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minix/lib/libexec/exec_elf.c

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VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#define _SYSTEM 1
#include <minix/type.h>
#include <minix/const.h>
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
#include <minix/com.h>
#include <minix/syslib.h>
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#include <sys/param.h>
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
#include <sys/mman.h>
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#include <assert.h>
#include <unistd.h>
#include <errno.h>
#include <libexec.h>
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
#include <string.h>
#include <machine/elf.h>
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
#include <machine/vmparam.h>
#include <machine/memory.h>
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
/* For verbose logging */
#define ELF_DEBUG 0
/* Support only 32-bit ELF objects */
#define __ELF_WORD_SIZE 32
boot: Add multiboot support Not yet fully spec-compliant; work in progress
2011-06-24 17:20:25 +02:00
#define SECTOR_SIZE 512
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
static int check_header(Elf_Ehdr *hdr);
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
static int elf_sane(Elf_Ehdr *hdr)
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
{
if (check_header(hdr) != OK) {
return 0;
}
if((hdr->e_type != ET_EXEC) && (hdr->e_type != ET_DYN)) {
return 0;
}
if ((hdr->e_phoff > SECTOR_SIZE) ||
(hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > SECTOR_SIZE) {
#if ELF_DEBUG
printf("peculiar phoff\n");
#endif
return 0;
}
return 1;
}
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
static int elf_ph_sane(Elf_Phdr *phdr)
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
{
if (rounddown((uintptr_t)phdr, sizeof(Elf_Addr)) != (uintptr_t)phdr) {
return 0;
}
return 1;
}
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
static int elf_unpack(char *exec_hdr,
int hdr_len, Elf_Ehdr **hdr, Elf_Phdr **phdr)
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
{
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
*hdr = (Elf_Ehdr *) exec_hdr;
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
if(!elf_sane(*hdr)) {
#if ELF_DEBUG
printf("elf_sane failed\n");
#endif
return ENOEXEC;
}
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
*phdr = (Elf_Phdr *)(exec_hdr + (*hdr)->e_phoff);
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
if(!elf_ph_sane(*phdr)) {
#if ELF_DEBUG
printf("elf_ph_sane failed\n");
#endif
return ENOEXEC;
}
#if 0
if((int)((*phdr) + (*hdr)->e_phnum) >= hdr_len) return ENOEXEC;
#endif
return OK;
}
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
int read_header_elf(
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
char *exec_hdr, /* executable header */
int hdr_len, /* significant bytes in exec_hdr */
vir_bytes *text_vaddr, /* text virtual address */
phys_bytes *text_paddr, /* text physical address */
vir_bytes *text_filebytes, /* text segment size (in the file) */
vir_bytes *text_membytes, /* text segment size (in memory) */
vir_bytes *data_vaddr, /* data virtual address */
phys_bytes *data_paddr, /* data physical address */
vir_bytes *data_filebytes, /* data segment size (in the file) */
vir_bytes *data_membytes, /* data segment size (in memory) */
vir_bytes *pc, /* program entry point (initial PC) */
off_t *text_offset, /* file offset to text segment */
off_t *data_offset /* file offset to data segment */
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
)
{
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
Elf_Ehdr *hdr = NULL;
Elf_Phdr *phdr = NULL;
libexec: return physaddr info from ELF headers
2011-04-07 14:22:36 +02:00
unsigned long seg_filebytes, seg_membytes;
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
int e, i = 0;
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
libexec: return physaddr info from ELF headers
2011-04-07 14:22:36 +02:00
*text_vaddr = *text_paddr = 0;
*text_filebytes = *text_membytes = 0;
*data_vaddr = *data_paddr = 0;
*data_filebytes = *data_membytes = 0;
*pc = *text_offset = *data_offset = 0;
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
if((e=elf_unpack(exec_hdr, hdr_len, &hdr, &phdr)) != OK) {
#if ELF_DEBUG
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
printf("elf_unpack failed\n");
