ash,hush: fold shell_builtin_read() way-too-many params into a struct param

function                                             old     new   delta
getoptscmd                                           587     584      -3
readcmd                                              240     224     -16
shell_builtin_read                                  1426    1399     -27
builtin_read                                         210     182     -28
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-74)             Total: -74 bytes

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

4 files changed, 64 insertions, 84 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 4641dfd19..f74bef6b1 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13762,38 +13762,35 @@ letcmd(int argc UNUSED_PARAM, char **argv)
 static int FAST_FUNC
 readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
-        char *opt_n = NULL;
-        char *opt_p = NULL;
-        char *opt_t = NULL;
-        char *opt_u = NULL;
-        char *opt_d = NULL; /* optimized out if !BASH */
-        int read_flags = 0;
+        struct builtin_read_params params;
         const char *r;
         int i;
 
+        memset(&params, 0, sizeof(params));
+
         while ((i = nextopt("p:u:rt:n:sd:")) != '\0') {
                 switch (i) {
                 case 'p':
-                        opt_p = optionarg;
+                        params.opt_p = optionarg;
                         break;
                 case 'n':
-                        opt_n = optionarg;
+                        params.opt_n = optionarg;
                         break;
                 case 's':
-                        read_flags |= BUILTIN_READ_SILENT;
+                        params.read_flags |= BUILTIN_READ_SILENT;
                         break;
                 case 't':
-                        opt_t = optionarg;
+                        params.opt_t = optionarg;
                         break;
                 case 'r':
-                        read_flags |= BUILTIN_READ_RAW;
+                        params.read_flags |= BUILTIN_READ_RAW;
                         break;
                 case 'u':
-                        opt_u = optionarg;
+                        params.opt_u = optionarg;
                         break;
 #if BASH_READ_D
                 case 'd':
-                        opt_d = optionarg;
+                        params.opt_d = optionarg;
                         break;
 #endif
                 default:
@@ -13801,21 +13798,16 @@ readcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                 }
         }
 
+        params.argv = argptr;
+        params.setvar = setvar0;
+        params.ifs = bltinlookup("IFS"); /* can be NULL */
+
         /* "read -s" needs to save/restore termios, can't allow ^C
          * to jump out of it.
          */
  again:
         INT_OFF;
-        r = shell_builtin_read(setvar0,
-                argptr,
-                bltinlookup("IFS"), /* can be NULL */
-                read_flags,
-                opt_n,
-                opt_p,
-                opt_t,
-                opt_u,
-                opt_d
-        );
+        r = shell_builtin_read(&params);
         INT_ON;
 
         if ((uintptr_t)r == 1 && errno == EINTR) {
diff --git a/shell/hush.c b/shell/hush.c
index 4c8814a01..3c19bceaa 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -10500,40 +10500,29 @@ static int FAST_FUNC builtin_type(char **argv)
 static int FAST_FUNC builtin_read(char **argv)
 {
         const char *r;
-        char *opt_n = NULL;
-        char *opt_p = NULL;
-        char *opt_t = NULL;
-        char *opt_u = NULL;
-        char *opt_d = NULL; /* optimized out if !BASH */
-        const char *ifs;
-        int read_flags;
+        struct builtin_read_params params;
+
+        memset(&params, 0, sizeof(params));
 
         /* "!": do not abort on errors.
          * Option string must start with "sr" to match BUILTIN_READ_xxx
          */
-        read_flags = getopt32(argv,
+        params.read_flags = getopt32(argv,
 #if BASH_READ_D
-                "!srn:p:t:u:d:", &opt_n, &opt_p, &opt_t, &opt_u, &opt_d
+                "!srn:p:t:u:d:", &params.opt_n, &params.opt_p, &params.opt_t, &params.opt_u, &params.opt_d
 #else
-                "!srn:p:t:u:", &opt_n, &opt_p, &opt_t, &opt_u
+                "!srn:p:t:u:", &params.opt_n, &params.opt_p, &params.opt_t, &params.opt_u
 #endif
         );
-        if (read_flags == (uint32_t)-1)
+        if ((uint32_t)params.read_flags == (uint32_t)-1)
                 return EXIT_FAILURE;
         argv += optind;
-        ifs = get_local_var_value("IFS"); /* can be NULL */
+        params.argv = argv;
+        params.setvar = set_local_var_from_halves;
+        params.ifs = get_local_var_value("IFS"); /* can be NULL */
 
