1MAGIC(3) BSD Library Functions Manual MAGIC(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 Return a mime string, instead of a textual description.
65 MAGIC_CONTINUE Return all matches, not just the first.
67 MAGIC_CHECK Check the magic database for consistency and print warn‐
69 ings to stderr.
70 MAGIC_PRESERVE_ATIME
72 On systems that support utime(2) or utimes(2), attempt to
73 preserve the access time of files analyzed.
74 MAGIC_RAW Don't translate unprintable characters to a \ooo octal
76 representation.
77 MAGIC_ERROR Treat operating system errors while trying to open files
79 and follow symlinks as real errors, instead of printing
80 them in the magic buffer.
81 MAGIC_NO_CHECK_APPTYPE
83 Check for EMX application type (only on EMX).
84 MAGIC_NO_CHECK_ASCII
86 Check for various types of ascii files.
87 MAGIC_NO_CHECK_COMPRESS
89 Don't look for, or inside compressed files.
90 MAGIC_NO_CHECK_ELF
92 Don't print elf details.
93 MAGIC_NO_CHECK_FORTRAN
95 Don't look for fortran sequences inside ascii files.
96 MAGIC_NO_CHECK_SOFT
98 Don't consult magic files.
99 MAGIC_NO_CHECK_TAR
101 Don't examine tar files.
102 MAGIC_NO_CHECK_TOKENS
104 Don't look for known tokens inside ascii files.
105 MAGIC_NO_CHECK_TROFF
107 Don't look for troff sequences inside ascii files.
108 The magic_close() function closes the magic(5) database and deallocates
110 any resources used.
111 The magic_error() function returns a textual explanation of the last
113 error, or NULL if there was no error.
114 The magic_errno() function returns the last operating system error number
116 (errno(2)) that was encountered by a system call.
117 The magic_file() function returns a textual description of the contents
119 of the filename argument, or NULL if an error occurred. If the filename
120 is NULL, then stdin is used.
121 The magic_buffer() function returns a textual description of the contents
123 of the buffer argument with length bytes size.
124 The magic_setflags() function, sets the flags described above.
126 The magic_check() function can be used to check the validity of entries
128 in the colon separated database files passed in as filename, or NULL for
129 the default database. It returns 0 on success and -1 on failure.
130 The magic_compile() function can be used to compile the the colon sepa‐
132 rated list of database files passed in as filename, or NULL for the
133 default database. It returns 0 on success and -1 on failure. The compiled
134 files created are named from the basename(1) of each file argument with
135 ".mgc" appended to it.
136 The magic_load() function must be used to load the the colon separated
138 list of database files passed in as filename, or NULL for the default
139 database file before any magic queries can performed.
140 The default database file is named by the MAGIC environment variable. If
142 that variable is not set, the default database file name is
143 /usr/share/file/magic.
144 magic_load() adds ".mime" and/or ".mgc" to the database filename as
146 appropriate.
147
149 The function magic_open() returns a magic cookie on success and NULL on
150 failure setting errno to an appropriate value. It will set errno to EIN‐
151 VAL if an unsupported value for flags was given. The magic_load(),
152 magic_compile(), and magic_check() functions return 0 on success and -1
153 on failure. The magic_file(), and magic_buffer() functions return a
154 string on success and NULL on failure. The magic_error() function returns
155 a textual description of the errors of the above functions, or NULL if
156 there was no error. Finally, magic_setflags() returns -1 on systems that
157 don't support utime(2), or utimes(2) when MAGIC_PRESERVE_ATIME is set.
158
160 /usr/share/file/magic.mime The non-compiled default magic mime data‐
161 base.
162 /usr/share/file/magic.mime.mgc The compiled default magic mime database.
163 /usr/share/file/magic The non-compiled default magic database.
164 /usr/share/file/magic.mgc The compiled default magic database.
165
167 file(1), magic(5)
168
170 Måns Rullgård Initial libmagic implementation, and configuration. Chris‐
171 tos Zoulas API cleanup, error code and allocation handling.
172BSD November 15, 2006 BSD