From 62774c1deef7eb01108ac65636e2ccf974992d85 Mon Sep 17 00:00:00 2001
From: Aleksandar Ristovski <aristovski@qnx.com>
Date: Mon, 5 Oct 2015 10:32:16 -0400
Subject: [PATCH] [nto] Fixes for nto procfs.

gdb/ChangeLog:

	* nto-procfs.c (sys/auxv.h): Include.
	(nto_procfs_path): Rename to...
	(nodestr): ... this, and change type.
	(nto_node): Use new variable and logic accordingly.
	(procfs_open_1): Use new variable name. Use local buffer to construct
	procfs path.
	(procfs_pidlist): Use NODESTR to construct procfs path.
	(procfs_files_info): Use NODESTR to output meaningful text.
	(procfs_pid_to_exec_file): New target function.
	(do_attach): Construct procfs using NODESTR.
	(procfs_xfer_partial): Logic for reading TARGET_OBJECT_AUXV.
	(procfs_create_inferior): Compare pointer to NULL.
	(init_procfs_targets): Wire procfs_pid_to_exec_file.
	* nto-tdep.c (symfile.h): Include.
	(nto_read_auxv_from_initial_stack): New function.
	* nto-tdep.h (nto_read_auxv_from_initial_stack): New function
	declaration.
---
 gdb/nto-procfs.c | 128 ++++++++++++++++++++++++++++++++++++++++++++-----------
 gdb/nto-tdep.c   |  87 +++++++++++++++++++++++++++++++++++++
 gdb/nto-tdep.h   |   4 ++
 3 files changed, 194 insertions(+), 25 deletions(-)

diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index d659f79..176ceea 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -30,6 +30,8 @@
 #include <sys/syspage.h>
 #include <dirent.h>
 #include <sys/netmgr.h>
+#include <sys/auxv.h>
+
 #include "gdbcore.h"
 #include "inferior.h"
 #include "target.h"
@@ -73,7 +75,7 @@ static int procfs_stopped_by_watchpoint (struct target_ops *ops);
    referenced elsewhere.  'nto_procfs_node' is a flag used to say
    whether we are local, or we should get the current node descriptor
    for the remote QNX node.  */
-static char nto_procfs_path[PATH_MAX] = { "/proc" };
+static char *nodestr;
 static unsigned nto_procfs_node = ND_LOCAL_NODE;
 
 /* Return the current QNX Node, or error out.  This is a simple
@@ -85,10 +87,11 @@ nto_node (void)
 {
   unsigned node;
 
-  if (ND_NODE_CMP (nto_procfs_node, ND_LOCAL_NODE) == 0)
+  if (ND_NODE_CMP (nto_procfs_node, ND_LOCAL_NODE) == 0
+      || nodestr == NULL)
     return ND_LOCAL_NODE;
 
-  node = netmgr_strtond (nto_procfs_path, 0);
+  node = netmgr_strtond (nodestr, 0);
   if (node == -1)
     error (_("Lost the QNX node.  Debug session probably over."));
 
@@ -108,12 +111,12 @@ procfs_is_nto_target (bfd *abfd)
 static void
 procfs_open_1 (struct target_ops *ops, const char *arg, int from_tty)
 {
-  char *nodestr;
   char *endstr;
   char buffer[50];
   int fd, total_size;
   procfs_sysinfo *sysinfo;
   struct cleanup *cleanups;
+  char nto_procfs_path[PATH_MAX];
 
   /* Offer to kill previous inferiors before opening this target.  */
   target_preopen (from_tty);
@@ -123,8 +126,11 @@ procfs_open_1 (struct target_ops *ops, const char *arg, int from_tty)
   /* Set the default node used for spawning to this one,
      and only override it if there is a valid arg.  */
 
+  xfree (nodestr);
+  nodestr = NULL;
+
   nto_procfs_node = ND_LOCAL_NODE;
-  nodestr = arg ? xstrdup (arg) : NULL;
+  nodestr = (arg != NULL) ? xstrdup (arg) : NULL;
 
   init_thread_list ();
 