Build NetBSD libc library in world in ELF mode. 3 sets of libraries are built now: . ack: all libraries that ack can compile (/usr/lib/i386/) . clang+elf: all libraries with minix headers (/usr/lib/) . clang+elf: all libraries with netbsd headers (/usr/netbsd/) Once everything can be compiled with netbsd libraries and headers, the /usr/netbsd hierarchy will be obsolete and its libraries compiled with netbsd headers will be installed in /usr/lib, and its headers in /usr/include. (i.e. minix libc and current minix headers set will be gone.) To use the NetBSD libc system (libraries + headers) before it is the default libc, see: http://wiki.minix3.org/en/DevelopersGuide/UsingNetBSDCode This wiki page also documents the maintenance of the patch files of minix-specific changes to imported NetBSD code. Changes in this commit: . libsys: Add NBSD compilation and create a safe NBSD-based libc. . Port rest of libraries (except libddekit) to new header system. . Enable compilation of libddekit with new headers. . Enable kernel compilation with new headers. . Enable drivers compilation with new headers. . Port legacy commands to new headers and libc. . Port servers to new headers. . Add <sys/sigcontext.h> in compat library. . Remove dependency file in tree. . Enable compilation of common/lib/libc/atomic in libsys . Do not generate RCSID strings in libc. . Temporarily disable zoneinfo as they are incompatible with NetBSD format . obj-nbsd for .gitignore . Procfs: use only integer arithmetic. (Antoine Leca) . Increase ramdisk size to create NBSD-based images. . Remove INCSYMLINKS handling hack. . Add nbsd_include/sys/exec_elf.h . Enable ELF compilation with NBSD libc. . Add 'make nbsdsrc' in tools to download reference NetBSD sources. . Automate minix-port.patch creation. . Avoid using fstavfs() as it is *extremely* slow and unneeded. . Set err() as PRIVATE to avoid name clash with libc. . [NBSD] servers/vm: remove compilation warnings. . u32 is not a long in NBSD headers. . UPDATING info on netbsd hierarchy . commands fixes for netbsd libc
2011-04-27 15:00:52 +02:00
#endif
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
return e;
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
}
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#if ELF_DEBUG
boot: Add multiboot support Not yet fully spec-compliant; work in progress
2011-06-24 17:20:25 +02:00
printf("Program header file offset (phoff): %ld\n", hdr->e_phoff);
printf("Section header file offset (shoff): %ld\n", hdr->e_shoff);
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
printf("Program header entry size (phentsize): %d\n", hdr->e_phentsize);
printf("Program header entry num (phnum): %d\n", hdr->e_phnum);
printf("Section header entry size (shentsize): %d\n", hdr->e_shentsize);
printf("Section header entry num (shnum): %d\n", hdr->e_shnum);
printf("Section name strings index (shstrndx): %d\n", hdr->e_shstrndx);
boot: Add multiboot support Not yet fully spec-compliant; work in progress
2011-06-24 17:20:25 +02:00
printf("Entry Point: 0x%lx\n", hdr->e_entry);
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#endif
for (i = 0; i < hdr->e_phnum; i++) {
switch (phdr[i].p_type) {
case PT_LOAD:
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
if (phdr[i].p_memsz == 0)
break;
seg_filebytes = phdr[i].p_filesz;
seg_membytes = round_page(phdr[i].p_memsz + phdr[i].p_vaddr -
trunc_page(phdr[i].p_vaddr));
if (hdr->e_entry >= phdr[i].p_vaddr &&
hdr->e_entry < (phdr[i].p_vaddr + phdr[i].p_memsz)) {
*text_vaddr = phdr[i].p_vaddr;
*text_paddr = phdr[i].p_paddr;
*text_filebytes = seg_filebytes;
*text_membytes = seg_membytes;
*pc = (vir_bytes)hdr->e_entry;
*text_offset = phdr[i].p_offset;
} else {
*data_vaddr = phdr[i].p_vaddr;
*data_paddr = phdr[i].p_paddr;
*data_filebytes = seg_filebytes;
*data_membytes = seg_membytes;
*data_offset = phdr[i].p_offset;
}
break;
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
default:
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
break;
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
}
}
#if ELF_DEBUG
boot: Add multiboot support Not yet fully spec-compliant; work in progress
2011-06-24 17:20:25 +02:00
printf("Text vaddr: 0x%lx\n", *text_vaddr);
printf("Text paddr: 0x%lx\n", *text_paddr);
printf("Text filebytes: 0x%lx\n", *text_filebytes);
printf("Text membytes: 0x%lx\n", *text_membytes);
printf("Data vaddr: 0x%lx\n", *data_vaddr);
printf("Data paddr: 0x%lx\n", *data_paddr);
printf("Data filebyte: 0x%lx\n", *data_filebytes);
printf("Data membytes: 0x%lx\n", *data_membytes);
printf("PC: 0x%lx\n", *pc);
printf("Text offset: 0x%lx\n", *text_offset);
printf("Data offset: 0x%lx\n", *data_offset);
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
#endif
return OK;
}
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
#define IS_ELF(ehdr) ((ehdr).e_ident[EI_MAG0] == ELFMAG0 && \
(ehdr).e_ident[EI_MAG1] == ELFMAG1 && \
(ehdr).e_ident[EI_MAG2] == ELFMAG2 && \
(ehdr).e_ident[EI_MAG3] == ELFMAG3)
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
static int check_header(Elf_Ehdr *hdr)
VFS/RS support for ELF
2010-12-10 10:27:56 +01:00
{
if (!IS_ELF(*hdr) ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_phentsize != sizeof(Elf_Phdr) ||
hdr->e_version != ELF_TARG_VER)
return ENOEXEC;
return OK;
}
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
/* Return >0 if there is an ELF interpreter (i.e. it is a dynamically linked
* executable) and we could extract it successfully.
* Return 0 if there isn't one.
* Return <0 on error.
