[Samsung Galaxy Player 4.0, 5.0] S_m_O_k:
Build a good one.

I do not know how to in 3.0, but earlier versions are not affixed symlink busybox.

Here is my code where the symlink busybox works.

symlink("busybox", "/system/xbin/[", "/system/xbin/[[",
"/system/xbin/acpid", "/system/xbin/addgroup", "/system/xbin/add-shell",
"/system/xbin/adduser", "/system/xbin/adjtimex",
"/system/xbin/arp", "/system/xbin/arping", "/system/xbin/ash", "/system/xbin/awk",
"/system/xbin/base64", "/system/xbin/basename", "/system/xbin/beep",
"/system/xbin/blkid", "/system/xbin/blockdev", "/system/xbin/bootchartd",
"/system/xbin/brctl", "/system/xbin/bunzip2", "/system/xbin/bzcat",
"/system/xbin/bzip2", "/system/xbin/cal", "/system/xbin/cat",
"/system/xbin/catv", "/system/xbin/chat", "/system/xbin/chattr",
"/system/xbin/chgrp", "/system/xbin/chmod", "/system/xbin/chown",
"/system/xbin/chpasswd", "/system/xbin/chpst", "/system/xbin/chroot",
"/system/xbin/chrt", "/system/xbin/chvt", "/system/xbin/cksum",
"/system/xbin/clear", "/system/xbin/cmp", "/system/xbin/comm",
"/system/xbin/cp", "/system/xbin/cpio", "/system/xbin/crond",
"/system/xbin/crontab", "/system/xbin/cryptpw", "/system/xbin/cttyhack",
"/system/xbin/cut", "/system/xbin/date", "/system/xbin/dc",
"/system/xbin/dd", "/system/xbin/deallocvt", "/system/xbin/delgroup",
"/system/xbin/deluser", "/system/xbin/depmod", "/system/xbin/devmem",
"/system/xbin/df", "/system/xbin/dhcprelay", "/system/xbin/diff",
"/system/xbin/dirname", "/system/xbin/dmesg", "/system/xbin/dnsd",
"/system/xbin/dnsdomainname", "/system/xbin/dos2unix", "/system/xbin/du",
"/system/xbin/dumpkmap", "/system/xbin/dumpleases", "/system/xbin/echo",
"/system/xbin/ed", "/system/xbin/egrep", "/system/xbin/eject",
"/system/xbin/env", "/system/xbin/envdir", "/system/xbin/ether-wake",
"/system/xbin/expand", "/system/xbin/expr", "/system/xbin/fakeidentd",
"/system/xbin/false", "/system/xbin/fbset", "/system/xbin/fbsplash",
"/system/xbin/fdflush", "/system/xbin/fdformat", "/system/xbin/fdisk",
"/system/xbin/fgconsole", "/system/xbin/fgrep", "/system/xbin/find",
"/system/xbin/findfs", "/system/xbin/flock", "/system/xbin/fold",
"/system/xbin/free", "/system/xbin/freeramdisk", "/system/xbin/fsck",
"/system/xbin/fsck.minix", "/system/xbin/fsync", "/system/xbin/ftpd",
"/system/xbin/ftpget", "/system/xbin/ftpput", "/system/xbin/fuser",
"/system/xbin/getopt", "/system/xbin/getty", "/system/xbin/grep",
"/system/xbin/gunzip", "/system/xbin/gzip", "/system/xbin/halt",
"/system/xbin/hd", "/system/xbin/hdparm", "/system/xbin/head",
"/system/xbin/hexdump", "/system/xbin/hostid", "/system/xbin/hostname",
"/system/xbin/httpd", "/system/xbin/hush", "/system/xbin/hwclock",
"/system/xbin/id", "/system/xbin/ifconfig", "/system/xbin/ifdown",
"/system/xbin/ifenslave", "/system/xbin/ifplugd", "/system/xbin/ifup",
"/system/xbin/inetd", "/system/xbin/init", "/system/xbin/insmod",
"/system/xbin/install", "/system/xbin/ionice", "/system/xbin/iostat",
"/system/xbin/ip", "/system/xbin/ipaddr", "/system/xbin/ipcalc",
"/system/xbin/ipcrm", "/system/xbin/ipcs", "/system/xbin/iplink",
"/system/xbin/iproute", "/system/xbin/iprule", "/system/xbin/iptunnel",
"/system/xbin/kbd_mode", "/system/xbin/kill", "/system/xbin/killall",
"/system/xbin/killall5", "/system/xbin/klogd", "/system/xbin/last",
"/system/xbin/length", "/system/xbin/less", "/system/xbin/linux32",
"/system/xbin/linux64", "/system/xbin/linuxrc", "/system/xbin/ln",
"/system/xbin/loadfont", "/system/xbin/loadkmap", "/system/xbin/logger",
"/system/xbin/login", "/system/xbin/logname", "/system/xbin/logread",
"/system/xbin/losetup", "/system/xbin/lpd", "/system/xbin/lpq",
"/system/xbin/lpr", "/system/xbin/ls", "/system/xbin/lsattr",
"/system/xbin/lsmod", "/system/xbin/lspci", "/system/xbin/lsusb",
"/system/xbin/lzcat", "/system/xbin/lzma", "/system/xbin/lzop",
"/system/xbin/lzopcat", "/system/xbin/makedevs", "/system/xbin/makemime",
"/system/xbin/man", "/system/xbin/md5sum", "/system/xbin/mdev",
"/system/xbin/mesg", "/system/xbin/microcom", "/system/xbin/mkdir",
