glibcの "/bin/sh" はどこにあるのか

libcライブラリをstringsすると、"/bin/sh" などのパス文字列を見つけることができる。

$ strings -tx /lib/i386-linux-gnu/libc-2.15.so | grep " /"
 ...
 161d98 /bin/sh
 161ee4 /tmp
 162bf8 /dev/tty
 162c3d /proc/self/maps
 1633bf /etc/localtime
 ...

これらの定義は、主に次のファイルにある。

• [svn] View of /branches/eglibc-2_15/libc/sysdeps/generic/paths.h

/* Default search path. */
#define _PATH_DEFPATH   "/usr/bin:/bin"
/* All standard utilities path. */
#define _PATH_STDPATH \
        "/usr/bin:/bin:/usr/sbin:/sbin:/usr/contrib/bin:/usr/old/bin"

#define _PATH_BSHELL    "/bin/sh"
#define _PATH_CONSOLE   "/dev/console"
#define _PATH_CSHELL    "/bin/csh"
#define _PATH_DEVDB     "/var/run/dev.db"
#define _PATH_DEVNULL   "/dev/null"
#define _PATH_DRUM      "/dev/drum"
#define _PATH_GSHADOW   "/etc/gshadow"
#define _PATH_KMEM      "/dev/kmem"
#define _PATH_MAILDIR   "/var/mail"
#define _PATH_LASTLOG   "/var/log/lastlog"
#define _PATH_MAN       "/usr/man"
#define _PATH_MEM       "/dev/mem"
#define _PATH_MNTTAB    "/etc/fstab"
#define _PATH_MOUNTED   "/var/run/mtab"
#define _PATH_NOLOGIN   "/etc/nologin"
#define _PATH_PRESERVE  "/var/preserve"
#define _PATH_RWHODIR   "/var/rwho"
#define _PATH_SENDMAIL  "/usr/sbin/sendmail"
#define _PATH_SHADOW    "/etc/shadow"
#define _PATH_SHELLS    "/etc/shells"
#define _PATH_TTY       "/dev/tty"
#define _PATH_UNIX      "/vmunix"
#define _PATH_UTMP      "/var/run/utmp"
#define _PATH_UTMP_DB   "/var/run/utmp.db"
#define _PATH_VI        "/usr/bin/vi"
#define _PATH_WTMP      "/var/log/wtmp"

/* Provide trailing slash, since mostly used for building pathnames. */
#define _PATH_DEV       "/dev/"
#define _PATH_TMP       "/tmp/"
#define _PATH_VARDB     "/var/db/"
#define _PATH_VARRUN    "/var/run/"
#define _PATH_VARTMP    "/var/tmp/"

_PATH_VIが興味深いが、定義されているだけで実際には使われておらず、バイナリ中にも存在しないようである。