Merge branch 'busybox' into merge

Disable FEATURE_TIMEZONE for now.

11 files changed, 194 insertions, 92 deletions

diff --git a/configs/mingw32_defconfig b/configs/mingw32_defconfig
index 765653a43..0882741d5 100644
--- a/configs/mingw32_defconfig
+++ b/configs/mingw32_defconfig
@@ -147,6 +147,7 @@ CONFIG_FEATURE_COPYBUF_KB=4
 # CONFIG_MONOTONIC_SYSCALL is not set
 # CONFIG_IOCTL_HEX2STR_ERROR is not set
 # CONFIG_FEATURE_HWIB is not set
+# CONFIG_FEATURE_TIMEZONE is not set
 
 #
 # Applets
diff --git a/configs/mingw64_defconfig b/configs/mingw64_defconfig
index 656ebb101..358d19d4e 100644
--- a/configs/mingw64_defconfig
+++ b/configs/mingw64_defconfig
@@ -147,6 +147,7 @@ CONFIG_FEATURE_COPYBUF_KB=4
 # CONFIG_MONOTONIC_SYSCALL is not set
 # CONFIG_IOCTL_HEX2STR_ERROR is not set
 # CONFIG_FEATURE_HWIB is not set
+# CONFIG_FEATURE_TIMEZONE is not set
 
 #
 # Applets
diff --git a/coreutils/date.c b/coreutils/date.c
index d64ff94b9..4e62a6fb0 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -291,6 +291,7 @@ int date_main(int argc UNUSED_PARAM, char **argv)
 
         /* If date string is given, update tm_time, and maybe set date */
         if (date_str != NULL) {
+                int check_dst = 1;
                 /* Zero out fields - take her back to midnight! */
                 tm_time.tm_sec = 0;
                 tm_time.tm_min = 0;
@@ -301,12 +302,12 @@ int date_main(int argc UNUSED_PARAM, char **argv)
                         if (strptime(date_str, fmt_str2dt, &tm_time) == NULL)
                                 bb_error_msg_and_die(bb_msg_invalid_date, date_str);
                 } else {
-                        parse_datestr(date_str, &tm_time);
+                        check_dst = parse_datestr(date_str, &tm_time);
                 }
 
                 /* Correct any day of week and day of year etc. fields */
-                /* Be sure to recheck dst (but not if date is time_t format) */
-                if (date_str[0] != '@')
+                /* Be sure to recheck dst (but not if date is UTC) */
+                if (check_dst)
                         tm_time.tm_isdst = -1;
                 ts.tv_sec = validate_tm_time(date_str, &tm_time);
                 ts.tv_nsec = 0;
diff --git a/coreutils/df.c b/coreutils/df.c
index e8d4bc8f2..9f8b3a71e 100644
--- a/coreutils/df.c
+++ b/coreutils/df.c
@@ -99,15 +99,16 @@ int df_main(int argc UNUSED_PARAM, char **argv)
         struct mntent *mount_entry;
         struct statvfs s;
         enum {
-                OPT_KILO   = (1 << 0),
-                OPT_POSIX  = (1 << 1),
-                OPT_FSTYPE = (1 << 2),
-                OPT_t      = (1 << 3),
-                OPT_ALL    = (1 << 4) * ENABLE_FEATURE_DF_FANCY,
-                OPT_INODE  = (1 << 5) * ENABLE_FEATURE_DF_FANCY,
-                OPT_BSIZE  = (1 << 6) * ENABLE_FEATURE_DF_FANCY,
-                OPT_HUMAN  = (1 << (4 + 3*ENABLE_FEATURE_DF_FANCY)) * ENABLE_FEATURE_HUMAN_READABLE,
-                OPT_MEGA   = (1 << (5 + 3*ENABLE_FEATURE_DF_FANCY)) * ENABLE_FEATURE_HUMAN_READABLE,
+                OPT_KILO     = (1 << 0),
+                OPT_POSIX    = (1 << 1),
+                OPT_FSTYPE   = (1 << 2),
+                OPT_t        = (1 << 3),
+                OPT_ALL      = (1 << 4) * ENABLE_FEATURE_DF_FANCY,
+                OPT_INODE    = (1 << 5) * ENABLE_FEATURE_DF_FANCY,
+                OPT_BSIZE    = (1 << 6) * ENABLE_FEATURE_DF_FANCY,
+                OPT_HUMAN    = (1 << (4 + 3*ENABLE_FEATURE_DF_FANCY)) * ENABLE_FEATURE_HUMAN_READABLE,
+                OPT_HUMANDEC = (1 << (5 + 3*ENABLE_FEATURE_DF_FANCY)) * ENABLE_FEATURE_HUMAN_READABLE,
+                OPT_MEGA     = (1 << (6 + 3*ENABLE_FEATURE_DF_FANCY)) * ENABLE_FEATURE_HUMAN_READABLE,
         };
         const char *disp_units_hdr = NULL;
         char *chp, *opt_t;
@@ -124,7 +125,7 @@ int df_main(int argc UNUSED_PARAM, char **argv)
         opt = getopt32(argv, "^"
                         "kPTt:"
                         IF_FEATURE_DF_FANCY("aiB:")
-                        IF_FEATURE_HUMAN_READABLE("hm")
+                        IF_FEATURE_HUMAN_READABLE("hHm")
                         "\0"
 #if ENABLE_FEATURE_HUMAN_READABLE && ENABLE_FEATURE_DF_FANCY
                         "k-mB:m-Bk:B-km"
@@ -151,8 +152,11 @@ int df_main(int argc UNUSED_PARAM, char **argv)
  got_it: ;
         }
 
