1. Article purpose
This article provides the basic information needed to start using the Linux tool: ltrace[1].
2. Introduction
The following table provides a brief description of the tool, as well as its availability depending on the software packages:
: this tool is either present (ready to use or to be activated), or can be integrated and activated on the software package.
: this tool is not present and cannot be integrated, or it is present but cannot be activated on the software package.
| Tool | STM32MPU Embedded Software distribution | STM32MPU Embedded Software distribution for Android™ | ||||||
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| Name | Category | Purpose | Starter Package | Developer Package | Distribution Package | Starter Package | Developer Package | Distribution Package |
| ltrace | Tracing tools | ltrace[1] is used to display the calls to shared libraries made by a userspace application. ltrace is a userspace application. Its use is very similar to strace. |
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3. Installing the trace and debug tool on your target board
3.1. Using the STM32MPU Embedded Software distribution
ltrace is not part of the standard STM32MPU Embedded Software distribution image.
3.1.1. Distribution Package
To include ltrace in your Distribution Package image build, please follow steps below:
- Add ltrace package for the image building
cd <your_Distribution_Package_root_dir>
echo 'IMAGE_INSTALL_append += "ltrace"' >> layers/meta-st/meta-st-openstlinux/recipes-st/images/st-image-weston.bbappend
- Rebuild your full image
bitbake <full_image_name> # Needed to include ltrace into the final image rootfs
- Reload the new image on your board: see Flashing the built image
4. Getting started
To use ltrace, there are two main methods:
- by giving, as parameter, the name of program for which you want to list dynamic library calls, and its arguments if required:
ltrace <Program> [ARGS]
- As example:
ltrace weston-simple-egl __libc_start_main(0x11a90, 1, 0xbec45d04, 0x131f0 <unfinished ...> memset(0xbec456f8, 0, 72, 0x11a90) = 0xbec456f8 memset(0xbec45754, 0, 68, 0xbec45740) = 0xbec45754 wl_display_connect(0, 250, 32, 0xbec45750) = 0x26150 wl_proxy_marshal_constructor(0x26150, 1, 0x24e90, 0) = 0x2a268 wl_proxy_add_listener(0x2a268, 0x132e0, 0xbec456f8, 0) = 0 wl_display_roundtrip(0x26150, 0x132e0, 0xbec456f8, 0 <unfinished ...> strcmp(0x2a404, 0x133e8, 1, 0x2a404) = 0 wl_proxy_marshal_constructor_versioned(0x2a268, 0, 0x24ed8, 1) = 0x2b070 strcmp(0x2a49c, 0x133e8, 2, 0x2a49c) = 16 strcmp(0x2a49c, 0x133f8, 115, 0x635f6c77) = -3 ...
- by giving, as parameter, the PID of the process to be studied:
ltrace -p <PID>
Note: <PID> value can be replace by `pidof <process_name>`
- As example:
weston-simple-egl & ltrace -p `pidof weston-simple-egl` has EGL_EXT_buffer_age and EGL_EXT_swap_buffers_with_damage glGetShaderiv(1, 0x8b81, 0xbee14260, 0) = 0 glCreateShader(0x8b31, 0x8b31, 256, 1) = 2 glShaderSource(2, 1, 0xbee1425c, 0) = 0x1a96f0 glCompileShader(2, 0, 154, 0xbee14260) = 1 glGetShaderiv(2, 0x8b81, 0xbee14260, 0) = 0 glCreateProgram(2, 2, 256, 1) = 3 glAttachShader(3, 1, -1, 1) = 0 glAttachShader(3, 2, 0x8b30, 1) = 0 glLinkProgram(3, 0x8dd9, 0x8b31, 1) = 0x285234 glGetProgramiv(3, 0x8b82, 0xbee14698, 0) = 0 glUseProgram(3, 3, 256, 1) = 1 glBindAttribLocation(3, 0, 0x13884, 1) = 1 glBindAttribLocation(3, 1, 0x13888, 0) = 1 glLinkProgram(3, 0x1388e, 0, 0x1b9090) = 1 ... killall weston-simple-egl
5. To go further
Other options can be set. For details, please refer to the manual page[2].
6. References
- Useful external links
| Document link | Document Type | Description |
|---|---|---|
| ltrace linux.die.net | Standard | linux.die.net |
| ltrace wikipedia.org | Standard | wikipedia.org |
| ltrace tutorial | User Guide | go4expert.com |