diff options
Diffstat (limited to 'contrib/cvs/src/rcscmds.c')
| -rw-r--r-- | contrib/cvs/src/rcscmds.c | 63 |
1 files changed, 61 insertions, 2 deletions
diff --git a/contrib/cvs/src/rcscmds.c b/contrib/cvs/src/rcscmds.c index ea638b3..e290b68 100644 --- a/contrib/cvs/src/rcscmds.c +++ b/contrib/cvs/src/rcscmds.c @@ -599,7 +599,42 @@ diff_exec (file1, file2, options, out) char *options; char *out; { - char *args = xmalloc (strlen (options) + 10); + char *args; + +#ifdef PRESERVE_PERMISSIONS_SUPPORT + /* If either file1 or file2 are special files, pretend they are + /dev/null. Reason: suppose a file that represents a block + special device in one revision becomes a regular file. CVS + must find the `difference' between these files, but a special + file contains no data useful for calculating this metric. The + safe thing to do is to treat the special file as an empty file, + thus recording the regular file's full contents. Doing so will + create extremely large deltas at the point of transition + between device files and regular files, but this is probably + very rare anyway. + + There may be ways around this, but I think they are fraught + with danger. -twp */ + + if (preserve_perms && + strcmp (file1, DEVNULL) != 0 && + strcmp (file2, DEVNULL) != 0) + { + struct stat sb1, sb2; + + if (CVS_LSTAT (file1, &sb1) < 0) + error (1, errno, "cannot get file information for %s", file1); + if (CVS_LSTAT (file2, &sb2) < 0) + error (1, errno, "cannot get file information for %s", file2); + + if (!S_ISREG (sb1.st_mode) && !S_ISDIR (sb1.st_mode)) + file1 = DEVNULL; + if (!S_ISREG (sb2.st_mode) && !S_ISDIR (sb2.st_mode)) + file2 = DEVNULL; + } +#endif + + args = xmalloc (strlen (options) + 10); /* The first word in this string is used only for error reporting. */ sprintf (args, "diff %s", options); call_diff_setup (args); @@ -619,7 +654,31 @@ diff_execv (file1, file2, label1, label2, options, out) char *options; char *out; { - char *args = xmalloc (strlen (options) + 10); + char *args; + +#ifdef PRESERVE_PERMISSIONS_SUPPORT + /* Pretend that special files are /dev/null for purposes of making + diffs. See comments in diff_exec. */ + + if (preserve_perms && + strcmp (file1, DEVNULL) != 0 && + strcmp (file2, DEVNULL) != 0) + { + struct stat sb1, sb2; + + if (CVS_LSTAT (file1, &sb1) < 0) + error (1, errno, "cannot get file information for %s", file1); + if (CVS_LSTAT (file2, &sb2) < 0) + error (1, errno, "cannot get file information for %s", file2); + + if (!S_ISREG (sb1.st_mode) && !S_ISDIR (sb1.st_mode)) + file1 = DEVNULL; + if (!S_ISREG (sb2.st_mode) && !S_ISDIR (sb2.st_mode)) + file2 = DEVNULL; + } +#endif + + args = xmalloc (strlen (options) + 10); /* The first word in this string is used only for error reporting. */ /* I guess we are pretty confident that options starts with a space. */ sprintf (args, "diff%s", options); |
