[git commit] ash: expand: Fix ghost fields with unquoted $@/$*
Denys Vlasenko
vda.linux at googlemail.com
Sun Aug 5 12:29:58 UTC 2018
commit: https://git.busybox.net/busybox/commit/?id=440da97ed79841b55f0b61e4108a336b61642bff
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master
Upstream commit:
Date: Fri, 23 Mar 2018 18:58:47 +0800
expand: Fix ghost fields with unquoted $@/$*
You're right. The proper fix to this is to ensure that nulonly
is not set in varvalue for $*. It should only be set for $@ when
it's inside double quotes.
In fact there is another bug while we're playing with $@/$*.
When IFS is set to a non-whitespace character such as :, $*
outside quotes won't remove empty fields as it should.
This patch fixes both problems.
Reported-by: Martijn Dekker <martijn at inlv.org>
Suggested-by: Harald van Dijk <harald at gigawatt.nl>
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
function old new delta
argstr 1111 1113 +2
evalvar 571 569 -2
varvalue 579 576 -3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 2/-5) Total: -3 bytes
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/ash.c | 38 +++++++++++++++-------
shell/ash_test/ash-vars/var_wordsplit_ifs5.right | 1 +
shell/ash_test/ash-vars/var_wordsplit_ifs5.tests | 4 +++
shell/hush_test/hush-vars/var_wordsplit_ifs5.right | 1 +
shell/hush_test/hush-vars/var_wordsplit_ifs5.tests | 4 +++
5 files changed, 36 insertions(+), 12 deletions(-)
diff --git a/shell/ash.c b/shell/ash.c
index 6ef0a7ac2..4641dfd19 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5902,7 +5902,7 @@ static int substr_atoi(const char *s)
#define EXP_CASE 0x10 /* keeps quotes around for CASE pattern */
#define EXP_VARTILDE2 0x20 /* expand tildes after colons only */
#define EXP_WORD 0x40 /* expand word in parameter expansion */
-#define EXP_QUOTED 0x80 /* expand word in double quotes */
+#define EXP_QUOTED 0x100 /* expand word in double quotes */
/*
* rmescape() flags
*/
@@ -7175,14 +7175,13 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
* ash -c 'echo ${#1#}' name:'1=#'
*/
static NOINLINE ssize_t
-varvalue(char *name, int varflags, int flags, int *quotedp)
+varvalue(char *name, int varflags, int flags, int quoted)
{
const char *p;
int num;
int i;
ssize_t len = 0;
int sep;
- int quoted = *quotedp;
int subtype = varflags & VSTYPE;
int discard = subtype == VSPLUS || subtype == VSLENGTH;
int quotes = (discard ? 0 : (flags & QUOTES_ESC)) | QUOTES_KEEPNUL;
@@ -7230,13 +7229,27 @@ varvalue(char *name, int varflags, int flags, int *quotedp)
case '*': {
char **ap;
char sepc;
+ char c;
- if (quoted)
- sep = 0;
- sep |= ifsset() ? ifsval()[0] : ' ';
+ /* We will set c to 0 or ~0 depending on whether
+ * we're doing field splitting. We won't do field
+ * splitting if either we're quoted or sep is zero.
+ *
+ * Instead of testing (quoted || !sep) the following
+ * trick optimises away any branches by using the
+ * fact that EXP_QUOTED (which is the only bit that
+ * can be set in quoted) is the same as EXP_FULL <<
+ * CHAR_BIT (which is the only bit that can be set
+ * in sep).
+ */
+#if EXP_QUOTED >> CHAR_BIT != EXP_FULL
+#error The following two lines expect EXP_QUOTED == EXP_FULL << CHAR_BIT
+#endif
+ c = !((quoted | ~sep) & EXP_QUOTED) - 1;
+ sep &= ~quoted;
+ sep |= ifsset() ? (unsigned char)(c & ifsval()[0]) : ' ';
param:
sepc = sep;
- *quotedp = !sepc;
ap = shellparam.p;
if (!ap)
return -1;
@@ -7301,7 +7314,6 @@ evalvar(char *p, int flag)
char varflags;
char subtype;
int quoted;
- char easy;
char *var;
int patloc;
int startloc;
@@ -7315,12 +7327,11 @@ evalvar(char *p, int flag)
quoted = flag & EXP_QUOTED;
var = p;
- easy = (!quoted || (*var == '@' && shellparam.nparam));
startloc = expdest - (char *)stackblock();
p = strchr(p, '=') + 1; //TODO: use var_end(p)?
again:
- varlen = varvalue(var, varflags, flag, "ed);
+ varlen = varvalue(var, varflags, flag, quoted);
if (varflags & VSNUL)
varlen--;
@@ -7366,8 +7377,11 @@ evalvar(char *p, int flag)
if (subtype == VSNORMAL) {
record:
- if (!easy)
- goto end;
+ if (quoted) {
+ quoted = *var == '@' && shellparam.nparam;
+ if (!quoted)
+ goto end;
+ }
recordregion(startloc, expdest - (char *)stackblock(), quoted);
goto end;
}
diff --git a/shell/ash_test/ash-vars/var_wordsplit_ifs5.right b/shell/ash_test/ash-vars/var_wordsplit_ifs5.right
new file mode 100644
index 000000000..46ffcece7
--- /dev/null
+++ b/shell/ash_test/ash-vars/var_wordsplit_ifs5.right
@@ -0,0 +1 @@
+Zero:0
diff --git a/shell/ash_test/ash-vars/var_wordsplit_ifs5.tests b/shell/ash_test/ash-vars/var_wordsplit_ifs5.tests
new file mode 100755
index 000000000..d382116df
--- /dev/null
+++ b/shell/ash_test/ash-vars/var_wordsplit_ifs5.tests
@@ -0,0 +1,4 @@
+IFS=
+set --
+set -- $@ $*
+echo Zero:$#
diff --git a/shell/hush_test/hush-vars/var_wordsplit_ifs5.right b/shell/hush_test/hush-vars/var_wordsplit_ifs5.right
new file mode 100644
index 000000000..46ffcece7
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_wordsplit_ifs5.right
@@ -0,0 +1 @@
+Zero:0
diff --git a/shell/hush_test/hush-vars/var_wordsplit_ifs5.tests b/shell/hush_test/hush-vars/var_wordsplit_ifs5.tests
new file mode 100755
index 000000000..d382116df
--- /dev/null
+++ b/shell/hush_test/hush-vars/var_wordsplit_ifs5.tests
@@ -0,0 +1,4 @@
+IFS=
+set --
+set -- $@ $*
+echo Zero:$#
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