From: Andrew Burgess Date: Fri, 4 Oct 2024 18:30:04 +0000 (+0100) Subject: gdbserver: pass osabi to GDB in target description X-Git-Tag: gdb-16-branchpoint~686 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=98bcde5e268ea7cd54186c5f2c27c65103218fc3;p=thirdparty%2Fbinutils-gdb.git gdbserver: pass osabi to GDB in target description On a Windows machine I built gdbserver, configured for the target 'x86_64-w64-mingw32', then on a GNU/Linux machine I built GDB with support for all target (--enable-targets=all). On the Windows machine I start gdbserver with a small test binary: $ gdbserver 192.168.129.25:54321 C:\some\directory\executable.exe On the GNU/Linux machine I start GDB without the test binary, and connect to gdbserver. As I have not given GDB the test binary, my expectation is that GDB would connect to gdbserver and then download the file over the remote protocol, but instead I was presented with this message: (gdb) target remote 192.168.129.25:54321 Remote debugging using 192.168.129.25:54321 warning: C:\some\directory\executable.exe: No such file or directory. 0x00007ffa3e1e1741 in ?? () (gdb) What I found is that if I told GDB where to find the binary, like this: (gdb) file target:C:/some/directory/executable.exe A program is being debugged already. Are you sure you want to change the file? (y or n) y Reading C:/some/directory/executable.exe from remote target... warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead. Reading C:/some/directory/executable.exe from remote target... Reading symbols from target:C:/some/directory/executable.exe... (gdb) then GDB would download the executable. I eventually tracked the problem down to exec_file_find (solib.c). The remote target was passing an absolute Windows filename (beginning with "C:/" in this case), but in exec_file_find GDB was failing the IS_TARGET_ABSOLUTE_PATH call, and so was treating the filename as relative. The IS_TARGET_ABSOLUTE_PATH call was failing because GDB thought that the file system kind was "unix", and as the filename didn't start with a "/" it assumed the filename was not absolute. But I'm connecting to a Windows target, my 'target-file-system-kind' was set to "auto", so should be figuring out that my file-system is "dos-based". Looking in effective_target_file_system_kind (filesystem.c), we find that the logic of "auto" is delegated to the current gdbarch. However in windows-tdep.c we see: set_gdbarch_has_dos_based_file_system (gdbarch, 1); So if we are using a Windows gdbarch we should have "dos-based" filesystems. What this means is that after connecting to the remote target GDB has selected the wrong gdbarch. What's happening is that the target description sent back by the remote target only includes the x86-64 registers. There's no information about which OS we're on. As a consequence, GDB picks the first x86-64 gdbarch which can handle the provided register set, which happens to be a GNU/Linux gdbarch. And indeed, there doesn't appear to be anywhere in gdbserver that sets the osabi on the target descriptions, though some target descriptions do have their osabi set when the description is created, e.g. in: gdb/arch/amd64.c - Sets GNU/Linux osabi when appropriate. gdb/arch/i386.c - Likewise. gdb/arch/tic6x.c - Always set GNU/Linux osabi. Most target descriptions are created without