X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Ffork-child.c;h=718a3d2de2129e84b596ed292c4608efb7ba4284;hb=c1299d67f5e87927ba19ac99524d238905b9c406;hp=9fc11310fe6e984f372af408eae7f02cc86200a9;hpb=4142aab89d7ed976a29a01a7b955ac87d3d4b450;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/fork-child.c b/gdb/fork-child.c index 9fc11310fe..718a3d2de2 100644 --- a/gdb/fork-child.c +++ b/gdb/fork-child.c @@ -1,63 +1,130 @@ /* Fork a Unix child process, and set up to debug it, for GDB. - Copyright 1990, 1991, 1992 Free Software Foundation, Inc. + + Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, + 2000, 2001, 2004 Free Software Foundation, Inc. + Contributed by Cygnus Support. -This file is part of GDB. + 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 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. + 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ + 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 "defs.h" -#include "frame.h" /* required by inferior.h */ +#include "gdb_string.h" +#include "frame.h" /* required by inferior.h */ #include "inferior.h" #include "target.h" -#include "wait.h" +#include "gdb_wait.h" +#include "gdb_vfork.h" #include "gdbcore.h" #include "terminal.h" -#include "thread.h" +#include "gdbthread.h" +#include "command.h" /* for dont_repeat () */ #include -#ifdef SET_STACK_LIMIT_HUGE -#include -#include - -extern int original_stack_limit; -#endif /* SET_STACK_LIMIT_HUGE */ +/* This just gets used as a default if we can't find SHELL. */ +#ifndef SHELL_FILE +#define SHELL_FILE "/bin/sh" +#endif extern char **environ; -/* Start an inferior Unix child process and sets inferior_pid to its pid. - EXEC_FILE is the file to run. - ALLARGS is a string containing the arguments to the program. - ENV is the environment vector to pass. Errors reported with error(). */ +/* Break up SCRATCH into an argument vector suitable for passing to + execvp and store it in ARGV. E.g., on "run a b c d" this routine + would get as input the string "a b c d", and as output it would + fill in ARGV with the four arguments "a", "b", "c", "d". */ -#ifndef SHELL_FILE -#define SHELL_FILE "/bin/sh" -#endif +static void +breakup_args (char *scratch, char **argv) +{ + char *cp = scratch; + + for (;;) + { + /* Scan past leading separators */ + while (*cp == ' ' || *cp == '\t' || *cp == '\n') + cp++; + + /* Break if at end of string. */ + if (*cp == '\0') + break; + + /* Take an arg. */ + *argv++ = cp; + + /* Scan for next arg separator. */ + cp = strchr (cp, ' '); + if (cp == NULL) + cp = strchr (cp, '\t'); + if (cp == NULL) + cp = strchr (cp, '\n'); + + /* No separators => end of string => break. */ + if (cp == NULL) + break; + + /* Replace the separator with a terminator. */ + *cp++ = '\0'; + } + + /* Null-terminate the vector. */ + *argv = NULL; +} + +/* When executing a command under the given shell, return non-zero if + the '!' character should be escaped when embedded in a quoted + command-line argument. */ + +static int +escape_bang_in_quoted_argument (const char *shell_file) +{ + const int shell_file_len = strlen (shell_file); + + /* Bang should be escaped only in C Shells. For now, simply check + that the shell name ends with 'csh', which covers at least csh + and tcsh. This should be good enough for now. */ + + if (shell_file_len < 3) + return 0; + + if (shell_file[shell_file_len - 3] == 'c' + && shell_file[shell_file_len - 2] == 's' + && shell_file[shell_file_len - 1] == 'h') + return 1; + + return 0; +} + +/* Start an inferior Unix child process and sets inferior_ptid to its + pid. EXEC_FILE is the file to run. ALLARGS is a string containing + the arguments to the program. ENV is the environment vector to + pass. SHELL_FILE is the shell file, or NULL if we should pick + one. */ + +/* This function is NOT reentrant. Some of the variables have been + made static to ensure that they survive the vfork call. */ void -fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun) - char *exec_file; - char *allargs; - char **env; - void (*traceme_fun) PARAMS ((void)); - void (*init_trace_fun) PARAMS ((int)); +fork_inferior (char *exec_file_arg, char *allargs, char **env, + void (*traceme_fun) (void), void (*init_trace_fun) (int), + void (*pre_trace_fun) (void), char *shell_file_arg) { int pid; char *shell_command; - char *shell_file; static char default_shell_file[] = SHELL_FILE; int len; /* Set debug_fork then attach to the child while it sleeps, to debug. */ @@ -65,26 +132,36 @@ fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun) /* This is set to the result of setpgrp, which if vforked, will be visible to you in