[PATCH 3/7] Use gdb_sysroot for main executable on attach

Gary Benson
2015-04-01T11:22:36Z

This commit updates exec_file_locate_attach to use exec_file_find
to compute the full pathname of the main executable in some cases.
The net effect of this is that the main executable's path will be
prefixed with gdb_sysroot in the same way that shared library paths
currently are.

gdb/ChangeLog:

* exec.c (solist.h): New include.
(exec_file_locate_attach): Prefix absolute executable
paths with gdb_sysroot if set.
* NEWS: Mention that executable paths may be prepended
with sysroot on attach.

gdb/doc/ChangeLog:

* gdb.texinfo (set sysroot): Document that "set sysroot" also
applies to executable paths if supplied to GDB as absolute.
---
gdb/ChangeLog | 8 ++++++++
gdb/NEWS | 5 +++++
gdb/doc/ChangeLog | 5 +++++
gdb/doc/gdb.texinfo | 22 ++++++++++++----------
gdb/exec.c | 32 ++++++++++++++++++++++++--------
5 files changed, 54 insertions(+), 18 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index f2a51a4..dec60cb 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -16,6 +16,11 @@
system, be it local or remote. This replaces the prefix "remote:".
The default sysroot has been changed from "" to "target:".

+* Paths specified by "set sysroot" will be prepended to the path of
+ the main executable when attaching to already-running processes
+ (local and remote) if the path of the main executable is reported
+ to GDB as absolute by the operating system.
+
* Python Scripting

** gdb.Objfile objects have a new attribute "username",
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 93e7e87..692d70e 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -17800,18 +17800,20 @@ may try to load the host's libraries. @value{GDBN} has two variables
to specify the search directories for target libraries.

@table @code
-@cindex prefix for shared library file names
+@cindex prefix for executable and shared library file names
@cindex system root, alternate
@kindex set solib-absolute-prefix
@kindex set sysroot
@item set sysroot @var{path}
Use @var{path} as the system root for the program being debugged. Any
-absolute shared library paths will be prefixed with @var{path}; many
-runtime loaders store the absolute paths to the shared library in the
-target program's memory. If you use @code{set sysroot} to find shared
-libraries, they need to be laid out in the same way that they are on
-the target, with e.g.@: a @file{/lib} and @file{/usr/lib} hierarchy
-under @var{path}.
+shared library paths will be prefixed with @var{path}; many runtime
+loaders store the absolute paths to the shared library in the target
+program's memory. When attaching to already-running processes, their
+paths will be prefixed with @var{path} if reported to @value{GDBN} as
+absolute by the operating system. If you use @code{set sysroot} to
+find executables and shared libraries, they need to be laid out in
+the same way that they are on the target, with e.g.@: a @file{/bin},
+@file{/lib} and @file{/usr/lib} hierarchy under @var{path}.

If @var{path} starts with the sequence @file{target:} and the target
system is remote then @value{GDBN} will retrieve the target binaries
@@ -17846,7 +17848,7 @@ system:
c:/foo/bar.dll @result{} /path/to/sysroot/c:/foo/bar.dll
@end smallexample

-If that does not find the shared library, @value{GDBN} tries removing
+If that does not find the binary, @value{GDBN} tries removing
the @samp{:} character from the drive spec, both for convenience, and,
for the case of the host file system not supporting file names with
colons:
@@ -17871,7 +17873,7 @@ and point the system root at @file{/path/to/sysroot}, so that
@value{GDBN} can find the correct copies of both
@file{c:\sys\bin\foo.dll}, and @file{z:\sys\bin\bar.dll}.

-If that still does not find the shared library, @value{GDBN} tries
+If that still does not find the binary, @value{GDBN} tries
removing the whole drive spec from the target file name:

@smallexample
@@ -17895,7 +17897,7 @@ location.

@kindex show sysroot
@item show sysroot
-Display the current shared library prefix.
+Display the current executable and shared library prefix.

@kindex set solib-search-path
@item set solib-search-path @var{path}
diff --git a/gdb/exec.c b/gdb/exec.c
index ab7fcbb..99c0cd4 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -42,6 +42,7 @@

#include <ctype.h>
#include <sys/stat.h>
+#include "solist.h"

void (*deprecated_file_changed_hook) (char *);

@@ -151,15 +152,30 @@ exec_file_locate_attach (int pid, int from_tty)
if (exec_file == NULL)
return;

- /* It's possible we don't have a full path, but rather just a
- filename. Some targets, such as HP-UX, don't provide the
- full path, sigh.
+ /* If gdb_sysroot is not empty and the discovered filename
+ is absolute then prefix the filename with gdb_sysroot. */
+ if (gdb_sysroot != NULL && *gdb_sysroot != '\0'
+ && IS_ABSOLUTE_PATH (exec_file))
+ {
+ int fd = -1;
+
+ full_exec_path = exec_file_find (exec_file, &fd);
+ if (fd >= 0)
+ close (fd);
+ }

- Attempt to qualify the filename against the source path.
- (If that fails, we'll just fall back on the original
- filename. Not much more we can do...) */
- if (!source_full_path_of (exec_file, &full_exec_path))
- full_exec_path = xstrdup (exec_file);
+ if (full_exec_path == NULL)
+ {
+ /* It's possible we don't have a full path, but rather just a
+ filename. Some targets, such as HP-UX, don't provide the
+ full path, sigh.
+
+ Attempt to qualify the filename against the source path.
+ (If that fails, we'll just fall back on the original
+ filename. Not much more we can do...) */
+ if (!source_full_path_of (exec_file, &full_exec_path))
+ full_exec_path = xstrdup (exec_file);
+ }

exec_file_attach (full_exec_path, from_tty);
symbol_file_add_main (full_exec_path, from_tty);
--
1.7.1