Installing apps dynamically in runtime
Hi, A smartwatch manufacturer company wants to dynamically add/remove apps at runtime on their MCU based devices . Similarly to how it works on smartphones. Example: The user wants to extend the smartwatch with an Alarm clock app. On Linux we just needed to copy the binary to the watch and it could be launched with any number of instances. With NuttX can we extend the application which is already flashed? We can assume that all the required libraries (UI, communication, drivers etc) are already there and there is a stable ABI.
Re: Installing apps dynamically in runtime
On Fri, Jun 21, 2024 at 5:50 PM Gábor Kiss-Vámosi wrote: > Hi, > > A smartwatch manufacturer company wants to dynamically add/remove apps at > runtime on their MCU based devices . Similarly to how it works on > smartphones. > > Example: The user wants to extend the smartwatch with an Alarm clock app. > On Linux we just needed to copy the binary to the watch and it could be > launched with any number of instances. With NuttX can we extend the > application which is already flashed? Yes, you can load program(e.g. elf) from file system: https://nuttx.apache.org/docs/latest/components/binfmt.html > We can assume that all the required > libraries (UI, communication, drivers etc) are already there and there is a > stable ABI. > but there is no stable ABI on NuttX, so you can't copy elf from one type of device to another.
Re: Installing apps dynamically in runtime
It's awesome! but there is no stable ABI on NuttX, so you can't copy elf from one type of > device to another. Does it mean that the loaded apps should be self contained and not interact with any other code on the MCU? Xiang Xiao ezt írta (időpont: 2024. jún. 21., P, 11:55): > On Fri, Jun 21, 2024 at 5:50 PM Gábor Kiss-Vámosi > wrote: > > > Hi, > > > > A smartwatch manufacturer company wants to dynamically add/remove apps at > > runtime on their MCU based devices . Similarly to how it works on > > smartphones. > > > > Example: The user wants to extend the smartwatch with an Alarm clock app. > > On Linux we just needed to copy the binary to the watch and it could be > > launched with any number of instances. With NuttX can we extend the > > application which is already flashed? > > > Yes, you can load program(e.g. elf) from file system: > https://nuttx.apache.org/docs/latest/components/binfmt.html > > > > We can assume that all the required > > libraries (UI, communication, drivers etc) are already there and there > is a > > stable ABI. > > > > but there is no stable ABI on NuttX, so you can't copy elf from one type of > device to another. >
Re: Installing apps dynamically in runtime
On Fri, Jun 21, 2024 at 6:20 PM Gábor Kiss-Vámosi wrote: > It's awesome! > > but there is no stable ABI on NuttX, so you can't copy elf from one type of > > device to another. > > > Does it mean that the loaded apps should be self contained and not interact > with any other code on the MCU? > > no, elf can call functions in base image. But since the different image expose a different API set, you can't launch elf on other devices. > > > Xiang Xiao ezt írta (időpont: 2024. jún. 21., > P, 11:55): > > > On Fri, Jun 21, 2024 at 5:50 PM Gábor Kiss-Vámosi > > wrote: > > > > > Hi, > > > > > > A smartwatch manufacturer company wants to dynamically add/remove apps > at > > > runtime on their MCU based devices . Similarly to how it works on > > > smartphones. > > > > > > Example: The user wants to extend the smartwatch with an Alarm clock > app. > > > On Linux we just needed to copy the binary to the watch and it could be > > > launched with any number of instances. With NuttX can we extend the > > > application which is already flashed? > > > > > > Yes, you can load program(e.g. elf) from file system: > > https://nuttx.apache.org/docs/latest/components/binfmt.html > > > > > > > We can assume that all the required > > > libraries (UI, communication, drivers etc) are already there and there > > is a > > > stable ABI. > > > > > > > but there is no stable ABI on NuttX, so you can't copy elf from one type > of > > device to another. > > >
Re: Installing apps dynamically in runtime
