ash: if tcgetattr(stdin) fails, don't mess with tcsetattr

ash: size-optimize ulimit's table of limits

   text    data     bss     dec     hex filename
 777345     974    9676  787995   c061b busybox_old
 777253     974    9676  787903   c05bf busybox_unstripped

1 files changed, 75 insertions, 35 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 58527bf9b..bb930f55f 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -11575,26 +11575,31 @@ readcmd(int argc, char **argv)
                 ifs = defifs;
 #if ENABLE_ASH_READ_NCHARS
         if (n_flag || silent) {
-                tcgetattr(0, &tty);
-                old_tty = tty;
-                if (n_flag) {
-                        tty.c_lflag &= ~ICANON;
-                        tty.c_cc[VMIN] = nchars;
-                }
-                if (silent) {
-                        tty.c_lflag &= ~(ECHO|ECHOK|ECHONL);
+                if (tcgetattr(0, &tty) != 0) {
+                        /* Not a tty */
+                        n_flag = 0;
+                        silent = 0;
+                } else {
+                        old_tty = tty;
+                        if (n_flag) {
+                                tty.c_lflag &= ~ICANON;
+                                tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
+                        }
+                        if (silent) {
+                                tty.c_lflag &= ~(ECHO | ECHOK | ECHONL);
+                        }
+                        tcsetattr(0, TCSANOW, &tty);
                 }
-                tcsetattr(0, TCSANOW, &tty);
         }
 #endif
 #if ENABLE_ASH_READ_TIMEOUT
         if (ts.tv_sec || ts.tv_usec) {
-// TODO: replace with poll, it is smaller
                 FD_ZERO(&set);
                 FD_SET(0, &set);
 
-                i = select(FD_SETSIZE, &set, NULL, NULL, &ts);
-                if (!i) {
+                /* poll-based wait produces bigger code, using select */
+                i = select(1, &set, NULL, NULL, &ts);
+                if (!i) { /* timed out! */
 #if ENABLE_ASH_READ_NCHARS
                         if (n_flag)
                                 tcsetattr(0, TCSANOW, &old_tty);
@@ -11742,48 +11747,81 @@ umaskcmd(int argc, char **argv)
  */
 
 struct limits {
-        const char *name;
-        int     cmd;
-        int     factor; /* multiply by to get rlim_{cur,max} values */
+        uint8_t cmd;          /* RLIMIT_xxx fit into it */
+        uint8_t factor_shift; /* shift by to get rlim_{cur,max} values */
         char    option;
 };
 
-static const struct limits limits[] = {
+static const struct limits limits_tbl[] = {
 #ifdef RLIMIT_CPU
-        { "time(seconds)",              RLIMIT_CPU,        1, 't' },
+        { RLIMIT_CPU,        0, 't' },
 #endif
 #ifdef RLIMIT_FSIZE
-        { "file(blocks)",               RLIMIT_FSIZE,    512, 'f' },
+        { RLIMIT_FSIZE,      9, 'f' },
 #endif
 #ifdef RLIMIT_DATA
-        { "data(kbytes)",               RLIMIT_DATA,    1024, 'd' },
+        { RLIMIT_DATA,      10, 'd' },
 #endif
 #ifdef RLIMIT_STACK
-        { "stack(kbytes)",              RLIMIT_STACK,   1024, 's' },
+        { RLIMIT_STACK,     10, 's' },
 #endif
-#ifdef  RLIMIT_CORE
-        { "coredump(blocks)",           RLIMIT_CORE,     512, 'c' },
+#ifdef RLIMIT_CORE
+        { RLIMIT_CORE,       9, 'c' },
 #endif
 #ifdef RLIMIT_RSS
-        { "memory(kbytes)",             RLIMIT_RSS,     1024, 'm' },
+        { RLIMIT_RSS,       10, 'm' },
 #endif
 #ifdef RLIMIT_MEMLOCK
-        { "locked memory(kbytes)",      RLIMIT_MEMLOCK, 1024, 'l' },
+        { RLIMIT_MEMLOCK,   10, 'l' },
 #endif
 #ifdef RLIMIT_NPROC
-        { "process",                    RLIMIT_NPROC,      1, 'p' },
+        { RLIMIT_NPROC,      0, 'p' },
 #endif
 #ifdef RLIMIT_NOFILE
-        { "nofiles",                    RLIMIT_NOFILE,     1, 'n' },
+        { RLIMIT_NOFILE,     0, 'n' },
 #endif
 #ifdef RLIMIT_AS
-        { "vmemory(kbytes)",            RLIMIT_AS,      1024, 'v' },
+        { RLIMIT_AS,        10, 'v' },
 #endif
 #ifdef RLIMIT_LOCKS
-        { "locks",                      RLIMIT_LOCKS,      1, 'w' },
+        { RLIMIT_LOCKS,      0, 'w' },
 #endif
-        { NULL,                         0,                 0,  '\0' }
 };
+static const char limits_name[] =
+#ifdef RLIMIT_CPU
+        "time(seconds)" "\0"
+#endif
+#ifdef RLIMIT_FSIZE
+        "file(blocks)" "\0"
+#endif
+#ifdef RLIMIT_DATA
+        "data(kb)" "\0"
+#endif
+#ifdef RLIMIT_STACK
+        "stack(kb)" "\0"
+#endif
+#ifdef RLIMIT_CORE
+        "coredump(blocks)" "\0"
+#endif
+#ifdef RLIMIT_RSS
+        "memory(kb)" "\0"
+#endif
+#ifdef RLIMIT_MEMLOCK
+        "locked memory(kb)" "\0"
+#endif
+#ifdef RLIMIT_NPROC
+        "process" "\0"
+#endif
+#ifdef RLIMIT_NOFILE
+        "nofiles" "\0"
+#endif
+#ifdef RLIMIT_AS
+        "vmemory(kb)" "\0"
+#endif
+#ifdef RLIMIT_LOCKS
+        "locks" "\0"
+#endif
+;
 
 enum limtype { SOFT = 0x1, HARD = 0x2 };
 
@@ -11800,7 +11838,7 @@ printlim(enum limtype how, const struct rlimit *limit,
         if (val == RLIM_INFINITY)
                 out1fmt("unlimited\n");
         else {
-                val /= l->factor;
+                val >>= l->factor_shift;
                 out1fmt("%lld\n", (long long) val);
         }
 }
@@ -11866,8 +11904,8 @@ ulimitcmd(int argc, char **argv)
                         what = optc;
                 }
 
-        for (l = limits; l->option != what; l++)
-                ;
+        for (l = limits_tbl; l->option != what; l++)
+                continue;
 
         set = *argptr ? 1 : 0;
         if (set) {
@@ -11887,13 +11925,15 @@ ulimitcmd(int argc, char **argv)
                         }
                         if (c)
                                 ash_msg_and_raise_error("bad number");
-                        val *= l->factor;
+                        val <<= l->factor_shift;
                 }
         }
         if (all) {
-                for (l = limits; l->name; l++) {
+                const char *lname = limits_name;
+                for (l = limits_tbl; l != &limits_tbl[ARRAY_SIZE(limits_tbl)]; l++) {
                         getrlimit(l->cmd, &limit);
-                        out1fmt("%-20s ", l->name);
+                        out1fmt("%-20s ", lname);
+                        lname += strlen(lname) + 1;
                         printlim(how, &limit, l);
                 }
                 return 0;