xref: /freebsd/contrib/expat/xmlwf/unixfilemap.c (revision 5dae51da3da0cc94d17bd67b308fad304ebec7e0)
1 /* Copyright (c) 1998, 1999 Thai Open Source Software Center Ltd
2    See the file COPYING for copying permission.
3 */
4 
5 #include <sys/types.h>
6 #include <sys/mman.h>
7 #include <sys/stat.h>
8 #include <fcntl.h>
9 #include <errno.h>
10 #include <string.h>
11 #include <stdio.h>
12 #include <unistd.h>
13 
14 #ifndef MAP_FILE
15 #define MAP_FILE 0
16 #endif
17 
18 #include "filemap.h"
19 
20 int
21 filemap(const char *name,
22         void (*processor)(const void *, size_t, const char *, void *arg),
23         void *arg)
24 {
25   int fd;
26   size_t nbytes;
27   struct stat sb;
28   void *p;
29 
30   fd = open(name, O_RDONLY);
31   if (fd < 0) {
32     perror(name);
33     return 0;
34   }
35   if (fstat(fd, &sb) < 0) {
36     perror(name);
37     close(fd);
38     return 0;
39   }
40   if (!S_ISREG(sb.st_mode)) {
41     close(fd);
42     fprintf(stderr, "%s: not a regular file\n", name);
43     return 0;
44   }
45 
46   nbytes = sb.st_size;
47   /* mmap fails for zero length files */
48   if (nbytes == 0) {
49     static const char c = '\0';
50     processor(&c, 0, name, arg);
51     close(fd);
52     return 1;
53   }
54   p = (void *)mmap((void *)0, (size_t)nbytes, PROT_READ,
55                    MAP_FILE|MAP_PRIVATE, fd, (off_t)0);
56   if (p == (void *)-1) {
57     perror(name);
58     close(fd);
59     return 0;
60   }
61   processor(p, nbytes, name, arg);
62   munmap((void *)p, nbytes);
63   close(fd);
64   return 1;
65 }
66