/* Low level interface to ptrace, for the remote server for GDB. Copyright 1995, 1996, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc. This file is part of GDB. 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 2 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, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "server.h" #include "linux-low.h" #include #include #include #include #include #include #include #include #include #include #include #include static CORE_ADDR linux_bp_reinsert; static void linux_resume (int step, int signal); #define PTRACE_ARG3_TYPE long #define PTRACE_XFER_TYPE long #ifdef HAVE_LINUX_REGSETS static int use_regsets_p = 1; #endif extern int errno; static int inferior_pid; struct inferior_linux_data { int pid; }; /* Start an inferior process and returns its pid. ALLARGS is a vector of program-name and args. */ static int linux_create_inferior (char *program, char **allargs) { struct inferior_linux_data *tdata; int pid; pid = fork (); if (pid < 0) perror_with_name ("fork"); if (pid == 0) { ptrace (PTRACE_TRACEME, 0, 0, 0); execv (program, allargs); fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror (errno)); fflush (stderr); _exit (0177); } add_inferior (pid); tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata)); tdata->pid = pid; set_inferior_target_data (current_inferior, tdata); /* FIXME remove */ inferior_pid = pid; return 0; } /* Attach to an inferior process. */ static int linux_attach (int pid) { struct inferior_linux_data *tdata; if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0) { fprintf (stderr, "Cannot attach to process %d: %s (%d)\n", pid, errno < sys_nerr ? sys_errlist[errno] : "unknown error", errno); fflush (stderr); _exit (0177); } add_inferior (pid); tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata)); tdata->pid = pid; set_inferior_target_data (current_inferior, tdata); return 0; } /* Kill the inferior process. Make us have no inferior. */ static void linux_kill (void) { if (inferior_pid == 0) return; ptrace (PTRACE_KILL, inferior_pid, 0, 0); wait (0); clear_inferiors (); } /* Return nonzero if the given thread is still alive. */ static int linux_thread_alive (int pid) { return 1; } static int linux_wait_for_one_inferior (struct inferior_info *child) { struct inferior_linux_data *child_data = inferior_target_data (child); int pid, wstat; while (1) { pid = waitpid (child_data->pid, &wstat, 0); if (pid != child_data->pid) perror_with_name ("wait"); /* If this target supports breakpoints, see if we hit one. */ if (the_low_target.stop_pc != NULL && WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP) { CORE_ADDR stop_pc; if (linux_bp_reinsert != 0) { reinsert_breakpoint (linux_bp_reinsert); linux_bp_reinsert = 0; linux_resume (0, 0); continue; } fetch_inferior_registers (0); stop_pc = (*the_low_target.stop_pc) (); if (check_breakpoints (stop_pc) != 0) { if (the_low_target.set_pc != NULL) (*the_low_target.set_pc) (stop_pc); if (the_low_target.breakpoint_reinsert_addr == NULL) { linux_bp_reinsert = stop_pc; uninsert_breakpoint (stop_pc); linux_resume (1, 0); } else { reinsert_breakpoint_by_bp (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ()); linux_resume (0, 0); } continue; } } return wstat; } /* NOTREACHED */ return 0; } /* Wait for process, returns status */ static unsigned char linux_wait (char *status) { int w; enable_async_io (); w = linux_wait_for_one_inferior (current_inferior); disable_async_io (); if (WIFEXITED (w)) { fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w)); *status = 'W'; clear_inferiors (); return ((unsigned char) WEXITSTATUS (w)); } else if (!WIFSTOPPED (w)) { fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w)); clear_inferiors (); *status = 'X'; return ((unsigned char) WTERMSIG (w)); } fetch_inferior_registers (0); *status = 'T'; return ((unsigned char) WSTOPSIG (w)); } /* Resume execution of the inferior process. If STEP is nonzero, single-step it. If SIGNAL is nonzero, give it that signal. */ static void linux_resume (int step, int signal) { errno = 0; ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal); if (errno) perror_with_name ("ptrace"); } #ifdef HAVE_LINUX_USRREGS #define REGISTER_RAW_SIZE(regno) register_size((regno)) int register_addr (int regnum) { int addr; if (regnum < 0 || regnum >= the_low_target.num_regs) error ("Invalid register number %d.", regnum); addr = the_low_target.regmap[regnum]; if (addr == -1) addr = 0; return addr; } /* Fetch one register. */ static void fetch_register (int regno) { CORE_ADDR regaddr; register int i; if (regno >= the_low_target.num_regs) return; if ((*the_low_target.cannot_fetch_register) (regno)) return; regaddr = register_addr (regno); if (regaddr == -1) return; for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE)) { errno = 0; *(PTRACE_XFER_TYPE *) (register_data (regno) + i) = ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0); regaddr += sizeof (PTRACE_XFER_TYPE); if (errno != 0) { /* Warning, not error, in case we are attached; sometimes the kernel doesn't let us at the registers. */ char *err = strerror (errno); char *msg = alloca (strlen (err) + 128); sprintf (msg, "reading register %d: %s", regno, err); error (msg); goto error_exit; } } error_exit:; } /* Fetch all registers, or just one, from the child process. */ static void usr_fetch_inferior_registers (int regno) { if (regno == -1 || regno == 0) for (regno = 