busybox/coreutils/dd.c
Denis Vlasenko 99912ca733 audit small applets and mark some of them as NOFORK.
Put big scary warnings in relevant places.
2007-04-10 15:43:37 +00:00

309 lines
6.9 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini dd implementation for busybox
*
*
* Copyright (C) 2000,2001 Matt Kraai
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <signal.h> /* For FEATURE_DD_SIGNAL_HANDLING */
#include "busybox.h"
/* This is a NOEXEC applet. Be very careful! */
static const struct suffix_mult dd_suffixes[] = {
{ "c", 1 },
{ "w", 2 },
{ "b", 512 },
{ "kD", 1000 },
{ "k", 1024 },
{ "K", 1024 }, /* compat with coreutils dd */
{ "MD", 1000000 },
{ "M", 1048576 },
{ "GD", 1000000000 },
{ "G", 1073741824 },
{ NULL, 0 }
};
struct globals {
off_t out_full, out_part, in_full, in_part;
};
#define G (*(struct globals*)&bb_common_bufsiz1)
static void dd_output_status(int ATTRIBUTE_UNUSED cur_signal)
{
fprintf(stderr, "%"OFF_FMT"d+%"OFF_FMT"d records in\n"
"%"OFF_FMT"d+%"OFF_FMT"d records out\n",
G.in_full, G.in_part,
G.out_full, G.out_part);
}
static ssize_t full_write_or_warn(int fd, const void *buf, size_t len,
const char * const filename)
{
ssize_t n = full_write(fd, buf, len);
if (n < 0)
bb_perror_msg("writing '%s'", filename);
return n;
}
static bool write_and_stats(int fd, const void *buf, size_t len, size_t obs,
const char * const filename)
{
ssize_t n = full_write_or_warn(fd, buf, len, filename);
if (n < 0)
return 1;
if (n == obs)
G.out_full++;
else if (n > 0)
G.out_part++;
return 0;
}
#if ENABLE_LFS
#define XATOU_SFX xatoull_sfx
#else
#define XATOU_SFX xatoul_sfx
#endif
int dd_main(int argc, char **argv);
int dd_main(int argc, char **argv)
{
enum {
sync_flag = 1 << 0,
noerror = 1 << 1,
trunc_flag = 1 << 2,
twobufs_flag = 1 << 3,
};
static const char * const keywords[] = {
"bs=", "count=", "seek=", "skip=", "if=", "of=",
#if ENABLE_FEATURE_DD_IBS_OBS
"ibs=", "obs=", "conv=", "notrunc", "sync", "noerror",
#endif
NULL
};
#define OP_bs 0 + 1
#define OP_count OP_bs + 1
#define OP_seek OP_count + 1
#define OP_skip OP_seek + 1
#define OP_if OP_skip + 1
#define OP_of OP_if + 1
#define OP_ibs OP_of + ENABLE_FEATURE_DD_IBS_OBS
#define OP_obs OP_ibs + ENABLE_FEATURE_DD_IBS_OBS
#define OP_conv OP_obs + ENABLE_FEATURE_DD_IBS_OBS
#define OP_conv_notrunc OP_conv + ENABLE_FEATURE_DD_IBS_OBS
#define OP_conv_sync OP_conv_notrunc + ENABLE_FEATURE_DD_IBS_OBS
#define OP_conv_noerror OP_conv_sync + ENABLE_FEATURE_DD_IBS_OBS
int flags = trunc_flag;
size_t oc = 0, ibs = 512, obs = 512;
ssize_t n, w;
off_t seek = 0, skip = 0, count = OFF_T_MAX;
int ifd, ofd;
const char *infile = NULL, *outfile = NULL;
char *ibuf, *obuf;
if (ENABLE_FEATURE_DD_SIGNAL_HANDLING) {
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = dd_output_status;
sa.sa_flags = SA_RESTART;
sigemptyset(&sa.sa_mask);
sigaction(SIGUSR1, &sa, 0);
}
for (n = 1; n < argc; n++) {
smalluint key_len, what;
char *key;
char *arg = argv[n];
//XXX:FIXME: we reject plain "dd --" This would cost ~20 bytes, so..
