in boot/elf2ecoff.c [268:621]
int main(int argc, char *argv[])
{
Elf32_Ehdr ex;
Elf32_Phdr *ph;
Elf32_Shdr *sh;
int i, pad;
struct sect text, data, bss;
struct filehdr efh;
struct aouthdr eah;
struct scnhdr esecs[6];
int infile, outfile;
uint32_t cur_vma = UINT32_MAX;
int addflag = 0;
int nosecs;
text.len = data.len = bss.len = 0;
text.vaddr = data.vaddr = bss.vaddr = 0;
/* Check args... */
if (argc < 3 || argc > 4) {
usage:
fprintf(stderr,
"usage: elf2ecoff <elf executable> <ecoff executable> [-a]\n");
exit(1);
}
if (argc == 4) {
if (strcmp(argv[3], "-a"))
goto usage;
addflag = 1;
}
/* Try the input file... */
if ((infile = open(argv[1], O_RDONLY)) < 0) {
fprintf(stderr, "Can't open %s for read: %s\n",
argv[1], strerror(errno));
exit(1);
}
/* Read the header, which is at the beginning of the file... */
i = read(infile, &ex, sizeof ex);
if (i != sizeof ex) {
fprintf(stderr, "ex: %s: %s.\n",
argv[1],
i ? strerror(errno) : "End of file reached");
exit(1);
}
if (ex.e_ident[EI_DATA] == ELFDATA2MSB)
format_bigendian = 1;
if (ntohs(0xaa55) == 0xaa55) {
if (!format_bigendian)
must_convert_endian = 1;
} else {
if (format_bigendian)
must_convert_endian = 1;
}
if (must_convert_endian)
convert_elf_hdr(&ex);
/* Read the program headers... */
ph = (Elf32_Phdr *) saveRead(infile, ex.e_phoff,
ex.e_phnum * sizeof(Elf32_Phdr),
"ph");
if (must_convert_endian)
convert_elf_phdrs(ph, ex.e_phnum);
/* Read the section headers... */
sh = (Elf32_Shdr *) saveRead(infile, ex.e_shoff,
ex.e_shnum * sizeof(Elf32_Shdr),
"sh");
if (must_convert_endian)
convert_elf_shdrs(sh, ex.e_shnum);
/* Figure out if we can cram the program header into an ECOFF
header... Basically, we can't handle anything but loadable
segments, but we can ignore some kinds of segments. We can't
handle holes in the address space. Segments may be out of order,
so we sort them first. */
qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr), phcmp);
for (i = 0; i < ex.e_phnum; i++) {
/* Section types we can ignore... */
switch (ph[i].p_type) {
case PT_NULL:
case PT_NOTE:
case PT_PHDR:
case PT_MIPS_REGINFO:
case PT_MIPS_ABIFLAGS:
continue;
case PT_LOAD:
/* Writable (data) segment? */
if (ph[i].p_flags & PF_W) {
struct sect ndata, nbss;
ndata.vaddr = ph[i].p_vaddr;
ndata.len = ph[i].p_filesz;
nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
nbss.len = ph[i].p_memsz - ph[i].p_filesz;
combine(&data, &ndata, 0);
combine(&bss, &nbss, 1);
} else {
struct sect ntxt;
ntxt.vaddr = ph[i].p_vaddr;
ntxt.len = ph[i].p_filesz;
combine(&text, &ntxt, 0);
}
/* Remember the lowest segment start address. */
if (ph[i].p_vaddr < cur_vma)
cur_vma = ph[i].p_vaddr;
break;
default:
/* Section types we can't handle... */
fprintf(stderr,
"Program header %d type %d can't be converted.\n",
ex.e_phnum, ph[i].p_type);
exit(1);
}
}
/* Sections must be in order to be converted... */
if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
text.vaddr + text.len > data.vaddr
