Merge branch 'busybox' into merge

5 files changed, 190 insertions, 182 deletions

diff --git a/libbb/Config.src b/libbb/Config.src
index 16c79dbf0..9da8b65ee 100644
--- a/libbb/Config.src
+++ b/libbb/Config.src
@@ -11,14 +11,14 @@ choice
         prompt "Buffer allocation policy"
         default FEATURE_BUFFERS_USE_MALLOC
         help
-          There are 3 ways BusyBox can handle buffer allocations:
-          - Use malloc. This costs code size for the call to xmalloc.
-          - Put them on stack. For some very small machines with limited stack
-            space, this can be deadly. For most folks, this works just fine.
-          - Put them in BSS. This works beautifully for computers with a real
-            MMU (and OS support), but wastes runtime RAM for uCLinux. This
-            behavior was the only one available for BusyBox versions 0.48 and
-            earlier.
+        There are 3 ways BusyBox can handle buffer allocations:
+        - Use malloc. This costs code size for the call to xmalloc.
+        - Put them on stack. For some very small machines with limited stack
+        space, this can be deadly. For most folks, this works just fine.
+        - Put them in BSS. This works beautifully for computers with a real
+        MMU (and OS support), but wastes runtime RAM for uCLinux. This
+        behavior was the only one available for BusyBox versions 0.48 and
+        earlier.
 
 config FEATURE_BUFFERS_USE_MALLOC
         bool "Allocate with Malloc"
@@ -36,52 +36,52 @@ config PASSWORD_MINLEN
         default 6
         range 5 32
         help
-          Minimum allowable password length.
+        Minimum allowable password length.
 
 config MD5_SMALL
         int "MD5: Trade bytes for speed (0:fast, 3:slow)"
         default 1  # all "fast or small" options default to small
         range 0 3
         help
-          Trade binary size versus speed for the md5sum algorithm.
-          Approximate values running uClibc and hashing
-          linux-2.4.4.tar.bz2 were:
-                            user times (sec)  text size (386)
-          0 (fastest)         1.1                6144
-          1                   1.4                5392
-          2                   3.0                5088
-          3 (smallest)        5.1                4912
+        Trade binary size versus speed for the md5sum algorithm.
+        Approximate values running uClibc and hashing
+        linux-2.4.4.tar.bz2 were:
+        value               user times (sec)  text size (386)
+        0 (fastest)         1.1                6144
+        1                   1.4                5392
+        2                   3.0                5088
+        3 (smallest)        5.1                4912
 
 config SHA3_SMALL
         int "SHA3: Trade bytes for speed (0:fast, 1:slow)"
         default 1  # all "fast or small" options default to small
         range 0 1
         help
-          Trade binary size versus speed for the sha3sum algorithm.
-          SHA3_SMALL=0 compared to SHA3_SMALL=1 (approximate):
-          64-bit x86: +270 bytes of code, 45% faster
-          32-bit x86: +450 bytes of code, 75% faster
+        Trade binary size versus speed for the sha3sum algorithm.
+        SHA3_SMALL=0 compared to SHA3_SMALL=1 (approximate):
+        64-bit x86: +270 bytes of code, 45% faster
+        32-bit x86: +450 bytes of code, 75% faster
 
 config FEATURE_FAST_TOP
         bool "Faster /proc scanning code (+100 bytes)"
         default n  # all "fast or small" options default to small
         help
-          This option makes top and ps ~20% faster (or 20% less CPU hungry),
-          but code size is slightly bigger.
+        This option makes top and ps ~20% faster (or 20% less CPU hungry),
+        but code size is slightly bigger.
 
 config FEATURE_ETC_NETWORKS
         bool "Support /etc/networks"
         default n
         help
-          Enable support for network names in /etc/networks. This is
-          a rarely used feature which allows you to use names
-          instead of IP/mask pairs in route command.
+        Enable support for network names in /etc/networks. This is
+        a rarely used feature which allows you to use names
+        instead of IP/mask pairs in route command.
 
 config FEATURE_EDITING
         bool "Command line editing"
         default y
         help
-          Enable line editing (mainly for shell command line).
+        Enable line editing (mainly for shell command line).
 