"/system/xbin/mkdosfs", "/system/xbin/mke2fs", "/system/xbin/mkfifo",
"/system/xbin/mkfs.ext2", "/system/xbin/mkfs.minix", "/system/xbin/mkfs.vfat",
"/system/xbin/mknod", "/system/xbin/mkpasswd", "/system/xbin/mkswap",
"/system/xbin/mktemp", "/system/xbin/modinfo", "/system/xbin/modprobe",
"/system/xbin/more", "/system/xbin/mount", "/system/xbin/mountpoint",
"/system/xbin/mpstat", "/system/xbin/mt", "/system/xbin/mv",
"/system/xbin/nameif", "/system/xbin/nbd-client", "/system/xbin/nc",
"/system/xbin/netstat", "/system/xbin/nice", "/system/xbin/nmeter",
"/system/xbin/nohup", "/system/xbin/nslookup", "/system/xbin/ntpd",
"/system/xbin/od", "/system/xbin/openvt", "/system/xbin/passwd",
"/system/xbin/patch", "/system/xbin/pgrep", "/system/xbin/pidof",
"/system/xbin/ping", "/system/xbin/ping6", "/system/xbin/pipe_progress",
"/system/xbin/pivot_root", "/system/xbin/pkill", "/system/xbin/pmap",
"/system/xbin/popmaildir", "/system/xbin/poweroff", "/system/xbin/powertop",
"/system/xbin/printenv", "/system/xbin/printf", "/system/xbin/ps",
"/system/xbin/pscan", "/system/xbin/pwd", "/system/xbin/raidautorun",
"/system/xbin/rdate", "/system/xbin/rdev", "/system/xbin/readahead",
"/system/xbin/readlink", "/system/xbin/readprofile", "/system/xbin/realpath",
"/system/xbin/reboot", "/system/xbin/reformime", "/system/xbin/remove-shell",
"/system/xbin/renice", "/system/xbin/reset", "/system/xbin/resize",
"/system/xbin/rev", "/system/xbin/rm", "/system/xbin/rmdir",
"/system/xbin/rmmod", "/system/xbin/route", "/system/xbin/rpm",
"/system/xbin/rpm2cpio", "/system/xbin/rtcwake", "/system/xbin/runlevel",
"/system/xbin/run-parts", "/system/xbin/runsv", "/system/xbin/runsvdir",
"/system/xbin/rx", "/system/xbin/script", "/system/xbin/scriptreplay",
"/system/xbin/sed", "/system/xbin/sendmail", "/system/xbin/seq",
"/system/xbin/setarch", "/system/xbin/setconsole", "/system/xbin/setfont",
"/system/xbin/setkeycodes", "/system/xbin/setlogcons", "/system/xbin/setsid",
"/system/xbin/setuidgid", "/system/xbin/sh", "/system/xbin/sha1sum",
"/system/xbin/sha256sum", "/system/xbin/sha512sum", "/system/xbin/showkey",
"/system/xbin/slattach", "/system/xbin/sleep", "/system/xbin/smemcap",
"/system/xbin/softlimit", "/system/xbin/sort", "/system/xbin/split",
"/system/xbin/start-stop-daemon", "/system/xbin/stat", "/system/xbin/strings",
"/system/xbin/stty", "/system/xbin/sulogin", "/system/xbin/sum",
"/system/xbin/sv", "/system/xbin/svlogd", "/system/xbin/swapoff",
"/system/xbin/swapon", "/system/xbin/switch_root", "/system/xbin/sync",
"/system/xbin/sysctl", "/system/xbin/syslogd", "/system/xbin/tac",
"/system/xbin/tail", "/system/xbin/tar", "/system/xbin/tcpsvd",
"/system/xbin/tee", "/system/xbin/telnet", "/system/xbin/telnetd",
"/system/xbin/test", "/system/xbin/tftp", "/system/xbin/tftpd",
"/system/xbin/time", "/system/xbin/timeout", "/system/xbin/top",
"/system/xbin/touch", "/system/xbin/tr", "/system/xbin/traceroute",
"/system/xbin/traceroute6", "/system/xbin/true", "/system/xbin/tty",
"/system/xbin/ttysize", "/system/xbin/tunctl", "/system/xbin/udhcpc",
"/system/xbin/udhcpd", "/system/xbin/udpsvd", "/system/xbin/umount",
"/system/xbin/uname", "/system/xbin/unexpand", "/system/xbin/uniq",
"/system/xbin/unix2dos", "/system/xbin/unlzma", "/system/xbin/unlzop",
"/system/xbin/unxz", "/system/xbin/unzip", "/system/xbin/uptime",
"/system/xbin/usleep", "/system/xbin/uudecode", "/system/xbin/uuencode",
"/system/xbin/vconfig", "/system/xbin/vi", "/system/xbin/vlock",
"/system/xbin/volname", "/system/xbin/wall", "/system/xbin/watch",
"/system/xbin/watchdog", "/system/xbin/wc", "/system/xbin/wget",
"/system/xbin/which", "/system/xbin/who", "/system/xbin/whoami",
"/system/xbin/xargs", "/system/xbin/xz", "/system/xbin/xzcat",
"/system/xbin/yes", "/system/xbin/zcat", "/system/xbin/zcip");

Just now, working on my assembly in the AROMA Installer 2.00, was the same code as you have on busybox, purely by chance I saw an error when trying to run a script in the terminal.

Sorry for my english =)