gdb_assert (info == nullptr);
}
+/* Open the /proc/PID/mem file for PROC. */
+
+static void
+open_proc_mem_file (process_info *proc)
+{
+ gdb_assert (proc->priv->mem_fd == -1);
+
+ char filename[64];
+ xsnprintf (filename, sizeof filename, "/proc/%d/mem", proc->pid);
+
+ proc->priv->mem_fd
+ = gdb_open_cloexec (filename, O_RDWR | O_LARGEFILE, 0).release ();
+}
+
process_info *
-linux_process_target::add_linux_process (int pid, int attached)
+linux_process_target::add_linux_process_no_mem_file (int pid, int attached)
{
struct process_info *proc;
proc->priv = XCNEW (struct process_info_private);
proc->priv->arch_private = low_new_process ();
+ proc->priv->mem_fd = -1;
+
+ return proc;
+}
+
+process_info *
+linux_process_target::add_linux_process (int pid, int attached)
+{
+ process_info *proc = add_linux_process_no_mem_file (pid, attached);
+ open_proc_mem_file (proc);
return proc;
}
NULL, NULL, NULL, NULL);
}
- add_linux_process (pid, 0);
+ /* When spawning a new process, we can't open the mem file yet. We
+ still have to nurse the process through the shell, and that execs
+ a couple times. The address space a /proc/PID/mem file is
+ accessing is destroyed on exec. */
+ process_info *proc = add_linux_process_no_mem_file (pid, 0);
ptid = ptid_t (pid, pid);
new_lwp = add_lwp (ptid);
post_fork_inferior (pid, program);
+ /* PROC is now past the shell running the program we want, so we can
+ open the /proc/PID/mem file. */
+ open_proc_mem_file (proc);
+
return pid;
}
ptid_t ptid = ptid_t (pid, pid);
int err;
- proc = add_linux_process (pid, 1);
+ /* Delay opening the /proc/PID/mem file until we've successfully
+ attached. */
+ proc = add_linux_process_no_mem_file (pid, 1);
/* Attach to PID. We will check for other threads
soon. */
error ("Cannot attach to process %ld: %s", pid, reason.c_str ());
}
+ open_proc_mem_file (proc);
+
/* Don't ignore the initial SIGSTOP if we just attached to this
process. It will be collected by wait shortly. */
initial_thread = find_thread_ptid (ptid_t (pid, pid));
/* Freeing all private data. */
priv = process->priv;
+ close (priv->mem_fd);
low_delete_process (priv->arch_private);
free (priv);
process->priv = NULL;
return the_target->read_memory (memaddr, myaddr, len);
}
-/* Copy LEN bytes from inferior's memory starting at MEMADDR
- to debugger memory starting at MYADDR. */
-int
-linux_process_target::read_memory (CORE_ADDR memaddr,
- unsigned char *myaddr, int len)
+/* Helper for read_memory/write_memory using /proc/PID/mem. Because
+ we can use a single read/write call, this can be much more
+ efficient than banging away at PTRACE_PEEKTEXT. Also, unlike
+ PTRACE_PEEKTEXT/PTRACE_POKETEXT, this works with running threads.
+ One an only one of READBUF and WRITEBUF is non-null. If READBUF is
+ not null, then we're reading, otherwise we're writing. */
+
+static int
+proc_xfer_memory (CORE_ADDR memaddr, unsigned char *readbuf,
+ const gdb_byte *writebuf, int len)
{
- int pid = lwpid_of (current_thread);
- PTRACE_XFER_TYPE *buffer;
- CORE_ADDR addr;
- int count;
- char filename[64];
- int i;
- int ret;
- int fd;
+ gdb_assert ((readbuf == nullptr) != (writebuf == nullptr));
- /* Try using /proc. Don't bother for one word. */
- if (len >= 3 * sizeof (long))
+ process_info *proc = current_process ();
+
+ int fd = proc->priv->mem_fd;
+ if (fd == -1)
+ return EIO;
+
+ while (len > 0)
{
int bytes;
- /* We could keep this file open and cache it - possibly one per
- thread. That requires some juggling, but is even faster. */
- sprintf (filename, "/proc/%d/mem", pid);
- fd = open (filename, O_RDONLY | O_LARGEFILE);
- if (fd == -1)
- goto no_proc;
-
/* If pread64 is available, use it. It's faster if the kernel
supports it (only one syscall), and it's 64-bit safe even on
32-bit platforms (for instance, SPARC debugging a SPARC64
application). */
#ifdef HAVE_PREAD64
- bytes = pread64 (fd, myaddr, len, memaddr);
+ bytes = (readbuf != nullptr
+ ? pread64 (fd, readbuf, len, memaddr)
+ : pwrite64 (fd, writebuf, len, memaddr));
#else
bytes = -1;
if (lseek (fd, memaddr, SEEK_SET) != -1)
- bytes = read (fd, myaddr, len);
+ bytes = (readbuf != nullptr
+ ? read (fd, readbuf, len)
+ ? write (fd, writebuf, len));
#endif
- close (fd);
- if (bytes == len)
- return 0;
-
- /* Some data was read, we'll try to get the rest with ptrace. */
- if (bytes > 0)
+ if (bytes < 0)
+ return errno;
+ else if (bytes == 0)
{
