diff options
Diffstat (limited to 'trap.c')
| -rw-r--r-- | trap.c | 75 |
1 files changed, 70 insertions, 5 deletions
@@ -7,7 +7,7 @@ Bash 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 1, or (at your option) any later + Software Foundation; either version 2, or (at your option) any later version. Bash is distributed in the hope that it will be useful, but WITHOUT ANY @@ -17,7 +17,7 @@ You should have received a copy of the GNU General Public License along with Bash; see the file COPYING. If not, write to the Free Software - Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ + Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */ #include "config.h" @@ -29,13 +29,19 @@ #include "bashansi.h" #include <stdio.h> +#include <errno.h> #include "trap.h" #include "shell.h" +#include "input.h" /* for save_token_state, restore_token_state */ #include "signames.h" #include "builtins/common.h" +#ifndef errno +extern int errno; +#endif + /* Flags which describe the current handling state of a signal. */ #define SIG_INHERITED 0x0 /* Value inherited from parent. */ #define SIG_TRAPPED 0x1 /* Currently trapped. */ @@ -135,6 +141,25 @@ initialize_traps () } } +#ifdef INCLUDE_UNUSED +/* Return a printable representation of the trap handler for SIG. */ +static char * +trap_handler_string (sig) + int sig; +{ + if (trap_list[sig] == (char *)DEFAULT_SIG) + return "DEFAULT_SIG"; + else if (trap_list[sig] == (char *)IGNORE_SIG) + return "IGNORE_SIG"; + else if (trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) + return "IMPOSSIBLE_TRAP_HANDLER"; + else if (trap_list[sig]) + return trap_list[sig]; + else + return "NULL"; +} +#endif + /* Return the print name of this signal. */ char * signal_name (sig) @@ -183,7 +208,7 @@ void run_pending_traps () { register int sig; - int old_exit_value; + int old_exit_value, *token_state; if (catch_flag == 0) /* simple optimization */ return; @@ -218,8 +243,38 @@ run_pending_traps () run_interrupt_trap (); CLRINTERRUPT; } + else if (trap_list[sig] == (char *)DEFAULT_SIG || + trap_list[sig] == (char *)IGNORE_SIG || + trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) + { + /* This is possible due to a race condition. Say a bash + process has SIGTERM trapped. A subshell is spawned + using { list; } & and the parent does something and kills + the subshell with SIGTERM. It's possible for the subshell + to set pending_traps[SIGTERM] to 1 before the code in + execute_cmd.c eventually calls restore_original_signals + to reset the SIGTERM signal handler in the subshell. The + next time run_pending_traps is called, pending_traps[SIGTERM] + will be 1, but the trap handler in trap_list[SIGTERM] will + be invalid (probably DEFAULT_SIG, but it could be IGNORE_SIG). + Unless we catch this, the subshell will dump core when + trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is + usually 0x0. */ + internal_warning ("run_pending_traps: bad value in trap_list[%d]: 0x%x", + sig, (int)trap_list[sig]); + if (trap_list[sig] == (char *)DEFAULT_SIG) + { + internal_warning ("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself", sig, signal_name (sig)); + kill (getpid (), sig); + } + } else - parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST); + { + token_state = save_token_state (); + parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST); + restore_token_state (token_state); + free (token_state); + } pending_traps[sig] = 0; @@ -240,12 +295,15 @@ sighandler trap_handler (sig) int sig; { + int oerrno; + if ((sig >= NSIG) || (trap_list[sig] == (char *)DEFAULT_SIG) || (trap_list[sig] == (char *)IGNORE_SIG)) programming_error ("trap_handler: bad signal %d", sig); else { + errno = oerrno; #if defined (MUST_REINSTALL_SIGHANDLERS) set_signal_handler (sig, trap_handler); #endif /* MUST_REINSTALL_SIGHANDLERS */ @@ -255,6 +313,8 @@ trap_handler (sig) if (interrupt_immediately) run_pending_traps (); + + errno = oerrno; } SIGRETURN (0); @@ -563,7 +623,7 @@ _run_trap_internal (sig, tag) char *tag; { char *trap_command, *old_trap; - int old_exit_value, old_line_number; + int old_exit_value, old_line_number, *token_state; /* Run the trap only if SIG is trapped and not ignored, and we are not currently executing in the trap handler. */ @@ -581,7 +641,12 @@ _run_trap_internal (sig, tag) /* Need to copy the value of line_number because parse_and_execute resets it to 1, and the trap command might want it. */ trap_line_number = line_number; + + token_state = save_token_state (); parse_and_execute (trap_command, tag, SEVAL_NONINT|SEVAL_NOHIST); + restore_token_state (token_state); + free (token_state); + last_command_exit_value = old_exit_value; running_trap = 0; |