59 lines
1.2 KiB
C
59 lines
1.2 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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/* $Id$ */
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#include <sys/types.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <unistd.h>
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#define FAIL 127
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static const char* exec_tab[] = {
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"sh", /* argv[0] */
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"-c", /* argument to the shell */
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NULL, /* to be filled with user command */
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NULL /* terminating NULL */
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};
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int system(const char* str)
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{
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int pid, exitstatus, waitval;
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int i;
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if ((pid = fork()) < 0)
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return str ? -1 : 0;
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if (pid == 0)
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{
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for (i = 3; i <= 20; i++)
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close(i);
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if (!str)
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str = "cd ."; /* just testing for a shell */
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exec_tab[2] = str; /* fill in command */
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execve("/bin/sh", (char* const*)exec_tab, (char* const*)environ);
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/* get here if execve fails ... */
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_exit(FAIL); /* see manual page */
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}
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while ((waitval = wait(&exitstatus)) != pid)
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{
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if (waitval == -1)
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break;
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}
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if (waitval == -1)
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{
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/* no child ??? or maybe interrupted ??? */
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exitstatus = -1;
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}
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if (!str)
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{
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if (exitstatus == FAIL << 8) /* execve() failed */
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exitstatus = 0;
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else
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exitstatus = 1; /* /bin/sh exists */
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}
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return exitstatus;
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}
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