1LIBMAGIC(3) BSD Library Functions Manual LIBMAGIC(3)
2
4 magic_open, magic_close, magic_error, magic_file, magic_buffer,
5 magic_setflags, magic_check, magic_compile, magic_load — Magic number
6 recognition library.
7
9 Magic Number Recognition Library (libmagic, -lmagic)
10
12 #include <magic.h>
13 magic_t
15 magic_open(int flags);
16 void
18 magic_close(magic_t cookie);
19 const char *
21 magic_error(magic_t cookie);
22 int
24 magic_errno(magic_t cookie);
25 const char *
27 magic_file(magic_t cookie, const char *filename);
28 const char *
30 magic_buffer(magic_t cookie, const void *buffer, size_t length);
31 int
33 magic_setflags(magic_t cookie, int flags);
34 int
36 magic_check(magic_t cookie, const char *filename);
37 int
39 magic_compile(magic_t cookie, const char *filename);
40 int
42 magic_load(magic_t cookie, const char *filename);
43
45 These functions operate on the magic database file which is described in
46 magic(5).
47 The function magic_open() creates a magic cookie pointer and returns it.
49 It returns NULL if there was an error allocating the magic cookie. The
50 flags argument specifies how the other magic functions should behave:
51 MAGIC_NONE No special handling.
53 MAGIC_DEBUG Print debugging messages to stderr.
55 MAGIC_SYMLINK If the file queried is a symlink, follow it.
57 MAGIC_COMPRESS If the file is compressed, unpack it and look at the con‐
59 tents.
60 MAGIC_DEVICES If the file is a block or character special device, then
62 open the device and try to look in its contents.
63 MAGIC_MIME_TYPE
65 Return a MIME type string, instead of a textual descrip‐
66 tion.
67 MAGIC_MIME_ENCODING
69 Return a MIME encoding, instead of a textual description.
70 MAGIC_CONTINUE Return all matches, not just the first.
72 MAGIC_CHECK Check the magic database for consistency and print warn‐
74 ings to stderr.
75 MAGIC_PRESERVE_ATIME
77 On systems that support utime(2) or utimes(2), attempt to
78 preserve the access time of files analyzed.
79 MAGIC_RAW Don't translate unprintable characters to a \ooo octal
81 representation.
82 MAGIC_ERROR Treat operating system errors while trying to open files
84 and follow symlinks as real errors, instead of printing
85 them in the magic buffer.
86 MAGIC_NO_CHECK_APPTYPE
88 Check for EMX application type (only on EMX).
89 MAGIC_NO_CHECK_ASCII
91 Check for various types of ascii files.
92 MAGIC_NO_CHECK_COMPRESS
94 Don't look for, or inside compressed files.
95 MAGIC_NO_CHECK_ELF
97 Don't print elf details.
98 MAGIC_NO_CHECK_FORTRAN
100 Don't look for fortran sequences inside ascii files.
101 MAGIC_NO_CHECK_SOFT
103 Don't consult magic files.
104 MAGIC_NO_CHECK_TAR
106 Don't examine tar files.
107 MAGIC_NO_CHECK_TOKENS
109 Don't look for known tokens inside ascii files.
110 MAGIC_NO_CHECK_TROFF
112 Don't look for troff sequences inside ascii files.
113 The magic_close() function closes the magic(5) database and deallocates
115 any resources used.
116 The magic_error() function returns a textual explanation of the last
118 error, or NULL if there was no error.
119 The magic_errno() function returns the last operating system error number
121 (errno(2)) that was encountered by a system call.
122 The magic_file() function returns a textual description of the contents
124 of the filename argument, or NULL if an error occurred. If the filename
125 is NULL, then stdin is used.
126 The magic_buffer() function returns a textual description of the contents
128 of the buffer argument with length bytes size.
129 The magic_setflags() function sets the flags described above. Note that
131 using both MIME flags together can also return extra information on the
132 charset.
133 The magic_check() function can be used to check the validity of entries
135 in the colon separated database files passed in as filename, or NULL for
136 the default database. It returns 0 on success and -1 on failure.
137 The magic_compile() function can be used to compile the the colon sepa‐
139 rated list of database files passed in as filename, or NULL for the
140 default database. It returns 0 on success and -1 on failure. The compiled
141 files created are named from the basename(1) of each file argument with
142 “.mgc” appended to it.
143 The magic_load() function must be used to load the the colon separated
145 list of database files passed in as filename, or NULL for the default
146 database file before any magic queries can performed.
147 The default database file is named by the MAGIC environment variable. If
149 that variable is not set, the default database file name is
150 /usr/share/misc/magic. magic_load() adds “.mgc” to the database filename
151 as appropriate.
152
154 The function magic_open() returns a magic cookie on success and NULL on
155 failure setting errno to an appropriate value. It will set errno to EIN‐
156 VAL if an unsupported value for flags was given. The magic_load(),
157 magic_compile(), and magic_check() functions return 0 on success and -1
158 on failure. The magic_file(), and magic_buffer() functions return a
159 string on success and NULL on failure. The magic_error() function returns
160 a textual description of the errors of the above functions, or NULL if
161 there was no error. Finally, magic_setflags() returns -1 on systems that
162 don't support utime(2), or utimes(2) when MAGIC_PRESERVE_ATIME is set.
163
165 /usr/share/misc/magic The non-compiled default magic database.
166 /usr/share/misc/magic.mgc The compiled default magic database.
167
169 file(1), magic(5)
170
172 Måns Rullgård Initial libmagic implementation, and configuration. Chris‐
173 tos Zoulas API cleanup, error code and allocation handling.
174BSD November 24, 2009 BSD