man/zip_fopen_encrypted.man

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.\" zip_fopen_encrypted.mdoc -- open encrypted file in zip archive for reading
.\" Copyright (C) 2011-2021 Dieter Baron and Thomas Klausner
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.TH "ZIP_FOPEN_ENCRYPTED" "3" "September 15, 2020" "NiH" "Library Functions Manual"
.nh
.if n .ad l
.SH "NAME"
\fBzip_fopen_encrypted\fR,
\fBzip_fopen_index_encrypted\fR
\- open encrypted file in zip archive for reading
.SH "LIBRARY"
libzip (-lzip)
.SH "SYNOPSIS"
\fB#include <zip.h>\fR
.sp
\fIzip_file_t *\fR
.br
.PD 0
.HP 4n
\fBzip_fopen_encrypted\fR(\fIzip_t\ *archive\fR, \fIconst\ char\ *fname\fR, \fIzip_flags_t\ flags\fR, \fIconst\ char\ *password\fR);
.PD
.PP
\fIzip_file_t *\fR
.br
.PD 0
.HP 4n
\fBzip_fopen_index_encrypted\fR(\fIzip_t\ *archive\fR, \fIzip_uint64_t\ index\fR, \fIzip_flags_t\ flags\fR, \fIconst\ char\ *password\fR);
.PD
.SH "DESCRIPTION"
The
\fBzip_fopen_encrypted\fR()
function opens the encrypted file name
\fIfname\fR
in
\fIarchive\fR
using the password given in the
\fIpassword\fR
argument.
If
\fIpassword\fR
is
\fRNULL\fR
or the empty string, the default password is used (see
zip_set_default_password(3)).
The
\fIflags\fR
argument are the same as for
zip_fopen(3).
.PP
The
\fBzip_fopen_index_encrypted\fR()
function opens the file at position
\fIindex\fR,
see
zip_fopen_index(3).
These functions are called automatically by
zip_fopen(3);
you only need to call them if you want to specify a non-default password
(see
zip_set_default_password(3)).
.SH "RETURN VALUES"
Upon successful completion, a
\fIstruct zip_file\fR
pointer is returned.
Otherwise,
\fRNULL\fR
is returned and the error code in
\fIarchive\fR
is set to indicate the error.
.SH "ERRORS"
.TP 22n
[\fRZIP_ER_NOPASSWD\fR]
No password was provided.
.PP
The function
\fBzip_fopen_encrypted\fR()
may also fail and set
\fIzip_err\fR
for any of the errors specified for the routine
zip_fopen(3).
.PP
The function
\fBzip_fopen_index_encrypted\fR()
may also fail and set
\fIzip_err\fR
for any of the errors specified for the routine
zip_fopen_index(3).
.SH "SEE ALSO"
libzip(3),
zip_fclose(3),
zip_fopen(3),
zip_fread(3),
zip_get_num_entries(3),
zip_name_locate(3)
.SH "HISTORY"
\fBzip_fopen_encrypted\fR()
and
\fBzip_fopen_index_encrypted\fR()
were added in libzip 1.0.
.SH "AUTHORS"
Dieter Baron <\fIdillo@nih.at\fR>
and
Thomas Klausner <\fItk@giga.or.at\fR>
.SH "CAVEATS"
The zip file format provides very limited possibility for password
verification (a short hash of is compared against one byte in the zip
archive).
For this reason, reading a file while using an incorrect password may
immediately fail with
\fRZIP_ER_WRONGPASSWD\fR,
but if the mismatch is not detected, a zlib error may be returned
later instead.
Since zlib errors can also be caused by broken compressed data, there
is no way to make sure if the password was incorrect or if it was
correct, but the compressed data was invalid.