-        if (opt & OPT_HUMAN) {
+        if (opt & (OPT_HUMAN|OPT_HUMANDEC)) {
                 df_disp_hr = 0;
+//TODO: need to add support in make_human_readable_str() for "decimal human readable"
+                //if (opt & OPT_HUMANDEC)
+                //      df_disp_hr--;
                 disp_units_hdr = "     Size";
         }
         if (opt & OPT_INODE)
diff --git a/coreutils/touch.c b/coreutils/touch.c
index 78100ba1d..7e13a27be 100644
--- a/coreutils/touch.c
+++ b/coreutils/touch.c
@@ -140,15 +140,17 @@ int touch_main(int argc UNUSED_PARAM, char **argv)
         if (opts & (OPT_d|OPT_t)) {
                 struct tm tm_time;
                 time_t t;
+                int check_dst;
 
                 //memset(&tm_time, 0, sizeof(tm_time));
                 /* Better than memset: makes "HH:MM" dates meaningful */
                 time(&t);
                 localtime_r(&t, &tm_time);
-                parse_datestr(date_str, &tm_time);
+                check_dst = parse_datestr(date_str, &tm_time);
 
                 /* Correct any day of week and day of year etc. fields */
-                tm_time.tm_isdst = -1;  /* Be sure to recheck dst */
+                if (check_dst)
+                        tm_time.tm_isdst = -1;  /* recheck dst unless date is UTC */
                 t = validate_tm_time(date_str, &tm_time);
 
                 timebuf[1].tv_sec = timebuf[0].tv_sec = t;
diff --git a/include/libbb.h b/include/libbb.h
index 7a43967cb..cee37f9d8 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -730,7 +730,7 @@ struct BUG_too_small {
 };
 
 
-void parse_datestr(const char *date_str, struct tm *ptm) FAST_FUNC;
+int parse_datestr(const char *date_str, struct tm *ptm) FAST_FUNC;
 time_t validate_tm_time(const char *date_str, struct tm *ptm) FAST_FUNC;
 char *strftime_HHMMSS(char *buf, unsigned len, time_t *tp) FAST_FUNC;
 char *strftime_YYYYMMDDHHMMSS(char *buf, unsigned len, time_t *tp) FAST_FUNC;
diff --git a/libbb/Config.src b/libbb/Config.src
index f97de8ef7..58c5fad50 100644
--- a/libbb/Config.src
+++ b/libbb/Config.src
@@ -395,3 +395,14 @@ config FEATURE_HWIB
         default y
         help
         Support for printing infiniband addresses in network applets.
+
+config FEATURE_TIMEZONE
+        bool "Allow timezone in dates"
+        default y
+        depends on DESKTOP
+        help
+        Permit the use of timezones when parsing user-provided data
+        strings, e.g. '1996-04-09 12:45:00 -0500'.
+
+        This requires support for the '%z' extension to strptime() which
+        may not be available in all implementations.
diff --git a/libbb/time.c b/libbb/time.c
index cf5f2e5c8..41a69c754 100644
--- a/libbb/time.c
+++ b/libbb/time.c
@@ -8,16 +8,74 @@
  */
 #include "libbb.h"
 
