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#include <sys/stat.h>
#include <fcntl.h>
#include <elf.h>
#include <string.h>
#include "file.h"
#include "pk.h"
long load_elf(const char* fn, int* user64)
{
sysret_t ret = file_open(fn, strlen(fn)+1, O_RDONLY, 0);
file_t* file = (file_t*)ret.result;
if(ret.result == -1)
goto fail;
char buf[2048]; // XXX
int header_size = file_read(file, buf, sizeof(buf)).result;
const Elf64_Ehdr* eh64 = (const Elf64_Ehdr*)buf;
if(header_size < (int)sizeof(Elf64_Ehdr) ||
!(eh64->e_ident[0] == '\177' && eh64->e_ident[1] == 'E' &&
eh64->e_ident[2] == 'L' && eh64->e_ident[3] == 'F'))
goto fail;
#define LOAD_ELF do { \
eh = (typeof(eh))buf; \
kassert(header_size >= eh->e_phoff + eh->e_phnum*sizeof(*ph)); \
ph = (typeof(ph))(buf+eh->e_phoff); \
for(int i = 0; i < eh->e_phnum; i++, ph++) { \
if(ph->p_type == SHT_PROGBITS && ph->p_memsz) { \
extern char _end; \
if((char*)(long)ph->p_vaddr < &_end) \
{ \
long diff = &_end - (char*)(long)ph->p_vaddr; \
ph->p_vaddr += diff; \
ph->p_offset += diff; \
ph->p_memsz = diff >= ph->p_memsz ? 0 : ph->p_memsz - diff; \
ph->p_filesz = diff >= ph->p_filesz ? 0 : ph->p_filesz - diff; \
} \
if(file_pread(file, (char*)(long)ph->p_vaddr, ph->p_filesz, ph->p_offset).result != ph->p_filesz) \
goto fail; \
memset((char*)(long)ph->p_vaddr+ph->p_filesz, 0, ph->p_memsz-ph->p_filesz); \
} \
} \
} while(0)
long entry;
if(eh64->e_ident[EI_CLASS] == ELFCLASS32)
{
Elf32_Ehdr* eh;
Elf32_Phdr* ph;
LOAD_ELF;
entry = eh->e_entry;
}
else if(eh64->e_ident[EI_CLASS] == ELFCLASS64)
{
Elf64_Ehdr* eh;
Elf64_Phdr* ph;
LOAD_ELF;
entry = eh->e_entry;
}
else
goto fail;
*user64 = eh64->e_ident[EI_CLASS] == ELFCLASS64;
file_decref(file);
return entry;
fail:
panic("couldn't open ELF program: %s!", fn);
}
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