an osabi, gdbserver does nothing to fix this, and the description is returned to GDB without an osabi included. I propose that we always set the osabi name on the target descriptions returned from gdbserver. We could try to do this when the description is first created, but that would mean passing extra flags into the tdesc creation code (or just passing the osabi string in), and I don't think that's really necessary. If we consider the tdesc creation as being about figuring out which registers are on the target, then it makes sense that the osabi information is injected later. So what I've done is require the osabi name to be passed to the init_target_desc function. This is called, I believe, for all targets, in the gdbserver code. Now when I connect to the Windows remote the target description returned includes the osabi name. With this extra information GDB selects the correct gdbarch object, which means that GDB understands the target has a "dos-based" file-system. With that correct GDB understands that the filename it was given is absolute, and so fetches the file from the remote as we'd like. Approved-By: Luis Machado Approved-By: Simon Marchi --- diff --git a/gdbserver/linux-aarch32-tdesc.cc b/gdbserver/linux-aarch32-tdesc.cc index b8987752b9f..441fe668e6a 100644 --- a/gdbserver/linux-aarch32-tdesc.cc +++ b/gdbserver/linux-aarch32-tdesc.cc @@ -34,7 +34,7 @@ aarch32_linux_read_description () tdesc_aarch32 = aarch32_create_target_description (false); static const char *expedite_regs[] = { "r11", "sp", "pc", 0 }; - init_target_desc (tdesc_aarch32, expedite_regs); + init_target_desc (tdesc_aarch32, expedite_regs, GDB_OSABI_LINUX); } return tdesc_aarch32; } diff --git a/gdbserver/linux-aarch64-tdesc.cc b/gdbserver/linux-aarch64-tdesc.cc index 31ec7854cc0..39d5bccdce1 100644 --- a/gdbserver/linux-aarch64-tdesc.cc +++ b/gdbserver/linux-aarch64-tdesc.cc @@ -67,7 +67,8 @@ aarch64_linux_read_description (const aarch64_features &features) expedited_registers.push_back (nullptr); - init_target_desc (tdesc, (const char **) expedited_registers.data ()); + init_target_desc (tdesc, (const char **) expedited_registers.data (), + GDB_OSABI_LINUX); tdesc_aarch64_map[features] = tdesc; } diff --git a/gdbserver/linux-arc-low.cc b/gdbserver/linux-arc-low.cc index 1bcaf6c3f91..16d8d5824aa 100644 --- a/gdbserver/linux-arc-low.cc +++ b/gdbserver/linux-arc-low.cc @@ -114,7 +114,7 @@ arc_linux_read_description (void) target_desc_up tdesc = arc_create_target_description (features); static const char *expedite_regs[] = { "sp", "status32", nullptr }; - init_target_desc (tdesc.get (), expedite_regs); + init_target_desc (tdesc.get (), expedite_regs, GDB_OSABI_LINUX); return tdesc.release (); } diff --git a/gdbserver/linux-arm-tdesc.cc b/gdbserver/linux-arm-tdesc.cc index 559f9b0f3dc..fff2e948f81 100644 --- a/gdbserver/linux-arm-tdesc.cc +++ b/gdbserver/linux-arm-tdesc.cc @@ -37,7 +37,7 @@ arm_linux_read_description (arm_fp_type fp_type) tdesc = arm_create_target_description (fp_type, false); static const char *expedite_regs[] = { "r11", "sp", "pc", 0 }; - init_target_desc (tdesc, expedite_regs); + init_target_desc (tdesc, expedite_regs, GDB_OSABI_LINUX); tdesc_arm_list[fp_type] = tdesc; } diff --git a/gdbserver/linux-csky-low.cc b/gdbserver/linux-csky-low.cc index 2eb5a2df17b..18a0d152b5a 100644 --- a/gdbserver/linux-csky-low.cc +++ b/gdbserver/linux-csky-low.cc @@ -133,7 +133,7 @@ csky_target::low_arch_setup () if (tdesc->expedite_regs.empty ()) { - init_target_desc (tdesc.get (), expedite_regs); + init_target_desc (tdesc.get (), expedite_regs, GDB_OSABI_LINUX); gdb_assert (!tdesc->expedite_regs.empty ()); } diff --git a/gdbserver/linux-loongarch-low.cc b/gdbserver/linux-loongarch-low.cc index 584ea64a7d9..cf7d6c0743c 100644 --- a/gdbserver/linux-loongarch-low.cc +++ b/gdbserver/linux-loongarch-low.cc @@ -85,7 +85,7 @@ loongarch_target::low_arch_setup () if (tdesc->expedite_regs.empty ()) { - init_target_desc (tdesc.get (), expedite_regs); + init_target_desc (tdesc.get (), expedite_regs, GDB_OSABI_LINUX); gdb_assert (!tdesc->expedite_regs.empty ()); } current_process ()->tdesc = tdesc.release (); diff --git a/gdbserver/linux-riscv-low.cc b/gdbserver/linux-riscv-low.cc index c4554c507a8..7170ad9922e 100644 --- a/gdbserver/linux-riscv-low.cc +++ b/gdbserver/linux-riscv-low.cc @@ -91,7 +91,7 @@ riscv_target::low_arch_setup () if (tdesc->expedite_regs.empty ()) { - init_target_desc (tdesc.get (), expedite_regs); + init_target_desc (tdesc.get (), expedite_regs, GDB_OSABI_LINUX); gdb_assert (!tdesc->expedite_regs.empty ()); } diff --git a/gdbserver/linux-tic6x-low.cc b/gdbserver/linux-tic6x-low.cc index 707be2e7b0f..754dd00590c 100644 --- a/gdbserver/linux-tic6x-low.cc +++ b/gdbserver/linux-tic6x-low.cc @@ -228,7 +228,7 @@ tic6x_read_description (enum c6x_feature feature) { *tdesc = tic6x_create_target_description (feature); static const char *expedite_regs[] = { "A15", "PC", NULL }; - init_target_desc (*tdesc, expedite_regs); + init_target_desc (*tdesc, expedite_regs, GDB_OSABI_LINUX); } return *tdesc; diff --git a/gdbserver/linux-x86-tdesc.cc b/gdbserver/linux-x86-tdesc.cc index 13c80762605..6aa5c4ab970 100644 --- a/gdbserver/linux-x86-tdesc.cc +++ b/gdbserver/linux-x86-tdesc.cc @@ -26,10 +26,21 @@ void x86_linux_post_init_tdesc (target_desc *tdesc, bool is_64bit) { + enum gdb_osabi osabi = GDB_OSABI_LINUX; + +#ifndef IN_PROCESS_AGENT + /* x86 target descriptions are created with the osabi already set. + However, init_target_desc requires us to override the already set + value. That's fine, out new string should match the old one. */ + gdb_assert (tdesc_osabi_name (tdesc) != nullptr); + gdb_assert (strcmp (tdesc_osabi_name (tdesc), + gdbarch_osabi_name (osabi)) == 0); +#endif /* ! IN_PROCESS_AGENT */ + #ifdef __x86_64__ if (is_64bit) - init_target_desc (tdesc, amd64_expedite_regs); + init_target_desc (tdesc, amd64_expedite_regs, osabi); else #endif - init_target_desc (tdesc, i386_expedite_regs); + init_target_desc (tdesc, i386_expedite_regs, osabi); } diff --git a/gdbserver/netbsd-aarch64-low.cc b/gdbserver/netbsd-aarch64-low.cc index f20a1a71773..8834e0ad894 100644 --- a/gdbserver/netbsd-aarch64-low.cc +++ b/gdbserver/netbsd-aarch64-low.cc @@ -98,7 +98,7 @@ netbsd_aarch64_target::low_arch_setup () = aarch64_create_target_description ({}); static const char *expedite_regs_aarch64[] = { "x29", "sp", "pc", NULL }; - init_target_desc (tdesc, expedite_regs_aarch64); + init_target_desc (tdesc, expedite_regs_aarch64, GDB_OSABI_NETBSD); current_process ()->tdesc = tdesc; } diff --git a/gdbserver/netbsd-amd64-low.cc b/gdbserver/netbsd-amd64-low.cc index b3f3aab5ec3..ad7cb430b92 