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