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more: use libmagic to identify binary files 

As the old commend said: 'This code would best be shared with the file(1)
program or, perhaps, more should not try to be so smart'.  Now at configure
time one can choose whether more(1) is sharing code with file(1), or not.

Addresses: http://bugs.debian.org/139205
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
This commit is contained in:
Sami Kerola 2020-05-06 20:19:22 +01:00 committed by Karel Zak
parent 9bf7517162
commit 09070e1a65
3 changed files with 46 additions and 20 deletions
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12
configure.ac
View File

@ -1501,6 +1501,18 @@ AS_IF([test "x$with_libz" = xno], [have_z=no], [
AC_CHECK_LIB([z], [crc32], [have_z=yes], [have_z=no])
])
AC_ARG_WITH([libmagic],
AS_HELP_STRING([--without-libmagic], [compile without libmagic]),
[], [with_libmagic=auto]
)
AS_IF([test "x$with_libmagic" = xno], [have_magic=no], [
AC_CHECK_LIB([magic], [magic_open], [
AC_DEFINE([HAVE_MAGIC], [1], [Define to 1 if you have the libmagic present.])
MAGIC_LIBS="-lmagic"
])
])
AC_SUBST([MAGIC_LIBS])
AC_ARG_ENABLE([cramfs],
AS_HELP_STRING([--disable-cramfs], [do not build fsck.cramfs, mkfs.cramfs]),

2
text-utils/Makemodule.am
View File

@ -80,7 +80,7 @@ bin_PROGRAMS += more
dist_man_MANS += text-utils/more.1
more_SOURCES = text-utils/more.c
more_CFLAGS = $(AM_CFLAGS) $(BSD_WARN_CFLAGS)
more_LDADD = $(LDADD) libcommon.la
more_LDADD = $(LDADD) $(MAGIC_LIBS) libcommon.la
if HAVE_TINFO
more_LDADD += $(TINFO_LIBS)
more_LDADD += $(TINFO_CFLAGS)

52
text-utils/more.c
View File

@ -74,13 +74,17 @@
# include <term.h>
#endif
#include "env.h"
#ifdef HAVE_MAGIC
# include <magic.h>
#endif
#include "strutils.h"
#include "nls.h"
#include "xalloc.h"
#include "widechar.h"
#include "closestream.h"
#include "rpmatch.h"
#include "env.h"
#ifdef TEST_PROGRAM
# define NON_INTERACTIVE_MORE 1
@ -157,6 +161,9 @@ struct more_control {
int last_key_arg; /* previous key command argument */
int last_colon_command; /* is a colon-prefixed key command */
char *shell_line; /* line to execute in subshell */
#ifdef HAVE_MAGIC
magic_t magic; /* libmagic database entries */
#endif
unsigned int
bad_stdout:1, /* true if overwriting does not turn off standout */
catch_suspend:1, /* we should catch the SIGTSTP signal */
@ -350,19 +357,24 @@ static void print_separator(const int c, int n)
putchar('\n');
}
/* magic --
* check for file magic numbers. This code would best be shared
* with the file(1) program or, perhaps, more should not try to be
* so smart. */
static int check_magic(FILE *f, char *fs)
/* check_magic -- check for file magic numbers. */
static int check_magic(struct more_control *ctl, char *fs)
{
#ifdef HAVE_MAGIC
const char *mime_encoding = magic_descriptor(ctl->magic, fileno(ctl->current_file));
if (!mime_encoding || !(strcmp("binary", mime_encoding))) {
printf(_("\n******** %s: Not a text file ********\n\n"), fs);
return 1;
}
#else
signed char twobytes[2];
/* don't try to look ahead if the input is unseekable */
if (fseek(f, 0L, SEEK_SET))
if (fseek(ctl->current_file, 0L, SEEK_SET))
return 0;
if (fread(twobytes, 2, 1, f) == 1) {
if (fread(twobytes, 2, 1, ctl->current_file) == 1) {
switch (twobytes[0] + (twobytes[1] << 8)) {
case 0407: /* a.out obj */
case 0410: /* a.out exec */
@ -376,7 +388,8 @@ static int check_magic(FILE *f, char *fs)
return 1;
}
}
fseek(f, 0L, SEEK_SET); /* rewind() not necessary */
fseek(ctl->current_file, 0L, SEEK_SET); /* rewind() not necessary */
#endif
return 0;
}
@ -394,23 +407,17 @@ static void checkf(struct more_control *ctl, char *fs)
(fstat(fileno(ctl->current_file), &st) != 0)) {
if (ctl->clear_line_ends)
putp(ctl->erase_line);
warn(_("stat of %s failed"), fs);
ctl->current_file = NULL;
warn(_("cannot open %s"), fs);
return;
}
#ifndef HAVE_MAGIC
if ((st.st_mode & S_IFMT) == S_IFDIR) {
printf(_("\n*** %s: directory ***\n\n"), fs);
ctl->current_file = NULL;
return;
}
ctl->current_line = 0;
ctl->file_position = 0;
if ((ctl->current_file = fopen(fs, "r")) == NULL) {
fflush(stdout);
warn(_("cannot open %s"), fs);
return;
}
if (check_magic(ctl->current_file, fs)) {
#endif
if (check_magic(ctl, fs)) {
fclose(ctl->current_file);
ctl->current_file = NULL;
return;
@ -704,6 +711,9 @@ static void reset_tty(struct more_control *ctl)
/* Clean up terminal state and exit. Also come here if interrupt signal received */
static void __attribute__((__noreturn__)) more_exit(struct more_control *ctl)
{
#ifdef HAVE_MAGIC
magic_close(ctl->magic);
#endif
reset_tty(ctl);
if (ctl->clear_line_ends) {
putchar('\r');
@ -1906,6 +1916,10 @@ int main(int argc, char **argv)
initterm(&ctl);
#ifdef HAVE_MAGIC
ctl.magic = magic_open(MAGIC_MIME_ENCODING | MAGIC_SYMLINK);
magic_load(ctl.magic, NULL);
#endif
prepare_line_buffer(&ctl);
ctl.d_scroll_len = ctl.lines_per_page / 2 - 1;