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915086731 09-14-2010 10:23 PM

Why can't me execute a symbolic link : "No such file or directory"
 
Assume the directory I locate is /mypath/bin/ , there exists a file named "ccache"
Then I execute ccache:
Code:

[saturn@21004872 bin]$ ./ccache
ccache, a compiler cache. Version 2.4
Copyright Andrew Tridgell, 2002

Usage:
        ccache [options]
        ccache compiler [compile options]
        compiler [compile options]    (via symbolic link)

Options:
-s                      show statistics summary
-z                      zero statistics
-c                      run a cache cleanup
-C                      clear the cache completely
-F <maxfiles>          set maximum files in cache
-M <maxsize>            set maximum size of cache (use G, M or K)
-h                      this help page
-V                      print version number

Then I execute :
Code:

[saturn@21004872 bin]$ ln -s ccache  mycc
[saturn@21004872 bin]$ ls -l ccache mycc
-rwxrwxrwx. 1 root root 31876  9月 13 22:31 ccache
lrwxrwxrwx. 1 root root    20  9月 15 18:20 mycc -> ccache

After I execute ./mycc, error comes !!
Code:

[saturn@21004872 bin]$ ./mycc
mycc: No such file or directory

Why does me get the error, it seems I can't execute the symbolic link! Help!
Thanks for everyone.

slakmagik 09-14-2010 10:36 PM

ccache tries to guess what to execute as by looking at the command line invocation. You're running it as 'mycc' but that compiler (presumably) doesn't exist on your system. You can set CCACHE_CC to some valid compiler and then invoke it as './mycc'.

915086731 09-14-2010 10:53 PM

Sorry, I don't know what you mean, since mycc links to ccache, then I think ./mycc equals to ./ccache.
And I don't what can I set to CCACHE_CC .
The command " export CCACHE_CC=gcc " doesn't solve problem.

slakmagik 09-14-2010 10:59 PM

That's odd. I get:
Code:

:ls -l mycc
lrwxrwxrwx 1 j users 6 2010-09-14 22:33 mycc -> ccache

:./mycc
mycc: No such file or directory

:export CCACHE_CC=gcc

:./mycc
gcc: no input files


915086731 09-14-2010 11:18 PM

But I got :

Code:

[saturn@21004872 bin]$ ls -l mycc
lrwxrwxrwx. 1 root root 20  9月 15 19:14 mycc -> ccache

[saturn@21004872 bin]$ export CCACHE_CC=gcc

[saturn@21004872 bin]$ ./mycc
gcc: No such file or directory

Not solved...

slakmagik 09-15-2010 02:02 AM

Well, the only thing I can think of is that gcc isn't installed. If not that, sorry, and hopefully someone else can help.

i92guboj 09-16-2010 04:09 AM

Quote:

Originally Posted by slakmagik (Post 4097866)
Well, the only thing I can think of is that gcc isn't installed. If not that, sorry, and hopefully someone else can help.

I don't know if it's the issue at hand, but some binaries and scripts will behave differently depending no the name you use to call them, a typical example is busybox. A simple example so you get what I mean.

Code:

$ which busybox
/bin/busybox
$ busybox
BusyBox v1.17.1 (2010-08-17 09:57:50 CEST) multi-call binary.
Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.

Usage: busybox [function] [arguments]...
  or: function [arguments]...

        BusyBox is a multi-call binary that combines many common Unix
        utilities into a single executable.  Most people will create a
        link to busybox for each function they wish to use and BusyBox
        will act like whatever it was invoked as.