 config FEATURE_EDITING_MAX_LEN
         int "Maximum length of input"
@@ -89,17 +89,17 @@ config FEATURE_EDITING_MAX_LEN
         default 1024
         depends on FEATURE_EDITING
         help
-          Line editing code uses on-stack buffers for storage.
-          You may want to decrease this parameter if your target machine
-          benefits from smaller stack usage.
+        Line editing code uses on-stack buffers for storage.
+        You may want to decrease this parameter if your target machine
+        benefits from smaller stack usage.
 
 config FEATURE_EDITING_VI
         bool "vi-style line editing commands"
         default n
         depends on FEATURE_EDITING
         help
-          Enable vi-style line editing. In shells, this mode can be
-          turned on and off with "set -o vi" and "set +o vi".
+        Enable vi-style line editing. In shells, this mode can be
+        turned on and off with "set -o vi" and "set +o vi".
 
 config FEATURE_EDITING_HISTORY
         int "History size"
@@ -108,29 +108,29 @@ config FEATURE_EDITING_HISTORY
         default 255
         depends on FEATURE_EDITING
         help
-          Specify command history size (0 - disable).
+        Specify command history size (0 - disable).
 
 config FEATURE_EDITING_SAVEHISTORY
         bool "History saving"
         default y
         depends on FEATURE_EDITING
         help
-          Enable history saving in shells.
+        Enable history saving in shells.
 
 config FEATURE_EDITING_SAVE_ON_EXIT
         bool "Save history on shell exit, not after every command"
         default n
         depends on FEATURE_EDITING_SAVEHISTORY
         help
-          Save history on shell exit, not after every command.
+        Save history on shell exit, not after every command.
 
 config FEATURE_REVERSE_SEARCH
         bool "Reverse history search"
         default y
         depends on FEATURE_EDITING
         help
-          Enable readline-like Ctrl-R combination for reverse history search.
-          Increases code by about 0.5k.
+        Enable readline-like Ctrl-R combination for reverse history search.
+        Increases code by about 0.5k.
 
 config FEATURE_TAB_COMPLETION
         bool "Tab completion"
@@ -147,237 +147,237 @@ config FEATURE_EDITING_FANCY_PROMPT
         default y
         depends on FEATURE_EDITING
         help
-          Setting this option allows for prompts to use things like \w and
-          \$ and escape codes.
+        Setting this option allows for prompts to use things like \w and
+        \$ and escape codes.
 
 config FEATURE_EDITING_ASK_TERMINAL
         bool "Query cursor position from terminal"
         default n
         depends on FEATURE_EDITING
         help
-          Allow usage of "ESC [ 6 n" sequence. Terminal answers back with
-          current cursor position. This information is used to make line
-          editing more robust in some cases.
-          If you are not sure whether your terminals respond to this code
-          correctly, or want to save on code size (about 400 bytes),
-          then do not turn this option on.
+        Allow usage of "ESC [ 6 n" sequence. Terminal answers back with
+        current cursor position. This information is used to make line
+        editing more robust in some cases.
+        If you are not sure whether your terminals respond to this code
+        correctly, or want to save on code size (about 400 bytes),
+        then do not turn this option on.
 
 config LOCALE_SUPPORT
         bool "Enable locale support (system needs locale for this to work)"
         default n
         help
-          Enable this if your system has locale support and you would like
-          busybox to support locale settings.
+        Enable this if your system has locale support and you would like
+        busybox to support locale settings.
 
 config UNICODE_SUPPORT
         bool "Support Unicode"
         default y
         help
-          This makes various applets aware that one byte is not
-          one character on screen.
+        This makes various applets aware that one byte is not
+        one character on screen.
 
-          Busybox aims to eventually work correctly with Unicode displays.
-          Any older encodings are not guaranteed to work.
-          Probably by the time when busybox will be fully Unicode-clean,
-          other encodings will be mainly of historic interest.
+        Busybox aims to eventually work correctly with Unicode displays.
+        Any older encodings are not guaranteed to work.
+        Probably by the time when busybox will be fully Unicode-clean,
+        other encodings will be mainly of historic interest.
 
 config UNICODE_USING_LOCALE
         bool "Use libc routines for Unicode (else uses internal ones)"
         default n
         depends on UNICODE_SUPPORT && LOCALE_SUPPORT
         help
-          With this option on, Unicode support is implemented using libc
-          routines. Otherwise, internal implementation is used.
-          Internal implementation is smaller.
+        With this option on, Unicode support is implemented using libc
+        routines. Otherwise, internal implementation is used.
+        Internal implementation is smaller.
 
