diff options
Diffstat (limited to 'shell/hush.c')
| -rw-r--r-- | shell/hush.c | 98 |
1 files changed, 40 insertions, 58 deletions
diff --git a/shell/hush.c b/shell/hush.c index c8bcf9b..6734c92 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -90,14 +90,6 @@ #define SKIP_FEATURE_SH_STANDALONE(...) __VA_ARGS__ #endif -#if !BB_MMU && ENABLE_HUSH_TICK -//#undef ENABLE_HUSH_TICK -//#define ENABLE_HUSH_TICK 0 -#warning On NOMMU, hush command substitution is dangerous. -#warning Dont use it for commands which produce lots of output. -#warning For more info see shell/hush.c, generate_stream_from_list(). -#endif - #if !ENABLE_HUSH_INTERACTIVE #undef ENABLE_FEATURE_EDITING #define ENABLE_FEATURE_EDITING 0 @@ -1649,7 +1641,7 @@ static char **o_finalize_list(o_string *o, int n) /* Expansion can recurse */ #if ENABLE_HUSH_TICK -static int process_command_subs(o_string *dest, struct in_str *input); +static int process_command_subs(o_string *dest, const char *s); #endif static char *expand_string_to_string(const char *str); static int parse_stream_dquoted(o_string *dest, struct in_str *input, int dquote_end); @@ -1798,18 +1790,15 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask) ored_ch = 0x80; break; #if ENABLE_HUSH_TICK - case '`': { /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */ - struct in_str input; + case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */ *p = '\0'; arg++; //TODO: can we just stuff it into "output" directly? debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch); - setup_string_in_str(&input, arg); - process_command_subs(&subst_result, &input); + process_command_subs(&subst_result, arg); debug_printf_subst("SUBST RES '%s'\n", subst_result.data); val = subst_result.data; goto store_val; - } #endif #if ENABLE_SH_MATH_SUPPORT case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */ @@ -3711,35 +3700,20 @@ static int redirect_opt_num(o_string *o) } static struct pipe *parse_stream(struct in_str *input, int end_trigger); +static void parse_and_run_string(const char *s); #if ENABLE_HUSH_TICK -static FILE *generate_stream_from_list(struct pipe *head) +static FILE *generate_stream_from_string(const char *s) { FILE *pf; int pid, channel[2]; xpipe(channel); -/* *** NOMMU WARNING *** */ -/* By using vfork here, we suspend parent till child exits or execs. - * If child will not do it before it fills the pipe, it can block forever - * in write(STDOUT_FILENO), and parent (shell) will be also stuck. - * Try this script: - * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE - * huge=`cat TESTFILE` # will block here forever - * echo OK - */ pid = BB_MMU ? fork() : vfork(); if (pid < 0) bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork"); + if (pid == 0) { /* child */ - if (ENABLE_HUSH_JOB) - die_sleep = 0; /* let nofork's xfuncs die */ - close(channel[0]); /* NB: close _first_, then move fd! */ - xmove_fd(channel[1], 1); - /* Prevent it from trying to handle ctrl-z etc */ -#if ENABLE_HUSH_JOB - G.run_list_level = 1; -#endif /* Process substitution is not considered to be usual * 'command execution'. * SUSv3 says ctrl-Z should be ignored, ctrl-C should not. @@ -3749,40 +3723,47 @@ static FILE *generate_stream_from_list(struct pipe *head) + (1 << SIGTTIN) + (1 << SIGTTOU) , SIG_IGN); - - /* Note: freeing 'head' here would break NOMMU. */ - _exit(run_list(head)); + if (ENABLE_HUSH_JOB) + die_sleep = 0; /* let nofork's xfuncs die */ + close(channel[0]); /* NB: close _first_, then move fd! */ + xmove_fd(channel[1], 1); + /* Prevent it from trying to handle ctrl-z etc */ + USE_HUSH_JOB(G.run_list_level = 1;) +#if BB_MMU + parse_and_run_string(s); + _exit(G.last_return_code); +#else + /* We re-execute after vfork on NOMMU. This makes this script safe: + * yes "0123456789012345678901234567890" | dd bs=32 count=64k >TESTFILE + * huge=`cat TESTFILE` # was blocking here forever + * echo OK + */ +//TODO: pass non-exported variables, traps, and functions + execl(CONFIG_BUSYBOX_EXEC_PATH, "hush", "-c", s, NULL); + _exit(127); +#endif } + + /* parent */ close(channel[1]); pf = fdopen(channel[0], "r"); return pf; - /* 'head' is freed by the caller */ } /* Return code is exit status of the process that is run. */ -static int process_command_subs(o_string *dest, - struct in_str *input) +static int process_command_subs(o_string *dest, const char *s) { - int retcode, ch, eol_cnt; - struct pipe *pipe_list; - FILE *p; + FILE *pf; struct in_str pipe_str; + int ch, eol_cnt; - /* Recursion to generate command */ - pipe_list = parse_stream(input, '\0'); - if (pipe_list == NULL) - return 0; /* EOF: empty `cmd`: ``, ` ` etc */ - if (pipe_list == ERR_PTR) - return 1; /* parse error. can this really happen? */ - - p = generate_stream_from_list(pipe_list); - free_pipe_list(pipe_list, /* indent: */ 0); - if (p == NULL) + pf = generate_stream_from_string(s); + if (pf == NULL) return 1; - close_on_exec_on(fileno(p)); + close_on_exec_on(fileno(pf)); /* Now send results of command back into original context */ - setup_file_in_str(&pipe_str, p); + setup_file_in_str(&pipe_str, pf); eol_cnt = 0; while ((ch = i_getch(&pipe_str)) != EOF) { if (ch == '\n') { @@ -3799,12 +3780,13 @@ static int process_command_subs(o_string *dest, debug_printf("done reading from pipe, pclose()ing\n"); /* Note: we got EOF, and we just close the read end of the pipe. * We do not wait for the `cmd` child to terminate. bash and ash do. - * Try this: - * echo `echo Hi; exec 1>&-; sleep 2` + * Try these: + * echo `echo Hi; exec 1>&-; sleep 2` - bash waits 2 sec + * `false`; echo $? - bash outputs "1" */ - retcode = fclose(p); - debug_printf("closed FILE from child, retcode=%d\n", retcode); - return retcode; + fclose(pf); + debug_printf("closed FILE from child. return 0\n"); + return 0; } #endif |