copy.c

   1 #include "git-compat-util.h"
   2 #include "copy.h"
   3 #include "path.h"
   4 #include "gettext.h"
   5 #include "strbuf.h"
   6 #include "abspath.h"
   7
   8 int copy_fd(int ifd, int ofd)
   9 {
  10         while (1) {
  11                 char buffer[8192];
  12                 ssize_t len = xread(ifd, buffer, sizeof(buffer));
  13                 if (!len)
  14                         break;
  15                 if (len < 0)
  16                         return COPY_READ_ERROR;
  17                 if (write_in_full(ofd, buffer, len) < 0)
  18                         return COPY_WRITE_ERROR;
  19         }
  20         return 0;
  21 }
  22
  23 static int copy_times(const char *dst, const char *src)
  24 {
  25         struct stat st;
  26         struct utimbuf times;
  27         if (stat(src, &st) < 0)
  28                 return -1;
  29         times.actime = st.st_atime;
  30         times.modtime = st.st_mtime;
  31         if (utime(dst, &times) < 0)
  32                 return -1;
  33         return 0;
  34 }
  35
  36 int copy_file(const char *dst, const char *src, int mode)
  37 {
  38         int fdi, fdo, status;
  39
  40         mode = (mode & 0111) ? 0777 : 0666;
  41         if ((fdi = open(src, O_RDONLY)) < 0)
  42                 return fdi;
  43         if ((fdo = open(dst, O_WRONLY | O_CREAT | O_EXCL, mode)) < 0) {
  44                 close(fdi);
  45                 return fdo;
  46         }
  47         status = copy_fd(fdi, fdo);
  48         switch (status) {
  49         case COPY_READ_ERROR:
  50                 error_errno("copy-fd: read returned");
  51                 break;
  52         case COPY_WRITE_ERROR:
  53                 error_errno("copy-fd: write returned");
  54                 break;
  55         }
  56         close(fdi);
  57         if (close(fdo) != 0)
  58                 return error_errno("%s: close error", dst);
  59
  60         if (!status && adjust_shared_perm(dst))
  61                 return -1;
  62
  63         return status;
  64 }
  65
  66 int copy_file_with_time(const char *dst, const char *src, int mode)
  67 {
  68         int status = copy_file(dst, src, mode);
  69         if (!status)
  70                 return copy_times(dst, src);
  71         return status;
  72 }
  73
  74 static int do_symlinks_match(const char *path1, const char *path2)
  75 {
  76         struct strbuf buf1 = STRBUF_INIT, buf2 = STRBUF_INIT;
  77         int ret = 0;
  78
  79         if (!strbuf_readlink(&buf1, path1, 0) &&
  80             !strbuf_readlink(&buf2, path2, 0))
  81                 ret = !strcmp(buf1.buf, buf2.buf);
  82
  83         strbuf_release(&buf1);
  84         strbuf_release(&buf2);
  85         return ret;
  86 }
  87
  88 int do_files_match(const char *path1, const char *path2)
  89 {
  90         struct stat st1, st2;
  91         int fd1 = -1, fd2 = -1, ret = 1;
  92         char buf1[8192], buf2[8192];
  93
  94         if ((fd1 = open_nofollow(path1, O_RDONLY)) < 0 ||
  95             fstat(fd1, &st1) || !S_ISREG(st1.st_mode)) {
  96                 if (fd1 < 0 && errno == ELOOP)
  97                         /* maybe this is a symbolic link? */
  98                         return do_symlinks_match(path1, path2);
  99                 ret = 0;
 100         } else if ((fd2 = open_nofollow(path2, O_RDONLY)) < 0 ||
 101                    fstat(fd2, &st2) || !S_ISREG(st2.st_mode)) {
 102                 ret = 0;
 103         }
 104
 105         if (ret)
 106                 /* to match, neither must be executable, or both */
 107                 ret = !(st1.st_mode & 0111) == !(st2.st_mode & 0111);
 108
 109         if (ret)
 110                 ret = st1.st_size == st2.st_size;
 111
 112         while (ret) {
 113                 ssize_t len1 = read_in_full(fd1, buf1, sizeof(buf1));
 114                 ssize_t len2 = read_in_full(fd2, buf2, sizeof(buf2));
 115
 116                 if (len1 < 0 || len2 < 0 || len1 != len2)
 117                         ret = 0; /* read error or different file size */
 118                 else if (!len1) /* len2 is also 0; hit EOF on both */
 119                         break; /* ret is still true */
 120                 else
 121                         ret = !memcmp(buf1, buf2, len1);
 122         }
 123
 124         if (fd1 >= 0)
 125                 close(fd1);
 126         if (fd2 >= 0)
 127                 close(fd2);
 128
 129         return ret;
 130 }