@@ -149,10 +155,8 @@ procfs_open_1 (struct target_ops *ops, const char *arg, int from_tty)
 	    *endstr = 0;
 	}
     }
-  snprintf (nto_procfs_path, PATH_MAX - 1, "%s%s", nodestr ? nodestr : "",
-	    "/proc");
-  if (nodestr)
-    xfree (nodestr);
+  snprintf (nto_procfs_path, PATH_MAX - 1, "%s%s",
+	    (nodestr != NULL) ? nodestr : "", "/proc");
 
   fd = open (nto_procfs_path, O_RDONLY);
   if (fd == -1)
@@ -174,7 +178,7 @@ procfs_open_1 (struct target_ops *ops, const char *arg, int from_tty)
     {
       total_size = sysinfo->total_size;
       sysinfo = alloca (total_size);
-      if (!sysinfo)
+      if (sysinfo == NULL)
 	{
 	  printf_filtered ("Memory error: %d (%s)\n", errno,
 			   safe_strerror (errno));
@@ -359,7 +363,7 @@ procfs_pidlist (char *args, int from_tty)
 {
   DIR *dp = NULL;
   struct dirent *dirp = NULL;
-  char buf[512];
+  char buf[PATH_MAX];
   procfs_info *pidinfo = NULL;
   procfs_debuginfo *info = NULL;
   procfs_status *status = NULL;
@@ -367,12 +371,16 @@ procfs_pidlist (char *args, int from_tty)
   pid_t pid;
   char name[512];
   struct cleanup *cleanups;
+  char procfs_dir[PATH_MAX];
 
-  dp = opendir (nto_procfs_path);
+  snprintf (procfs_dir, sizeof (procfs_dir), "%s%s",
+	    (nodestr != NULL) ? nodestr : "", "/proc");
+
+  dp = opendir (procfs_dir);
   if (dp == NULL)
     {
       fprintf_unfiltered (gdb_stderr, "failed to opendir \"%s\" - %d (%s)",
-			  nto_procfs_path, errno, safe_strerror (errno));
+			  procfs_dir, errno, safe_strerror (errno));
       return;
     }
 
@@ -395,7 +403,9 @@ procfs_pidlist (char *args, int from_tty)
 	      do_cleanups (cleanups);
 	      return;
 	    }
-	  snprintf (buf, 511, "%s/%s/as", nto_procfs_path, dirp->d_name);
+	  snprintf (buf, sizeof (buf), "%s%s/%s/as",
+		    (nodestr != NULL) ? nodestr : "",
+		    "/proc", dirp->d_name);
 	  pid = atoi (dirp->d_name);
 	}
       while (pid == 0);
@@ -406,8 +416,7 @@ procfs_pidlist (char *args, int from_tty)
 	{
 	  fprintf_unfiltered (gdb_stderr, "failed to open %s - %d (%s)\n",
 			      buf, errno, safe_strerror (errno));
-	  do_cleanups (cleanups);
-	  return;
+	  continue;
 	}
       inner_cleanup = make_cleanup_close (fd);
 
@@ -431,11 +440,16 @@ procfs_pidlist (char *args, int from_tty)
       status = (procfs_status *) buf;
       for (status->tid = 1; status->tid <= num_threads; status->tid++)
 	{
-	  if (devctl (fd, DCMD_PROC_TIDSTATUS, status, sizeof (buf), 0) != EOK
-	      && status->tid != 0)
-	    break;
-	  if (status->tid != 0)
-	    printf_filtered ("%s - %d/%d\n", name, pid, status->tid);
+	  const int err
+	    = devctl (fd, DCMD_PROC_TIDSTATUS, status, sizeof (buf), 0);
+	  printf_filtered ("%s - %d", name, pid);
+	  if (err == EOK && status->tid != 0)
+	    printf_filtered ("/%d\n", status->tid);
+	  else
+	    {
+	      printf_filtered ("\n");
+	      break;
+	    }
 	}
 
       do_cleanups (inner_cleanup);
@@ -599,9 +613,38 @@ procfs_files_info (struct target_ops *ignore)
 
   printf_unfiltered ("\tUsing the running image of %s %s via %s.\n",
 		     inf->attach_flag ? "attached" : "child",
-		     target_pid_to_str (inferior_ptid), nto_procfs_path);
+		     target_pid_to_str (inferior_ptid),
+		     (nodestr != NULL) ? nodestr : "local node");
 }
 
