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Widened the lseek capacity determination to SEEK_SET with wanted size

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This commit is contained in:
Thomas Schmitt 2022-05-30 18:38:54 +02:00
parent ad55ec78e4
commit c6cb7dfa3e
4 changed files with 59 additions and 10 deletions
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51
libisofs/fsource.c
View File

@ -135,11 +135,12 @@ int iso_file_source_get_aa_string(IsoFileSource *src,
}
/* Determine whether src is random-access readable and return its capacity.
@flag bit0= Open and close src
/* @flag bit0= Open and close src
bit1= Try iso_file_source_lseek(, 0) (=SEEK_SET) with wanted_size
@return <0 iso_file_source_lseek failed , >= 0 readable capacity
*/
off_t iso_file_source_lseek_capacity(IsoFileSource *src, int flag)
off_t iso_file_source_lseek_capacity(IsoFileSource *src, off_t wanted_size,
int flag)
{
int ret, opened = 0;
off_t end, old, reset;
@ -173,7 +174,11 @@ off_t iso_file_source_lseek_capacity(IsoFileSource *src, int flag)
end = -1;
goto ex;
}
if(flag & 2) {
end = iso_file_source_lseek(src, wanted_size, 0);
} else {
end = iso_file_source_lseek(src, 0, 2);
}
if (end < 0) {
end = -1;
goto ex;
@ -190,3 +195,43 @@ ex:;
return end;
}
/* Determine whether src is random-access readable and return its capacity.
@flag bit0= For iso_file_source_lseek_capacity(): Open and close src
bit1= wanted_size is valid
*/
off_t iso_file_source_determine_capacity(IsoFileSource *src, off_t wanted_size,
int flag)
{
int ret;
off_t src_size, src_seek_size= -1;
struct stat info;
ret = iso_file_source_stat(src, &info);
if (ret < 0) {
return (off_t) -1;
}
if (S_ISREG(info.st_mode)) {
return info.st_size;
}
src_size = iso_file_source_lseek_capacity(src, wanted_size, (flag & 1));
if (src_size > 0) {
return src_size;
}
if (!(flag & 2)) {
if (src_size == 0) {
return 0;
}
return -1;
}
src_seek_size= src_size;
src_size = iso_file_source_lseek_capacity(src, wanted_size,
2 | (flag & 1));
if (src_size >= 0) {
return src_size;
} else if (src_seek_size >= 0) {
return src_seek_size;
}
return -1;
}

8
libisofs/fsource.h
View File

@ -49,10 +49,14 @@ int iso_ifs_source_clone(IsoFileSource *old_source, IsoFileSource **new_source,
int flag);
off_t iso_file_source_lseek_capacity(IsoFileSource *src, off_t wanted_size,
int flag);
/* Determine whether src is random-access readable and return its capacity.
@return -1 iso_file_source_lseek failed , >= 0 readable capacity
*/
off_t iso_file_source_lseek_capacity(IsoFileSource *src, int flag);
off_t iso_file_source_determine_capacity(IsoFileSource *src, off_t wanted_size,
int flag);
#endif /*LIBISO_FSOURCE_H_*/

5
libisofs/stream.c
View File

@ -353,7 +353,8 @@ int cut_out_open(IsoStream *stream)
src_size= info.st_size;
} else {
/* Determine src_size and lseekability of device */
src_size = iso_file_source_lseek_capacity(src, 0);
src_size = iso_file_source_determine_capacity(src,
data->offset + data->size, 2);
if (src_size <= 0)
return ISO_WRONG_ARG_VALUE;
}
@ -535,7 +536,7 @@ int iso_cut_out_stream_new(IsoFileSource *src, off_t offset, off_t size,
src_size = info.st_size;
} else {
/* Open src, do iso_source_lseek(SEEK_END), close src */
src_size = iso_file_source_lseek_capacity(src, 1);
src_size = iso_file_source_determine_capacity(src, offset + size, 3);
if (src_size <= 0)
return ISO_WRONG_ARG_VALUE;
}

3
libisofs/tree.c
View File

@ -720,8 +720,7 @@ int iso_tree_add_new_cut_out_node(IsoImage *image, IsoDir *parent,
if (S_ISREG(info.st_mode)) {
src_size = info.st_size;
} else {
/* Open src, do iso_source_lseek(SEEK_END), close src */
src_size = iso_file_source_lseek_capacity(src, 1);
src_size = iso_file_source_determine_capacity(src, offset + size, 3);
if (src_size <= 0)
return ISO_WRONG_ARG_VALUE;
}