52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
/* This procedure examines a file system and figures out whether it is
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* version 1 or version 2. It returns the result as an int. If the
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* file system is neither, it returns -1. A typical call is:
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*
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* n = fsversion("/dev/hd1", "df");
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*
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* The first argument is the special file for the file system.
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* The second is the program name, which is used in error messages.
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*/
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#include <sys/types.h>
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/minlib.h>
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#include <minix/type.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include "mfs/const.h"
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#include "mfs/type.h"
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#include "mfs/super.h"
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static struct super_block super, *sp;
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int fsversion(dev, prog)
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char *dev, *prog;
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{
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int fd;
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if ((fd = open(dev, O_RDONLY)) < 0) {
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std_err(prog);
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std_err(" cannot open ");
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perror(dev);
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return(-1);
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}
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lseek(fd, (off_t) SUPER_BLOCK_BYTES, SEEK_SET); /* skip boot block */
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if (read(fd, (char *) &super, (unsigned) SUPER_SIZE) != SUPER_SIZE) {
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std_err(prog);
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std_err(" cannot read super block on ");
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perror(dev);
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close(fd);
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return(-1);
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}
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close(fd);
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sp = &super;
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if (sp->s_magic == SUPER_MAGIC) return(1);
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if (sp->s_magic == SUPER_V2) return(2);
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if (sp->s_magic == SUPER_V3) return(3);
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return(-1);
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}
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