Libpayload
The wiki is being retired!
Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to https://doc.coreboot.org/. Contributions welcome!
libpayload is a small BSD-licensed "library" (a lightweight implementation of common and useful functions) intended to be used as a basis for coreboot payloads.
Overview
The benefits of linking a coreboot payload against libpayload are:
- Payloads do not have to implement and maintain low-level code for I/O, common functions, etc.
- Payloads can be recompiled and deployed for CPU architectures supported by coreboot in the future.
- The libpayload functions can be tested and scrutinized outside payload development.
- Payloads themselves may be partly host-tested, e.g. against an emulation libpayload.
- Leads to the possibility of payloads using dynamic linking, reducing total payload footprint.
Just give us a main() and a pocket full of dreams and we'll do the rest.
Feature Wish List
- Basics
- coreboot services and structures (e.g. read CMOS, device tree)
- subset of C-library functions (e.g. printf, puts, getch)
- light ncurses from the Google Summer Of Code project
- Fancies
- directFB
- TWIN
Libc Coverage
| Function/Macro/Variable | Status |
|---|---|
| assert.h | |
assert( ) (macro)
|
no |
| ctype.h | |
int isalnum(int character)
|
no |
int isalpha(int character)
|
no |
int iscntrl(int character)
|
no |
int isdigit(int character)
|
no |
int isgraph(int character)
|
no |
int islower(int character)
|
no |
int isprint(int character)
|
no |
int ispunct(int character)
|
no |
int isspace(int character)
|
no |
int isupper(int character)
|
no |
int isxdigit(int character)
|
no |
| errno.h | |
errno (global)
|
no |
| float.h | |
| limits.h | |
| locale.h | |
char *setlocale(int category, const char *locale)
|
no |
struct lconv *localeconv(void)
|
no |
| math.h | |
double exp(double x)
|
no |
double log(double x)
|
no |
double log10(double x)
|
no |
double pow(double x, double y)
|
no |
double sqrt(double x)
|
no |
double ceil(double x)
|
no |
double floor(double x)
|
no |
double fabs(double x)
|
no |
double ldexp(double x, int n)
|
no |
double frexp(double x, int* exp)
|
no |
double modf(double x, double* ip)
|
no |
double fmod(double x, double y)
|
no |
double sin(double x)
|
no |
double cos(double x)
|
no |
double tan(double x)
|
no |
double asin(double x)
|
no |
double acos(double x)
|
no |
double atan(double x)
|
no |
double atan2(double y, double x)
|
no |
double sinh(double x)
|
no |
double cosh(double x)
|
no |
double tanh(double x)
|
no |
| setjmp.h | |
int setjmp(jmp_buf env)
|
no |
void longjmp(jmp_buf env, int val)
|
no |
| signal.h | |
void (*signal(int sig, void (*handler)(int)))(int)
|
no |
int raise(int sig)
|
no |
| stdarg.h | |
void va_start(va_list ap, lastarg)
|
no |
type va_arg(va_list ap, type)
|
no |
void va_end(va_list ap)
|
no |
| stddef.h | |
| TODO | |
| stdio.h | |
FILE* fopen(const char* filename, const char* mode)
|
no |
FILE* freopen(const char* filename, const char* mode, FILE* stream)
|
no |
int fflush(FILE* stream)
|
no |
int fclose(FILE* stream)
|
no |
int remove(const char* filename)
|
no |
int rename(const char* oldname, const char* newname)
|
no |
FILE* tmpfile()
|
no |
char* tmpnam(char s[L_tmpnam])
|
no |
int setvbuf(FILE* stream, char* buf, int mode, size_t size)
|
no |
void setbuf(FILE* stream, char* buf)
|
no |
int fprintf(FILE* stream, const char* format, ...)
|
no |
int printf(const char* format, ...)
|
partial |
int sprintf(char* s, const char* format, ...)
|
partial |
int vfprintf(FILE* stream, const char* format, va_list arg)
|
no |
int vprintf(const char* format, va_list arg)
|
no |
int vsprintf(char* s, const char* format, va_list arg)
|
partial |
int fscanf(FILE* stream, const char* format, ...)
|
no |
int scanf(const char* format, ...)
|
no |
int sscanf(char* s, const char* format, ...)
|
no |
int fgetc(FILE* stream)
|
no |
char* fgets(char* s, int n, FILE* stream)
|
no |
int fputc(int c, FILE* stream)
|
no |
char* fputs(const char* s, FILE* stream)
|
no |
int getc(FILE* stream)
|
no |
int getchar(void)
|
yes |
char* gets(char* s)
|
no |
int putc(int c, FILE* stream)
|
no |
int putchar(int c)
|
yes |
int puts(const char* s)
|
yes |
int ungetc(int c, FILE* stream)
|
no |
size_t fread(void* ptr, size_t size, size_t nobj, FILE* stream)
|
no |
size_t fwrite(const void* ptr, size_t size, size_t nobj, FILE* stream)
|
no |
int fseek(FILE* stream, long offset, int origin)
|
no |
long ftell(FILE* stream)
|
no |
void rewind(FILE* stream)
|
no |
int fgetpos(FILE* stream, fpos_t* ptr)
|
no |
int fsetpos(FILE* stream, const fpos_t* ptr)
|
no |
void clearerr(FILE* stream)
|
no |
int feof(FILE* stream)
|
no |
int ferror(FILE* stream)
|
no |
void perror(const char* s)
|
no |
| stdlib.h | |
| TODO | |
| string.h | |
| TODO | |
| time.h | |
| TODO | |
| No Support |
| Partial Support |
| Full Support |
Usage Example
hello_payload.c:
#include <libpayload.h>
int main(void)
{
printf("Hello, world!\n");
halt();
return 0;
}
Build example (basic idea):
gcc -o hello_payload hello_payload.c
|
I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.
In case this is not legally possible: |