From: Denys Vlasenko Date: Tue, 29 Aug 2017 11:38:30 +0000 (+0200) Subject: hush: fix "getopts" builtin to not be upset by other builtins calling getopt() X-Git-Tag: 1_28_0~89 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=238ff98bb85adfb5563d10b37ea4c33fef3af2f2;p=oweals%2Fbusybox.git hush: fix "getopts" builtin to not be upset by other builtins calling getopt() function old new delta builtin_getopts 363 403 +40 unset_local_var_len 185 215 +30 set_local_var 440 466 +26 reset_traps_to_defaults 151 157 +6 pseudo_exec_argv 320 326 +6 install_special_sighandlers 52 58 +6 pick_sighandler 62 65 +3 execvp_or_die 85 88 +3 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 8/0 up/down: 120/0) Total: 120 bytes Signed-off-by: Denys Vlasenko --- diff --git a/shell/ash_test/ash-getopts/getopt_nested.right b/shell/ash_test/ash-getopts/getopt_nested.right new file mode 100644 index 000000000..b0c339db1 --- /dev/null +++ b/shell/ash_test/ash-getopts/getopt_nested.right @@ -0,0 +1,14 @@ +var:a +var:b +var:c +var:a +var:b +var:c +Illegal option -d +var:? +Illegal option -e +var:? +Illegal option -f +var:? +var:a +End: var:? OPTIND:6 diff --git a/shell/ash_test/ash-getopts/getopt_nested.tests b/shell/ash_test/ash-getopts/getopt_nested.tests new file mode 100755 index 000000000..1b48b4075 --- /dev/null +++ b/shell/ash_test/ash-getopts/getopt_nested.tests @@ -0,0 +1,21 @@ +# Test that there is no interference of getopt() +# in getopts and unset. +# It's unclear what "correct" OPTIND values should be +# for "b" and "c" results from "-bc": 2? 3? +# What we focus on here is that all options are reported +# correct number of times and in correct sequence. + +( + +loop=99 +while getopts "abc" var -a -bc -abc -def -a; do + echo "var:$var" #OPTIND:$OPTIND + # this may use getopt(): + unset -ff func + test $((--loop)) = 0 && break # BUG if this triggers +done +echo "End: var:$var OPTIND:$OPTIND" + +) 2>&1 \ +| sed -e 's/ unrecognized option: / invalid option -- /' \ + -e 's/ illegal option -- / invalid option -- /' \ diff --git a/shell/hush.c b/shell/hush.c index cdc3a8618..ceb8cbb0a 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -906,6 +906,9 @@ struct globals { #if ENABLE_HUSH_LOOPS unsigned depth_break_continue; unsigned depth_of_loop; +#endif +#if ENABLE_HUSH_GETOPTS + unsigned getopt_count; #endif const char *ifs; const char *cwd; @@ -2214,6 +2217,10 @@ static int set_local_var(char *str, unsigned flags) cur->flg_export = 1; if (name_len == 4 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S') cmdedit_update_prompt(); +#if ENABLE_HUSH_GETOPTS + if (strncmp(cur->varstr, "OPTIND=", 7) == 0) + G.getopt_count = 0; +#endif if (cur->flg_export) { if (flags & SETFLAG_UNEXPORT) { cur->flg_export = 0; @@ -2244,6 +2251,10 @@ static int unset_local_var_len(const char *name, int name_len) if (!name) return EXIT_SUCCESS; +#if ENABLE_HUSH_GETOPTS + if (name_len == 6 && strncmp(name, "OPTIND", 6) == 0) + G.getopt_count = 0; +#endif var_pp = &G.top_var; while ((cur = *var_pp) != NULL) { if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') { @@ -9889,7 +9900,8 @@ Test that VAR is a valid variable name? */ char cbuf[2]; const char *cp, *optstring, *var; - int c, exitcode; + int c, n, exitcode, my_opterr; + unsigned count; optstring = *++argv; if (!optstring || !