 config FEATURE_CHECK_UNICODE_IN_ENV
         bool "Check $LC_ALL, $LC_CTYPE and $LANG environment variables"
         default n
         depends on UNICODE_SUPPORT && !UNICODE_USING_LOCALE
         help
-          With this option on, Unicode support is activated
-          only if locale-related variables have the value of the form
-          "xxxx.utf8"
+        With this option on, Unicode support is activated
+        only if locale-related variables have the value of the form
+        "xxxx.utf8"
 
-          Otherwise, Unicode support will be always enabled and active.
+        Otherwise, Unicode support will be always enabled and active.
 
 config SUBST_WCHAR
         int "Character code to substitute unprintable characters with"
         depends on UNICODE_SUPPORT
         default 63
         help
-          Typical values are 63 for '?' (works with any output device),
-          30 for ASCII substitute control code,
-          65533 (0xfffd) for Unicode replacement character.
+        Typical values are 63 for '?' (works with any output device),
+        30 for ASCII substitute control code,
+        65533 (0xfffd) for Unicode replacement character.
 
 config LAST_SUPPORTED_WCHAR
         int "Range of supported Unicode characters"
         depends on UNICODE_SUPPORT
         default 767
         help
-          Any character with Unicode value bigger than this is assumed
-          to be non-printable on output device. Many applets replace
-          such characters with substitution character.
-
-          The idea is that many valid printable Unicode chars
-          nevertheless are not displayed correctly. Think about
-          combining charachers, double-wide hieroglyphs, obscure
-          characters in dozens of ancient scripts...
-          Many terminals, terminal emulators, xterms etc will fail
-          to handle them correctly. Choose the smallest value
-          which suits your needs.
-
-          Typical values are:
-          126 - ASCII only
-          767 (0x2ff) - there are no combining chars in [0..767] range
+        Any character with Unicode value bigger than this is assumed
+        to be non-printable on output device. Many applets replace
+        such characters with substitution character.
+
+        The idea is that many valid printable Unicode chars
+        nevertheless are not displayed correctly. Think about
+        combining charachers, double-wide hieroglyphs, obscure
+        characters in dozens of ancient scripts...
+        Many terminals, terminal emulators, xterms etc will fail
+        to handle them correctly. Choose the smallest value
+        which suits your needs.
+
+        Typical values are:
+        126 - ASCII only
+        767 (0x2ff) - there are no combining chars in [0..767] range
                         (the range includes Latin 1, Latin Ext. A and B),
                         code is ~700 bytes smaller for this case.
-          4351 (0x10ff) - there are no double-wide chars in [0..4351] range,
+        4351 (0x10ff) - there are no double-wide chars in [0..4351] range,
                         code is ~300 bytes smaller for this case.
-          12799 (0x31ff) - nearly all non-ideographic characters are
+        12799 (0x31ff) - nearly all non-ideographic characters are
                         available in [0..12799] range, including
                         East Asian scripts like katakana, hiragana, hangul,
                         bopomofo...
-          0 - off, any valid printable Unicode character will be printed.
+        0 - off, any valid printable Unicode character will be printed.
 
 config UNICODE_COMBINING_WCHARS
         bool "Allow zero-width Unicode characters on output"
         default n
         depends on UNICODE_SUPPORT
         help
-          With this option off, any Unicode char with width of 0
-          is substituted on output.
+        With this option off, any Unicode char with width of 0
+        is substituted on output.
 
 config UNICODE_WIDE_WCHARS
         bool "Allow wide Unicode characters on output"
         default n
         depends on UNICODE_SUPPORT
         help
-          With this option off, any Unicode char with width > 1
-          is substituted on output.
+        With this option off, any Unicode char with width > 1
+        is substituted on output.
 
 config UNICODE_BIDI_SUPPORT
         bool "Bidirectional character-aware line input"
         default n
         depends on UNICODE_SUPPORT && !UNICODE_USING_LOCALE
         help
-          With this option on, right-to-left Unicode characters
-          are treated differently on input (e.g. cursor movement).
+        With this option on, right-to-left Unicode characters
+        are treated differently on input (e.g. cursor movement).
 
 config UNICODE_NEUTRAL_TABLE
         bool "In bidi input, support non-ASCII neutral chars too"
         default n
         depends on UNICODE_BIDI_SUPPORT
         help
-          In most cases it's enough to treat only ASCII non-letters
-          (i.e. punctuation, numbers and space) as characters
-          with neutral directionality.
-          With this option on, more extensive (and bigger) table
-          of neutral chars will be used.
+        In most cases it's enough to treat only ASCII non-letters
+        (i.e. punctuation, numbers and space) as characters
+        with neutral directionality.
+        With this option on, more extensive (and bigger) table
+        of neutral chars will be used.
 