the parent process. It's only used by humans for debugging. */ static int debug_setpgrp = 657473; + static char *shell_file; + static char *exec_file; char **save_our_env; + int shell = 0; + static char **argv; - /* If no exec file handed to us, get it from the exec-file command -- with - a good, common error message if none is specified. */ + /* If no exec file handed to us, get it from the exec-file command + -- with a good, common error message if none is specified. */ + exec_file = exec_file_arg; if (exec_file == 0) - exec_file = get_exec_file(1); - - /* The user might want tilde-expansion, and in general probably wants - the program to behave the same way as if run from - his/her favorite shell. So we let the shell run it for us. - FIXME-maybe, we might want a "set shell" command so the user can change - the shell from within GDB. */ - shell_file = getenv ("SHELL"); - if (shell_file == NULL) - shell_file = default_shell_file; - - /* Multiplying the length of exec_file by 4 is to account for the fact - that it may expand when quoted; it is a worst-case number based on - every character being '. */ - len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 12; + exec_file = get_exec_file (1); + + /* STARTUP_WITH_SHELL is defined in inferior.h. If 0,e we'll just + do a fork/exec, no shell, so don't bother figuring out what + shell. */ + shell_file = shell_file_arg; + if (STARTUP_WITH_SHELL) + { + /* Figure out what shell to start up the user program under. */ + if (shell_file == NULL) + shell_file = getenv ("SHELL"); + if (shell_file == NULL) + shell_file = default_shell_file; + shell = 1; + } + + /* Multiplying the length of exec_file by 4 is to account for the + fact that it may expand when quoted; it is a worst-case number + based on every character being '. */ + len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop */ 12; /* If desired, concat something onto the front of ALLARGS. SHELL_COMMAND is the result. */ #ifdef SHELL_COMMAND_CONCAT @@ -94,160 +171,237 @@ fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun) shell_command = (char *) alloca (len); shell_command[0] = '\0'; #endif - strcat (shell_command, "exec "); - - /* Now add exec_file, quoting as necessary. */ - { - char *p; - int need_to_quote; - - /* Quoting in this style is said to work with all shells. But csh - on IRIX 4.0.1 can't deal with it. So we only quote it if we need - to. */ - p = exec_file; - while (1) - { - switch (*p) - { - case '\'': - case '"': - case '(': - case ')': - case '$': - case '&': - case ';': - case '<': - case '>': - case ' ': - case '\n': - case '\t': - need_to_quote = 1; - goto end_scan; - - case '\0': - need_to_quote = 0; - goto end_scan; - - default: - break; - } - ++p; - } - end_scan: - if (need_to_quote) - { - strcat (shell_command, "'"); - for (p = exec_file; *p != '\0'; ++p) - { - if (*p == '\'') - strcat (shell_command, "'\\''"); - else - strncat (shell_command, p, 1); - } - strcat (shell_command, "'"); - } - else - strcat (shell_command, exec_file); - } - - strcat (shell_command, " "); - strcat (shell_command, allargs); - - /* exec is said to fail if the executable is open. */ + + if (!shell) + { + /* We're going to call execvp. Create argument vector. + Calculate an upper bound on the length of the vector by + assuming that every other character is a separate + argument. */ + int argc = (strlen (allargs) + 1) / 2 + 2; + argv = (char **) xmalloc (argc * sizeof (*argv)); + argv[0] = exec_file; + breakup_args (allargs, &argv[1]); + } + else + { + /* We're going to call a shell. */ + + /* Now add exec_file, quoting as necessary. */ + + char *p; + int need_to_quote; + const int escape_bang = escape_bang_in_quoted_argument (shell_file); + + strcat (shell_command, "exec "); + + /* Quoting in this style is said to work with all shells. But + csh on IRIX 4.0.1 can't deal with it. So we only quote it if + we need to. */ + p = exec_file; + while (1) + { + switch (*p) + { + case '\'': + case '!': + case '"': + case '(': + case ')': + case '$': + case '&': + case ';': + case '<': + case '>': + case ' ': + case '\n': + case '\t': + need_to_quote = 1; + goto end_scan; + + case '\0': + need_to_quote = 0; + goto end_scan; + + default: + break; + } + ++p; + } + end_scan: + if (need_to_quote) + { + strcat (shell_command, "'"); + for (p = exec_file; *p != '\0'; ++p) + { + if (*p == '\'') + strcat (shell_command, "'\\''"); + else if (*p == '!' && escape_bang) + strcat (shell_command, "\\!"); + else + strncat (shell_command, p, 1); + } + strcat (shell_command, "'"); + } + else + strcat (shell_command, exec_file); + + strcat (shell_command, " "); + strcat (shell_command, allargs); + } + + /* On some systems an exec will fail if the executable is open. */ close_exec_file (); /* Retain a copy of our environment variables, since the child will - replace the value of environ and if we're vforked, we have to + replace the value of environ and if we're vforked, we have to restore it. */ save_our_env = environ; /* Tell the terminal handling subsystem what tty we plan to run on; it will just record the information for later. */ - new_tty_prefork (inferior_io_terminal); /* It is generally good practice to flush any possible pending stdio - output prior to doing a fork, to avoid the possibility of both the - parent and child flushing the same data after the fork. */ - + output prior to doing a fork, to avoid the possibility of both + the parent and child flushing the same data after the fork. */ gdb_flush (gdb_stdout); gdb_flush (gdb_stderr); -#if defined(USG) && !defined(HAVE_VFORK) - pid = fork (); -#else - if (debug_fork) + /* If there's any initialization of the target layers that must + happen to prepare to handle the child we're about fork, do it + now... */ + if (pre_trace_fun != NULL) + (*pre_trace_fun) (); + + /* Create the child process. Since the child process is going to + exec(3) shortlty afterwards, try to reduce the overhead by + calling vfork(2). However, if PRE_TRACE_FUN is non-null, it's + likely that this optimization won't work since there's too much + work to do between the vfork(2) and the exec(3). This is known + to be the case on ttrace(2)-based HP-UX, where some handshaking + between parent and child needs to happen between fork(2) and + exec(2). However, since the parent is suspended in the vforked + state, this doesn't work. Also note that the vfork(2) call might + actually be a call to fork(2) due to the fact that autoconf will + ``#define vfork fork'' on certain platforms. */ + if (pre_trace_fun || debug_fork) pid = fork (); else pid = vfork (); -#endif if (pid < 0) perror_with_name ("vfork"); if (pid == 0) { - if (debug_fork) + if (debug_fork) sleep (debug_fork); /* Run inferior in a separate process group. */ debug_setpgrp = gdb_setpgid (); if (debug_setpgrp == -1) - perror("setpgrp failed in child"); - -#ifdef SET_STACK_LIMIT_HUGE - /* Reset the stack limit back to what it was. */ - { - struct rlimit rlim; - - getrlimit (RLIMIT_STACK, &rlim); - rlim.rlim_cur = original_stack_limit; - setrlimit (RLIMIT_STACK, &rlim); - } -#endif /* SET_STACK_LIMIT_HUGE */ - - /* Ask the tty subsystem to switch to the one we specified earlier - (or to share the current terminal, if none was specified). */ + perror ("setpgrp failed in child"); + /* Ask the tty subsystem to switch to the one we specified + earlier (or to share the current terminal, if none was + specified). */ new_tty (); /* Changing the signal handlers for the inferior after - a vfork can also change them for the superior, so we don't mess - with signals here. See comments in - initialize_signals for how we get the right signal handlers - for the inferior. */ + a vfork can also change them for the superior, so we don't mess + with signals here. See comments in + initialize_signals for how we get the right signal handlers + for the inferior. */ /* "Trace me, Dr. Memory!" */ (*traceme_fun) (); + /* The call above set this process (the "child") as debuggable + by the original gdb process (the "parent"). Since processes + (unlike people) can have only one parent, if you are debugging + gdb itself (and your debugger is thus _already_ the + controller/parent for this child), code from here on out is + undebuggable. Indeed, you probably got an error message + saying "not parent". Sorry; you'll have to use print + statements! */ + /* There is no execlpe call, so we have to set the environment - for our child in the global variable. If we've vforked, this - clobbers the parent, but environ is restored a few lines down - in the parent. By the way, yes we do need to look down the - path to find $SHELL. Rich Pixley says so, and I agree. */ + for our child in the global variable. If we've vforked, this + clobbers the parent, but environ is restored a few lines down + in the parent. By the way, yes we do need to look down the + path to find $SHELL. Rich Pixley says so, and I agree. */ environ = env; - execlp (shell_file, shell_file, "-c", shell_command, (char *)0); - fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, - safe_strerror (errno)); - gdb_flush (gdb_stderr); - _exit (0177); + /* If we decided above to start up with a shell, we exec the + shell, "-c" says to interpret the next arg as a shell command + to