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https://github.com/clearlinux/graphene.git
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0c3324aa06
Previously, Graphene supported only /dev/tty (stdin/stdout terminal) device. This commit introduces support for other, arbitrary host devices. The devices must be explicitly allowed in the manifest via a mount point like this: fs.mount.devkmsg.type = chroot fs.mount.devkmsg.path = /dev/kmsg fs.mount.devkmsg.uri = dev:/dev/kmsg Currently only open/read/write/close/fstat are supported. lseek is supported only with offset 0 (and it is not device-specific). Support for IOCTLs will be introduced in future commits. A simple test is added to LibOS regression tests.
52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
#include <err.h>
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#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/types.h>
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#include <unistd.h>
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int main(int argc, char* arvg[]) {
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int devfd = open("/dev/kmsg", O_RDONLY);
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if (devfd < 0)
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err(1, "/dev/kmsg open");
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off_t offset;
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#if 0
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/* FIXME: doesn't work in Graphene because lseek() is fully emulated in LibOS and therefore
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* lseek() is not aware of device-specific semantics */
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offset = lseek(devfd, 0, SEEK_CUR);
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if (offset != -1 || errno != EINVAL) {
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errx(1, "/dev/kmsg lseek(0, SEEK_CUR) didn't return -EINVAL (returned: %ld, errno=%d)",
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offset, errno);
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}
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offset = lseek(devfd, 1, SEEK_CUR);
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if (offset != -1 || errno != ESPIPE) {
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errx(1, "/dev/kmsg lseek(1, SEEK_CUR) didn't return -ESPIPE (returned: %ld, errno=%d)",
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offset, errno);
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}
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#endif
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offset = lseek(devfd, /*offset=*/0, SEEK_SET);
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if (offset < 0)
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err(1, "/dev/kmsg lseek(0, SEEK_SET)");
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if (offset > 0)
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errx(1, "/dev/kmsg lseek(0, SEEK_SET) didn't return 0 (returned: %ld)", offset);
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char buf[1024];
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ssize_t bytes = read(devfd, buf, sizeof(buf) - 1);
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if (bytes < 0)
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err(1, "/dev/kmsg read");
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buf[bytes] = '\0';
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printf("First line of /dev/kmsg: %s", buf);
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int ret = close(devfd);
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if (ret < 0)
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err(1, "/dev/kmsg close");
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puts("TEST OK");
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return 0;
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}
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