 config UNICODE_PRESERVE_BROKEN
         bool "Make it possible to enter sequences of chars which are not Unicode"
         default n
         depends on UNICODE_SUPPORT
         help
-          With this option on, on line-editing input (such as used by shells)
-          invalid UTF-8 bytes are not substituted with the selected
-          substitution character.
-          For example, this means that entering 'l', 's', ' ', 0xff, [Enter]
-          at shell prompt will list file named 0xff (single char name
-          with char value 255), not file named '?'.
+        With this option on, on line-editing input (such as used by shells)
+        invalid UTF-8 bytes are not substituted with the selected
+        substitution character.
+        For example, this means that entering 'l', 's', ' ', 0xff, [Enter]
+        at shell prompt will list file named 0xff (single char name
+        with char value 255), not file named '?'.
 
 config FEATURE_NON_POSIX_CP
         bool "Non-POSIX, but safer, copying to special nodes"
         default y
         help
-          With this option, "cp file symlink" will delete symlink
-          and create a regular file. This does not conform to POSIX,
-          but prevents a symlink attack.
-          Similarly, "cp file device" will not send file's data
-          to the device. (To do that, use "cat file >device")
+        With this option, "cp file symlink" will delete symlink
+        and create a regular file. This does not conform to POSIX,
+        but prevents a symlink attack.
+        Similarly, "cp file device" will not send file's data
+        to the device. (To do that, use "cat file >device")
 
 config FEATURE_VERBOSE_CP_MESSAGE
         bool "Give more precise messages when copy fails (cp, mv etc)"
         default n
         help
-          Error messages with this feature enabled:
+        Error messages with this feature enabled:
 
-            $ cp file /does_not_exist/file
-            cp: cannot create '/does_not_exist/file': Path does not exist
-            $ cp file /vmlinuz/file
-            cp: cannot stat '/vmlinuz/file': Path has non-directory component
+        $ cp file /does_not_exist/file
+        cp: cannot create '/does_not_exist/file': Path does not exist
+        $ cp file /vmlinuz/file
+        cp: cannot stat '/vmlinuz/file': Path has non-directory component
 
-          If this feature is not enabled, they will be, respectively:
+        If this feature is not enabled, they will be, respectively:
 
-            cp: cannot create '/does_not_exist/file': No such file or directory
-            cp: cannot stat '/vmlinuz/file': Not a directory
+        cp: cannot create '/does_not_exist/file': No such file or directory
+        cp: cannot stat '/vmlinuz/file': Not a directory
 
-          This will cost you ~60 bytes.
+        This will cost you ~60 bytes.
 
 config FEATURE_USE_SENDFILE
         bool "Use sendfile system call"
         default y
         select PLATFORM_LINUX
         help
-          When enabled, busybox will use the kernel sendfile() function
-          instead of read/write loops to copy data between file descriptors
-          (for example, cp command does this a lot).
-          If sendfile() doesn't work, copying code falls back to read/write
-          loop. sendfile() was originally implemented for faster I/O
-          from files to sockets, but since Linux 2.6.33 it was extended
-          to work for many more file types.
+        When enabled, busybox will use the kernel sendfile() function
+        instead of read/write loops to copy data between file descriptors
+        (for example, cp command does this a lot).
+        If sendfile() doesn't work, copying code falls back to read/write
+        loop. sendfile() was originally implemented for faster I/O
+        from files to sockets, but since Linux 2.6.33 it was extended
+        to work for many more file types.
 
 config FEATURE_COPYBUF_KB
         int "Copy buffer size, in kilobytes"
         range 1 1024
         default 4
         help
-          Size of buffer used by cp, mv, install, wget etc.
-          Buffers which are 4 kb or less will be allocated on stack.
-          Bigger buffers will be allocated with mmap, with fallback to 4 kb
-          stack buffer if mmap fails.
+        Size of buffer used by cp, mv, install, wget etc.
+        Buffers which are 4 kb or less will be allocated on stack.
+        Bigger buffers will be allocated with mmap, with fallback to 4 kb
+        stack buffer if mmap fails.
 
 config FEATURE_SKIP_ROOTFS
         bool "Skip rootfs in mount table"
         default y
         help
-          Ignore rootfs entry in mount table.
+        Ignore rootfs entry in mount table.
 
