.\" .\" Copyright (c) Christos Zoulas 2003. .\" All Rights Reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice immediately at the beginning of the file, without modification, .\" this list of conditions, and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR .\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd March 22, 2003 .Dt MAGIC 3 .Os .Sh NAME .Nm magic_open , .Nm magic_close , .Nm magic_error , .Nm magic_file , .Nm magic_buffer , .Nm magic_setflags , .Nm magic_check , .Nm magic_compile , .Nm magic_load .Nd Magic number recognition library. .Sh LIBRARY .Lb libmagic .Sh SYNOPSIS .In magic.h .Ft magic_t .Fn magic_open "int flags" .Ft void .Fn magic_close "magic_t cookie" .Ft const char * .Fn magic_error "magic_t cookie" .Ft int .Fn magic_errno "magic_t cookie" .Ft const char * .Fn magic_file "magic_t cookie, const char *filename" .Ft const char * .Fn magic_buffer "magic_t cookie, const void *buffer, size_t length" .Ft int .Fn magic_setflags "magic_t cookie, int flags" .Ft int .Fn magic_check "magic_t cookie, const char *filename" .Ft int .Fn magic_compile "magic_t cookie, const char *filename" .Ft int .Fn magic_load "magic_t cookie, const char *filename" .Sh DESCRIPTION These functions operate on the magic database file which is described in .Xr magic __FSECTION__ . .Pp The function .Fn magic_open creates a magic cookie pointer and returns it. It returns NULL if there was an error allocating the magic cookie. The .Ar flags argument specifies how the other magic functions should behave: .Bl -tag -width MAGIC_COMPRESS .It Dv MAGIC_NONE No special handling. .It Dv MAGIC_DEBUG Print debugging messages to stderr. .It Dv MAGIC_SYMLINK If the file queried is a symlink, follow it. .It Dv MAGIC_COMPRESS If the file is compressed, unpack it and look at the contents. .It Dv MAGIC_DEVICES If the file is a block or character special device, then open the device and try to look in its contents. .It Dv MAGIC_MIME Return a mime string, instead of a textual description. .It Dv MAGIC_CONTINUE Return all matches, not just the first. .It Dv MAGIC_CHECK Check the magic database for consistency and print warnings to stderr. .It Dv MAGIC_PRESERVE_ATIME On systems that support .Xr utime 2 or .Xr utimes 2 , attempt to preserve the access time of files analyzed. .It Dv MAGIC_RAW Don't translate unprintable characters to a \eooo octal representation. .It Dv MAGIC_ERROR Treat operating system errors while trying to open files and follow symlinks as real errors, instead of printing them in the magic buffer. .El .Pp The .Fn magic_close function closes the .Xr magic __FSECTION__ database and deallocates any resources used. .Pp The .Fn magic_error function returns a textual explanation of the last error, or NULL if there was no error. .Pp The .Fn magic_errno function returns the last operating system error number ( .Xr errno 3 ) that was encountered by a system call. .Pp The .Fn magic_file function returns a textual description of the contents of the .Ar filename argument, or NULL if an error occurred. If the .Ar filename is NULL, then stdin is used. .Pp The .Fn magic_buffer function returns a textual description of the contents of the .Ar buffer argument with .Ar length bytes size. .Pp The .Fn magic_setflags function, sets the .Ar flags described above. .Pp The .Fn magic_check function can be used to check the validity of entries in the colon separated database files passed in as .Ar filename , or NULL for the default database. It returns 0 on success and -1 on failure. .Pp The .Fn magic_compile function can be used to compile the the colon separated list of database files passed in as .Ar filename , or NULL for the default database. It returns 0 on success and -1 on failure. The compiled files created are named from the .Xr basename 1 of each file argument with ".mgc" appended to it. .Pp The .Fn magic_load function must be used to load the the colon separated list of database files passed in as .Ar filename , or NULL for the default database file before any magic queries can performed. .Pp The default database file is named by the MAGIC environment variable. If that variable is not set, the default database file name is __MAGIC__. .Pp .Fn magic_load adds ".mime" and/or ".mgc" to the database filename as appropriate. .Sh RETURN VALUES The function .Fn magic_open returns a magic cookie on success and NULL on failure setting errno to an appropriate value. It will set errno to EINVAL if an unsupported value for flags was given. The .Fn magic_load , .Fn magic_compile , and .Fn magic_check functions return 0 on success and -1 on failure. The .Fn magic_file , and .Fn magic_buffer functions return a string on success and NULL on failure. The .Fn magic_error function returns a textual description of the errors of the above functions, or NULL if there was no error. Finally, .Fn magic_setflags returns -1 on systems that don't support .Xr utime 2 , or .Xr utimes 2 when .Dv MAGIC_PRESERVE_ATIME is set. .Sh FILES .Bl -tag -width __MAGIC__.mime.mgc -compact .It Pa __MAGIC__.mime The non-compiled default magic mime database. .It Pa __MAGIC__.mime.mgc The compiled default magic mime database. .It Pa __MAGIC__ The non-compiled default magic database. .It Pa __MAGIC__.mgc The compiled default magic database. .El .Sh SEE ALSO .Xr file __CSECTION__ , .Xr magic __FSECTION__ .Sh AUTHORS Måns Rullgård Initial libmagic implementation, and configuration. Christos Zoulas API cleanup, error code and allocation handling.