From e9abe75fda82a986b0b40969ebdd4aa92bcb52e3 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 19 Aug 2016 20:15:26 +0200 Subject: hush: `cmd` and arithmetic also need the fix for FILE rewind Discovered by running testsuite with a newest glibc Signed-off-by: Denys Vlasenko --- shell/hush.c | 71 +++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 39 insertions(+), 32 deletions(-) diff --git a/shell/hush.c b/shell/hush.c index be5c98a..b41d9d0 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -1477,19 +1477,50 @@ static sighandler_t install_sighandler(int sig, sighandler_t handler) return old_sa.sa_handler; } +static void hush_exit(int exitcode) NORETURN; +static void fflush_and__exit(void) NORETURN; +static void restore_ttypgrp_and__exit(void) NORETURN; + +static void restore_ttypgrp_and__exit(void) +{ + /* xfunc has failed! die die die */ + /* no EXIT traps, this is an escape hatch! */ + G.exiting = 1; + hush_exit(xfunc_error_retval); +} + +/* Needed only on some libc: + * It was observed that on exit(), fgetc'ed buffered data + * gets "unwound" via lseek(fd, -NUM, SEEK_CUR). + * With the net effect that even after fork(), not vfork(), + * exit() in NOEXECed applet in "sh SCRIPT": + * noexec_applet_here + * echo END_OF_SCRIPT + * lseeks fd in input FILE object from EOF to "e" in "echo END_OF_SCRIPT". + * This makes "echo END_OF_SCRIPT" executed twice. + * Similar problems can be seen with die_if_script() -> xfunc_die() + * and in `cmd` handling. + * If set as die_func(), this makes xfunc_die() exit via _exit(), not exit(): + */ +static void fflush_and__exit(void) +{ + fflush_all(); + _exit(xfunc_error_retval); +} + #if ENABLE_HUSH_JOB -static void xfunc_has_died(void); /* After [v]fork, in child: do not restore tty pgrp on xfunc death */ -# define disable_restore_tty_pgrp_on_exit() (die_func = NULL) +# define disable_restore_tty_pgrp_on_exit() (die_func = fflush_and__exit) /* After [v]fork, in parent: restore tty pgrp on xfunc death */ -# define enable_restore_tty_pgrp_on_exit() (die_func = xfunc_has_died) +# define enable_restore_tty_pgrp_on_exit() (die_func = restore_ttypgrp_and__exit) /* Restores tty foreground process group, and exits. * May be called as signal handler for fatal signal * (will resend signal to itself, producing correct exit state) * or called directly with -EXITCODE. - * We also call it if xfunc is exiting. */ + * We also call it if xfunc is exiting. + */ static void sigexit(int sig) NORETURN; static void sigexit(int sig) { @@ -1544,7 +1575,6 @@ static sighandler_t pick_sighandler(unsigned sig) } /* Restores tty foreground process group, and exits. */ -static void hush_exit(int exitcode) NORETURN; static void hush_exit(int exitcode) { #if ENABLE_FEATURE_EDITING_SAVE_ON_EXIT @@ -1588,15 +1618,6 @@ static void hush_exit(int exitcode) #endif } -static void xfunc_has_died(void) NORETURN; -static void xfunc_has_died(void) -{ - /* xfunc has failed! die die die */ - /* no EXIT traps, this is an escape hatch! */ - G.exiting = 1; - hush_exit(xfunc_error_retval); -} - //TODO: return a mask of ALL handled sigs? static int check_and_run_traps(void) @@ -5913,7 +5934,8 @@ static FILE *generate_stream_from_string(const char *s, pid_t *pid_p) ) { static const char *const argv[] = { NULL, NULL }; builtin_trap((char**)argv); - exit(0); /* not _exit() - we need to fflush */ + fflush_all(); /* important */ + _exit(0); } # if BB_MMU reset_traps_to_defaults(); @@ -6467,22 +6489,7 @@ static void dump_cmd_in_x_mode(char **argv) * Don't exit() here. If you don't exec, use _exit instead. * The at_exit handlers apparently confuse the calling process, * in particular stdin handling. Not sure why? -- because of vfork! (vda) - * Also, it was observed that on exit(), fgetc'ed buffered data - * gets "unwound" by some libcs, via lseek(fd, -NUM, SEEK_CUR). - * With the net effect that even after fork(), not vfork(), - * exit() in NOEXECed applet in "sh SCRIPT": - * noexec_applet_here - * echo END_OF_SCRIPT - * lseeks fd in input FILE object from EOF to "e" in "echo END_OF_SCRIPT". - * This makes "echo END_OF_SCRIPT" executed twice. exexit() is the fix. */ -#if ENABLE_FEATURE_SH_STANDALONE -static void exexit(void) -{ - fflush_all(); - _exit(xfunc_error_retval); -} -#endif static void pseudo_exec_argv(nommu_save_t *nommu_save, char **argv, int assignment_cnt, char **argv_expanded) NORETURN; @@ -6563,7 +6570,6 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save, # if BB_MMU /* see above why on NOMMU it is not allowed */ if (APPLET_IS_NOEXEC(a)) { debug_printf_exec("running applet '%s'\n", argv[0]); - die_func = exexit; run_applet_no_and_exit(a, argv); } # endif @@ -7804,6 +7810,7 @@ int hush_main(int argc, char **argv) INIT_G(); if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */ G.last_exitcode = EXIT_SUCCESS; + #if ENABLE_HUSH_FAST G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */ #endif @@ -7893,7 +7900,7 @@ int hush_main(int argc, char **argv) /* Initialize some more globals to non-zero values */ cmdedit_update_prompt(); - die_func = xfunc_has_died; + die_func = restore_ttypgrp_and__exit; /* Shell is non-interactive at first. We need to call * install_special_sighandlers() if we are going to execute "sh