100644 --- a/gdbserver/netbsd-amd64-low.cc +++ b/gdbserver/netbsd-amd64-low.cc @@ -193,7 +193,7 @@ netbsd_amd64_target::low_arch_setup () target_desc *tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false, false, false); - init_target_desc (tdesc, amd64_expedite_regs); + init_target_desc (tdesc, amd64_expedite_regs, GDB_OSABI_NETBSD); current_process ()->tdesc = tdesc; } diff --git a/gdbserver/netbsd-i386-low.cc b/gdbserver/netbsd-i386-low.cc index 247a39797c4..ea6fce4c6f9 100644 --- a/gdbserver/netbsd-i386-low.cc +++ b/gdbserver/netbsd-i386-low.cc @@ -142,7 +142,7 @@ netbsd_i386_target::low_arch_setup () target_desc *tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false); - init_target_desc (tdesc, i386_expedite_regs); + init_target_desc (tdesc, i386_expedite_regs, GDB_OSABI_NETBSD); current_process ()->tdesc = tdesc; } diff --git a/gdbserver/tdesc.cc b/gdbserver/tdesc.cc index d052f43c76e..da1287abbbe 100644 --- a/gdbserver/tdesc.cc +++ b/gdbserver/tdesc.cc @@ -53,7 +53,8 @@ void target_desc::accept (tdesc_element_visitor &v) const void init_target_desc (struct target_desc *tdesc, - const char **expedite_regs) + const char **expedite_regs, + enum gdb_osabi osabi) { int offset = 0; @@ -88,6 +89,8 @@ init_target_desc (struct target_desc *tdesc, int expedite_count = 0; while (expedite_regs[expedite_count] != nullptr) tdesc->expedite_regs.push_back (expedite_regs[expedite_count++]); + + set_tdesc_osabi (tdesc, osabi); #endif } diff --git a/gdbserver/tdesc.h b/gdbserver/tdesc.h index 4796b50b4d1..e6cefe5af3e 100644 --- a/gdbserver/tdesc.h +++ b/gdbserver/tdesc.h @@ -81,10 +81,11 @@ void copy_target_description (struct target_desc *dest, const struct target_desc *src); /* Initialize TDESC, and then set its expedite_regs field to - EXPEDITE_REGS. */ + EXPEDITE_REGS and its osabi to OSABI. */ void init_target_desc (struct target_desc *tdesc, - const char **expedite_regs); + const char **expedite_regs, + enum gdb_osabi osabi); /* Return the current inferior's target description. Never returns NULL. */ diff --git a/gdbserver/win32-i386-low.cc b/gdbserver/win32-i386-low.cc index 0a761ca58ef..13f9aca99b1 100644 --- a/gdbserver/win32-i386-low.cc +++ b/gdbserver/win32-i386-low.cc @@ -596,12 +596,12 @@ i386_arch_setup (void) #ifdef __x86_64__ tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false, false, false); - init_target_desc (tdesc, amd64_expedite_regs); + init_target_desc (tdesc, amd64_expedite_regs, WINDOWS_OSABI); win32_tdesc = tdesc; #endif tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false); - init_target_desc (tdesc, i386_expedite_regs); + init_target_desc (tdesc, i386_expedite_regs, WINDOWS_OSABI); #ifdef __x86_64__ wow64_win32_tdesc = tdesc; #else diff --git a/gdbserver/win32-low.h b/gdbserver/win32-low.h index ff997df0a66..daed16a6ae6 100644 --- a/gdbserver/win32-low.h +++ b/gdbserver/win32-low.h @@ -21,6 +21,7 @@ #include #include "nat/windows-nat.h" +#include "gdbsupport/osabi.h" struct target_desc; @@ -31,6 +32,12 @@ extern const struct target_desc *win32_tdesc; extern const struct target_desc *wow64_win32_tdesc; #endif +#ifdef __CYGWIN__ +constexpr enum gdb_osabi WINDOWS_OSABI = GDB_OSABI_CYGWIN; +#else +constexpr enum gdb_osabi WINDOWS_OSABI = GDB_OSABI_WINDOWS; +#endif + struct win32_target_ops { /* Architecture-specific setup. */