mincore.c

   1 #include "compat-util.h"
   2
   3 static void mincore_stats(const char *path, off_t offset, off_t len)
   4 {
   5         char *map;
   6         unsigned char *vec;
   7         size_t vec_len;
   8         size_t map_len;
   9         off_t map_offset;
  10         int fd;
  11         size_t i;
  12         static const char *fmt = sizeof(void *) == 8 ?
  13                                  "%s: %016lx %x\n": "%s: %08lx %x\n";
  14
  15         if ((fd = open(path, O_RDONLY|O_NOATIME)) < 0) {
  16                 fprintf(stderr, "%s: open(): %s\n", path, strerror(errno));
  17                 return;
  18         }
  19
  20         if (!len) {
  21                 struct stat sb;
  22
  23                 if (fstat(fd, &sb) < 0) {
  24                         fprintf(stderr, "%s: fstat(%d): %s\n",
  25                                 path, fd, strerror(errno));
  26                         goto err_close;
  27                 }
  28                 len = sb.st_size;
  29         }
  30
  31         vec_len = (len + page_size() - 1) / page_size();
  32         if (!(vec = malloc(vec_len))) {
  33                 fprintf(stderr, "%s: malloc(%lu): %s\n",
  34                         path, (unsigned long)vec_len, strerror(errno));
  35                 goto err_close;
  36         }
  37
  38         map_len = PAGE_ALIGN(len);
  39         map_offset = PAGE_ALIGN_DOWN(offset);
  40
  41         map = mmap(NULL, map_len, PROT_READ, MAP_SHARED, fd, map_offset);
  42         if (!map) {
  43                 fprintf(stderr, "%s: mmap(%lu): %s\n",
  44                         path, (unsigned long)vec_len, strerror(errno));
  45                 goto err_free;
  46         }
  47
  48         if (mincore(map, map_len, vec) < 0) {
  49                 fprintf(stderr, "%s: mincore(%lu): %s\n",
  50                         path, (unsigned long)vec_len, strerror(errno));
  51                 goto err_munmap;
  52         }
  53
  54         for (i = 0; i < vec_len; ++i)
  55                 printf(fmt, path,
  56                        (unsigned long)(page_size() * i) + map_offset,
  57                        vec[i]);
  58 err_munmap:
  59         munmap(map, map_len);
  60 err_free:
  61         free(vec);
  62 err_close:
  63         close(fd);
  64 }
  65
  66 int main(int argc, char * const argv[])
  67 {
  68         off_t offset = 0;
  69         off_t len = 0;
  70         int argi = 1;
  71         int opt;
  72
  73         while ((opt = getopt(argc, argv, "o:l:")) != -1) {
  74                 char *err;
  75
  76                 argi += 2;
  77                 switch(opt) {
  78                 case 'o':
  79                         offset = strtol(optarg, &err, 10);
  80                         if (*err || offset < 0) {
  81                                 fprintf(stderr, "offset must be >= 0\n");
  82                                 return 1;
  83                         }
  84                         break;
  85                 case 'l':
  86                         len = strtol(optarg, &err, 10);
  87                         if (*err || len < 0) {
  88                                 fprintf(stderr, "length must be >= 0\n");
  89                                 return 1;
  90                         }
  91                         break;
  92                 default:
  93                         fprintf(stderr,
  94                                 "Usage: %s [-o offset] "
  95                                 "[-l length] <files>\n", argv[0]);
  96                         return 1;
  97                 }
  98         }
  99
 100         for (; argi < argc; ++argi)
 101                 mincore_stats(argv[argi], offset, len);
 102         return 0;
 103 }