execute, and this command is "exec + ". "-f" means "fast startup" to the c-shell, which + means don't do .cshrc file. Doing .cshrc may cause fork/exec + events which will confuse debugger start-up code. */ + if (shell) + { + execlp (shell_file, shell_file, "-c", shell_command, (char *) 0); + + /* If we get here, it's an error. */ + fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, + safe_strerror (errno)); + gdb_flush (gdb_stderr); + _exit (0177); + } + else + { + /* Otherwise, we directly exec the target program with + execvp. */ + int i; + char *errstring; + + execvp (exec_file, argv); + + /* If we get here, it's an error. */ + errstring = safe_strerror (errno); + fprintf_unfiltered (gdb_stderr, "Cannot exec %s ", exec_file); + + i = 1; + while (argv[i] != NULL) + { + if (i != 1) + fprintf_unfiltered (gdb_stderr, " "); + fprintf_unfiltered (gdb_stderr, "%s", argv[i]); + i++; + } + fprintf_unfiltered (gdb_stderr, ".\n"); +#if 0 + /* This extra info seems to be useless. */ + fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring); +#endif + gdb_flush (gdb_stderr); + _exit (0177); + } } /* Restore our environment in case a vforked child clob'd it. */ environ = save_our_env; - init_thread_list(); + init_thread_list (); - inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ + /* Needed for wait_for_inferior stuff below. */ + inferior_ptid = pid_to_ptid (pid); /* Now that we have a child process, make it our target, and - initialize anything target-vector-specific that needs initializing. */ - (*init_trace_fun)(pid); + initialize anything target-vector-specific that needs + initializing. */ + (*init_trace_fun) (pid); /* We are now in the child process of interest, having exec'd the correct program, and are poised at the first instruction of the new program. */ + + /* Allow target dependent code to play with the new process. This + might be used to have target-specific code initialize a variable + in the new process prior to executing the first instruction. */ + TARGET_CREATE_INFERIOR_HOOK (pid); + #ifdef SOLIB_CREATE_INFERIOR_HOOK SOLIB_CREATE_INFERIOR_HOOK (pid); #endif @@ -256,30 +410,36 @@ fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun) /* Accept NTRAPS traps from the inferior. */ void -startup_inferior (ntraps) - int ntraps; +startup_inferior (int ntraps) { int pending_execs = ntraps; - int terminal_initted; + int terminal_initted = 0; - /* The process was started by the fork that created it, - but it will have stopped one instruction after execing the shell. - Here we must get it up to actual execution of the real program. */ + /* The process was started by the fork that created it, but it will + have stopped one instruction after execing the shell. Here we + must get it up to actual execution of the real program. */ clear_proceed_status (); init_wait_for_inferior (); - terminal_initted = 0; + if (STARTUP_WITH_SHELL) + inferior_ignoring_startup_exec_events = ntraps; + else + inferior_ignoring_startup_exec_events = 0; + inferior_ignoring_leading_exec_events = + target_reported_exec_events_per_exec_call () - 1; while (1) { - stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ + /* Make wait_for_inferior be quiet. */ + stop_soon = STOP_QUIETLY; wait_for_inferior (); - if (stop_signal != SIGTRAP) + if (stop_signal != TARGET_SIGNAL_TRAP) { - /* Let shell child handle its own signals in its own way */ - /* FIXME, what if child has exit()ed? Must exit loop somehow */ + /* Let shell child handle its own signals in its own way. + FIXME: what if child has exited? Must exit loop + somehow. */ resume (0, stop_signal); } else @@ -287,12 +447,13 @@ startup_inferior (ntraps) /* We handle SIGTRAP, however; it means child did an exec. */ if (!terminal_initted) { - /* Now that the child has exec'd we know it has already set its - process group. On POSIX systems, tcsetpgrp will fail with - EPERM if we try it before the child's setpgid. */ + /* Now that the child has exec'd we know it has already + set its process group. On POSIX systems, tcsetpgrp + will fail with EPERM if we try it before the child's + setpgid. */ /* Set up the "saved terminal modes" of the inferior - based on what modes we are starting it with. */ + based on what modes we are starting it with. */ target_terminal_init (); /* Install inferior's terminal modes. */ @@ -300,10 +461,12 @@ startup_inferior (ntraps) terminal_initted = 1; } - if (0 == --pending_execs) + + if (--pending_execs == 0) break; - resume (0, 0); /* Just make it go on */ + + resume (0, TARGET_SIGNAL_0); /* Just make it go on. */ } } - stop_soon_quietly = 0; + stop_soon = NO_STOP_QUIETLY; }