-          In Linux, kernel has a special filesystem, rootfs, which is initially
-          mounted on /. It contains initramfs data, if kernel is configured
-          to have one. Usually, another file system is mounted over / early
-          in boot process, and therefore most tools which manipulate
-          mount table, such as df, will skip rootfs entry.
+        In Linux, kernel has a special filesystem, rootfs, which is initially
+        mounted on /. It contains initramfs data, if kernel is configured
+        to have one. Usually, another file system is mounted over / early
+        in boot process, and therefore most tools which manipulate
+        mount table, such as df, will skip rootfs entry.
 
-          However, some systems do not mount anything on /.
-          If you need to configure busybox for one of these systems,
-          you may find it useful to turn this option off to make df show
-          initramfs statistics.
+        However, some systems do not mount anything on /.
+        If you need to configure busybox for one of these systems,
+        you may find it useful to turn this option off to make df show
+        initramfs statistics.
 
-          Otherwise, choose Y.
+        Otherwise, choose Y.
 
 config MONOTONIC_SYSCALL
         bool "Use clock_gettime(CLOCK_MONOTONIC) syscall"
         default y
         select PLATFORM_LINUX
         help
-          Use clock_gettime(CLOCK_MONOTONIC) syscall for measuring
-          time intervals (time, ping, traceroute etc need this).
-          Probably requires Linux 2.6+. If not selected, gettimeofday
-          will be used instead (which gives wrong results if date/time
-          is reset).
+        Use clock_gettime(CLOCK_MONOTONIC) syscall for measuring
+        time intervals (time, ping, traceroute etc need this).
+        Probably requires Linux 2.6+. If not selected, gettimeofday
+        will be used instead (which gives wrong results if date/time
+        is reset).
 
 config IOCTL_HEX2STR_ERROR
         bool "Use ioctl names rather than hex values in error messages"
         default y
         help
-          Use ioctl names rather than hex values in error messages
-          (e.g. VT_DISALLOCATE rather than 0x5608). If disabled this
-          saves about 1400 bytes.
+        Use ioctl names rather than hex values in error messages
+        (e.g. VT_DISALLOCATE rather than 0x5608). If disabled this
+        saves about 1400 bytes.
 
 config FEATURE_HWIB
         bool "Support infiniband HW"
         default y
         help
-          Support for printing infiniband addresses in network applets.
+        Support for printing infiniband addresses in network applets.
diff --git a/libbb/common_bufsiz.c b/libbb/common_bufsiz.c
index f1124ba0e..6bc6d7bc9 100644
--- a/libbb/common_bufsiz.c
+++ b/libbb/common_bufsiz.c
@@ -10,35 +10,35 @@
 //config:       bool "Use the end of BSS page"
 //config:       default n
 //config:       help
-//config:         Attempt to reclaim a small unused part of BSS.
+//config:       Attempt to reclaim a small unused part of BSS.
 //config:
-//config:         Executables have the following parts:
-//config:         = read-only executable code and constants, also known as "text"
-//config:         = read-write data
-//config:         = non-initialized (zeroed on demand) data, also known as "bss"
+//config:       Executables have the following parts:
+//config:       = read-only executable code and constants, also known as "text"
+//config:       = read-write data
+//config:       = non-initialized (zeroed on demand) data, also known as "bss"
 //config:
-//config:         At link time, "text" is padded to a full page. At runtime, all "text"
-//config:         pages are mapped RO and executable.
+//config:       At link time, "text" is padded to a full page. At runtime, all "text"
+//config:       pages are mapped RO and executable.
 //config:
-//config:         "Data" starts on the next page boundary, but is not padded
-//config:         to a full page at the end. "Bss" starts wherever "data" ends.
-//config:         At runtime, "data" pages are mapped RW and they are file-backed
-//config:         (this includes a small portion of "bss" which may live in the last
-//config:         partial page of "data").
-//config:         Pages which are fully in "bss" are mapped to anonymous memory.
+//config:       "Data" starts on the next page boundary, but is not padded
+//config:       to a full page at the end. "Bss" starts wherever "data" ends.
+//config:       At runtime, "data" pages are mapped RW and they are file-backed
+//config:       (this includes a small portion of "bss" which may live in the last
+//config:       partial page of "data").
+//config:       Pages which are fully in "bss" are mapped to anonymous memory.
 //config:
-//config:         "Bss" end is usually not page-aligned. There is an unused space
-//config:         in the last page. Linker marks its start with the "_end" symbol.
+//config:       "Bss" end is usually not page-aligned. There is an unused space
+//config:       in the last page. Linker marks its start with the "_end" symbol.
 //config:
-//config:         This option will attempt to use that space for bb_common_bufsiz1[]
-//config:         array. If it fits after _end, it will be used, and COMMON_BUFSIZE
-//config:         will be enlarged from its guaranteed minimum size of 1 kbyte.
-//config:         This may require recompilation a second time, since value of _end
-//config:         is known only after final link.
+//config:       This option will attempt to use that space for bb_common_bufsiz1[]
+//config:       array. If it fits after _end, it will be used, and COMMON_BUFSIZE
+//config:       will be enlarged from its guaranteed minimum size of 1 kbyte.
+//config:       This may require recompilation a second time, since value of _end
+//config:       is known only after final link.
 //config:
-//config:         If you are getting a build error like this:
-//config:               appletlib.c:(.text.main+0xd): undefined reference to '_end'
-//config:         disable this option.
+//config:       If you are getting a build error like this:
+//config:               appletlib.c:(.text.main+0xd): undefined reference to '_end'
+//config:       disable this option.
 