-void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
+/* Returns 0 if the time structure contains an absolute UTC time which
+ * should not be subject to DST adjustment by the caller. */
+int FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
 {
         char end = '\0';
+#if ENABLE_DESKTOP
+/*
+ * strptime is BIG: ~1k in uclibc, ~10k in glibc
+ * We need it for 'month_name d HH:MM:SS YYYY', supported by GNU date,
+ * but if we've linked it we might as well use it for everything.
+ */
+        static const char fmt_str[] ALIGN1 =
+                "%R" "\0"               /* HH:MM */
+                "%T" "\0"               /* HH:MM:SS */
+                "%m.%d-%R" "\0"         /* mm.dd-HH:MM */
+                "%m.%d-%T" "\0"         /* mm.dd-HH:MM:SS */
+                "%Y.%m.%d-%R" "\0"      /* yyyy.mm.dd-HH:MM */
+                "%Y.%m.%d-%T" "\0"      /* yyyy.mm.dd-HH:MM:SS */
+                "%b %d %T %Y" "\0"      /* month_name d HH:MM:SS YYYY */
+                "%Y-%m-%d %R" "\0"      /* yyyy-mm-dd HH:MM */
+                "%Y-%m-%d %T" "\0"      /* yyyy-mm-dd HH:MM:SS */
+#if ENABLE_FEATURE_TIMEZONE
+                "%Y-%m-%d %R %z" "\0"   /* yyyy-mm-dd HH:MM TZ */
+                "%Y-%m-%d %T %z" "\0"   /* yyyy-mm-dd HH:MM:SS TZ */
+#endif
+                "%Y-%m-%d %H" "\0"      /* yyyy-mm-dd HH */
+                "%Y-%m-%d" "\0"         /* yyyy-mm-dd */
+                /* extra NUL */;
+        struct tm save;
+        const char *fmt;
+        char *endp;
+
+        save = *ptm;
+        fmt = fmt_str;
+        while (*fmt) {
+                endp = strptime(date_str, fmt, ptm);
+                if (endp && *endp == '\0') {
+#if ENABLE_FEATURE_TIMEZONE
+                        if (strchr(fmt, 'z')) {
+                                time_t t;
+                                struct tm *utm;
+
+                                /* we have timezone offset: obtain Unix time_t */
+                                ptm->tm_sec -= ptm->tm_gmtoff;
+                                ptm->tm_isdst = 0;
+                                t = timegm(ptm);
+                                if (t == (time_t)-1)
+                                        break;
+                                /* convert Unix time_t to struct tm in user's locale */
+                                utm = localtime(&t);
+                                if (!utm)
+                                        break;
+                                *ptm = *utm;
+                                return 0;
+                        }
+#endif
+                        return 1;
+                }
+                *ptm = save;
+                while (*++fmt)
+                        continue;
+                ++fmt;
+        }
+#else
         const char *last_colon = strrchr(date_str, ':');
 
         if (last_colon != NULL) {
                 /* Parse input and assign appropriately to ptm */
-#if ENABLE_DESKTOP
-                const char *endp;
-#endif
 
                 /* HH:MM */
                 if (sscanf(date_str, "%u:%u%c",
@@ -50,14 +108,6 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
                         ptm->tm_year -= 1900; /* Adjust years */
                         ptm->tm_mon -= 1; /* Adjust month from 1-12 to 0-11 */
                 } else
-#if ENABLE_DESKTOP  /* strptime is BIG: ~1k in uclibc, ~10k in glibc */
-                /* month_name d HH:MM:SS YYYY. Supported by GNU date */
-                if ((endp = strptime(date_str, "%b %d %T %Y", ptm)) != NULL
-                 && *endp == '\0'
-                ) {
-                        return; /* don't fall through to end == ":" check */
-                } else
-#endif
                 {
                         bb_error_msg_and_die(bb_msg_invalid_date, date_str);
                 }
@@ -89,6 +139,7 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
                 ptm->tm_year -= 1900; /* Adjust years */
                 ptm->tm_mon -= 1; /* Adjust month from 1-12 to 0-11 */
         } else
+#endif /* ENABLE_DESKTOP */
         if (date_str[0] == '@') {
                 time_t t;
                 if (sizeof(t) <= sizeof(long))
@@ -99,7 +150,7 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
                         struct tm *lt = localtime(&t);
                         if (lt) {
                                 *ptm = *lt;
-                                return;
+                                return 0;
                         }
                 }
                 end = '1';
@@ -216,6 +267,7 @@ void FAST_FUNC parse_datestr(const char *date_str, struct tm *ptm)
         if (end != '\0') {
                 bb_error_msg_and_die(bb_msg_invalid_date, date_str);
         }
+        return 1;
 }
 