Clear, thank you! We will try it out! Xiang Xiao ezt írta (időpont: 2024. jún. 21., P, 13:25): > On Fri, Jun 21, 2024 at 6:20 PM Gábor Kiss-Vámosi > wrote: > > > It's awesome! > > > > but there is no stable ABI on NuttX, so you can't copy elf from one type > of > > > device to another. > > > > > > Does it mean that the loaded apps should be self contained and not > interact > > with any other code on the MCU? > > > > > no, elf can call functions in base image. But since the different image > expose a different API set, you can't launch elf on other devices. > > > > > > > > Xiang Xiao ezt írta (időpont: 2024. jún. > 21., > > P, 11:55): > > > > > On Fri, Jun 21, 2024 at 5:50 PM Gábor Kiss-Vámosi < > kisvega...@gmail.com> > > > wrote: > > > > > > > Hi, > > > > > > > > A smartwatch manufacturer company wants to dynamically add/remove > apps > > at > > > > runtime on their MCU based devices . Similarly to how it works on > > > > smartphones. > > > > > > > > Example: The user wants to extend the smartwatch with an Alarm clock > > app. > > > > On Linux we just needed to copy the binary to the watch and it could > be > > > > launched with any number of instances. With NuttX can we extend the > > > > application which is already flashed? > > > > > > > > > Yes, you can load program(e.g. elf) from file system: > > > https://nuttx.apache.org/docs/latest/components/binfmt.html > > > > > > > > > > We can assume that all the required > > > > libraries (UI, communication, drivers etc) are already there and > there > > > is a > > > > stable ABI. > > > > > > > > > > but there is no stable ABI on NuttX, so you can't copy elf from one > type > > of > > > device to another. > > > > > >
Re: Installing apps dynamically in runtime
On 6/21/2024 3:55 AM, Xiang Xiao wrote: but there is no stable ABI on NuttX, so you can't copy elf from one type of device to another. Wouldn't that work if (1) the ELF module is partially linked so that it relies a symbol table and dynamic linking at run time so that there is no a priori knowledge of any address, and (2) the APIs of the ELF application are restricted to standard APIs that should be common in most releases?
Re: Installing apps dynamically in runtime
On Fri, Jun 21, 2024 at 7:44 PM Gregory Nutt wrote: > On 6/21/2024 3:55 AM, Xiang Xiao wrote: > > but there is no stable ABI on NuttX, so you can't copy elf from one type > of > > device to another. > Wouldn't that work if (1) the ELF module is partially linked so that it > relies a symbol table and dynamic linking at run time so that there is > no a priori knowledge of any address, and (2) the APIs of the ELF > application are restricted to standard APIs that should be common in > most releases? > > but, different devices expose to the different subsets of API. e.g. some devices mayn't enable the net subsystem at all, any application which calls socket api will fail to load.
Re: Installing apps dynamically in runtime
On 6/21/2024 9:14 AM, Xiang Xiao wrote: but, different devices expose to the different subsets of API. e.g. some devices mayn't enable the net subsystem at all, any application which calls socket api will fail to load. Right, that is a consequence of size reduction using a minimal, incomplete configuration for resource-limited embedded systems. POSIX actually specifies which APIs must be present, be we ignore this requirement for a smaller footprint. You would probably have to adopt a standard, minimal configuration across products OR perhaps some stubs that return only ENOSYS for nonexistent APIs. You might even want a common version if you want completely consistent, bug-for-bug behavior. Such stubs really should be generated automatically is a system call is configured out. Returning ENOSYS if the API is not present is required by most POSIX APIs. But this all should be doable in principle. After all, the P in POSIX stands for portable.
Re: Installing apps dynamically in runtime
Hi Gábor, I created a video tutorial explaining how to do that: https://www.youtube.com/watch?v=oL6KAgkTb8M At that time NuttX had support only for ELF executable, now it also has support for ELF libraries (work done by WildernessLabs and improved by Xiaomi). About the idea of a NuttX distribution that you commented at NuttX Int. Workshop, I investigated a little bit about package management tools that could be used on NuttX. Unfortunately ipkg/opkg are GPL so we cannot use it for commercial products. There is the pkgin from NetBSD that is almost what we need, but it uses SQLite and although we have SQLite integrated in our apps/ I think it is too big for some low end microcontrollers. I think we will need to implement it ourselves, looking at pkgin I see it is not so complicated to implement and we need something simpler. Best Regards, Alan On Fri, Jun 21, 2024 at 6:50 AM Gábor Kiss-Vámosi wrote: > Hi, > > A smartwatch manufacturer company wants to dynamically add/remove apps at > runtime on their MCU based devices . Similarly to how it works on > smartphones. > > Example: The user wants to extend the smartwatch with an Alarm clock app. > On Linux we just needed to copy the binary to the watch and it could be > launched with any number of instances. With NuttX can we extend the > application which is already flashed? We can assume that all the required > libraries (UI, communication, drivers etc) are already there and there is a > stable ABI. >
