File: [local] / src / usr.bin / file / file.c (download)
Revision 1.33, Sun Apr 26 19:53:50 2015 UTC (9 years, 1 month ago) by nicm
Branch: MAIN
Changes since 1.32: +2 -2 lines
stat() the original link path not the resolved one which may be relative.
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/* $OpenBSD: file.c,v 1.33 2015/04/26 19:53:50 nicm Exp $ */
/*
* Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <errno.h>
#include <libgen.h>
#include <getopt.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdlib.h>
#include <unistd.h>
#include "file.h"
#include "magic.h"
#include "xmalloc.h"
struct input_file
{
struct magic *m;
const char *path;
const char *label;
int fd;
struct stat sb;
const char *error;
void *base;
size_t size;
int mapped;
char *result;
char link_path[PATH_MAX];
const char *link_error;
int link_target;
};
extern char *__progname;
__dead void usage(void);
static void prepare_file(struct input_file *, const char *, int *);
static void open_file(struct input_file *);
static void read_link(struct input_file *);
static void test_file(struct magic *, struct input_file *, int);
static int try_stat(struct input_file *);
static int try_empty(struct input_file *);
static int try_access(struct input_file *);
static int try_text(struct input_file *);
static int try_magic(struct input_file *);
static int try_unknown(struct input_file *);
static int bflag;
static int cflag;
static int iflag;
static int Lflag;
static int sflag;
static int Wflag;
static struct option longopts[] = {
{ "mime", no_argument, NULL, 'i' },
{ "mime-type", no_argument, NULL, 'i' },
{ NULL, 0, NULL, 0 }
};
__dead void
usage(void)
{
fprintf(stderr, "usage: %s [-bchiLsW] [file ...]\n", __progname);
exit(1);
}
int
main(int argc, char **argv)
{
struct input_file *files = NULL;
int opt, i, width = 0;
FILE *f;
struct magic *m;
char *home, *path;
struct passwd *pw;
for (;;) {
opt = getopt_long(argc, argv, "bchiLsW", longopts, NULL);
if (opt == -1)
break;
switch (opt) {
case 'b':
bflag = 1;
break;
case 'c':
cflag = 1;
break;
case 'h':
Lflag = 0;
break;
case 'i':
iflag = 1;
break;
case 'L':
Lflag = 1;
break;
case 's':
sflag = 1;
break;
case 'W':
Wflag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (cflag) {
if (argc != 0)
usage();
} else if (argc == 0)
usage();
f = NULL;
if (geteuid() != 0 && !issetugid()) {
home = getenv("HOME");
if (home == NULL || *home == '\0') {
pw = getpwuid(getuid());
if (pw != NULL)
home = pw->pw_dir;
else
home = NULL;
}
if (home != NULL) {
xasprintf(&path, "%s/.magic", home);
f = fopen(path, "r");
if (f == NULL && errno != ENOENT)
err(1, "%s", path);
if (f == NULL)
free(path);
}
}
if (f == NULL) {
path = xstrdup("/etc/magic");
f = fopen(path, "r");
}
if (f == NULL)
err(1, "%s", path);
m = magic_load(f, path, cflag || Wflag);
if (cflag) {
magic_dump(m);
exit(0);
}
files = xcalloc(argc, sizeof *files);
for (i = 0; i < argc; i++)
prepare_file(&files[i], argv[i], &width);
for (i = 0; i < argc; i++) {
open_file(&files[i]);
test_file(m, &files[i], width);
}
exit(0);
}
static void
prepare_file(struct input_file *inf, const char *path, int *width)
{
char *label;
int n;
inf->path = xstrdup(path);
n = xasprintf(&label, "%s:", inf->path);
if (n > *width)
*width = n;
inf->label = label;
}
static void
open_file(struct input_file *inf)
{
int retval;
retval = lstat(inf->path, &inf->sb);
if (retval == -1) {
inf->error = strerror(errno);
return;
}
if (S_ISLNK(inf->sb.st_mode))
read_link(inf);
inf->fd = open(inf->path, O_RDONLY|O_NONBLOCK);
}
static void
read_link(struct input_file *inf)
{
struct stat sb;
char path[PATH_MAX];
char *copy, *root;
int used;
ssize_t size;
size = readlink(inf->path, path, sizeof path);
if (size == -1) {
inf->link_error = strerror(errno);
return;
}
path[size] = '\0';
if (*path == '/')
strlcpy(inf->link_path, path, sizeof inf->link_path);
else {
copy = xstrdup(inf->path);
root = dirname(copy);
if (*root == '\0' || strcmp(root, ".") == 0 ||
strcmp (root, "/") == 0)
strlcpy(inf->link_path, path, sizeof inf->link_path);
else {
used = snprintf(inf->link_path, sizeof inf->link_path,
"%s/%s", root, path);
if (used < 0 || (size_t)used >= sizeof inf->link_path) {
inf->link_error = strerror(ENAMETOOLONG);
return;
}
}
free(copy);
}
if (Lflag) {
if (stat(inf->path, &inf->sb) == -1)
inf->error = strerror(errno);
} else {
if (stat(inf->path, &sb) == -1)
inf->link_target = errno;
}
}
static void *
fill_buffer(struct input_file *inf)
{
static void *buffer;
ssize_t got;
size_t left;
void *next;
if (buffer == NULL)
buffer = xmalloc(FILE_READ_SIZE);
next = buffer;
left = inf->size;
while (left != 0) {
