169 lines
3.9 KiB
C
169 lines
3.9 KiB
C
#include <lib.h>
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#include <unistd.h>
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#define execl _execl
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#define execle _execle
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#define execv _execv
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#define execve _execve
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extern char **environ; /* environment pointer */
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#define PTRSIZE (sizeof(char *))
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_PROTOTYPE( char *_sbrk, (int _incr) );
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#if _ANSI
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#include <stdarg.h>
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PUBLIC int execl(char *name, ...)
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{
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int retval;
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va_list ap;
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va_start(ap, name);
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retval = execve(name, (char **)ap, environ);
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va_end(ap);
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return retval;
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}
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#else
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PUBLIC int execl(name, arg0)
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char *name;
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char *arg0;
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{
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return(execve(name, &arg0, environ));
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}
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#endif
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#if _ANSI
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PUBLIC int execle(char *name, ...)
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{
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int retval;
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va_list ap;
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char *p;
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va_start(ap, name);
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do {
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p = va_arg(ap, char *);
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} while(p);
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p = (char *)va_arg(ap, char **);
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va_end(ap);
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va_start(ap, name);
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retval = execve(name, (char **)ap, (char **) p);
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va_end(ap);
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return retval;
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}
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#else
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PUBLIC int execle(name, argv)
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char *name, *argv;
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{
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char **p;
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p = (char **) &argv;
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while (*p++) /* null statement */
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;
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return(execve(name, &argv, (char **) *p));
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}
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#endif
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PUBLIC int execv(name, argv)
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char *name, *argv[];
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{
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return(execve(name, argv, environ));
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}
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PUBLIC int execve(path, argv, envp)
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char *path; /* pointer to name of file to be executed */
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char *argv[]; /* pointer to argument array */
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char *envp[]; /* pointer to environment */
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{
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register char **argtop;
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register char **envtop;
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/* Count the argument pointers and environment pointers. */
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for (argtop = argv; *argtop != (char *) NULL; ) argtop++;
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for (envtop = envp; *envtop != (char *) NULL; ) envtop++;
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return(__execve(path, argv, envp, (int)(argtop - argv), (int)(envtop - envp)));
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}
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PUBLIC int __execve(path, argv, envp, nargs, nenvps)
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char *path; /* pointer to name of file to be executed */
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char *argv[]; /* pointer to argument array */
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char *envp[]; /* pointer to environment */
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int nargs; /* number of args */
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int nenvps; /* number of environment strings */
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{
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/* This is split off from execve to be called from execvp, so execvp does not
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* have to allocate up to ARG_MAX bytes just to prepend "sh" to the arg array.
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*/
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char *hp, **ap, *p;
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int i, stackbytes, npointers, overflow, temp;
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char *stack;
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/* Decide how big a stack is needed. Be paranoid about overflow. */
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#if ARG_MAX > INT_MAX
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#error /* overflow checks and sbrk depend on sizes being ints */
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#endif
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overflow = FALSE;
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npointers = 1 + nargs + 1 + nenvps + 1; /* 1's for argc and NULLs */
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stackbytes = 0; /* changed because _len is used now */
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if (nargs < 0 || nenvps < 0 || nargs+nenvps < 0 || npointers < 0)
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overflow = TRUE;
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for (i = PTRSIZE; i != 0; i--) {
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temp = stackbytes + npointers;
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if (temp < stackbytes) overflow = TRUE;
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stackbytes = temp;
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}
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for (i = 0, ap = argv; i < nargs; i++) {
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temp = stackbytes + _len(*ap++);
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if (temp < stackbytes) overflow = TRUE;
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stackbytes = temp;
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}
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for (i = 0, ap = envp; i < nenvps; i++) {
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temp = stackbytes + _len(*ap++);
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if (temp < stackbytes) overflow = TRUE;
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stackbytes = temp;
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}
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temp = stackbytes + PTRSIZE - 1;
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if (temp < stackbytes) overflow = TRUE;
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stackbytes = (temp / PTRSIZE) * PTRSIZE;
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/* Check for overflow before committing sbrk. */
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if (overflow || stackbytes > ARG_MAX) {
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errno = E2BIG;
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return(-1);
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}
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/* Allocate the stack. */
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stack = _sbrk(stackbytes);
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if (stack == (char *) -1) {
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errno = E2BIG;
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return(-1);
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}
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/* Prepare the stack vector and argc. */
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ap = (char **) stack;
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hp = &stack[npointers * PTRSIZE];
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*ap++ = (char *) nargs;
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/* Prepare the argument pointers and strings. */
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for (i = 0; i < nargs; i++) {
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*ap++ = (char *) (hp - stack);
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p = *argv++;
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while ((*hp++ = *p++) != 0)
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;
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}
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*ap++ = (char *) NULL;
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/* Prepare the environment pointers and strings. */
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for (i = 0; i < nenvps; i++) {
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*ap++ = (char *) (hp - stack);
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p = *envp++;
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while ((*hp++ = *p++) != 0)
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;
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}
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*ap++ = (char *) NULL;
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/* Do the real work. */
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temp = _callm1(MM, EXEC, _len(path), stackbytes, 0, path, stack, NIL_PTR);
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_sbrk(-stackbytes);
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return(temp);
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}
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