Difference between revisions of "FEXBash"
(Created page with "FEXBash is a utility program provided by FEX-emu for quickly spinning up a bash instance. == What isn't FEXBash == FEXBash is '''not''': * A virtual machine * A chroot * A way...") |
|||
| (4 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
| + | [[Category:Utility_Type_Application]] | ||
FEXBash is a utility program provided by FEX-emu for quickly spinning up a bash instance. | FEXBash is a utility program provided by FEX-emu for quickly spinning up a bash instance. | ||
== What isn't FEXBash == | == What isn't FEXBash == | ||
FEXBash is '''not''': | FEXBash is '''not''': | ||
* A virtual machine | * A virtual machine | ||
| + | ** FEX is never a virtual machine. | ||
* A chroot | * A chroot | ||
| + | ** See [[Development:Setting_up_RootFS#Chrooting_in_to_rootfs_with_FEX-Emu_Rootfs|this wiki page]] if you want to chroot in to the rootfs. | ||
* A way to install packages inside the x86-64 rootfs | * A way to install packages inside the x86-64 rootfs | ||
| + | ** See [[Development:Setting_up_RootFS#If_you_want_to_install_packages_in_the_squashfs|this wiki page]] if you want to add packages to the rootfs. | ||
| + | ** Trying to install packages while running under FEXBash will not work. The rootfs is effectively read-only. | ||
== What is FEXBash == | == What is FEXBash == | ||
Latest revision as of 00:22, 5 October 2023
FEXBash is a utility program provided by FEX-emu for quickly spinning up a bash instance.
What isn't FEXBash
FEXBash is not:
- A virtual machine
- FEX is never a virtual machine.
- A chroot
- See this wiki page if you want to chroot in to the rootfs.
- A way to install packages inside the x86-64 rootfs
- See this wiki page if you want to add packages to the rootfs.
- Trying to install packages while running under FEXBash will not work. The rootfs is effectively read-only.
What is FEXBash
FEXBash is a wrapper program that executes FEXInterpreter to run x86-64 /bin/sh or /bin/bash. Which application is executed depends on the number of arguments passed in
Usage
Zero arguments
If the user passes in no arguments then FEXBash will execute x86-64 /bin/bash to give an emulated shell environment for tinkering around in.
ryanh@ubuntu:~$ uname -a Linux ubuntu 5.15.0-rc1+ #106 SMP Tue Aug 2 19:43:23 PDT 2022 aarch64 aarch64 aarch64 GNU/Linux ryanh@ubuntu:~$ FEXBash FEXBash-ryanh@ubuntu:~> uname -a Linux ubuntu 5.15.0 #FEX-2208-11-ga2f4f494a SMP Aug 13 2022 09:47:20 x86_64 x86_64 x86_64 GNU/Linux
This is not a virtual machine. It is just an emulated environment that overlays the AArch64 host environment. You can still execute AArch64 programs from the host and also x86-64 programs.
Any arguments
If any arguments are passed in then FEXBash executes /bin/sh -c with the provided arguments passed along. One must be careful with this as sh -c is usually expected to have its arguments wrapped in double quotes.
ryanh@ubuntu:~$ sh -c uname -a Linux ryanh@ubuntu:~$ sh -c "uname -a" Linux ubuntu 5.15.0-rc1+ #106 SMP Tue Aug 2 19:43:23 PDT 2022 aarch64 aarch64 aarch64 GNU/Linux ryanh@ubuntu:~$ FEXBash uname -a Linux ryanh@ubuntu:~$ FEXBash "uname -a" Linux ubuntu 5.15.0 #FEX-2208-11-ga2f4f494a SMP Aug 13 2022 09:47:20 x86_64 x86_64 x86_64 GNU/Linux
As one can see, without the double quotes you effectively lose the -a argument. This behaves the same as /bin/sh -c behaviour without FEXBash.
This is usually used for some sort of scripting wanting to enter the FEX emulated environment.