 time_t FAST_FUNC validate_tm_time(const char *date_str, struct tm *ptm)
diff --git a/shell/ash.c b/shell/ash.c
index 7544204d1..5adb95bc5 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2355,6 +2355,7 @@ static const struct {
         { VSTRFIXED|VTEXTFIXED       , defoptindvar, getoptsreset    },
 #endif
         { VSTRFIXED|VTEXTFIXED       , NULL /* inited to linenovar */, NULL },
+        { VSTRFIXED|VTEXTFIXED       , NULL /* inited to funcnamevar */, NULL },
 #if ENABLE_ASH_RANDOM_SUPPORT
         { VSTRFIXED|VTEXTFIXED|VUNSET|VDYNAMIC, "RANDOM", change_random },
 #endif
@@ -2384,6 +2385,8 @@ struct globals_var {
         struct var varinit[ARRAY_SIZE(varinit_data)];
         int lineno;
         char linenovar[sizeof("LINENO=") + sizeof(int)*3];
+        char funcnamevar[sizeof("FUNCNAME=") + 64];
+        char *funcname;
         unsigned trap_depth;
         bool in_trap_ERR; /* ERR cannot recurse, no need to be a counter */
 };
@@ -2396,6 +2399,8 @@ extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
 #define varinit       (G_var.varinit      )
 #define lineno        (G_var.lineno       )
 #define linenovar     (G_var.linenovar    )
+#define funcnamevar   (G_var.funcnamevar  )
+#define funcname      (G_var.funcname     )
 #define trap_depth    (G_var.trap_depth   )
 #define in_trap_ERR   (G_var.in_trap_ERR  )
 #define vifs      varinit[0]
@@ -2413,13 +2418,14 @@ extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
 #endif
 #define VAR_OFFSET2 (VAR_OFFSET1 + ENABLE_ASH_GETOPTS)
 #define vlineno   varinit[VAR_OFFSET2 + 5]
+#define vfuncname varinit[VAR_OFFSET2 + 6]
 #if ENABLE_ASH_RANDOM_SUPPORT
-# define vrandom  varinit[VAR_OFFSET2 + 6]
+# define vrandom  varinit[VAR_OFFSET2 + 7]
 #endif
 #define VAR_OFFSET3 (VAR_OFFSET2 + ENABLE_ASH_RANDOM_SUPPORT)
 #if BASH_EPOCH_VARS
-# define vepochs  varinit[VAR_OFFSET3 + 6]
-# define vepochr  varinit[VAR_OFFSET3 + 7]
+# define vepochs  varinit[VAR_OFFSET3 + 7]
+# define vepochr  varinit[VAR_OFFSET3 + 8]
 #endif
 #define INIT_G_var() do { \
         unsigned i; \
@@ -2432,6 +2438,8 @@ extern struct globals_var *BB_GLOBAL_CONST ash_ptr_to_globals_var;
         } \
         strcpy(linenovar, "LINENO="); \
         vlineno.var_text = linenovar; \
+        strcpy(funcnamevar, "FUNCNAME="); \
+        vfuncname.var_text = funcnamevar; \
 } while (0)
 
 /*
@@ -2571,6 +2579,9 @@ lookupvar(const char *name)
                 if (!(v->flags & VUNSET)) {
                         if (v->var_text == linenovar) {
                                 fmtstr(linenovar+7, sizeof(linenovar)-7, "%d", lineno);
+                        } else
+                        if (v->var_text == funcnamevar) {
+                                safe_strncpy(funcnamevar+9, funcname ? funcname : "", sizeof(funcnamevar)-9);
                         }
                         return var_end(v->var_text);
                 }
@@ -6015,7 +6026,7 @@ stoppedjobs(void)
         int retval;
 
         retval = 0;
-        if (job_warning)
+        if (!iflag || job_warning)
                 goto out;
         jp = curjob;
         if (jp && jp->state == JOBSTOPPED) {
@@ -10654,6 +10665,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         int e;
         int savelineno;
         int savefuncline;
+        char *savefuncname;
         char *savetrap = NULL;
 