|| data.vaddr + data.len > bss.vaddr) {
fprintf(stderr,
"Sections ordering prevents a.out conversion.\n");
exit(1);
}
/* If there's a data section but no text section, then the loader
combined everything into one section. That needs to be the
text section, so just make the data section zero length following
text. */
if (data.len && !text.len) {
text = data;
data.vaddr = text.vaddr + text.len;
data.len = 0;
}
/* If there is a gap between text and data, we'll fill it when we copy
the data, so update the length of the text segment as represented in
a.out to reflect that, since a.out doesn't allow gaps in the program
address space. */
if (text.vaddr + text.len < data.vaddr)
text.len = data.vaddr - text.vaddr;
/* We now have enough information to cons up an a.out header... */
eah.magic = OMAGIC;
eah.vstamp = 200;
eah.tsize = text.len;
eah.dsize = data.len;
eah.bsize = bss.len;
eah.entry = ex.e_entry;
eah.text_start = text.vaddr;
eah.data_start = data.vaddr;
eah.bss_start = bss.vaddr;
eah.gprmask = 0xf3fffffe;
memset(&eah.cprmask, '\0', sizeof eah.cprmask);
eah.gp_value = 0; /* unused. */
if (format_bigendian)
efh.f_magic = MIPSEBMAGIC;
else
efh.f_magic = MIPSELMAGIC;
if (addflag)
nosecs = 6;
else
nosecs = 3;
efh.f_nscns = nosecs;
efh.f_timdat = 0; /* bogus */
efh.f_symptr = 0;
efh.f_nsyms = 0;
efh.f_opthdr = sizeof eah;
efh.f_flags = 0x100f; /* Stripped, not sharable. */
memset(esecs, 0, sizeof esecs);
strcpy(esecs[0].s_name, ".text");
strcpy(esecs[1].s_name, ".data");
strcpy(esecs[2].s_name, ".bss");
if (addflag) {
strcpy(esecs[3].s_name, ".rdata");
strcpy(esecs[4].s_name, ".sdata");
strcpy(esecs[5].s_name, ".sbss");
}
esecs[0].s_paddr = esecs[0].s_vaddr = eah.text_start;
esecs[1].s_paddr = esecs[1].s_vaddr = eah.data_start;
esecs[2].s_paddr = esecs[2].s_vaddr = eah.bss_start;
if (addflag) {
esecs[3].s_paddr = esecs[3].s_vaddr = 0;
esecs[4].s_paddr = esecs[4].s_vaddr = 0;
esecs[5].s_paddr = esecs[5].s_vaddr = 0;
}
esecs[0].s_size = eah.tsize;
esecs[1].s_size = eah.dsize;
esecs[2].s_size = eah.bsize;
if (addflag) {
esecs[3].s_size = 0;
esecs[4].s_size = 0;
esecs[5].s_size = 0;
}
esecs[0].s_scnptr = N_TXTOFF(efh, eah);
esecs[1].s_scnptr = N_DATOFF(efh, eah);
#define ECOFF_SEGMENT_ALIGNMENT(a) 0x10
#define ECOFF_ROUND(s, a) (((s)+(a)-1)&~((a)-1))
esecs[2].s_scnptr = esecs[1].s_scnptr +
ECOFF_ROUND(esecs[1].s_size, ECOFF_SEGMENT_ALIGNMENT(&eah));
if (addflag) {
esecs[3].s_scnptr = 0;
esecs[4].s_scnptr = 0;
esecs[5].s_scnptr = 0;
}
esecs[0].s_relptr = esecs[1].s_relptr = esecs[2].s_relptr = 0;
esecs[0].s_lnnoptr = esecs[1].s_lnnoptr = esecs[2].s_lnnoptr = 0;
esecs[0].s_nreloc = esecs[1].s_nreloc = esecs[2].s_nreloc = 0;
esecs[0].s_nlnno = esecs[1].s_nlnno = esecs[2].s_nlnno = 0;
if (addflag) {
esecs[3].s_relptr = esecs[4].s_relptr
= esecs[5].s_relptr = 0;
esecs[3].s_lnnoptr = esecs[4].s_lnnoptr
= esecs[5].s_lnnoptr = 0;
esecs[3].s_nreloc = esecs[4].s_nreloc = esecs[5].s_nreloc =
0;
esecs[3].s_nlnno = esecs[4].s_nlnno = esecs[5].s_nlnno = 0;
