* exec/configure.ac (REENTRANT): Remove option for reentrancy.
(PROGRAM_COUNTER, HAVE_SECCOMP): Define register providing the
program counter and enable seccomp if its headers are available.
* exec/exec.c (write_load_command): Avoid defining unused
variable.
(exec_0): Remove code specific to REENTRANT configurations.
* exec/exec.h (struct exec_tracee) <exec_data, data_size>: New
fields for loader instructions and their size.
* exec/exec1.c (main): Call exec_init before forking.
* exec/mipsel-user.h (ELF_NGREG): Delete definition.
(struct mipsel_regs): Reduce number of gregs to 32, but
introduce separate fields for special registers.
* exec/trace.c (use_seccomp_p): New variable; defile to false if
!HAVE_SECCOMP.
(remove_tracee): Cease providing for non-reentrant
configurations. Release executable data if present.
(handle_clone_prepare): Likewise. Resume process with
PTRACE_CONT if seccomp-based interception is enabled.
(handle_clone, check_signal): Resume processes as above.
(handle_exec): Divide into two functions, with only rewriting
the system call and generating instructions for the loader
remaining in the first, and copying such instructions into the
loader's stack removed into a new function, `finish_exec'.
(finish_exec): New function.
(handle_readlinkat, handle_openat): Abolish non-REENTRANT
configurations.
(process_system_call): Divide exec system calls into two phases,
disambiguated by the value of tracee->waiting_for_syscall. Typo
fixes. Accommodate syscall-exit-stops where the signal was
initially intercepted by `seccomp_system_call'.
(interesting_syscalls): New array.
(ARRAYELTS): New macro.
(seccomp_system_call, establish_seccomp_filter): New function.
(tracing_execve) [HAVE_SECCOMP]: Establish a seccomp filter if
this is to be enabled.
(after_fork): Provide PTRACE_O_TRACESECCOMP. Resume process
with PTRACE_CONT if seccomp-based interception is enabled.
(exec_waitpid): Resume process with PTRACE_CONT if seccomp-based
interception is enabled. Dispatch stops identifying as
PTRACE_EVENT_SECCOMP to `seccomp_system_call'.
(exec_init): Establish whether it is possible to enable seccomp.
* exec/configure.ac (USER_SWORD): New macro.
* exec/exec.c (format_pid): Export this function.
* exec/exec.h:
* exec/trace.c (canon_path): New function.
(handle_readlinkat, handle_openat): Test complete file name
against /proc/self/exe, and further check for /proc/pid/exe.
* exec/configure.ac (OPEN_SYSCALL, OPENAT_SYSCALL): Define new
macros.
* exec/exec.h (struct exec_tracee): New field `sp'.
* exec/trace.c (handle_openat): New function.
(process_system_call): If handle_openat executes successfully,
save the unmodified stack pointer within the tracee structure to
be restored once the system call completes.
* exec/exec.h (struct exec_tracee): New field `new_child'.
Also, make `waiting_for_syscall' a bitfield.
* exec/trace.c (PTRACE_GETEVENTMSG): New declaration.
(MAX_TRACEES): Bump to 4096.
(handle_clone_prepare): New function.
(handle_clone): If required, set `new_child' and wait for a
ptrace event describing the parent to arrive.
(after_fork): Clear new field.
(exec_waitpid): Upon a ptrace event describing a clone, create
the child's tracee if it doesn't already exist. Otherwise, copy
over the parent's cmdline and start running it.
* exec/config.h.in (__bool_true_false_are_defined):
* exec/configure.ac (REENTRANT): New definition.
(READLINKAT_SYSCALL, READLINK_SYSCALL): New defines. Set on all
hosts.
* exec/exec.c (MIN, MAX): Remove redundant declarations. Move
to config.h.
(exec_0): Copy name of executable into NAME when !REENTRANT.
* exec/exec.h (struct exec_tracee): New struct `exec_file'.
* exec/trace.c (remove_tracee, handle_exec, handle_readlinkat)
(process_system_call, after_fork): Handle readlinkat system
calls.
