[PATCH 2/7] Introduce target_fileio_set_fs

[Gary Benson <gbenson@redhat.com>]

This commit introduces a new target method target_fileio_set_fs
and adds calls to it in various places.  This allows support to
be added for targets where processes do not share a common
filesystem.

gdb/ChangeLog:

	* target.h (struct inferior): New forward declaration.
	(struct target_ops) <to_fileio_set_fs>: New field.
	(target_fileio_set_fs): New declaration.
	* target-delegates.c: Regenerate.
	* target.c (target_fileio_set_fs): New function.
	* exec.c (exec_file_attach): Call target_fileio_set_fs.
	* gdb_bfd.c (inferior.h): New include.
	(gdb_bfd_iovec_fileio_open): Rename argument.  Call
	target_fileio_set_fs.
	(gdb_bfd_open): Call target_fileio_set_fs.  Pass current
	inferior as argument to gdb_bfd_iovec_fileio_open.
	* linux-tdep.c (linux_info_proc): Call target_fileio_set_fs.
	(linux_find_memory_regions_full): Likewise.
	(linux_fill_prpsinfo): Likewise.
	* solib.c (solib_find_1): Likewise.
---
 gdb/ChangeLog          |   18 ++++++++++++++++++
 gdb/exec.c             |    2 ++
 gdb/gdb_bfd.c          |   10 ++++++++--
 gdb/linux-tdep.c       |    9 +++++++++
 gdb/solib.c            |    9 +++++++--
 gdb/target-delegates.c |   28 ++++++++++++++++++++++++++++
 gdb/target.c           |   23 +++++++++++++++++++++++
 gdb/target.h           |   23 +++++++++++++++++++++++
 8 files changed, 118 insertions(+), 4 deletions(-)

diff --git a/gdb/exec.c b/gdb/exec.c
index 872b86c..e97793a 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -231,6 +231,8 @@ exec_file_attach (const char *filename, int from_tty)
 
       if (is_target_filename (filename))
 	{
+	  target_fileio_set_fs (current_inferior ());
+
 	  if (target_filesystem_is_local ())
 	    filename += strlen (TARGET_SYSROOT_PREFIX);
 	  else
diff --git a/gdb/gdb_bfd.c b/gdb/gdb_bfd.c
index 3d5d23f..bdcf985 100644
--- a/gdb/gdb_bfd.c
+++ b/gdb/gdb_bfd.c
@@ -32,6 +32,7 @@
 #endif
 #include "target.h"
 #include "gdb/fileio.h"
+#include "inferior.h"
 
 typedef bfd *bfdp;
 DEF_VEC_P (bfdp);
@@ -213,7 +214,7 @@ fileio_errno_to_host (int errnum)
    OPEN_CLOSURE is unused.  */
 
 static void *
-gdb_bfd_iovec_fileio_open (struct bfd *abfd, void *open_closure)
+gdb_bfd_iovec_fileio_open (struct bfd *abfd, void *inferior)
 {
   const char *filename = bfd_get_filename (abfd);
   int fd, target_errno;
@@ -221,6 +222,8 @@ gdb_bfd_iovec_fileio_open (struct bfd *abfd, void *open_closure)
 
   gdb_assert (is_target_filename (filename));
 
+  target_fileio_set_fs ((struct inferior *) inferior);
+
   fd = target_fileio_open (filename + strlen (TARGET_SYSROOT_PREFIX),
 			   FILEIO_O_RDONLY, 0,
 			   &target_errno);
@@ -322,12 +325,15 @@ gdb_bfd_open (const char *name, const char *target, int fd)
 
   if (is_target_filename (name))
     {
+      target_fileio_set_fs (current_inferior ());
+
       if (!target_filesystem_is_local ())
 	{
 	  gdb_assert (fd == -1);
 
 	  abfd = gdb_bfd_openr_iovec (name, target,
-				      gdb_bfd_iovec_fileio_open, NULL,
+				      gdb_bfd_iovec_fileio_open,
+				      current_inferior (),
 				      gdb_bfd_iovec_fileio_pread,
 				      gdb_bfd_iovec_fileio_close,
 				      gdb_bfd_iovec_fileio_fstat);
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index 9d75b66..44b2970 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -715,6 +715,9 @@ linux_info_proc (struct gdbarch *gdbarch, const char *args,
   if (args && args[0])
     error (_("Too many parameters: %s"), args);
 