 //kbuild:lib-y += common_bufsiz.o
 
diff --git a/libbb/parse_config.c b/libbb/parse_config.c
index 408439766..307ae2cd2 100644
--- a/libbb/parse_config.c
+++ b/libbb/parse_config.c
@@ -13,7 +13,7 @@
 ////config:     bool "Uniform config file parser debugging applet: parse"
 ////config:     default n
 ////config:     help
-////config:       Typical usage of parse API:
+////config:     Typical usage of parse API:
 ////config:             char *t[3];
 ////config:             parser_t *p = config_open(filename);
 ////config:             while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
diff --git a/libbb/u_signal_names.c b/libbb/u_signal_names.c
index b49714f2a..bf984a44e 100644
--- a/libbb/u_signal_names.c
+++ b/libbb/u_signal_names.c
@@ -11,8 +11,8 @@
 //config:       bool "Support RTMIN[+n] and RTMAX[-n] signal names"
 //config:       default y
 //config:       help
-//config:         Support RTMIN[+n] and RTMAX[-n] signal names
-//config:         in kill, killall etc. This costs ~250 bytes.
+//config:       Support RTMIN[+n] and RTMAX[-n] signal names
+//config:       in kill, killall etc. This costs ~250 bytes.
 
 #include "libbb.h"
 
diff --git a/libbb/xfuncs_printf.c b/libbb/xfuncs_printf.c
index 1b11caf6b..f569b0263 100644
--- a/libbb/xfuncs_printf.c
+++ b/libbb/xfuncs_printf.c
@@ -344,20 +344,28 @@ void FAST_FUNC xsetenv(const char *key, const char *value)
  */
 void FAST_FUNC bb_unsetenv(const char *var)
 {
-        char *tp = strchr(var, '=');
-
-        if (!tp) {
-                unsetenv(var);
-                return;
+        char onstack[128 - 16]; /* smaller stack setup code on x86 */
+        char *tp;
+
+        tp = strchr(var, '=');
+        if (tp) {
+                /* In case var was putenv'ed, we can't replace '='
+                 * with NUL and unsetenv(var) - it won't work,
+                 * env is modified by the replacement, unsetenv
+                 * sees "VAR" instead of "VAR=VAL" and does not remove it!
+                 * Horror :(
+                 */
+                unsigned sz = tp - var;
+                if (sz < sizeof(onstack)) {
+                        ((char*)mempcpy(onstack, var, sz))[0] = '\0';
+                        tp = NULL;
+                        var = onstack;
+                } else {
+                        /* unlikely: very long var name */
+                        var = tp = xstrndup(var, sz);
+                }
         }
-
-        /* In case var was putenv'ed, we can't replace '='
-         * with NUL and unsetenv(var) - it won't work,
-         * env is modified by the replacement, unsetenv
-         * sees "VAR" instead of "VAR=VAL" and does not remove it!
-         * horror :( */
-        tp = xstrndup(var, tp - var);
-        unsetenv(tp);
+        unsetenv(var);
         free(tp);
 }