copy.c

   1 #include "cache.h"
   2
   3 int copy_fd(int ifd, int ofd)
   4 {
   5         while (1) {
   6                 char buffer[8192];
   7                 ssize_t len = xread(ifd, buffer, sizeof(buffer));
   8                 if (!len)
   9                         break;
  10                 if (len < 0)
  11                         return COPY_READ_ERROR;
  12                 if (write_in_full(ofd, buffer, len) < 0)
  13                         return COPY_WRITE_ERROR;
  14         }
  15         return 0;
  16 }
  17
  18 static int copy_times(const char *dst, const char *src)
  19 {
  20         struct stat st;
  21         struct utimbuf times;
  22         if (stat(src, &st) < 0)
  23                 return -1;
  24         times.actime = st.st_atime;
  25         times.modtime = st.st_mtime;
  26         if (utime(dst, &times) < 0)
  27                 return -1;
  28         return 0;
  29 }
  30
  31 int copy_file(const char *dst, const char *src, int mode)
  32 {
  33         int fdi, fdo, status;
  34
  35         mode = (mode & 0111) ? 0777 : 0666;
  36         if ((fdi = open(src, O_RDONLY)) < 0)
  37                 return fdi;
  38         if ((fdo = open(dst, O_WRONLY | O_CREAT | O_EXCL, mode)) < 0) {
  39                 close(fdi);
  40                 return fdo;
  41         }
  42         status = copy_fd(fdi, fdo);
  43         switch (status) {
  44         case COPY_READ_ERROR:
  45                 error_errno("copy-fd: read returned");
  46                 break;
  47         case COPY_WRITE_ERROR:
  48                 error_errno("copy-fd: write returned");
  49                 break;
  50         }
  51         close(fdi);
  52         if (close(fdo) != 0)
  53                 return error_errno("%s: close error", dst);
  54
  55         if (!status && adjust_shared_perm(dst))
  56                 return -1;
  57
  58         return status;
  59 }
  60
  61 int copy_file_with_time(const char *dst, const char *src, int mode)
  62 {
  63         int status = copy_file(dst, src, mode);
  64         if (!status)
  65                 return copy_times(dst, src);
  66         return status;
  67 }
  68
  69 static int do_symlinks_match(const char *path1, const char *path2)
  70 {
  71         struct strbuf buf1 = STRBUF_INIT, buf2 = STRBUF_INIT;
  72         int ret = 0;
  73
  74         if (!strbuf_readlink(&buf1, path1, 0) &&
  75             !strbuf_readlink(&buf2, path2, 0))
  76                 ret = !strcmp(buf1.buf, buf2.buf);
  77
  78         strbuf_release(&buf1);
  79         strbuf_release(&buf2);
  80         return ret;
  81 }
  82
  83 int do_files_match(const char *path1, const char *path2)
  84 {
  85         struct stat st1, st2;
  86         int fd1 = -1, fd2 = -1, ret = 1;
  87         char buf1[8192], buf2[8192];
  88
  89         if ((fd1 = open_nofollow(path1, O_RDONLY)) < 0 ||
  90             fstat(fd1, &st1) || !S_ISREG(st1.st_mode)) {
  91                 if (fd1 < 0 && errno == ELOOP)
  92                         /* maybe this is a symbolic link? */
  93                         return do_symlinks_match(path1, path2);
  94                 ret = 0;
  95         } else if ((fd2 = open_nofollow(path2, O_RDONLY)) < 0 ||
  96                    fstat(fd2, &st2) || !S_ISREG(st2.st_mode)) {
  97                 ret = 0;
  98         }
  99
 100         if (ret)
 101                 /* to match, neither must be executable, or both */
 102                 ret = !(st1.st_mode & 0111) == !(st2.st_mode & 0111);
 103
 104         if (ret)
 105                 ret = st1.st_size == st2.st_size;
 106
 107         while (ret) {
 108                 ssize_t len1 = read_in_full(fd1, buf1, sizeof(buf1));
 109                 ssize_t len2 = read_in_full(fd2, buf2, sizeof(buf2));
 110
 111                 if (len1 < 0 || len2 < 0 || len1 != len2)
 112                         ret = 0; /* read error or different file size */
 113                 else if (!len1) /* len2 is also 0; hit EOF on both */
 114                         break; /* ret is still true */
 115                 else
 116                         ret = !memcmp(buf1, buf2, len1);
 117         }
 118
 119         if (fd1 >= 0)
 120                 close(fd1);
 121         if (fd2 >= 0)
 122                 close(fd2);
 123
 124         return ret;
 125 }