+  /* Access /proc/ from our filesystem.  */
+  target_fileio_set_fs (NULL);
+
   printf_filtered (_("process %ld\n"), pid);
   if (cmdline_f)
     {
@@ -1130,6 +1133,9 @@ linux_find_memory_regions_full (struct gdbarch *gdbarch,
 
   pid = current_inferior ()->pid;
 
+  /* Access /proc/ from our filesystem.  */
+  target_fileio_set_fs (NULL);
+
   if (use_coredump_filter)
     {
       xsnprintf (coredumpfilter_name, sizeof (coredumpfilter_name),
@@ -1752,6 +1758,9 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
 
   gdb_assert (p != NULL);
 
+  /* Access /proc/ from our filesystem.  */
+  target_fileio_set_fs (NULL);
+
   /* Obtaining PID and filename.  */
   pid = ptid_get_pid (inferior_ptid);
   xsnprintf (filename, sizeof (filename), "/proc/%d/cmdline", (int) pid);
diff --git a/gdb/solib.c b/gdb/solib.c
index 2466235..f1e694f 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -167,8 +167,13 @@ solib_find_1 (char *in_pathname, int *fd, int is_solib)
 	 ensures that the same search algorithm is used for
 	 all local files regardless of whether a "target:"
 	 prefix was used.  */
-      if (is_target_filename (sysroot) && target_filesystem_is_local ())
-	sysroot += strlen (TARGET_SYSROOT_PREFIX);
+      if (is_target_filename (sysroot))
+	{
+	  target_fileio_set_fs (current_inferior ());
+
+	  if (target_filesystem_is_local ())
+	    sysroot += strlen (TARGET_SYSROOT_PREFIX);
+	}
 
       if (*sysroot == '\0')
 	sysroot = NULL;
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index 36eacbf..0c16f9e 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -2343,6 +2343,30 @@ debug_thread_address_space (struct target_ops *self, ptid_t arg1)
   return result;
 }
 
+static void
+delegate_fileio_set_fs (struct target_ops *self, int arg1)
+{
+  self = self->beneath;
+  self->to_fileio_set_fs (self, arg1);
+}
+
+static void
+tdefault_fileio_set_fs (struct target_ops *self, int arg1)
+{
+}
+
+static void
+debug_fileio_set_fs (struct target_ops *self, int arg1)
+{
+  fprintf_unfiltered (gdb_stdlog, "-> %s->to_fileio_set_fs (...)\n", debug_target.to_shortname);
+  debug_target.to_fileio_set_fs (&debug_target, arg1);
+  fprintf_unfiltered (gdb_stdlog, "<- %s->to_fileio_set_fs (", debug_target.to_shortname);
+  target_debug_print_struct_target_ops_p (&debug_target);
+  fputs_unfiltered (", ", gdb_stdlog);
+  target_debug_print_int (arg1);
+  fputs_unfiltered (")\n", gdb_stdlog);
+}
+
 static int
 delegate_filesystem_is_local (struct target_ops *self)
 {
@@ -4049,6 +4073,8 @@ install_delegators (struct target_ops *ops)
     ops->to_thread_architecture = delegate_thread_architecture;
   if (ops->to_thread_address_space == NULL)
     ops->to_thread_address_space = delegate_thread_address_space;
+  if (ops->to_fileio_set_fs == NULL)
+    ops->to_fileio_set_fs = delegate_fileio_set_fs;
   if (ops->to_filesystem_is_local == NULL)
     ops->to_filesystem_is_local = delegate_filesystem_is_local;
   if (ops->to_trace_init == NULL)
@@ -4254,6 +4280,7 @@ install_dummy_methods (struct target_ops *ops)
   ops->to_can_run_breakpoint_commands = tdefault_can_run_breakpoint_commands;
   ops->to_thread_architecture = default_thread_architecture;
   ops->to_thread_address_space = default_thread_address_space;
+  ops->to_fileio_set_fs = tdefault_fileio_set_fs;
   ops->to_filesystem_is_local = tdefault_filesystem_is_local;
   ops->to_trace_init = tdefault_trace_init;
   ops->to_download_tracepoint = tdefault_download_tracepoint;
@@ -4402,6 +4429,7 @@ init_debug_target (struct target_ops *ops)
   ops->to_can_run_breakpoint_commands = debug_can_run_breakpoint_commands;
   ops->to_thread_architecture = debug_thread_architecture;
   ops->to_thread_address_space = debug_thread_address_space;
+  ops->to_fileio_set_fs = debug_fileio_set_fs;
   ops->to_filesystem_is_local = debug_filesystem_is_local;
   ops->to_trace_init = debug_trace_init;
   ops->to_download_tracepoint = debug_download_tracepoint;
diff --git a/gdb/target.c b/gdb/target.c
index 306c21d..0b78512 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -2684,6 +2684,29 @@ default_fileio_target (void)
     return find_default_run_target ("file I/O");
 }
 
