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Add own implementation of archive entry extraction to allow custom filters.

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Fix magic number check for endianness.
This commit is contained in:
Moinak Ghosh 2013-11-09 21:55:18 +05:30
parent 6aacd903ff
commit a5f1624a33
1 changed files with 78 additions and 7 deletions
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85
archive/pc_archive.c
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@ -1026,6 +1026,66 @@ start_archiver(pc_ctx_t *pctx) {
return (pthread_create(&(pctx->archive_thread), NULL, archiver_thread_func, (void *)pctx));
}
/*
* The next two functions are from libArchive source/example:
* https://github.com/libarchive/libarchive/wiki/Examples#wiki-A_Complete_Extractor
*
* We have to use low-level APIs to extract entries to disk. Normally one would use
* archive_read_extract2() but LibArchive has no option to set user-defined filter
* routines, so we have to handle here.
*/
static int
copy_data_out(struct archive *ar, struct archive *aw)
{
int64_t offset;
const void *buff;
size_t size;
int r;
for (;;) {
r = archive_read_data_block(ar, &buff, &size, &offset);
if (r == ARCHIVE_EOF)
return (ARCHIVE_OK);
if (r != ARCHIVE_OK)
return (r);
r = (int)archive_write_data_block(aw, buff, size, offset);
if (r < ARCHIVE_WARN)
r = ARCHIVE_WARN;
if (r != ARCHIVE_OK) {
archive_set_error(ar, archive_errno(aw),
"%s", archive_error_string(aw));
return (r);
}
}
}
static int
archive_extract_entry(struct archive *a, struct archive_entry *entry,
struct archive *ad)
{
int r, r2;
r = archive_write_header(ad, entry);
if (r < ARCHIVE_WARN)
r = ARCHIVE_WARN;
if (r != ARCHIVE_OK)
/* If _write_header failed, copy the error. */
archive_copy_error(a, ad);
else if (!archive_entry_size_is_set(entry) || archive_entry_size(entry) > 0)
/* Otherwise, pour data into the entry. */
r = copy_data_out(a, ad);
r2 = archive_write_finish_entry(ad);
if (r2 < ARCHIVE_WARN)
r2 = ARCHIVE_WARN;
/* Use the first message. */
if (r2 != ARCHIVE_OK && r == ARCHIVE_OK)
archive_copy_error(a, ad);
/* Use the worst error return. */
if (r2 < r)
r = r2;
return (r);
}
/*
* Extract Thread function. Read an uncompressed archive from the pipe and extract
* members to disk. The decompressor writes to the other end of the pipe.
@ -1121,7 +1181,7 @@ extractor_thread_func(void *dat) {
}
#endif
rv = archive_read_extract2(arc, entry, awd);
rv = archive_extract_entry(arc, entry, awd);
if (rv != ARCHIVE_OK) {
log_msg(LOG_WARN, 0, "%s: %s", archive_entry_pathname(entry),
archive_error_string(arc));
@ -1224,14 +1284,25 @@ out:
return (TYPE_UNKNOWN);
}
#ifdef WORDS_BIGENDIAN
/* 0x7fELF packed into 32-bit integer. */
#define ELFSHORT (0x7f454c46U)
# define ELFINT (0x7f454c46U)
/* TZif packed into 32-bit integer. */
#define TZSHORT (0x545a6966U)
# define TZSINT (0x545a6966U)
/* PPMZ packed into 32-bit integer. */
#define PPMSHORT (0x50504d5aU)
# define PPMINT (0x50504d5aU)
#else
/* 0x7fELF packed into 32-bit integer. */
# define ELFINT (0x464c457fU)
/* TZif packed into 32-bit integer. */
# define TZINT (0x66695a54U)
/* PPMZ packed into 32-bit integer. */
# define PPMINT (0x5a4d5050U)
#endif
/*
* Detect a few file types from looking at magic signatures.
@ -1242,15 +1313,15 @@ detect_type_by_data(uchar_t *buf, size_t len)
// At least a few bytes.
if (len < 16) return (TYPE_UNKNOWN);
if (U32_P(buf) == ELFSHORT)
if (U32_P(buf) == ELFINT)
return (TYPE_BINARY|TYPE_EXE); // Regular ELF
if ((buf[0] == 'M' || buf[0] == 'L') && buf[1] == 'Z')
return (TYPE_BINARY|TYPE_EXE); // MSDOS Exe
if (buf[0] == 0xe9)
return (TYPE_BINARY|TYPE_EXE); // MSDOS COM
if (U32_P(buf) == TZSHORT)
if (U32_P(buf) == TZINT)
return (TYPE_BINARY); // Timezone data
if (U32_P(buf) == PPMSHORT)
if (U32_P(buf) == PPMINT)
return (TYPE_BINARY|TYPE_COMPRESSED|TYPE_COMPRESSED_PPMD); // PPM Compressed archive
return (TYPE_UNKNOWN);