minix/lib/libc/sys-minix/execve.c
Lionel Sambuc cfd3379bb1 Removing CSU patches
* Removed startup code patches in lib/csu regarding kernel to userland
   ABI.

 * Aligned stack layout on NetBSD stack layout.

 * Generate valid stack pointers instead of offsets by taking into account
   _minix_kerninfo->kinfo->user_sp.

 * Refactored stack generation, by moving part of execve in two
   functions {minix_stack_params(), minix_stack_fill()} and using them
   in execve(), rs and vm.

 * Changed load offset of rtld (ld.so) to:
      execi.args.stack_high - execi.args.stack_size - 0xa00000
   which is 10MB below the main executable stack.

Change-Id: I839daf3de43321cded44105634102d419cb36cec
2014-02-18 11:25:02 +01:00

63 lines
1.5 KiB
C

/* execve() - basic program execution call */
#include <sys/cdefs.h>
#include "namespace.h"
#include <lib.h>
#include <unistd.h>
#include <string.h>
#include <stddef.h>
#include <minix/param.h>
#include <sys/exec_elf.h>
#include <sys/exec.h>
#ifdef __weak_alias
__weak_alias(execve, _execve)
#endif
int execve(const char *path, char * const *argv, char * const *envp)
{
message m;
size_t frame_size = 0; /* Size of the new initial stack. */
int argc = 0; /* Argument count. */
int envc = 0; /* Environment count */
char overflow = 0; /* No overflow yet. */
char *frame;
struct ps_strings *psp;
int vsp = 0; /* (virtual) Stack pointer in new address space. */
minix_stack_params(path, argv, envp, &frame_size, &overflow,
&argc, &envc);
/* The party is off if there is an overflow. */
if (overflow) {
errno = E2BIG;
return -1;
}
/* Allocate space for the stack frame. */
if ((frame = (char *) sbrk(frame_size)) == (char *) -1) {
errno = E2BIG;
return -1;
}
minix_stack_fill(path, argc, argv, envc, envp, frame_size, frame,
&vsp, &psp);
/* Clear unused message fields */
memset(&m, 0, sizeof(m));
/* We can finally make the system call. */
m.m1_i1 = strlen(path) + 1;
m.m1_i2 = frame_size;
m.m1_p1 = (char *) __UNCONST(path);
m.m1_p2 = frame;
m.m1_p4 = (char *)(vsp + ((char *)psp - frame));
(void) _syscall(PM_PROC_NR, EXEC, &m);
/* Failure, return the memory used for the frame and exit. */
(void) sbrk(-frame_size);
return -1;
}