         if (!Eflag) {
@@ -10663,6 +10675,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         savelineno = lineno;
         saveparam = shellparam;
         savefuncline = funcline;
+        savefuncname = funcname;
         savehandler = exception_handler;
         e = setjmp(jmploc.loc);
         if (e) {
@@ -10672,6 +10685,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         exception_handler = &jmploc;
         shellparam.malloced = 0;
         func->count++;
+        funcname = func->n.ndefun.text;
         funcline = func->n.ndefun.linno;
         INT_ON;
         shellparam.nparam = argc - 1;
@@ -10683,6 +10697,7 @@ evalfun(struct funcnode *func, int argc, char **argv, int flags)
         evaltree(func->n.ndefun.body, flags & EV_TESTED);
  funcdone:
         INT_OFF;
+        funcname = savefuncname;
         if (savetrap) {
                 if (!trap[NTRAP_ERR])
                         trap[NTRAP_ERR] = savetrap;
@@ -11650,9 +11665,7 @@ preadfd(void)
  * Refill the input buffer and return the next input character:
  *
  * 1) If a string was pushed back on the input, pop it;
- * 2) If an EOF was pushed back (g_parsefile->left_in_line < -BIGNUM)
- *    or we are reading from a string so we can't refill the buffer,
- *    return EOF.
+ * 2) If we are reading from a string we can't refill the buffer, return EOF.
  * 3) If there is more stuff in this buffer, use it else call read to fill it.
  * 4) Process input up to the next newline, deleting nul characters.
  */
@@ -11669,21 +11682,9 @@ preadbuffer(void)
                 popstring();
                 return __pgetc();
         }
-        /* on both branches above g_parsefile->left_in_line < 0.
-         * "pgetc" needs refilling.
-         */
 
-        /* -90 is our -BIGNUM. Below we use -99 to mark "EOF on read",
-         * pungetc() may increment it a few times.
-         * Assuming it won't increment it to less than -90.
-         */
-        if (g_parsefile->left_in_line < -90 || g_parsefile->buf == NULL) {
+        if (g_parsefile->buf == NULL) {
                 pgetc_debug("preadbuffer PEOF1");
-                /* even in failure keep left_in_line and next_to_pgetc
-                 * in lock step, for correct multi-layer pungetc.
-                 * left_in_line was decremented before preadbuffer(),
-                 * must inc next_to_pgetc: */
-                g_parsefile->next_to_pgetc++;
                 return PEOF;
         }
 
@@ -11693,10 +11694,8 @@ preadbuffer(void)
  again:
                 more = preadfd();
                 if (more <= 0) {
-                        /* don't try reading again */
-                        g_parsefile->left_in_line = -99;
+                        g_parsefile->left_in_buffer = g_parsefile->left_in_line = 0;
                         pgetc_debug("preadbuffer PEOF2");
-                        g_parsefile->next_to_pgetc++;
                         return PEOF;
                 }
         }
@@ -14376,12 +14375,13 @@ cmdloop(int top)
                         if (!top || numeof >= 50)
                                 break;
                         if (!stoppedjobs()) {
+                                if (!iflag)
+                                        break;
                                 if (!Iflag) {
-                                        if (iflag) {
-                                                newline_and_flush(stderr);
-                                        }
+                                        newline_and_flush(stderr);
                                         break;
                                 }
+                                /* "set -o ignoreeof" active, do not exit command loop on ^D */
                                 out2str("\nUse \"exit\" to leave shell.\n");
                         }
                         numeof++;
@@ -14508,6 +14508,12 @@ exitcmd(int argc UNUSED_PARAM, char **argv)
         if (argv[1])
                 savestatus = number(argv[1]);
 