(var = *++argv)) { @@ -9897,17 +9909,18 @@ Test that VAR is a valid variable name? return EXIT_FAILURE; } - c = 0; + if (argv[1]) + argv[0] = G.global_argv[0]; /* for error messages in getopt() */ + else + argv = G.global_argv; + cbuf[1] = '\0'; + + my_opterr = 0; if (optstring[0] != ':') { cp = get_local_var_value("OPTERR"); /* 0 if "OPTERR=0", 1 otherwise */ - c = (!cp || NOT_LONE_CHAR(cp, '0')); + my_opterr = (!cp || NOT_LONE_CHAR(cp, '0')); } - opterr = c; - cp = get_local_var_value("OPTIND"); - optind = cp ? atoi(cp) : 0; - optarg = NULL; - cbuf[1] = '\0'; /* getopts stops on first non-option. Add "+" to force that */ /*if (optstring[0] != '+')*/ { @@ -9916,11 +9929,47 @@ Test that VAR is a valid variable name? optstring = s; } - if (argv[1]) - argv[0] = G.global_argv[0]; /* for error messages */ - else - argv = G.global_argv; - c = getopt(string_array_len(argv), argv, optstring); + /* Naively, now we should just + * cp = get_local_var_value("OPTIND"); + * optind = cp ? atoi(cp) : 0; + * optarg = NULL; + * opterr = my_opterr; + * c = getopt(string_array_len(argv), argv, optstring); + * and be done? Not so fast... + * Unlike normal getopt() usage in C programs, here + * each successive call will (usually) have the same argv[] CONTENTS, + * but not the ADDRESSES. Worse yet, it's possible that between + * invocations of "getopts", there will be calls to shell builtins + * which use getopt() internally. Example: + * while getopts "abc" RES -a -bc -abc de; do + * unset -ff func + * done + * This would not work correctly: getopt() call inside "unset" + * modifies internal libc state which is tracking position in + * multi-option strings ("-abc"). At best, it can skip options + * or return the same option infinitely. With glibc implementation + * of getopt(), it would use outright invalid pointers and return + * garbage even _without_ "unset" mangling internal state. + * + * We resort to resetting getopt() state and calling it N times, + * until we get Nth result (or failure). + * (N == G.getopt_count is reset to 0 whenever OPTIND is [un]set). + */ + optind = 0; /* reset getopt() state */ + count = 0; + n = string_array_len(argv); + do { + optarg = NULL; + opterr = (count < G.getopt_count) ? 0 : my_opterr; + c = getopt(n, argv, optstring); + if (c < 0) + break; + count++; + } while (count <= G.getopt_count); + + /* Set OPTIND. Prevent resetting of the magic counter! */ + set_local_var_from_halves("OPTIND", utoa(optind)); + G.getopt_count = count; /* "next time, give me N+1'th result" */ /* Set OPTARG */ /* Always set or unset, never left as-is, even on exit/error: @@ -9949,10 +9998,9 @@ Test that VAR is a valid variable name? c = '?'; } - /* Set VAR and OPTIND */ + /* Set VAR */ cbuf[0] = c; set_local_var_from_halves(var, cbuf); - set_local_var_from_halves("OPTIND", utoa(optind)); return exitcode; } diff --git a/shell/hush_test/hush-getopts/getopt_nested.right b/shell/hush_test/hush-getopts/getopt_nested.right new file mode 100644 index 000000000..0218dba56 --- /dev/null +++ b/shell/hush_test/hush-getopts/getopt_nested.right @@ -0,0 +1,14 @@ +var:a +var:b +var:c +var:a +var:b +var:c +./getopt_nested.tests: invalid option -- d +var:? +./getopt_nested.tests: invalid option -- e +var:? +./getopt_nested.tests: invalid option -- f +var:? +var:a +End: var:? OPTIND:6 diff --git a/shell/hush_test/hush-getopts/getopt_nested.tests b/shell/hush_test/hush-getopts/getopt_nested.tests new file mode 100755 index 000000000..1b48b4075 --- /dev/null +++ b/shell/hush_test/hush-getopts/getopt_nested.tests @@ -0,0 +1,21 @@ +# Test that there is no interference of getopt() +# in getopts and unset. +# It's unclear what "correct" OPTIND values should be +# for "b" and "c" results from "-bc": 2? 3? +# What we focus on here is that all options are reported +# correct number of times and in correct sequence. + +( + +loop=99 +while getopts "abc" var -a -bc -abc -def -a; do + echo "var:$var" #OPTIND:$OPTIND + # this may use getopt(): + unset -ff func + test $((--loop)) = 0 && break # BUG if this triggers +done +echo "End: var:$var OPTIND:$OPTIND" + +) 2>&1 \ +| sed -e 's/ unrecognized option: / invalid option -- /' \ + -e 's/ illegal option -- / invalid option -- /' \