}
esecs[0].s_flags = 0x20;
esecs[1].s_flags = 0x40;
esecs[2].s_flags = 0x82;
if (addflag) {
esecs[3].s_flags = 0x100;
esecs[4].s_flags = 0x200;
esecs[5].s_flags = 0x400;
}
/* Make the output file... */
if ((outfile = open(argv[2], O_WRONLY | O_CREAT, 0777)) < 0) {
fprintf(stderr, "Unable to create %s: %s\n", argv[2],
strerror(errno));
exit(1);
}
if (must_convert_endian)
convert_ecoff_filehdr(&efh);
/* Write the headers... */
i = write(outfile, &efh, sizeof efh);
if (i != sizeof efh) {
perror("efh: write");
exit(1);
for (i = 0; i < nosecs; i++) {
printf
("Section %d: %s phys %"PRIx32" size %"PRIx32"\t file offset %"PRIx32"\n",
i, esecs[i].s_name, esecs[i].s_paddr,
esecs[i].s_size, esecs[i].s_scnptr);
}
}
fprintf(stderr, "wrote %d byte file header.\n", i);
if (must_convert_endian)
convert_ecoff_aouthdr(&eah);
i = write(outfile, &eah, sizeof eah);
if (i != sizeof eah) {
perror("eah: write");
exit(1);
}
fprintf(stderr, "wrote %d byte a.out header.\n", i);
if (must_convert_endian)
convert_ecoff_esecs(&esecs[0], nosecs);
i = write(outfile, &esecs, nosecs * sizeof(struct scnhdr));
if (i != nosecs * sizeof(struct scnhdr)) {
perror("esecs: write");
exit(1);
}
fprintf(stderr, "wrote %d bytes of section headers.\n", i);
pad = (sizeof(efh) + sizeof(eah) + nosecs * sizeof(struct scnhdr)) & 15;
if (pad) {
pad = 16 - pad;
i = write(outfile, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0", pad);
if (i < 0) {
perror("ipad: write");
exit(1);
}
fprintf(stderr, "wrote %d byte pad.\n", i);
}
/*
* Copy the loadable sections. Zero-fill any gaps less than 64k;
* complain about any zero-filling, and die if we're asked to zero-fill
* more than 64k.
*/
for (i = 0; i < ex.e_phnum; i++) {
/* Unprocessable sections were handled above, so just verify that
the section can be loaded before copying. */
if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
if (cur_vma != ph[i].p_vaddr) {
uint32_t gap = ph[i].p_vaddr - cur_vma;
char obuf[1024];
if (gap > 65536) {
fprintf(stderr,
"Intersegment gap (%"PRId32" bytes) too large.\n",
gap);
exit(1);
}
fprintf(stderr,
"Warning: %d byte intersegment gap.\n",
gap);
memset(obuf, 0, sizeof obuf);
while (gap) {
int count =
write(outfile, obuf,
(gap >
sizeof obuf ? sizeof
obuf : gap));
if (count < 0) {
fprintf(stderr,
"Error writing gap: %s\n",
strerror(errno));
exit(1);
}
gap -= count;
}
}
fprintf(stderr, "writing %d bytes...\n",
ph[i].p_filesz);
copy(outfile, infile, ph[i].p_offset,
ph[i].p_filesz);
cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
}
}
/*
* Write a page of padding for boot PROMS that read entire pages.
* Without this, they may attempt to read past the end of the
* data section, incur an error, and refuse to boot.
*/
{
char obuf[4096];
memset(obuf, 0, sizeof obuf);
if (write(outfile, obuf, sizeof(obuf)) != sizeof(obuf)) {
fprintf(stderr, "Error writing PROM padding: %s\n",
strerror(errno));
exit(1);
}
}
/* Looks like we won... */
exit(0);
}