*/
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
int elf_has_interpreter(char *exec_hdr, /* executable header */
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
int hdr_len, char *interp, int maxsz)
{
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
Elf_Ehdr *hdr = NULL;
Elf_Phdr *phdr = NULL;
recognize and execute dynamically linked executables . generalize libexec slightly to get some more necessary information from ELF files, e.g. the interpreter . execute dynamically linked executables when exec()ed by VFS . switch to netbsd variant of elf32.h exclusively, solves some conflicting headers
2012-04-03 15:52:25 +02:00
int e, i;
if((e=elf_unpack(exec_hdr, hdr_len, &hdr, &phdr)) != OK) return e;
for (i = 0; i < hdr->e_phnum; i++) {
switch (phdr[i].p_type) {
case PT_INTERP:
if(!interp) return 1;
if(phdr[i].p_filesz >= maxsz)
return -1;
if(phdr[i].p_offset + phdr[i].p_filesz >= hdr_len)
return -1;
memcpy(interp, exec_hdr + phdr[i].p_offset, phdr[i].p_filesz);
interp[phdr[i].p_filesz] = '\0';
return 1;
default:
continue;
}
}
return 0;
}
exec() cleanup, generalization, improvement . make exec() callers (i.e. vfs and rs) determine the memory layout by explicitly reserving regions using mmap() calls on behalf of the exec()ing process, i.e. handling all of the exec logic, thereby eliminating all special exec() knowledge from VM. . the new procedure is: clear the exec()ing process first, then call third-party mmap()s to reserve memory, then copy the executable file section contents in, all using callbacks tailored to the caller's way of starting an executable . i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM as with rigid 2-section arguments . this naturally allows generalizing exec() by simply loading all ELF sections . drop/merge of lots of duplicate exec() code into libexec . not copying the code sections to vfs and into the executable again is a measurable performance improvement (about 3.3% faster for 'make' in src/servers/)
2012-05-30 19:34:07 +02:00
int libexec_load_elf(struct exec_info *execi)
{
int r;
Elf_Ehdr *hdr = NULL;
Elf_Phdr *phdr = NULL;
int e, i = 0;
int first = 1;
vir_bytes startv, stacklow;
assert(execi != NULL);
assert(execi->hdr != NULL);
if((e=elf_unpack(execi->hdr, execi->hdr_len, &hdr, &phdr)) != OK) {
printf("libexec_load_elf: elf_unpack failed\n");
return e;
}
/* this function can load the dynamic linker, but that
* shouldn't require an interpreter itself.
*/
i = elf_has_interpreter(execi->hdr, execi->hdr_len, NULL, 0);
if(i > 0) {
printf("libexec: cannot load dynamically linked executable\n");
return ENOEXEC;
}
/* Make VM forget about all existing memory in process. */
vm_procctl(execi->proc_e, VMPPARAM_CLEAR);
execi->stack_size = roundup(execi->stack_size, PAGE_SIZE);
execi->stack_high = VM_STACKTOP;
assert(!(VM_STACKTOP % PAGE_SIZE));
stacklow = execi->stack_high - execi->stack_size;
for (i = 0; i < hdr->e_phnum; i++) {
vir_bytes seg_membytes, page_offset, vaddr;
Elf_Phdr *ph = &phdr[i];
if (ph->p_type != PT_LOAD || ph->p_memsz == 0) continue;
#if 0
printf("index %d memsz 0x%lx vaddr 0x%lx\n", i, ph->p_memsz, ph->p_vaddr);
#endif
vaddr = ph->p_vaddr;
seg_membytes = ph->p_memsz;
page_offset = vaddr % PAGE_SIZE;
vaddr -= page_offset;
seg_membytes += page_offset;
seg_membytes = roundup(seg_membytes, PAGE_SIZE);
if(first || startv > vaddr) startv = vaddr;
first = 0;
#if 0
printf("libexec_load_elf: mmap 0x%lx bytes at 0x%lx\n",
seg_membytes, vaddr);
#endif
/* Tell VM to make us some memory */
if(minix_mmap_for(execi->proc_e, (void *) vaddr, seg_membytes,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_ANON|MAP_PREALLOC|MAP_FIXED, -1, 0) == MAP_FAILED) {
printf("libexec_load_elf: mmap of 0x%lx bytes failed\n", seg_membytes);
vm_procctl(execi->proc_e, VMPPARAM_CLEAR);
return ENOMEM;
}
/* Copy executable section into it */
if(execi->load(execi, ph->p_offset, ph->p_vaddr, ph->p_filesz) != OK) {
printf("libexec_load_elf: load callback failed\n");
vm_procctl(execi->proc_e, VMPPARAM_CLEAR);
return ENOMEM;
}
}
/* Make it a stack */
if(minix_mmap_for(execi->proc_e, (void *) stacklow, execi->stack_size,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_ANON|MAP_FIXED, -1, 0) == MAP_FAILED) {
printf("libexec_load_elf: mmap for stack failed\n");
vm_procctl(execi->proc_e, VMPPARAM_CLEAR);
return ENOMEM;
}
/* record entry point and lowest load vaddr for caller */
execi->pc = hdr->e_entry;
execi->load_base = startv;
if((r = libexec_pm_newexec(execi->proc_e, execi)) != OK) {
printf("libexec_load_elf: pm_newexec failed: %d\n", r);
}
return(r);
}
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