Hi!
23-Фев-2004 09:03 [EMAIL PROTECTED] (Kenneth J. Davis) wrote to
[EMAIL PROTECTED]:
>>> else if (memicmp(argp, "BOTH", 4) == 0 && !both)
>>- AIU, there should be stricmp() (or third parameter of memicmp() should be
>> increased to include zero byte)?
KJD> Could, but its more of, are exact arguments here really necessary?
I think, yes.
KJD> There is next to no chance
?
KJD> of a user accidently typing the initial part and expecting it to fail
KJD> because they [purposely or accidently] tacted on some additional letters.
? Not very understand these sentences. Also, imagine next command line:
SYS A: BOOTONLY/K mykernel.sys
KJD> Wasn't this originally a stricmp?
Don't know.
>> printf("%s: drive %c must be A:..Z:\n", pgm, *argv[drivearg]);
>> but I think, this diagnostic may be ommited completely.
KJD> It can help pinpoint problems (such as what argument one types that it
KJD> thinks is the drive
This bug will be diagnosted later, by code, which will try to access
drive.
>> strncpy(srcPath, argv[srcarg], sizeof srcPath - 12);
>> /* leave room for COMMAND.COM\0 */
>> srcPath[sizeof srcPath - 12] = '\0';
>>-----------------------------^^
KJD> There are 13 characters in '\\COMMAND.COM\0', which there must be room
KJD> for, so the 13 is correct, but the comment could be updated to include
KJD> the separator.
Precisely. Anyway, in my current code I rewrote this part.
>>> if ((srcPath[slen - 1] != ':') &&
>>> ((srcPath[slen - 1] != '\\') || (srcPath[slen - 1] != '/')))
>>- bug? AIU, should be:
>> if (slen) {
KJD> I think at some point the preconditions meant this check was not
KJD> required, but perhaps I'm mistaken and it was overlooked.
Probably, there _was_ ready precondition, but not in code, which I see.
>> if (ch != ':' && ch != '\\' && ch != '/')
>>-----------------------------------^^
KJD> good catch, I think I originally meant [but screwed up]
BTW, who currently officialy mantain SYS?
>> srcPath [slen] = '\\', srcPath [slen + 1] = '\0';
KJD> I'd rather see
KJD> {
KJD> srcPath[slen] = '\\';
KJD> srcPath[slen+1] = '\0';
KJD> }
KJD> over the use of the comma operator, as it makes it more clear that a
KJD> compound statement is executed.
:) Question of taste, which easy to fix/change.
KJD> slen++ or [slen+1] makes little difference to me
KJD> (whichever produces more efficent code)
This depends. In case if srcPath is an array, then additional constant
offset is "hidden" in other displacements. If srcPath is a pointer, you
simply get one-byte instruction increase, but this removes _extra_
instruction(s) to increase slen (which later not used).
>>> /* Don't try root if src==dst drive or source path given */
>>> if ((drive == srcDrive)
>>> || (*srcPath
>>> && ((srcPath[1] != ':') || ((srcPath[1] == ':') && srcPath[2]))))
>>> *rootPath = '\0';
>>> else
>>> sprintf(rootPath, "%c:\\", 'A' + srcDrive);
>>- (x || (~x && y)) equal to (x && y), so, there should be:
>> /* Don't try root if src==dst drive or source path given */
>> static char root [] = "\0:\\";
>> if (drive != srcDrive &&
>> (srcPath [0] == '\0' || /* empty string or */
>> (srcPath [1] == ':' && srcPath [2] == '\0'))) /* drive only "A:" */
>> root [0] = 'A' + srcDrive;
KJD> I'm glad you can figure what's being checked for,
Yes.
KJD> ?something about not trying root directory for copies if a path is given
Yes. Root is tried only of source ommited or given as drive letter
("A:"), else ("c:\temp", "d:dir", "subdir") only given directory is
accessed.
KJD> as we may be trying to run sys onto same drive as source using
KJD> kernel & command.com contained within a subdirectory of itself
This prevented by "srcDrive != drive". Though, I under doubt: may be in
case of "" and "D:" always should be checked only root - if you wish to get
current directory, you may use "." and "D:."?
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