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/* This test program is part of GDB, the GNU debugger.
Copyright 2011-2019 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Simulate loading of JIT code. */
#include <elf.h>
#include <link.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
/* ElfW is coming from linux. On other platforms it does not exist.
Let us define it here. */
#ifndef ElfW
# if (defined (_LP64) || defined (__LP64__))
# define WORDSIZE 64
# else
# define WORDSIZE 32
# endif /* _LP64 || __LP64__ */
#define ElfW(type) _ElfW (Elf, WORDSIZE, type)
#define _ElfW(e,w,t) _ElfW_1 (e, w, _##t)
#define _ElfW_1(e,w,t) e##w##t
#endif /* !ElfW */
typedef enum
{
JIT_NOACTION = 0,
JIT_REGISTER_FN,
JIT_UNREGISTER_FN
} jit_actions_t;
struct jit_code_entry
{
struct jit_code_entry *next_entry;
struct jit_code_entry *prev_entry;
const char *symfile_addr;
uint64_t symfile_size;
};
struct jit_descriptor
{
uint32_t version;
/* This type should be jit_actions_t, but we use uint32_t
to be explicit about the bitwidth. */
uint32_t action_flag;
struct jit_code_entry *relevant_entry;
struct jit_code_entry *first_entry;
};
/* GDB puts a breakpoint in this function. */
void __attribute__((noinline)) __jit_debug_register_code () { }
/* Make sure to specify the version statically, because the
debugger may check the version before we can set it. */
struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
static void
usage (const char *const argv0)
{
fprintf (stderr, "Usage: %s library [count]\n", argv0);
exit (1);
}
/* Update .p_vaddr and .sh_addr as if the code was JITted to ADDR. */
static void
update_locations (const void *const addr, int idx)
{
const ElfW (Ehdr) *const ehdr = (ElfW (Ehdr) *)addr;
ElfW (Shdr) *const shdr = (ElfW (Shdr) *)((char *)addr + ehdr->e_shoff);
ElfW (Phdr) *const phdr = (ElfW (Phdr) *)((char *)addr + ehdr->e_phoff);
int i;
for (i = 0; i < ehdr->e_phnum; ++i)
if (phdr[i].p_type == PT_LOAD)
phdr[i].p_vaddr += (ElfW (Addr))addr;
for (i = 0; i < ehdr->e_shnum; ++i)
{
if (shdr[i].sh_type == SHT_STRTAB)
{
/* Note: we update both .strtab and .dynstr. The latter would
not be correct if this were a regular shared library (.hash
would be wrong), but this is a simulation -- the library is
never exposed to the dynamic loader, so it all ends up ok. */
char *const strtab = (char *)((ElfW (Addr))addr + shdr[i].sh_offset);
char *const strtab_end = strtab + shdr[i].sh_size;
char *p;
for (p = strtab; p < strtab_end; p += strlen (p) + 1)
if (strcmp (p, "jit_function_XXXX") == 0)
sprintf (p, "jit_function_%04d", idx);
}
if (shdr[i].sh_flags & SHF_ALLOC)
shdr[i].sh_addr += (ElfW (Addr))addr;
}
}
/* Defined by the .exp file if testing attach. */
#ifndef ATTACH
#define ATTACH 0
#endif
#ifndef MAIN
#define MAIN main
#endif
/* Used to spin waiting for GDB. */
volatile int wait_for_gdb = ATTACH;
#define WAIT_FOR_GDB while (wait_for_gdb)
/* The current process's PID. GDB retrieves this. */
int mypid;
int
MAIN (int argc, char *argv[])
{
/* These variables are here so they can easily be set from jit.exp. */
const char *libname = NULL;
int count = 0, i, fd;
struct stat st;
alarm (300);
mypid = getpid ();
count = count; /* gdb break here 0 */
if (argc < 2)
{
usage (argv[0]);
exit (1);
}
if (libname == NULL)
/* Only set if not already set from GDB. */
libname = argv[1];
if (argc > 2 && count == 0)
/* Only set if not already set from GDB. */
count = atoi (argv[2]);
printf ("%s:%d: libname = %s, count = %d\n", __FILE__, __LINE__,
libname, count);
if ((fd = open (libname, O_RDONLY)) == -1)
{
fprintf (stderr, "open (\"%s\", O_RDONLY): %s\n", libname,
strerror (errno));
exit (1);
}
if (fstat (fd, &st) != 0)
{
fprintf (stderr, "fstat (\"%d\"): %s\n", fd, strerror (errno));
exit (1);
}
for (i = 0; i < count; ++i)
{
const void *const addr = mmap (0, st.st_size, PROT_READ|PROT_WRITE,
MAP_PRIVATE, fd, 0);
struct jit_code_entry *const entry = calloc (1, sizeof (*entry));
if (addr == MAP_FAILED)
{
fprintf (stderr, "mmap: %s\n", strerror (errno));
exit (1);
}
update_locations (addr, i);
/* Link entry at the end of the list. */
entry->symfile_addr = (const char *)addr;
entry->symfile_size = st.st_size;
entry->prev_entry = __jit_debug_descriptor.relevant_entry;
__jit_debug_descriptor.relevant_entry = entry;
if (entry->prev_entry != NULL)
entry->prev_entry->next_entry = entry;
else
__jit_debug_descriptor.first_entry = entry;
/* Notify GDB. */
__jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
__jit_debug_register_code ();
}
WAIT_FOR_GDB; i = 0; /* gdb break here 1 */
/* Now unregister them all in reverse order. */
while (__jit_debug_descriptor.relevant_entry != NULL)
{
struct jit_code_entry *const entry =
__jit_debug_descriptor.relevant_entry;
struct jit_code_entry *const prev_entry = entry->prev_entry;
if (prev_entry != NULL)
{
prev_entry->next_entry = NULL;
entry->prev_entry = NULL;
}
else
__jit_debug_descriptor.first_entry = NULL;
/* Notify GDB. */
__jit_debug_descriptor.action_flag = JIT_UNREGISTER_FN;
__jit_debug_register_code ();
__jit_debug_descriptor.relevant_entry = prev_entry;
free (entry);
}
WAIT_FOR_GDB; return 0; /* gdb break here 2 */
}
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