hush: fix IFS handling in read

$ echo "X:Y:" | (IFS=": " read x y; echo "|$x|$y|")
|X|Y|
$ echo "X:Y  :  " | (IFS=": " read x y; echo "|$x|$y|")
|X|Y|

function                                             old     new   delta
shell_builtin_read                                  1320    1426    +106

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/shell/hush_test/hush-read/read_ifs2.right b/shell/hush_test/hush-read/read_ifs2.right
new file mode 100644 (file)
index 0000000..797137d
--- /dev/null
+++ b/shell/hush_test/hush-read/read_ifs2.right
@@ -0,0 +1,9 @@
+|X|Y:Z:|
+|X|Y:Z|
+|X|Y|
+|X|Y|
+|X||
+|X||
+|||
+Whitespace should be trimmed too:
+|X|Y|

diff --git a/shell/hush_test/hush-read/read_ifs2.tests b/shell/hush_test/hush-read/read_ifs2.tests
new file mode 100755 (executable)
index 0000000..f01a689
--- /dev/null
+++ b/shell/hush_test/hush-read/read_ifs2.tests
@@ -0,0 +1,9 @@
+echo "X:Y:Z:" | (IFS=": " read x y; echo "|$x|$y|")
+echo "X:Y:Z"  | (IFS=": " read x y; echo "|$x|$y|")
+echo "X:Y:"   | (IFS=": " read x y; echo "|$x|$y|")
+echo "X:Y"    | (IFS=": " read x y; echo "|$x|$y|")
+echo "X:"     | (IFS=": " read x y; echo "|$x|$y|")
+echo "X"      | (IFS=": " read x y; echo "|$x|$y|")
+echo ""       | (IFS=": " read x y; echo "|$x|$y|")
+echo Whitespace should be trimmed too:
+echo "X:Y  : " | (IFS=": " read x y; echo "|$x|$y|")

diff --git a/shell/shell_common.c b/shell/shell_common.c
index 9e58ee4feaceac607a272a2c86eb4834e4c20944..0a07296f30b253377a3a4a3abcf12fad31e542b3 100644 (file)
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -274,9 +274,44 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
 
        if (argv[0]) {
                /* Remove trailing space $IFS chars */
-               while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
+               while (--bufpos >= 0
+                && isspace(buffer[bufpos])
+                && strchr(ifs, buffer[bufpos]) != NULL
+               ) {
                        continue;
+               }
                buffer[bufpos + 1] = '\0';
+
+               /* Last variable takes the entire remainder with delimiters
+                * (sans trailing whitespace $IFS),
+                * but ***only "if there are fewer vars than fields"(c)***!
+                * The "X:Y:" case below: there are two fields,
+                * and therefore last delimiter (:) is eaten:
+                * IFS=": "
+                * echo "X:Y:Z:"  | (read x y; echo "|$x|$y|") # |X|Y:Z:|
+                * echo "X:Y:Z"   | (read x y; echo "|$x|$y|") # |X|Y:Z|
+                * echo "X:Y:"    | (read x y; echo "|$x|$y|") # |X|Y|, not |X|Y:|
+                * echo "X:Y  : " | (read x y; echo "|$x|$y|") # |X|Y|
+                */
+               if (bufpos >= 0
+                && strchr(ifs, buffer[bufpos]) != NULL
+               ) {
+                       /* There _is_ a non-whitespace IFS char */
+                       /* Skip whitespace IFS char before it */
+                       while (--bufpos >= 0
+                        && isspace(buffer[bufpos])
+                        && strchr(ifs, buffer[bufpos]) != NULL
+                       ) {
+                               continue;
+                       }
+                       /* Are there $IFS chars? */
+                       if (strcspn(buffer, ifs) >= ++bufpos) {
+                               /* No: last var takes one field, not more */
+                               /* So, drop trailing IFS delims */
+                               buffer[bufpos] = '\0';
+                       }
+               }
+
                /* Use the remainder as a value for the next variable */
                setvar(*argv, buffer);
                /* Set the rest to "" */