+//TODO: this script
+// trap 'echo trap:$FUNCNAME' EXIT
+// f() { exit; }
+// f
+//prints "trap:f" in bash. We can call exitshell() here to achieve this.
+//For now, keeping dash code:
         raise_exception(EXEXIT);
         /* NOTREACHED */
 }
diff --git a/testsuite/date/date-timezone b/testsuite/date/date-timezone
new file mode 100644
index 000000000..8628aa1d7
--- /dev/null
+++ b/testsuite/date/date-timezone
@@ -0,0 +1,32 @@
+# FEATURE: CONFIG_FEATURE_TIMEZONE
+
+# 'Z' is UTC
+dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5Z')
+dt=$(echo "$dt" | cut -b1-19)
+test x"$dt" = x"Sat Jan  2 03:04:05"
+
+# '+0600' is six hours ahead of UTC
+dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5 +0600')
+dt=$(echo "$dt" | cut -b1-19)
+test x"$dt" = x"Fri Jan  1 21:04:05"
+
+# '-0600' is six hours behind UTC
+dt=$(TZ=UTC0 busybox date -d '1999-1-2 3:4:5 -0600')
+dt=$(echo "$dt" | cut -b1-19)
+test x"$dt" = x"Sat Jan  2 09:04:05"
+
+# before dst is switched on
+dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-03-28 00:59:59 +0000')
+test x"$dt" = x"Sun Mar 28 00:59:59 GMT 2021"
+
+# after dst is switched on
+dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-03-28 01:00:01 +0000')
+test x"$dt" = x"Sun Mar 28 02:00:01 BST 2021"
+
+# before dst is switched off
+dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-10-31 00:00:01 +0000')
+test x"$dt" = x"Sun Oct 31 01:00:01 BST 2021"
+
+# after dst is switched off: back to 01:00:01 but with different TZ
+dt=$(TZ=GMT0BST,M3.5.0/1,M10.5.0/2 busybox date -d '2021-10-31 01:00:01 +0000')
+test x"$dt" = x"Sun Oct 31 01:00:01 GMT 2021"
diff --git a/util-linux/getopt.c b/util-linux/getopt.c
index 1fa402429..4148586d3 100644
--- a/util-linux/getopt.c
+++ b/util-linux/getopt.c
@@ -156,57 +156,43 @@ enum {
 static const char *normalize(const char *arg)
 {
         char *bufptr;
-#if ENABLE_FEATURE_CLEAN_UP
-        static char *BUFFER = NULL;
-        free(BUFFER);
-#else
         char *BUFFER;
-#endif
 
-        if (!quote) { /* Just copy arg */
-                BUFFER = xstrdup(arg);
-                return BUFFER;
+        if (!quote) { /* Just return arg */
+                return arg;
         }
 
         /* Each character in arg may take up to four characters in the result:
            For a quote we need a closing quote, a backslash, a quote and an
            opening quote! We need also the global opening and closing quote,
            and one extra character for '\0'. */
-        BUFFER = xmalloc(strlen(arg)*4 + 3);
+        BUFFER = auto_string(xmalloc(strlen(arg)*4 + 3));
 
         bufptr = BUFFER;
         *bufptr ++= '\'';
 
         while (*arg) {
-                if (*arg == '\'') {
-                        /* Quote: replace it with: '\'' */
-                        *bufptr ++= '\'';
-                        *bufptr ++= '\\';
-                        *bufptr ++= '\'';
-                        *bufptr ++= '\'';
-                } else if (shell_TCSH && *arg == '!') {
-                        /* Exclamation mark: replace it with: \! */
-                        *bufptr ++= '\'';
-                        *bufptr ++= '\\';
-                        *bufptr ++= '!';
-                        *bufptr ++= '\'';
-                } else if (shell_TCSH && *arg == '\n') {
+                if (shell_TCSH && *arg == '\n') {
                         /* Newline: replace it with: \n */
-                        *bufptr ++= '\\';
-                        *bufptr ++= 'n';
-                } else if (shell_TCSH && isspace(*arg)) {
-                        /* Non-newline whitespace: replace it with \<ws> */
-                        *bufptr ++= '\'';
-                        *bufptr ++= '\\';
-                        *bufptr ++= *arg;
-                        *bufptr ++= '\'';
+                        *bufptr++ = '\\';
+                        *bufptr++ = 'n';
                 } else
+                if ((shell_TCSH && (*arg == '!' || isspace(*arg)))
+                 || *arg == '\''
+                ) {
+                        /* Quote exclamation marks, non-NL whitespace and quotes */
+                        *bufptr++ = '\'';
+                        *bufptr++ = '\\';
+                        *bufptr++ = *arg;
+                        *bufptr++ = '\'';
+                } else {
                         /* Just copy */
                         *bufptr ++= *arg;
+                }
                 arg++;
         }
-        *bufptr ++= '\'';
-        *bufptr ++= '\0';
+        *bufptr++ = '\'';
+        *bufptr++ = '\0';
         return BUFFER;
 }
 
@@ -327,12 +313,18 @@ static struct option *add_long_options(struct option *long_options, char *option
 
 static void set_shell(const char *new_shell)
 {
-        if (strcmp(new_shell, "bash") == 0 || strcmp(new_shell, "sh") == 0)
-                return;
-        if (strcmp(new_shell, "tcsh") == 0 || strcmp(new_shell, "csh") == 0)
+        switch (index_in_strings("bash\0sh\0tcsh\0csh\0", new_shell)) {
+        case 0:
+        case 1:
+                break;
+        case 2:
+        case 3:
                 option_mask32 |= SHELL_IS_TCSH;
-        else
+                break;
+        default:
                 bb_error_msg("unknown shell '%s', assuming bash", new_shell);
+                break;
+        }
 }