- memaddr += bytes;
- myaddr += bytes;
- len -= bytes;
+ /* EOF means the address space is gone, the whole process
+ exited or execed. */
+ return EIO;
}
- }
- no_proc:
- /* Round starting address down to longword boundary. */
- addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
- /* Round ending address up; get number of longwords that makes. */
- count = ((((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
- / sizeof (PTRACE_XFER_TYPE));
- /* Allocate buffer of that many longwords. */
- buffer = XALLOCAVEC (PTRACE_XFER_TYPE, count);
-
- /* Read all the longwords */
- errno = 0;
- for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
- {
- /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning
- about coercing an 8 byte integer to a 4 byte pointer. */
- buffer[i] = ptrace (PTRACE_PEEKTEXT, pid,
- (PTRACE_TYPE_ARG3) (uintptr_t) addr,
- (PTRACE_TYPE_ARG4) 0);
- if (errno)
- break;
+ memaddr += bytes;
+ if (readbuf != nullptr)
+ readbuf += bytes;
+ else
+ writebuf += bytes;
+ len -= bytes;
}
- ret = errno;
- /* Copy appropriate bytes out of the buffer. */
- if (i > 0)
- {
- i *= sizeof (PTRACE_XFER_TYPE);
- i -= memaddr & (sizeof (PTRACE_XFER_TYPE) - 1);
- memcpy (myaddr,
- (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
- i < len ? i : len);
- }
+ return 0;
+}
- return ret;
+int
+linux_process_target::read_memory (CORE_ADDR memaddr,
+ unsigned char *myaddr, int len)
+{
+ return proc_xfer_memory (memaddr, myaddr, nullptr, len);
}
/* Copy LEN bytes of data from debugger memory at MYADDR to inferior's
linux_process_target::write_memory (CORE_ADDR memaddr,
const unsigned char *myaddr, int len)
{
- int i;
- /* Round starting address down to longword boundary. */
- CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE);
- /* Round ending address up; get number of longwords that makes. */
- int count
- = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1)
- / sizeof (PTRACE_XFER_TYPE);
-
- /* Allocate buffer of that many longwords. */
- PTRACE_XFER_TYPE *buffer = XALLOCAVEC (PTRACE_XFER_TYPE, count);
-
- int pid = lwpid_of (current_thread);
-
- if (len == 0)
- {
- /* Zero length write always succeeds. */
- return 0;
- }
-
if (debug_threads)
{
/* Dump up to four bytes. */
char *p = str;
int dump = len < 4 ? len : 4;
- for (i = 0; i < dump; i++)
+ for (int i = 0; i < dump; i++)
{
sprintf (p, "%02x", myaddr[i]);
p += 2;
*p = '\0';
threads_debug_printf ("Writing %s to 0x%08lx in process %d",
- str, (long) memaddr, pid);
+ str, (long) memaddr, current_process ()->pid);
}
- /* Fill start and end extra bytes of buffer with existing memory data. */
-
- errno = 0;
- /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning
- about coercing an 8 byte integer to a 4 byte pointer. */
- buffer[0] = ptrace (PTRACE_PEEKTEXT, pid,
- (PTRACE_TYPE_ARG3) (uintptr_t) addr,
- (PTRACE_TYPE_ARG4) 0);
- if (errno)
- return errno;
-
- if (count > 1)
- {
- errno = 0;
- buffer[count - 1]
- = ptrace (PTRACE_PEEKTEXT, pid,
- /* Coerce to a uintptr_t first to avoid potential gcc warning
- about coercing an 8 byte integer to a 4 byte pointer. */
- (PTRACE_TYPE_ARG3) (uintptr_t) (addr + (count - 1)
- * sizeof (PTRACE_XFER_TYPE)),
- (PTRACE_TYPE_ARG4) 0);
- if (errno)
- return errno;
- }
-
- /* Copy data to be written over corresponding part of buffer. */
-
- memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)),
- myaddr, len);
-
- /* Write the entire buffer. */
-
- for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE))
- {
- errno = 0;
- ptrace (PTRACE_POKETEXT, pid,
- /* Coerce to a uintptr_t first to avoid potential gcc warning
- about coercing an 8 byte integer to a 4 byte pointer. */
- (PTRACE_TYPE_ARG3) (uintptr_t) addr,
- (PTRACE_TYPE_ARG4) buffer[i]);
- if (errno)
- return errno;
- }
-
- return 0;
+ return proc_xfer_memory (memaddr, nullptr, myaddr, len);
}
void
unstop_all_lwps (unfreeze, NULL);
}
-int
-linux_process_target::prepare_to_access_memory ()
-{
- /* Neither ptrace nor /proc/PID/mem allow accessing memory through a
- running LWP. */
- if (non_stop)
- target_pause_all (true);
- return 0;
-}
-
-void
-linux_process_target::done_accessing_memory ()
-{
- /* Neither ptrace nor /proc/PID/mem allow accessing memory through a
- running LWP. */
- if (non_stop)
- target_unpause_all (true);
-}
-
/* Extract &phdr and num_phdr in the inferior. Return 0 on success. */
static int
projects / binutils-gdb.git / commitdiff