From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martijn Dekker Subject: [PATCH] quote arguments in xtrace output Date: Mon, 27 Feb 2017 07:22:13 +0100 Message-ID: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------575F76EA48A7C7B9A53C9EC3" Return-path: Received: from kahlil.inlv.org ([37.59.109.123]:57590 "EHLO kahlil.inlv.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751484AbdB0GlQ (ORCPT ); Mon, 27 Feb 2017 01:41:16 -0500 Received: from breedzicht.local (inlv.demon.nl [212.238.240.159]) (authenticated bits=0) by kahlil.inlv.org (8.14.9/8.14.4) with ESMTP id v1R6MDQ0005866 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Mon, 27 Feb 2017 07:22:14 +0100 Sender: dash-owner@vger.kernel.org List-Id: dash@vger.kernel.org To: dash This is a multi-part message in MIME format. --------------575F76EA48A7C7B9A53C9EC3 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit The xtrace (set -x) output in dash is a bit of a pain, because arguments containing whitespace aren't quoted. This can it impossible to tell which bit belongs to which argument: $ dash -c 'set -x; printf "%s\n" one "two three" four' + printf %s\n one two three four one two three four Another disadvantage is you cannot simply copy and paste the commands from this xtrace output to repeat them for debugging purposes. I wrote the attached patch which fixes this. I've been testing it for about a week and had no issues. The patch changes the following: - Since we don't want every command name and argument quoted but only those containing non-shell-safe characters, single_quote() has acquired an extra argument indicating whether quoting should be conditional upon the string containing non-shell-safe characters (1) or unconditional (0). Shell-safe characters are defined as this set: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz%+,./:=@_^!- - Quoting of variable assignments preceding commands needs to be handled specially; in order for the output to be suitable for re-entry into the shell, only the part after the "=" must be quoted. For this purpose, I changed eprintlist() into two functions, eprintvarlist() to print the variable assignments and eprintarglist() to print the rest. Hope this is useful, - Martijn --------------575F76EA48A7C7B9A53C9EC3 Content-Type: text/x-patch; name="dash-shellquoted-xtrace.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="dash-shellquoted-xtrace.patch" diff -ur dash-0.5.9.1.orig/src/alias.c dash-0.5.9.1/src/alias.c --- dash-0.5.9.1.orig/src/alias.c 2014-09-28 10:19:32.000000000 +0200 +++ dash-0.5.9.1/src/alias.c 2017-02-23 03:01:57.000000000 +0100 @@ -197,7 +197,7 @@ void printalias(const struct alias *ap) { - out1fmt("%s=%s\n", ap->name, single_quote(ap->val)); + out1fmt("%s=%s\n", ap->name, single_quote(ap->val, 0)); } STATIC struct alias ** diff -ur dash-0.5.9.1.orig/src/eval.c dash-0.5.9.1/src/eval.c --- dash-0.5.9.1.orig/src/eval.c 2016-09-02 16:12:23.000000000 +0200 +++ dash-0.5.9.1/src/eval.c 2017-02-23 03:14:56.000000000 +0100 @@ -95,7 +95,8 @@ STATIC int evalbltin(const struct builtincmd *, int, char **, int); STATIC int evalfun(struct funcnode *, int, char **, int); STATIC void prehash(union node *); -STATIC int eprintlist(struct output *, struct strlist *, int); +STATIC int eprintvarlist(struct output *, struct strlist *, int); +STATIC void eprintarglist(struct output *, struct strlist *, int); STATIC int bltincmd(int, char **); @@ -786,8 +787,8 @@ out = &preverrout; outstr(expandstr(ps4val()), out); sep = 0; - sep = eprintlist(out, varlist.list, sep); - eprintlist(out, arglist.list, sep); + sep = eprintvarlist(out, varlist.list, sep); + eprintarglist(out, arglist.list, sep); outcslow('\n', out); #ifdef FLUSHERR flushout(out); @@ -1107,16 +1108,35 @@ STATIC int -eprintlist(struct output *out, struct strlist *sp, int sep) +eprintvarlist(struct output *out, struct strlist *sp, int sep) { while (sp) { const char *p; + int i; - p = " %s" + (1 - sep); + if (sep) + outfmt(out, " "); sep |= 1; - outfmt(out, p, sp->text); + i = 0; + while (sp->text[i] != '=' && sp->text[i] != '\0') + outfmt(out, "%c", sp->text[i++]); + if (sp->text[i] == '=') + outfmt(out, "=%s", single_quote(sp->text+i+1, 1)); sp = sp->next; } return sep; } + +STATIC void +eprintarglist(struct output *out, struct strlist *sp, int sep) +{ + while (sp) { + const char *p; + + p = " %s" + (1 - sep); + sep |= 1; + outfmt(out, p, single_quote(sp->text, 1)); + sp = sp->next; + } +} diff -ur dash-0.5.9.1.orig/src/mystring.c dash-0.5.9.1/src/mystring.c --- dash-0.5.9.1.orig/src/mystring.c 2014-09-28 10:19:32.000000000 +0200 +++ dash-0.5.9.1/src/mystring.c 2017-02-23 03:10:48.000000000 +0100 @@ -184,13 +184,19 @@ /* * Produce a possibly single quoted string suitable as input to the shell. - * The return string is allocated on the stack. + * If 'conditional' is nonzero, quoting is only done if the string contains + * non-shellsafe characters; if it is zero, quoting is always done. + * If quoting was done, the return string is allocated on the stack, + * otherwise a pointer to the original string is returned. */ char * -single_quote(const char *s) { +single_quote(const char *s, int conditional) { char *p; + if (conditional && s[strspn(s, SHELLSAFECHARS)] == '\0') + return (char *)s; + STARTSTACKSTR(p); do { diff -ur dash-0.5.9.1.orig/src/mystring.h dash-0.5.9.1/src/mystring.h --- dash-0.5.9.1.orig/src/mystring.h 2014-09-28 10:19:32.000000000 +0200 +++ dash-0.5.9.1/src/mystring.h 2017-02-23 03:01:57.000000000 +0100 @@ -54,10 +54,13 @@ intmax_t atomax10(const char *); int number(const char *); int is_number(const char *); -char *single_quote(const char *); +char *single_quote(const char *, int); char *sstrdup(const char *); int pstrcmp(const void *, const void *); const char *const *findstring(const char *, const char *const *, size_t); #define equal(s1, s2) (strcmp(s1, s2) == 0) #define scopy(s1, s2) ((void)strcpy(s2, s1)) + +/* Characters that don't need quoting before re-entry into the shell */ +#define SHELLSAFECHARS "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz%+,./:=@_^!-" diff -ur dash-0.5.9.1.orig/src/trap.c dash-0.5.9.1/src/trap.c --- dash-0.5.9.1.orig/src/trap.c 2016-09-02 16:12:23.000000000 +0200 +++ dash-0.5.9.1/src/trap.c 2017-02-23 03:01:57.000000000 +0100 @@ -107,7 +107,7 @@ if (trap[signo] != NULL) { out1fmt( "trap -- %s %s\n", - single_quote(trap[signo]), + single_quote(trap[signo], 0), signal_names[signo] ); } diff -ur dash-0.5.9.1.orig/src/var.c dash-0.5.9.1/src/var.c --- dash-0.5.9.1.orig/src/var.c 2014-10-07 16:30:35.000000000 +0200 +++ dash-0.5.9.1/src/var.c 2017-02-23 03:01:57.000000000 +0100 @@ -417,7 +417,7 @@ p = strchrnul(*ep, '='); q = nullstr; if (*p) - q = single_quote(++p); + q = single_quote(++p, 0); out1fmt("%s%s%.*s%s\n", prefix, sep, (int)(p - *ep), *ep, q); } --------------575F76EA48A7C7B9A53C9EC3--