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fsp: Try to recover from ABI mismatches caused by _FILE_OFFSET_BITS.

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Kalle Olavi Niemitalo 2007-03-06 15:55:08 +02:00 committed by Kalle Olavi Niemitalo
parent 9f47368894
commit e517ef22a9
1 changed files with 35 additions and 0 deletions
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35
src/protocol/fsp/fsp.c
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@ -265,6 +265,25 @@ do_fsp(struct connection *conn)
ses = fsp_open_session(host, port, password);
if (!ses) fsp_error(errno);
/* fsplib 0.8 ABI depends on _FILE_OFFSET_BITS
* https://sourceforge.net/tracker/index.php?func=detail&aid=1674729&group_id=93841&atid=605738
* If ELinks and fsplib are using different values of
* _FILE_OFFSET_BITS, then they get different definitions of
* struct stat, and the st_size stored by fsp_stat is
* typically not the same as the st_size read by ELinks.
* Fortunately, st_mode seems to have the same offset and size
* in both versions of struct stat.
*
* If all the bytes used by the 32-bit st_size are also used
* by the 64-bit st_size, then ELinks may be able to guess
* which ones they are, because the current version 2 of FSP
* supports only 32-bit file sizes in protocol packets. Begin
* by filling struct stat with 0xAA so that it's easier to
* detect which bytes fsp_stat has left unchanged. (Only
* sb.st_size really needs to be filled, but filling the rest
* too helps viewing the data with a debugger.) */
memset(&sb, 0xAA, sizeof(sb));
if (fsp_stat(ses, data, &sb)) fsp_error(errno);
if (S_ISDIR(sb.st_mode)) {
@ -278,6 +297,22 @@ do_fsp(struct connection *conn)
fsp_error(errno);
}
#if SIZEOF_OFF_T >= 8
if (sb.st_size < 0 || sb.st_size > 0xFFFFFFFF) {
/* Probably a _FILE_OFFSET_BITS mismatch as
* described above. Try to detect which half
* of st_size is the real size. This may
* depend on the endianness of the processor
* and on the padding in struct stat. */
if ((sb.st_size & 0xFFFFFFFF00000000ULL) == 0xAAAAAAAA00000000ULL)
sb.st_size = sb.st_size & 0xFFFFFFFF;
else if ((sb.st_size & 0xFFFFFFFF) == 0xAAAAAAAA)
sb.st_size = (sb.st_size >> 32) & 0xFFFFFFFF;
else /* Can't figure it out. */
sb.st_size = 1;
}
#endif
/* Send filesize */
fprintf(stderr, "%" OFF_T_FORMAT "\n", (off_t)(sb.st_size));
fclose(stderr);