53 lines
1.0 KiB
C
53 lines
1.0 KiB
C
// init: The initial user-level program
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#include "kernel/types.h"
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#include "kernel/stat.h"
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#include "kernel/spinlock.h"
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#include "kernel/sleeplock.h"
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#include "kernel/fs.h"
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#include "kernel/file.h"
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#include "user/user.h"
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#include "kernel/fcntl.h"
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char *argv[] = {"sh", 0};
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int main(void) {
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int pid, wpid;
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if (open("console", O_RDWR) < 0) {
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mknod("console", CONSOLE, 0);
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open("console", O_RDWR);
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}
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dup(0); // stdout
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dup(0); // stderr
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for (;;) {
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printf("init: starting sh\n");
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pid = fork();
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if (pid < 0) {
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printf("init: fork failed\n");
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exit(1);
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}
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if (pid == 0) {
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exec("sh", argv);
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printf("init: exec sh failed\n");
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exit(1);
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}
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for (;;) {
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// this call to wait() returns if the shell exits,
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// or if a parentless process exits.
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wpid = wait((int *)0);
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if (wpid == pid) {
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// the shell exited; restart it.
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break;
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} else if (wpid < 0) {
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printf("init: wait returned an error\n");
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exit(1);
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} else {
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// it was a parentless process; do nothing.
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}
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}
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}
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}
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