0; regno < the_low_target.num_regs; regno++) fetch_register (regno); else fetch_register (regno); } /* Store our register values back into the inferior. If REGNO is -1, do this for all registers. Otherwise, REGNO specifies which register (so we can save time). */ static void usr_store_inferior_registers (int regno) { CORE_ADDR regaddr; int i; if (regno >= 0) { if (regno >= the_low_target.num_regs) return; if ((*the_low_target.cannot_store_register) (regno) == 1) return; regaddr = register_addr (regno); if (regaddr == -1) return; errno = 0; for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE)) { errno = 0; ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, *(int *) (register_data (regno) + i)); if (errno != 0) { if ((*the_low_target.cannot_store_register) (regno) == 0) { char *err = strerror (errno); char *msg = alloca (strlen (err) + 128); sprintf (msg, "writing register %d: %s", regno, err); error (msg); return; } } regaddr += sizeof (int); } } else for (regno = 0; regno < the_low_target.num_regs; regno++) store_inferior_registers (regno); } #endif /* HAVE_LINUX_USRREGS */ #ifdef HAVE_LINUX_REGSETS static int regsets_fetch_inferior_registers (void) { struct regset_info *regset; regset = target_regsets; while (regset->size >= 0) { void *buf; int res; if (regset->size == 0) { regset ++; continue; } buf = malloc (regset->size); res = ptrace (regset->get_request, inferior_pid, 0, buf); if (res < 0) { if (errno == EIO) { /* If we get EIO on the first regset, do not try regsets again. If we get EIO on a later regset, disable that regset. */ if (regset == target_regsets) { use_regsets_p = 0; return -1; } else { regset->size = 0; continue; } } else { perror ("Warning: ptrace(regsets_fetch_inferior_registers)"); } } regset->store_function (buf); regset ++; } return 0; } static int regsets_store_inferior_registers (void) { struct regset_info *regset; regset = target_regsets; while (regset->size >= 0) { void *buf; int res; if (regset->size == 0) { regset ++; continue; } buf = malloc (regset->size); regset->fill_function (buf); res = ptrace (regset->set_request, inferior_pid, 0, buf); if (res < 0) { if (errno == EIO) { /* If we get EIO on the first regset, do not try regsets again. If we get EIO on a later regset, disable that regset. */ if (regset == target_regsets) { use_regsets_p = 0; return -1; } else { regset->size = 0; continue; } } else { perror ("Warning: ptrace(regsets_store_inferior_registers)"); } } regset ++; } return 0; } #endif /* HAVE_LINUX_REGSETS */ void linux_fetch_registers (int regno) { #ifdef HAVE_LINUX_REGSETS if (use_regsets_p) { if (regsets_fetch_inferior_registers () == 0) return; } #endif #ifdef HAVE_LINUX_USRREGS usr_fetch_inferior_registers (regno); #endif } void linux_store_registers (int regno) { #ifdef HAVE_LINUX_REGSETS if (use_regsets_p) { if (regsets_store_inferior_registers () == 0) return; } #endif #ifdef HAVE_LINUX_USRREGS usr_store_inferior_registers (regno); #endif } /* Copy LEN bytes from inferior's memory starting at MEMADDR to debugger memory starting at MYADDR. */ static void linux_read_memory (CORE_ADDR memaddr, char *myaddr, int len) { register int i; /* Round starting address down to longword boundary. */ register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); /* Round ending address up; get number of longwords that makes. */ register int count = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); /* Allocate buffer of that many longwords. */ register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); /* Read all the longwords */ for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) { buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0); } /* Copy appropriate bytes out of the buffer. */ memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), len); } /* Copy LEN bytes of data from debugger memory at MYADDR to inferior's memory at MEMADDR. On failure (cannot write the inferior) returns the value of errno. */ static int linux_write_memory (CORE_ADDR memaddr, const char *myaddr, int len) { register int i; /* Round starting address down to longword boundary. */ register CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); /* Round ending address up; get number of longwords that makes. */ register int count = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) / sizeof (PTRACE_XFER_TYPE); /* Allocate buffer of that many longwords. */ register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE)); extern int errno; /* Fill start and end extra bytes of buffer with existing memory data. */ buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) addr, 0); if (count > 1) { buffer[count - 1] = ptrace (PTRACE_PEEKTEXT, inferior_pid, (PTRACE_ARG3_TYPE) (addr + (count - 1) * sizeof (PTRACE_XFER_TYPE)), 0); } /* 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, inferior_pid, (PTRACE_ARG3_TYPE) addr, buffer[i]); if (errno) return errno; } return 0; } static void linux_look_up_symbols (void) { /* Don't need to look up any symbols yet. */ } static struct target_ops linux_target_ops = { linux_create_inferior, linux_attach, linux_kill, linux_thread_alive, linux_resume, linux_wait, linux_fetch_registers, linux_store_registers, linux_read_memory, linux_write_memory, linux_look_up_symbols, }; void initialize_low (void) { set_target_ops (&linux_target_ops); set_breakpoint_data (the_low_target.breakpoint, the_low_target.breakpoint_len); init_registers (); }