From ef91d3d6a4c39421fd3a391e02cd82f9f3aee4a8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 29 Sep 2014 22:52:41 +0800 Subject: [PARSER] Handle backslash newlines properly after dollar sign On Tue, Aug 26, 2014 at 12:34:42PM +0000, Eric Blake wrote: > On 08/26/2014 06:15 AM, Oleg Bulatov wrote: > > Hi! > > > > While playing with sh generators I found that dash and bash have different > > interpretations for sequence. > > > > $ dash -c 'EDIT=xxx; echo $EDIT\ > >> OR' > > xxxOR > > Buggy. > > > $ bash -c 'EDIT=xxx; echo $EDIT\ > > OR' > > /usr/bin/vim > > Correct behavior. > > > > > $ dash -c 'echo "$\ > > (pwd)"' > > $(pwd) > > > > Is it undefined behaviour in POSIX? > > No, it's well-defined, and dash is buggy. POSIX says: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_03 > > "the shell shall break its input into tokens by applying the first > applicable rule below to the next character in its input" > > Rule 4 covers backslash handling, while rule 5 covers locating the end > of a word to be subject to $ expansion. Therefore, rule 4 should happen > first. Rule 4 defers to the section on quoting, with the caveat that > joining is the only substitution that happens immediately as > part of the parsing: > > http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02 > > "If a follows the , the shell shall interpret this > as line continuation. The and shall be removed > before splitting the input into tokens. Since the escaped is > removed entirely from the input and is not replaced by any white space, > it cannot serve as a token separator." > > So the fact that dash is treating the elided backslash-newline as a > token separator, and parsing your input as if ${EDIT}OR instead of > ${EDITOR} is a bug in dash. I agree. This patch should resolve this problem and similar ones affecting blackslash newlines after we encounter a dollar sign. Signed-off-by: Herbert Xu --- src/parser.c | 36 +++++++++++++++++++++++++++--------- 1 file changed, 27 insertions(+), 9 deletions(-) (limited to 'src') diff --git a/src/parser.c b/src/parser.c index c4eaae2..2b07437 100644 --- a/src/parser.c +++ b/src/parser.c @@ -827,6 +827,24 @@ breakloop: #undef RETURN } +static int pgetc_eatbnl(void) +{ + int c; + + while ((c = pgetc()) == '\\') { + if (pgetc() != '\n') { + pungetc(); + break; + } + + plinno++; + if (doprompt) + setprompt(2); + } + + return c; +} + /* @@ -1179,7 +1197,7 @@ parsesub: { char *p; static const char types[] = "}-+?="; - c = pgetc(); + c = pgetc_eatbnl(); if ( (checkkwd & CHKEOFMARK) || c <= PEOA || @@ -1188,7 +1206,7 @@ parsesub: { USTPUTC('$', out); pungetc(); } else if (c == '(') { /* $(command) or $((arith)) */ - if (pgetc() == '(') { + if (pgetc_eatbnl() == '(') { PARSEARITH(); } else { pungetc(); @@ -1200,25 +1218,25 @@ parsesub: { STADJUST(1, out); subtype = VSNORMAL; if (likely(c == '{')) { - c = pgetc(); + c = pgetc_eatbnl(); subtype = 0; } varname: if (is_name(c)) { do { STPUTC(c, out); - c = pgetc(); + c = pgetc_eatbnl(); } while (is_in_name(c)); } else if (is_digit(c)) { do { STPUTC(c, out); - c = pgetc(); + c = pgetc_eatbnl(); } while (is_digit(c)); } else if (is_special(c)) { int cc = c; - c = pgetc(); + c = pgetc_eatbnl(); if (!subtype && cc == '#') { subtype = VSLENGTH; @@ -1227,7 +1245,7 @@ varname: goto varname; cc = c; - c = pgetc(); + c = pgetc_eatbnl(); if (cc == '}' || c != '}') { pungetc(); subtype = 0; @@ -1245,7 +1263,7 @@ varname: switch (c) { case ':': subtype = VSNUL; - c = pgetc(); + c = pgetc_eatbnl(); /*FALLTHROUGH*/ default: p = strchr(types, c); @@ -1259,7 +1277,7 @@ varname: int cc = c; subtype = c == '#' ? VSTRIMLEFT : VSTRIMRIGHT; - c = pgetc(); + c = pgetc_eatbnl(); if (c == cc) subtype++; else -- cgit 1.4.1 file?id=f59e7e8d5ee1164ba3801cf32cd1ab4da6792b85&follow=1'>Publish "hot tips"June McEnroe 2020-11-26Publish "Inability"June McEnroe I don't know, it's something. 2020-11-26Render content into atom feedJune McEnroe And fix some atom lints. 2020-11-26Update plan with different things I won't doJune McEnroe 2020-11-19Add "Come On Petunia"June McEnroe 2020-11-13Add x4 to LESSJune McEnroe 2020-11-04Remove modified sensitivity settingsJune McEnroe 2020-10-29Remove editJune McEnroe 2020-10-27Switch gr alias back to git rebaseJune McEnroe I always type out git reset and sometimes still expect gr to be rebase... Never got used to it I guess. 2020-10-27Allow cd host: to cd to same path over sshJune McEnroe 2020-10-27Use SendEnv for cd host:pathJune McEnroe Works properly for weird paths, etc. 2020-10-27Allow cd host:path over sshJune McEnroe Requires AcceptEnv SSH_CD in the remote sshd_config. 2020-10-07Use mandoc -T utf8 for text.June McEnroe Don't depend on LANG being set. 2020-09-20Add The Awakened KingdomJune McEnroe A cute extra novella. Finally finished this series. 2020-09-12Move /opt/local back, cheat port select to use system manJune McEnroe This is not really how you're supposed to use the select system, I don't think, since the mandoc package actually creates those files, but it does work. This lets me actually use the git installed by MacPorts. 2020-09-12Move /opt/local behind /usr againJune McEnroe The reason I did this with pkgsrc was because I actually don't want the man(1) from mandoc, since it won't follow MANSECT. Same applies to MacPorts. 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