shell/read: fix "'read' without parameters" bash compat thingy

previous change:

function                                             old     new   delta
builtin_read                                          82    1074    +992
popstring                                            134     140      +6
readcmd                                             1034     148    -886
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 998/-886)          Total: 112 bytes

this change:

builtin_read                                        1074    1096     +22
static.arg_REPLY                                       8       -      -8
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/0 up/down: 22/-8)              Total: 14 bytes

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

1 files changed, 39 insertions, 31 deletions

diff --git a/shell/builtin_read.c b/shell/builtin_read.c
index 7f667e9c1..24cfe08fb 100644
--- a/shell/builtin_read.c
+++ b/shell/builtin_read.c
@@ -31,8 +31,6 @@ builtin_read(void (*setvar)(const char *name, const char *val, int flags),
         const char *opt_u
 )
 {
-        static const char *const arg_REPLY[] = { "REPLY", NULL };
-
         unsigned end_ms; /* -t TIMEOUT */
         int fd; /* -u FD */
         int nchars; /* -n NUM */
@@ -94,8 +92,6 @@ builtin_read(void (*setvar)(const char *name, const char *val, int flags),
                 fflush_all();
         }
 
-        if (argv[0] == NULL)
-                argv = (char**)arg_REPLY;
         if (ifs == NULL)
                 ifs = defifs;
 
@@ -125,7 +121,6 @@ builtin_read(void (*setvar)(const char *name, const char *val, int flags),
         bufpos = 0;
         do {
                 char c;
-                const char *is_ifs;
 
                 if (end_ms) {
                         int timeout;
@@ -163,40 +158,53 @@ builtin_read(void (*setvar)(const char *name, const char *val, int flags),
                 }
                 if (c == '\n')
                         break;
-                /* $IFS splitting */
+
+                /* $IFS splitting. NOT done if we run "read"
+                 * without variable names (bash compat).
+                 * Thus, "read" and "read REPLY" are not the same.
+                 */
+                if (argv[0]) {
 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
-                is_ifs = strchr(ifs, c);
-                if (startword && is_ifs) {
-                        if (isspace(c))
+                        const char *is_ifs = strchr(ifs, c);
+                        if (startword && is_ifs) {
+                                if (isspace(c))
+                                        continue;
+                                /* it is a non-space ifs char */
+                                startword--;
+                                if (startword == 1) /* first one? */
+                                        continue; /* yes, it is not next word yet */
+                        }
+                        startword = 0;
+                        if (argv[1] != NULL && is_ifs) {
+                                buffer[bufpos] = '\0';
+                                bufpos = 0;
+                                setvar(*argv, buffer, 0);
+                                argv++;
+                                /* can we skip one non-space ifs char? (2: yes) */
+                                startword = isspace(c) ? 2 : 1;
                                 continue;
-                        /* it is a non-space ifs char */
-                        startword--;
-                        if (startword == 1) /* first one? */
-                                continue; /* yes, it is not next word yet */
-                }
-                startword = 0;
-                if (argv[1] != NULL && is_ifs) {
-                        buffer[bufpos] = '\0';
-                        bufpos = 0;
-                        setvar(*argv, buffer, 0);
-                        argv++;
-                        /* can we skip one non-space ifs char? (2: yes) */
-                        startword = isspace(c) ? 2 : 1;
-                        continue;
+                        }
                 }
  put:
                 bufpos++;
         } while (--nchars);
 
-        /* Remove trailing space ifs chars */
-        while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
-                continue;
-        buffer[bufpos + 1] = '\0';
-
-        setvar(*argv, buffer, 0);
+        if (argv[0]) {
+                /* Remove trailing space $IFS chars */
+                while (--bufpos >= 0 && isspace(buffer[bufpos]) && strchr(ifs, buffer[bufpos]) != NULL)
+                        continue;
+                buffer[bufpos + 1] = '\0';
+                /* Use the remainder as a value for the next variable */
+                setvar(*argv, buffer, 0);
+                /* Set the rest to "" */
+                while (*++argv)
+                        setvar(*argv, "", 0);
+        } else {
+                /* Note: no $IFS removal */
+                buffer[bufpos] = '\0';
+                setvar("REPLY", buffer, 0);
+        }
 
-        while (*++argv != NULL)
-                setvar(*argv, "", 0);
  ret:
         free(buffer);
         if (read_flags & BUILTIN_READ_SILENT)