+/* Read executable file name for the given PID.  */
+
+static char *
+procfs_pid_to_exec_file (struct target_ops *ops, const int pid)
+{
+  int proc_fd;
+  static char proc_path[PATH_MAX];
+  ssize_t rd;
+
+  /* Read exe file name.  */
+  snprintf (proc_path, sizeof (proc_path), "%s/proc/%d/exefile",
+	    (nodestr != NULL) ? nodestr : "", pid);
+  proc_fd = open (proc_path, O_RDONLY);
+  if (proc_fd == -1)
+    return NULL;
+
+  rd = read (proc_fd, proc_path, sizeof (proc_path) - 1);
+  close (proc_fd);
+  if (rd <= 0)
+    {
+      proc_path[0] = '\0';
+      return NULL;
+    }
+  proc_path[rd] = '\0';
+  return proc_path;
+}
+
+
 /* Attach to process PID, then initialize for debugging it.  */
 static void
 procfs_attach (struct target_ops *ops, const char *args, int from_tty)
@@ -653,8 +696,8 @@ do_attach (ptid_t ptid)
   struct sigevent event;
   char path[PATH_MAX];
 
-  snprintf (path, PATH_MAX - 1, "%s/%d/as", nto_procfs_path,
-	    ptid_get_pid (ptid));
+  snprintf (path, PATH_MAX - 1, "%s%s/%d/as",
+	    (nodestr != NULL) ? nodestr : "", "/proc", ptid_get_pid (ptid));
   ctl_fd = open (path, O_RDWR);
   if (ctl_fd == -1)
     error (_("Couldn't open proc file %s, error %d (%s)"), path, errno,
@@ -872,6 +915,40 @@ procfs_xfer_partial (struct target_ops *ops, enum target_object object,
     {
     case TARGET_OBJECT_MEMORY:
       return procfs_xfer_memory (readbuf, writebuf, offset, len, xfered_len);
+    case TARGET_OBJECT_AUXV:
+      if (readbuf != NULL)
+	{
+	  int err;
+	  CORE_ADDR initial_stack;
+	  debug_process_t procinfo;
+	  /* For 32-bit architecture, size of auxv_t is 8 bytes.  */
+	  const unsigned int sizeof_auxv_t = sizeof (auxv_t);
+	  const unsigned int sizeof_tempbuf = 20 * sizeof_auxv_t;
+	  int tempread;
+	  gdb_byte *const tempbuf = alloca (sizeof_tempbuf);
+
+	  if (tempbuf == NULL)
+	    return TARGET_XFER_E_IO;
+
+	  err = devctl (ctl_fd, DCMD_PROC_INFO, &procinfo,
+		        sizeof procinfo, 0);
+	  if (err != EOK)
+	    return TARGET_XFER_E_IO;
+
+	  /* Similar as in the case of a core file, we read auxv from
+	     initial_stack.  */
+	  initial_stack = procinfo.initial_stack;
+
+	  /* procfs is always 'self-hosted', no byte-order manipulation. */
+	  tempread = nto_read_auxv_from_initial_stack (initial_stack, tempbuf,
+						       sizeof_tempbuf,
+						       sizeof (auxv_t));
+	  tempread = min (tempread, len) - offset;
+	  memcpy (readbuf, tempbuf + offset, tempread);
+	  *xfered_len = tempread;
+	  return tempread ? TARGET_XFER_OK : TARGET_XFER_EOF;
+	}
+      /* Fallthru */
     default:
       return ops->beneath->to_xfer_partial (ops->beneath, object, annex,
 					    readbuf, writebuf, offset, len,
@@ -1121,7 +1198,7 @@ procfs_create_inferior (struct target_ops *ops, char *exec_file,
     }
 
   args = xstrdup (allargs);
-  breakup_args (args, exec_file ? &argv[1] : &argv[0]);
+  breakup_args (args, (exec_file != NULL) ? &argv[1] : &argv[0]);
 
   argv = nto_parse_redirection (argv, &in, &out, &err);
 