  again:
-        r = shell_builtin_read(set_local_var_from_halves,
-                argv,
-                ifs,
-                read_flags,
-                opt_n,
-                opt_p,
-                opt_t,
-                opt_u,
-                opt_d
-        );
+        r = shell_builtin_read(&params);
 
         if ((uintptr_t)r == 1 && errno == EINTR) {
                 unsigned sig = check_and_run_traps();
diff --git a/shell/shell_common.c b/shell/shell_common.c
index 0a07296f3..f2bf5ab65 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -46,16 +46,7 @@ int FAST_FUNC is_well_formed_var_name(const char *s, char terminator)
 //Here we can simply store "VAR=" at buffer start and store read data directly
 //after "=", then pass buffer to setvar() to consume.
 const char* FAST_FUNC
-shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
-        char       **argv,
-        const char *ifs,
-        int        read_flags,
-        const char *opt_n,
-        const char *opt_p,
-        const char *opt_t,
-        const char *opt_u,
-        const char *opt_d
-)
+shell_builtin_read(struct builtin_read_params *params)
 {
         struct pollfd pfd[1];
 #define fd (pfd[0].fd) /* -u FD */
@@ -70,9 +61,13 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
         int bufpos; /* need to be able to hold -1 */
         int startword;
         smallint backslash;
+        char **argv;
+        const char *ifs;
+        int read_flags;
 
         errno = err = 0;
 
+        argv = params->argv;
         pp = argv;
         while (*pp) {
                 if (!is_well_formed_var_name(*pp, '\0')) {
@@ -84,29 +79,29 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
         }
 
         nchars = 0; /* if != 0, -n is in effect */
-        if (opt_n) {
-                nchars = bb_strtou(opt_n, NULL, 10);
+        if (params->opt_n) {
+                nchars = bb_strtou(params->opt_n, NULL, 10);
                 if (nchars < 0 || errno)
                         return "invalid count";
                 /* note: "-n 0": off (bash 3.2 does this too) */
         }
 
         end_ms = 0;
-        if (opt_t && !ENABLE_FEATURE_SH_READ_FRAC) {
-                end_ms = bb_strtou(opt_t, NULL, 10);
+        if (params->opt_t && !ENABLE_FEATURE_SH_READ_FRAC) {
+                end_ms = bb_strtou(params->opt_t, NULL, 10);
                 if (errno)
                         return "invalid timeout";
                 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
                         end_ms = UINT_MAX / 2048;
                 end_ms *= 1000;
         }
-        if (opt_t && ENABLE_FEATURE_SH_READ_FRAC) {
+        if (params->opt_t && ENABLE_FEATURE_SH_READ_FRAC) {
                 /* bash 4.3 (maybe earlier) supports -t N.NNNNNN */
                 char *p;
                 /* Eat up to three fractional digits */
                 int frac_digits = 3 + 1;
 
-                end_ms = bb_strtou(opt_t, &p, 10);
+                end_ms = bb_strtou(params->opt_t, &p, 10);
                 if (end_ms > UINT_MAX / 2048) /* be safely away from overflow */
                         end_ms = UINT_MAX / 2048;
 
@@ -128,13 +123,13 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
         }
 
         fd = STDIN_FILENO;
-        if (opt_u) {
-                fd = bb_strtou(opt_u, NULL, 10);
+        if (params->opt_u) {
+                fd = bb_strtou(params->opt_u, NULL, 10);
                 if (fd < 0 || errno)
                         return "invalid file descriptor";
         }
 
-        if (opt_t && end_ms == 0) {
+        if (params->opt_t && end_ms == 0) {
                 /* "If timeout is 0, read returns immediately, without trying
                  * to read any data. The exit status is 0 if input is available
                  * on the specified file descriptor, non-zero otherwise."
@@ -147,14 +142,16 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                 return (const char *)(uintptr_t)(r <= 0);
         }
 
