xref: /netbsd-src/external/mit/expat/dist/xmlwf/unixfilemap.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
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   if (sb.st_size > XML_MAX_CHUNK_LEN) {
46     close(fd);
47     return 2;  /* Cannot be passed to XML_Parse in one go */
48   }
49 
50   nbytes = sb.st_size;
51   /* mmap fails for zero length files */
52   if (nbytes == 0) {
53     static const char c = '\0';
54     processor(&c, 0, name, arg);
55     close(fd);
56     return 1;
57   }
58   p = (void *)mmap((void *)0, (size_t)nbytes, PROT_READ,
59                    MAP_FILE|MAP_PRIVATE, fd, (off_t)0);
60   if (p == (void *)-1) {
61     perror(name);
62     close(fd);
63     return 0;
64   }
65   processor(p, nbytes, name, arg);
66   munmap((void *)p, nbytes);
67   close(fd);
68   return 1;
69 }
70