got = read(inf->fd, next, left);
if (got == -1) {
if (errno == EINTR)
continue;
return NULL;
}
if (got == 0)
break;
next = (char *)next + got;
left -= got;
}
return buffer;
}
static int
load_file(struct input_file *inf)
{
int available;
inf->size = inf->sb.st_size;
if (inf->size > FILE_READ_SIZE)
inf->size = FILE_READ_SIZE;
if (S_ISFIFO(inf->sb.st_mode)) {
if (ioctl(inf->fd, FIONREAD, &available) == -1) {
xasprintf(&inf->result, "cannot read '%s' (%s)",
inf->path, strerror(errno));
return (1);
}
inf->size = available;
} else if (!S_ISREG(inf->sb.st_mode) && inf->size == 0)
inf->size = FILE_READ_SIZE;
if (inf->size == 0)
return (0);
inf->base = mmap(NULL, inf->size, PROT_READ, MAP_PRIVATE, inf->fd, 0);
if (inf->base == MAP_FAILED) {
inf->base = fill_buffer(inf);
if (inf->base == NULL) {
xasprintf(&inf->result, "cannot read '%s' (%s)",
inf->path, strerror(errno));
return (1);
}
} else
inf->mapped = 1;
return (0);
}
static int
try_stat(struct input_file *inf)
{
if (inf->error != NULL) {
xasprintf(&inf->result, "cannot stat '%s' (%s)", inf->path,
inf->error);
return (1);
}
if (sflag) {
switch (inf->sb.st_mode & S_IFMT) {
case S_IFBLK:
case S_IFCHR:
case S_IFIFO:
case S_IFREG:
return (0);
}
}
if (iflag && (inf->sb.st_mode & S_IFMT) != S_IFREG) {
xasprintf(&inf->result, "application/x-not-regular-file");
return (1);
}
switch (inf->sb.st_mode & S_IFMT) {
case S_IFDIR:
xasprintf(&inf->result, "directory");
return (1);
case S_IFLNK:
if (inf->link_error != NULL) {
xasprintf(&inf->result, "unreadable symlink '%s' (%s)",
inf->path, inf->link_error);
return (1);
}
if (inf->link_target == ELOOP)
xasprintf(&inf->result, "symbolic link in a loop");
else if (inf->link_target != 0) {
xasprintf(&inf->result, "broken symbolic link to '%s'",
inf->link_path);
} else {
xasprintf(&inf->result, "symbolic link to '%s'",
inf->link_path);
}
return (1);
case S_IFSOCK:
xasprintf(&inf->result, "socket");
return (1);
case S_IFBLK:
xasprintf(&inf->result, "block special (%ld/%ld)",
(long)major(inf->sb.st_rdev), (long)minor(inf->sb.st_rdev));
return (1);
case S_IFCHR:
xasprintf(&inf->result, "character special (%ld/%ld)",
(long)major(inf->sb.st_rdev), (long)minor(inf->sb.st_rdev));
return (1);
case S_IFIFO:
xasprintf(&inf->result, "fifo (named pipe)");
return (1);
}
return (0);
}
static int
try_empty(struct input_file *inf)
{
if (inf->size != 0)
return (0);
if (iflag)
xasprintf(&inf->result, "application/x-empty");
else
xasprintf(&inf->result, "empty");
return (1);
}
static int
try_access(struct input_file *inf)
{
char tmp[256] = "";
if (inf->fd != -1)
return (0);
if (inf->sb.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH))
strlcat(tmp, "writable, ", sizeof tmp);
if (inf->sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))
strlcat(tmp, "executable, ", sizeof tmp);
if (S_ISREG(inf->sb.st_mode))
strlcat(tmp, "regular file, ", sizeof tmp);
strlcat(tmp, "no read permission", sizeof tmp);
inf->result = xstrdup(tmp);
return (1);
}
static int
try_text(struct input_file *inf)
{
const char *type, *s;
int flags;
flags = MAGIC_TEST_TEXT;
if (iflag)
flags |= MAGIC_TEST_MIME;
type = text_get_type(inf->base, inf->size);
if (type == NULL)
return (0);
s = magic_test(inf->m, inf->base, inf->size, flags);
if (s != NULL) {
inf->result = xstrdup(s);
return (1);
}
s = text_try_words(inf->base, inf->size, flags);
if (s != NULL) {
if (iflag)
inf->result = xstrdup(s);
else
xasprintf(&inf->result, "%s %s text", type, s);
return (1);
}
if (iflag)
inf->result = xstrdup("text/plain");
else
xasprintf(&inf->result, "%s text", type);
return (1);
}
static int
try_magic(struct input_file *inf)
{
const char *s;
int flags;
flags = 0;
if (iflag)
flags |= MAGIC_TEST_MIME;
s = magic_test(inf->m, inf->base, inf->size, flags);
if (s != NULL) {
inf->result = xstrdup(s);
return (1);
}
return (0);
}
static int
try_unknown(struct input_file *inf)
{
if (iflag)
xasprintf(&inf->result, "application/x-not-regular-file");
else
xasprintf(&inf->result, "data");
return (1);
}
static void
test_file(struct magic *m, struct input_file *inf, int width)
{
int stop;
inf->m = m;
stop = 0;
if (!stop)
stop = try_stat(inf);
if (!stop)
stop = try_access(inf);
if (!stop)
stop = load_file(inf);
if (!stop)
stop = try_empty(inf);
if (!stop)
stop = try_magic(inf);
if (!stop)
stop = try_text(inf);
if (!stop)
stop = try_unknown(inf);
if (bflag)
printf("%s\n", inf->result);
else
printf("%-*s %s\n", width, inf->label, inf->result);
free(inf->result);
if (inf->mapped && inf->base != NULL)
munmap(inf->base, inf->size);
inf->base = NULL;
if (inf->fd != -1)
close(inf->fd);
free((void *)inf->label);
free((void *)inf->path);
}