-        if (opt_p && isatty(fd)) {
-                fputs(opt_p, stderr);
+        if (params->opt_p && isatty(fd)) {
+                fputs(params->opt_p, stderr);
                 fflush_all();
         }
 
+        ifs = params->ifs;
         if (ifs == NULL)
                 ifs = defifs;
 
+        read_flags = params->read_flags;
         if (nchars || (read_flags & BUILTIN_READ_SILENT)) {
                 tcgetattr(fd, &tty);
                 old_tty = tty;
@@ -181,11 +178,11 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
         retval = (const char *)(uintptr_t)0;
         startword = 1;
         backslash = 0;
-        if (opt_t)
+        if (params->opt_t)
                 end_ms += (unsigned)monotonic_ms();
         buffer = NULL;
         bufpos = 0;
-        delim = opt_d ? *opt_d : '\n';
+        delim = params->opt_d ? params->opt_d[0] : '\n';
         do {
                 char c;
                 int timeout;
@@ -194,7 +191,7 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                         buffer = xrealloc(buffer, bufpos + 0x101);
 
                 timeout = -1;
-                if (opt_t) {
+                if (params->opt_t) {
                         timeout = end_ms - (unsigned)monotonic_ms();
                         /* ^^^^^^^^^^^^^ all values are unsigned,
                          * wrapping math is used here, good even if
@@ -246,7 +243,7 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                  * without variable names (bash compat).
                  * Thus, "read" and "read REPLY" are not the same.
                  */
-                if (!opt_d && argv[0]) {
+                if (!params->opt_d && argv[0]) {
 /* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 */
                         const char *is_ifs = strchr(ifs, c);
                         if (startword && is_ifs) {
@@ -261,7 +258,7 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                         if (argv[1] != NULL && is_ifs) {
                                 buffer[bufpos] = '\0';
                                 bufpos = 0;
-                                setvar(*argv, buffer);
+                                params->setvar(*argv, buffer);
                                 argv++;
                                 /* can we skip one non-space ifs char? (2: yes) */
                                 startword = isspace(c) ? 2 : 1;
@@ -313,14 +310,14 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
                 }
 
                 /* Use the remainder as a value for the next variable */
-                setvar(*argv, buffer);
+                params->setvar(*argv, buffer);
                 /* Set the rest to "" */
                 while (*++argv)
-                        setvar(*argv, "");
+                        params->setvar(*argv, "");
         } else {
                 /* Note: no $IFS removal */
                 buffer[bufpos] = '\0';
-                setvar("REPLY", buffer);
+                params->setvar("REPLY", buffer);
         }
 
  ret:
diff --git a/shell/shell_common.h b/shell/shell_common.h
index 875fd9ea7..a1323021d 100644
--- a/shell/shell_common.h
+++ b/shell/shell_common.h
@@ -30,6 +30,17 @@ int FAST_FUNC is_well_formed_var_name(const char *s, char terminator);
 
 /* Builtins */
 
+struct builtin_read_params {
+        int        read_flags;
+        void FAST_FUNC (*setvar)(const char *name, const char *val);
+        char       **argv;
+        const char *ifs;
+        const char *opt_n;
+        const char *opt_p;
+        const char *opt_t;
+        const char *opt_u;
+        const char *opt_d;
+};
 enum {
         BUILTIN_READ_SILENT = 1 << 0,
         BUILTIN_READ_RAW    = 1 << 1,
@@ -40,16 +51,7 @@ enum {
 //      shell_builtin_read(setvar,argv,ifs,read_flags)
 //#endif
 const char* FAST_FUNC
-shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
-        char       **argv,
-        const char *ifs,
-        int        read_flags,
-        const char *opt_n,
-        const char *opt_p,
-        const char *opt_t,
-        const char *opt_u,
-        const char *opt_d
-);
+shell_builtin_read(struct builtin_read_params *params);
 
 int FAST_FUNC
 shell_builtin_ulimit(char **argv);