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PATCH: PR gdb/13969: GDBserver doesn't check unsupported binary
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GDB <gdb-patches at sourceware dot org>
- Date: Wed, 11 Apr 2012 12:16:09 -0700
- Subject: PATCH: PR gdb/13969: GDBserver doesn't check unsupported binary
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,
This patch checks if a binary is supported by GDBserver. Also checking
ELF64 isn't very reliable to detect 64bit register support since x32
is ELF32, but it does support 64bit register. This patch checks the
e_machine field for 64bit register support. OK for trunk?
Thanks.
H.J.
---
2012-04-11 H.J. Lu <hongjiu.lu@intel.com>
PR gdb/13969
* linux-low.c (linux_pid_exe_is_elf_64_file): Also return the
e_machine field.
(linux_qxfer_libraries_svr4): Update call to elf_64_file_p.
* linux-low.h (linux_pid_exe_is_elf_64_file): Updated.
* linux-x86-low.c (linux_is_64bit): New.
(x86_arch_setup): Check if GDBserver is compatible with
process.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index f7a83f4..35d7e69 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -263,13 +263,19 @@ static void wait_for_sigstop (struct inferior_list_entry *entry);
/* Return non-zero if HEADER is a 64-bit ELF file. */
static int
-elf_64_header_p (const Elf64_Ehdr *header)
+elf_64_header_p (const Elf64_Ehdr *header, unsigned int *machine)
{
- return (header->e_ident[EI_MAG0] == ELFMAG0
- && header->e_ident[EI_MAG1] == ELFMAG1
- && header->e_ident[EI_MAG2] == ELFMAG2
- && header->e_ident[EI_MAG3] == ELFMAG3
- && header->e_ident[EI_CLASS] == ELFCLASS64);
+ if (header->e_ident[EI_MAG0] == ELFMAG0
+ && header->e_ident[EI_MAG1] == ELFMAG1
+ && header->e_ident[EI_MAG2] == ELFMAG2
+ && header->e_ident[EI_MAG3] == ELFMAG3)
+ {
+ *machine = header->e_machine;
+ return header->e_ident[EI_CLASS] == ELFCLASS64;
+
+ }
+ *machine = EM_NONE;
+ return -1;
}
/* Return non-zero if FILE is a 64-bit ELF file,
@@ -277,7 +283,7 @@ elf_64_header_p (const Elf64_Ehdr *header)
and -1 if the file is not accessible or doesn't exist. */
static int
-elf_64_file_p (const char *file)
+elf_64_file_p (const char *file, unsigned int *machine)
{
Elf64_Ehdr header;
int fd;
@@ -293,19 +299,19 @@ elf_64_file_p (const char *file)
}
close (fd);
- return elf_64_header_p (&header);
+ return elf_64_header_p (&header, machine);
}
/* Accepts an integer PID; Returns true if the executable PID is
running is a 64-bit ELF file.. */
int
-linux_pid_exe_is_elf_64_file (int pid)
+linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine)
{
char file[MAXPATHLEN];
sprintf (file, "/proc/%d/exe", pid);
- return elf_64_file_p (file);
+ return elf_64_file_p (file, machine);
}
static void
@@ -5584,6 +5590,7 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
32 /* l_prev offset in link_map. */
};
const struct link_map_offsets *lmo;
+ unsigned int machine;
if (writebuf != NULL)
return -2;
@@ -5592,7 +5599,7 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
pid = lwpid_of (get_thread_lwp (current_inferior));
xsnprintf (filename, sizeof filename, "/proc/%d/exe", pid);
- is_elf64 = elf_64_file_p (filename);
+ is_elf64 = elf_64_file_p (filename, &machine);
lmo = is_elf64 ? &lmo_64bit_offsets : &lmo_32bit_offsets;
if (priv->r_debug == 0)
diff --git a/gdb/gdbserver/linux-low.h b/gdb/gdbserver/linux-low.h
index 07eda12..a1a6777 100644
--- a/gdb/gdbserver/linux-low.h
+++ b/gdb/gdbserver/linux-low.h
@@ -278,7 +278,7 @@ struct lwp_info
extern struct inferior_list all_lwps;
-int linux_pid_exe_is_elf_64_file (int pid);
+int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
void linux_attach_lwp (unsigned long pid);
struct lwp_info *find_lwp_pid (ptid_t ptid);
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index 7feb721..8a4ab50 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -1106,17 +1106,28 @@ x86_linux_process_qsupported (const char *query)
static void
x86_arch_setup (void)
{
-#ifdef __x86_64__
int pid = pid_of (get_thread_lwp (current_inferior));
- int use_64bit = linux_pid_exe_is_elf_64_file (pid);
+ unsigned int machine;
+ int use_64bit = linux_pid_exe_is_elf_64_file (pid, &machine);
+ if (sizeof (void *) == 4)
+ {
+ if (use_64bit > 0)
+ error (_("Can't debug 64-bit process with 32-bit GDBserver"));
+#ifndef __x86_64__
+ else if (machine == EM_X86_64)
+ error (_("Can't debug x86-64 process with 32-bit GDBserver"));
+#endif
+ }
+
+#ifdef __x86_64__
if (use_64bit < 0)
{
/* This can only happen if /proc/<pid>/exe is unreadable,
but "that can't happen" if we've gotten this far.
Fall through and assume this is a 32-bit program. */
}
- else if (use_64bit)
+ else if (machine == EM_X86_64)
{
/* Amd64 doesn't have HAVE_LINUX_USRREGS. */
the_low_target.num_regs = -1;