@@ -1444,6 +1521,7 @@ init_procfs_targets (void)
   t->to_interrupt = procfs_interrupt;
   t->to_have_continuable_watchpoint = 1;
   t->to_extra_thread_info = nto_extra_thread_info;
+  t->to_pid_to_exec_file = procfs_pid_to_exec_file;
 
   nto_native_ops = t;
 
diff --git a/gdb/nto-tdep.c b/gdb/nto-tdep.c
index 81ee7fb..63094e8 100644
--- a/gdb/nto-tdep.c
+++ b/gdb/nto-tdep.c
@@ -31,6 +31,7 @@
 #include "solib-svr4.h"
 #include "gdbcore.h"
 #include "objfiles.h"
+#include "symfile.h"
 
 #ifdef __CYGWIN__
 #include <sys/cygwin.h>
@@ -394,3 +395,89 @@ nto_initialize_signals (void)
   signal_pass_update (SIGPHOTON, 1);
 #endif
 }
+
+
+/* Read AUXV from initial_stack.  */
+LONGEST
+nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack, gdb_byte *readbuf,
+                                  LONGEST len, size_t sizeof_auxv_t)
+{
+  gdb_byte targ32[4]; /* For 32 bit target values.  */
+  gdb_byte targ64[8]; /* For 64 bit target values.  */
+  CORE_ADDR data_ofs = 0;
+  ULONGEST anint;
+  LONGEST len_read = 0;
+  gdb_byte *buff;
+  enum bfd_endian byte_order;
+  int ptr_size;
+
+  if (sizeof_auxv_t == 16)
+    ptr_size = 8;
+  else
+    ptr_size = 4;
+
+  /* Skip over argc, argv and envp... Comment from ldd.c:
+
+     The startup frame is set-up so that we have:
+     auxv
+     NULL
+     ...
+     envp2
+     envp1 <----- void *frame + (argc + 2) * sizeof(char *)
+     NULL
+     ...
+     argv2
+     argv1
+     argc  <------ void * frame
+
+     On entry to ldd, frame gives the address of argc on the stack.  */
+  /* Read argc. 4 bytes on both 64 and 32 bit arches and luckily little
+   * endian. So we just read first 4 bytes.  */
+  if (target_read_memory (initial_stack + data_ofs, targ32, 4) != 0)
+    return 0;
+
+  byte_order = gdbarch_byte_order (target_gdbarch ());
+
+  anint = extract_unsigned_integer (targ32, sizeof (targ32), byte_order);
+
+  /* Size of pointer is assumed to be 4 bytes (32 bit arch.) */
+  data_ofs += (anint + 2) * ptr_size; /* + 2 comes from argc itself and
+                                                NULL terminating pointer in
+                                                argv.  */
+
+  /* Now loop over env table:  */
+  anint = 0;
+  while (target_read_memory (initial_stack + data_ofs, targ64, ptr_size)
+         == 0)
+    {
+      if (extract_unsigned_integer (targ64, ptr_size, byte_order) == 0)
+	anint = 1; /* Keep looping until non-null entry is found.  */
+      else if (anint)
+	break;
+      data_ofs += ptr_size;
+    }
+  initial_stack += data_ofs;
+
+  memset (readbuf, 0, len);
+  buff = readbuf;
+  while (len_read <= len-sizeof_auxv_t)
+    {
+      if (target_read_memory (initial_stack + len_read, buff, sizeof_auxv_t)
+	  == 0)
+        {
+	  /* Both 32 and 64 bit structures have int as the first field.  */
+          const ULONGEST a_type
+	    = extract_unsigned_integer (buff, sizeof (targ32), byte_order);
+
+          if (a_type == AT_NULL)
+	    break;
+	  buff += sizeof_auxv_t;
+	  len_read += sizeof_auxv_t;
+        }
+      else
+        break;
+    }
+  return len_read;
+}
+
+
diff --git a/gdb/nto-tdep.h b/gdb/nto-tdep.h
index bd85d2a..7089a12 100644
--- a/gdb/nto-tdep.h
+++ b/gdb/nto-tdep.h
@@ -168,4 +168,8 @@ int nto_in_dynsym_resolve_code (CORE_ADDR pc);
 
 char *nto_extra_thread_info (struct target_ops *self, struct thread_info *);
 
+LONGEST nto_read_auxv_from_initial_stack (CORE_ADDR inital_stack,
+					  gdb_byte *readbuf,
+					  LONGEST len, size_t sizeof_auxv_t);
+
 #endif
-- 
1.9.1

