
+extern mode_t opt_stat_mode;
diff --git a/process.c b/process.c
index 65f0e50..f7a7a57 100644
--- a/process.c
+++ b/process.c
@@ -206,6 +206,7 @@ static struct procfs_dir_entry entries[] = {
     },
   },
   {
+    /* Beware of the hack below, which requires this to be entries[2].  */
     .name = "stat",
     .make_node = process_file_make_node,
     .hook = & (struct process_file_desc) {
@@ -235,6 +236,10 @@ process_lookup_pid (struct ps_context *pc, pid_t pid, struct node **np)
   if (err || ! (proc_stat_flags (ps) & PSTAT_OWNER_UID))
     return EIO;
 
+  /* FIXME: have a separate proc_desc structure for each file, so this can be
+     accessed in a more robust and straightforward way. */
+  ((struct process_file_desc *) entries[2].hook)->mode = opt_stat_mode;
+
   *np = procfs_dir_make_node (entries, ps, (void (*)(void *)) _proc_stat_free);
   if (! *np)
     return ENOMEM;