Currently defined functions:
        [, [[, acpid, addgroup, adduser, adjtimex, ar, arp, arping, ash, awk, basename, bb, bbconfig, bbsh, beep, blkid, bootchartd, brctl, bunzip2, bzcat, bzip2, cal, cat, catv, chat, chattr, chgrp, chmod, chown,
        chpasswd, chpst, chroot, chrt, chvt, cksum, clear, cmp, comm, conspy, cp, cpio, crond, cryptpw, cttyhack, cut, date, dd, deallocvt, delgroup, deluser, depmod, devmem, df, dhcprelay, diff, dirname, dmesg,
        dnsdomainname, dos2unix, dpkg-deb, du, dumpkmap, dumpleases, echo, ed, egrep, eject, env, envdir, envuidgid, ether-wake, expand, expr, false, fbset, fdflush, fdformat, fdisk, fgconsole, fgrep, find, findfs,
        flash_eraseall, flash_lock, flash_unlock, flashcp, flock, free, freeramdisk, fsck, fsck.minix, fsync, ftpd, fuser, getopt, getty, grep, gunzip, gzip, halt, hd, hdparm, head, hexdump, hostname, httpd, hwclock, id,
        ifconfig, ifdown, ifenslave, ifplugd, ifup, init, insmod, install, ionice, ip, ipaddr, ipcrm, ipcs, iplink, iproute, iprule, iptunnel, kbd_mode, kill, killall, killall5, klogd, last, length, less, linux32,
        linux64, linuxrc, ln, loadfont, loadkmap, logger, login, logread, losetup, lpq, lpr, ls, lsattr, lsmod, lspci, lsusb, lzcat, lzma, lzop, lzopcat, makedevs, makemime, man, md5sum, mdev, mesg, microcom, mkdir,
        mkdosfs, mke2fs, mkfifo, mkfs.ext2, mkfs.minix, mkfs.reiser, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp, modinfo, modprobe, more, mount, mountpoint, mt, mv, nameif, nc, netstat, nice, nmeter, nohup, nslookup,
        ntpd, openvt, passwd, patch, pgrep, pidof, ping, ping6, pipe_progress, pivot_root, pkill, popmaildir, poweroff, printenv, printf, ps, pscan, pwd, raidautorun, rdate, rdev, readahead, readlink, readprofile,
        realpath, reboot, reformime, renice, reset, resize, rev, rm, rmdir, rmmod, route, rtcwake, run-parts, runlevel, runsv, runsvdir, rx, script, scriptreplay, sed, sendmail, seq, setarch, setconsole, setfont,
        setkeycodes, setlogcons, setsid, setuidgid, sh, sha1sum, sha256sum, sha512sum, showkey, sleep, smemcap, softlimit, sort, split, start-stop-daemon, stat, strings, stty, su, sum, sv, svlogd, swapoff, swapon,
        switch_root, sync, sysctl, syslogd, tac, tail, tar, tee, telnet, telnetd, test, tftp, tftpd, time, timeout, top, touch, tr, traceroute, traceroute6, true, tty, ttysize, tunctl, tune2fs, ubiattach, ubidetach,
        udhcpc, udhcpd, umount, uname, uncompress, unexpand, uniq, unix2dos, unlzma, unlzop, unxz, unzip, uptime, usleep, vconfig, vi, vlock, volname, wall, watch, watchdog, wc, wget, which, who, whoami, xargs, xz,
        xzcat, yes, zcat, zcip

$ ln -s /bin/busybox ls
$ ls -l ls
lrwxrwxrwx 1 i92guboj i92guboj 12 sep 16 10:07 ls -> /bin/busybox
$ ./ls
COPYING      README        ccache.1      ccache.h      cleanup.c    configure    execute.c    install-sh    mdfour.c      packaging    stats.c      unify.c      web
Makefile.in  args.c        ccache.c      ccache.yo    config.h.in  configure.in  hash.c        ls            mdfour.h      snprintf.c    test.sh      util.c
$

In shell scripts this can be done by checking for the value of $0, or usually $(basename $0), which will hold the name of the command you used to invoke the script. The script can check for that value and act differently depending on such value.

slakmagik 09-16-2010 02:04 PM

Quote:

Originally Posted by i92guboj (Post 4099145)
I don't know if it's the issue at hand, but some binaries and scripts will behave differently depending no the name you use to call them, a typical example is busybox.

That was the point of my first reply.

Quote:

Originally Posted by slakmagik (Post 4097737)
ccache tries to guess what to execute as by looking at the command line invocation.


915086731 09-21-2010 12:44 AM

Thanks for everyone!!!


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