49 lines
1.3 KiB
C
49 lines
1.3 KiB
C
#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/stat.h>
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#include <sys/syscall.h>
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#include <sys/sysmacros.h>
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#include <unistd.h>
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#define xmknod(path, mode, maj, min) \
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if (mknod(path, mode, makedev(maj, min)) < 0) exit(255);
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// Too early for console logs (/dev/console is created here!), so we have to resort to exiting with a weird exit code in
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// case of failure.
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static void populate_devfs()
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{
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if (mkdir("/dev", 0755) < 0 && errno != EEXIST) exit(255);
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xmknod("/dev/console", 0666, 1, 0);
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xmknod("/dev/null", 0666, 2, 0);
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}
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int main()
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{
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if (getpid() != 1)
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{
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printf("error: init not running as PID 1.\n");
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return 1;
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}
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populate_devfs();
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// Before this point, we don't even have an stdout and stderr. Set it up now so that child processes (and us) can
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// print stuff.
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stdout = fopen("/dev/console", "w");
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stderr = fopen("/dev/console", "w");
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fprintf(stderr, "init is running as PID %d\n", getpid());
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pid_t ret = fork();
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if (ret == 0)
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{
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char* argv[] = { "/bin/hello", "--help", NULL };
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execv("/bin/hello", argv);
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}
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else { printf("my child is PID %d!\n", ret); }
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}
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