60 lines
1.2 KiB
C
60 lines
1.2 KiB
C
#include <errno.h>
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#include <signal.h>
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#include <sys/wait.h>
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#include <unistd.h>
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int system(const char *cmdstring) {
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pid_t pid;
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int status;
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struct sigaction ignore, saveintr, savequit;
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sigset_t chldmask, savemask;
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if (cmdstring == NULL)
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return 1;
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ignore.sa_handler = SIG_IGN;
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sigemptyset(&ignore.sa_mask);
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ignore.sa_flags = 0;
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if (sigaction(SIGINT, &ignore, &saveintr) < 0)
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return -1;
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if (sigaction(SIGQUIT, &ignore, &savequit) < 0)
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return -1;
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sigemptyset(&chldmask);
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sigaddset(&chldmask, SIGCHLD);
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if (sigprocmask(SIG_BLOCK, &chldmask, &savemask) < 0)
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return -1;
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if((pid = fork()) < 0) {
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status = -1;
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}
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else if (pid == 0) {
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sigaction(SIGINT, &saveintr, NULL);
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sigaction(SIGQUIT, &savequit, NULL);
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execl("/bin/sh", "sh", "-c", cmdstring, (char *)0);
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_exit(127);
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}
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else {
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while (waitpid(pid, &status, 0) < 0)
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if (errno != EINTR) {
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return -1;
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break;
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}
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}
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if(sigaction(SIGINT, &saveintr, NULL) < 0) {
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return -1;
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}
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if(sigaction(SIGQUIT, &savequit, NULL) < 0) {
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return -1;
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}
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if(sigprocmask(SIG_SETMASK, &savemask, NULL) < 0) {
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return -1;
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}
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return status;
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}
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int main(void) {
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return system("ls .");
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}
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