问题
I have a Java application installed on a USB which the user should be able to run from any OS.
For this,
- I'm packaging a JRE instance on the USB along with my application.
- I'm having a FAT32 file-system on the USB.
However, the problem is, FAT32 has no concept of execute ("+x") permissions. While I can launch a shell script, like so:
$ sh /path/to/fat32-usb/helloWorld.sh
, and while I can launch a simple ELF binary, like so:
$ /lib64/ld-linux-x86-64.so.2 /path/to/fat32-usb/helloWorld
, I can't seem to be able to launch the Java ELF program. I get these errors:
Error: could not find libjava.so
Error: Could not find Java SE Runtime Environment.
Before launching java, I've tried setting these environment variables as follows:
export JAVA_HOME=/path/to/fat32-usb/jre
export LD_LIBRARY_PATH="$JAVA_HOME/lib/amd64:.:$LD_LIBRARY_PATH"
export PATH="$JAVA_HOME/bin:.:$PATH"
I have also tried launching java from inside the $JAVA_HOME/bin directory. Finally, I've also tried copying all the libXXX.so's from $JAVA_HOME/lib/amd64/ to $JAVA_HOME/bin, hoping that they would get picked up from the current directory, ., somehow.
But nothing has worked.
EDIT
Here are the last few lines of strace output:
$ strace -vfo /tmp/java.strace /lib64/ld-linux-x86-64.so.2 /path/to/fat32-usb/jre ...
...
readlink("/proc/self/exe", "/lib/x86_64-linux-gnu/ld-2.17.so", 4096) = 32
write(2, "Error: could not find libjava.so", 32) = 32
write(2, "\n", 1) = 1
write(2, "Error: Could not find Java SE Ru"..., 50) = 50
write(2, "\n", 1) = 1
exit_group(2) = ?
EDIT2
And here is the output of ltrace (just a single line!):
$ ltrace -s 120 -e '*' -ifo /tmp/java.ltrace /lib64/ld-linux-x86-64.so.2 /path/to/fat32-usb/jre ...
30913 [0xffffffffffffffff] +++ exited (status 2) +++
EDIT 3
This is ltrace excerpt around loading of libjava.so by a Java on an ext4 partition (and not the problem FAT32 partition), which I can load fine:
5525 [0x7f7627600763] <... snprintf resumed> "/home/aaa/bbb/jdk1.7.0_40/lib/amd64/libjava.so", 4096, "%s/lib/%s/libjava.so", "/home/aaa/bbb/jdk1.7.0_40", "amd64") = 46
5525 [0x7f762760076d] libjli.so->access("/home/aaa/bbb/jdk1.7.0_40/lib/amd64/libjava.so", 0) = -1
5525 [0x7f762760078d] libjli.so->snprintf( <unfinished ...>
5525 [0x3085246bdb] libc.so.6->(0, 0x7fffffd8, 0x7f7627607363, 39) = 0
5525 [0x3085246be3] libc.so.6->(0, 0x7fffffd8, 0x7f7627607363, 39) = 0
5525 [0x7f762760078d] <... snprintf resumed> "/home/aaa/bbb/jdk1.7.0_40/jre/lib/amd64/libjava.so", 4096, "%s/jre/lib/%s/libjava.so", "/home/aaa/bbb/jdk1.7.0_40", "amd64") = 50
5525 [0x7f7627600797] libjli.so->access("/home/aaa/bbb/jdk1.7.0_40/jre/lib/amd64/libjava.so", 0) = 0
And this is the strace output of, again, the healthy/loading java.
5952 readlink("/proc/self/exe", "/home/aaa/bbb/jdk1.7.0_40/bin/ja"..., 4096) = 34
5952 access("/home/aaa/bbb/jdk1.7.0_40/lib/amd64/libjava.so", F_OK) = -1 ENOENT (No such file or directory)
5952 access("/home/aaa/bbb/jdk1.7.0_40/jre/lib/amd64/libjava.so", F_OK) = 0
5952 open("/home/aaa/bbb/jdk1.7.0_40/jre/lib/amd64/jvm.cfg", O_RDONLY) = 3
来源：https://stackoverflow.com/questions/22112371/launching-jre-in-linux-from-a-fat32-usb