+/* See target.h.  */
+
+void
+target_fileio_set_fs (struct inferior *inf)
+{
+  struct target_ops *t;
+  int pid = (inf == NULL || inf->fake_pid_p) ? 0 : inf->pid;
+
+  for (t = default_fileio_target (); t != NULL; t = t->beneath)
+    {
+      if (t->to_fileio_set_fs != NULL)
+	{
+	  t->to_fileio_set_fs (t, pid);
+
+	  if (targetdebug)
+	    fprintf_unfiltered (gdb_stdlog,
+				"target_fileio_set_fs (%d)\n", pid);
+
+	  break;
+	}
+    }
+}
+
 /* File handle for target file operations.  */
 
 typedef struct
diff --git a/gdb/target.h b/gdb/target.h
index 66bf91e..0472237 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -38,6 +38,7 @@ struct static_tracepoint_marker;
 struct traceframe_info;
 struct expression;
 struct dcache_struct;
+struct inferior;
 
 #include "infrun.h" /* For enum exec_direction_kind.  */
 
@@ -830,6 +831,15 @@ struct target_ops
 
     /* Target file operations.  */
 
+    /* Set the filesystem accessed by target_filesystem_is_local and
+       target_fileio_* methods that take FILENAME arguments to the
+       filesystem as seen by process PID on the target system.  If
+       PID is zero, set the filesystem to that seen by the GDB, or,
+       for remote targets, the remote stub.  See the comment on
+       target_fileio_set_fs for more details.  */
+    void (*to_fileio_set_fs) (struct target_ops *, int pid)
+      TARGET_DEFAULT_IGNORE ();
+
     /* Return nonzero if the filesystem accessed by the
        target_fileio_* methods is the local filesystem,
        zero otherwise.  */
@@ -1932,6 +1942,19 @@ extern int target_search_memory (CORE_ADDR start_addr,
 
 /* Target file operations.  */
 
+/* Set the filesystem accessed by target_filesystem_is_local and
+   target_fileio_* methods that take FILENAME arguments to the
+   filesystem as seen by INF iff INF is non-NULL and refers to
+   a running process with a non-faked PID.  Set the filesystem
+   to that seen by the debugger (GDB or the remote stub) in all
+   other cases.  All callers of target_filesystem_is_local and
+   target_fileio_* methods with FILENAME arguments should call
+   target_fileio_set_fs to ensure the correct filesystem is used.
+   File descriptors returned by target_fileio_open should continue
+   to reference the filesystem in which they were opened across
+   calls to target_fileio_set_fs.  */
+extern void target_fileio_set_fs (struct inferior *inf);
+
 /* Return nonzero if the filesystem accessed by the target_fileio_*
    methods is the local filesystem, zero otherwise.  */
 #define target_filesystem_is_local() \
-- 
1.7.1