//if (*arg == '-' && *++arg == '-' && !*++arg) continue;
key = strstr(arg, "=");
if (key == NULL)
bb_show_usage();
key_len = key - arg + 1;
key = xstrndup(arg, key_len);
what = index_in_str_array(keywords, key) + 1;
if (ENABLE_FEATURE_CLEAN_UP)
free(key);
if (what == 0)
bb_show_usage();
arg += key_len;
/* Must fit into positive ssize_t */
if (ENABLE_FEATURE_DD_IBS_OBS) {
if (what == OP_ibs) {
ibs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
if (what == OP_obs) {
obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
if (what == OP_conv) {
while (1) {
/* find ',', replace them with nil so we can use arg for
* index_in_str_array without copying.
* We rely on arg being non-null, else strstr would fault.
*/
key = strstr(arg, ",");
if (key)
*key = '\0';
what = index_in_str_array(keywords, arg) + 1;
if (what < OP_conv_notrunc)
bb_error_msg_and_die(bb_msg_invalid_arg, arg, "conv");
if (what == OP_conv_notrunc)
flags &= ~trunc_flag;
if (what == OP_conv_sync)
flags |= sync_flag;
if (what == OP_conv_noerror)
flags |= noerror;
if (!key) /* no ',' left, so this was the last specifier */
break;
arg += key - arg + 1; /* skip this keyword plus ',' */
}
continue;
}
}
if (what == OP_bs) {
ibs = obs = xatoul_range_sfx(arg, 1, ((size_t)-1L)/2, dd_suffixes);
continue;
}
/* These can be large: */
if (what == OP_count) {
count = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == OP_seek) {
seek = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == skip) {
skip = XATOU_SFX(arg, dd_suffixes);
continue;
}
if (what == OP_if) {
infile = arg;
continue;
}
if (what == OP_of)
outfile = arg;
}
//XXX:FIXME for huge ibs or obs, malloc'ing them isn't the brightest idea ever
ibuf = obuf = xmalloc(ibs);
if (ibs != obs) {
flags |= twobufs_flag;
obuf = xmalloc(obs);
}
if (infile != NULL)
ifd = xopen(infile, O_RDONLY);
else {
ifd = STDIN_FILENO;
infile = bb_msg_standard_input;
}
if (outfile != NULL) {
int oflag = O_WRONLY | O_CREAT;
if (!seek && (flags & trunc_flag))
oflag |= O_TRUNC;
ofd = xopen(outfile, oflag);
if (seek && (flags & trunc_flag)) {
if (ftruncate(ofd, seek * obs) < 0) {
struct stat st;
if (fstat(ofd, &st) < 0 || S_ISREG(st.st_mode) ||
S_ISDIR(st.st_mode))
goto die_outfile;
}
}
} else {
ofd = STDOUT_FILENO;
outfile = bb_msg_standard_output;
}
if (skip) {
if (lseek(ifd, skip * ibs, SEEK_CUR) < 0) {
while (skip-- > 0) {
n = safe_read(ifd, ibuf, ibs);
if (n < 0)
goto die_infile;
if (n == 0)
break;
}
}
}
if (seek) {
if (lseek(ofd, seek * obs, SEEK_CUR) < 0)
goto die_outfile;
}
while (G.in_full + G.in_part != count) {
if (flags & noerror) /* Pre-zero the buffer when for noerror */
memset(ibuf, '\0', ibs);
n = safe_read(ifd, ibuf, ibs);
if (n == 0)
break;
if (n < 0) {
if (flags & noerror) {
n = ibs;
bb_perror_msg("%s", infile);
} else
goto die_infile;
}
if ((size_t)n == ibs)
G.in_full++;
else {
G.in_part++;
if (flags & sync_flag) {
memset(ibuf + n, '\0', ibs - n);
n = ibs;
}
}
if (flags & twobufs_flag) {
char *tmp = ibuf;
while (n) {
size_t d = obs - oc;
if (d > n)
d = n;
memcpy(obuf + oc, tmp, d);
n -= d;
tmp += d;
oc += d;
if (oc == obs) {
if (write_and_stats(ofd, obuf, obs, obs, outfile))
goto out_status;
oc = 0;
}
}
} else
if (write_and_stats(ofd, ibuf, n, obs, outfile))
goto out_status;
}
if (ENABLE_FEATURE_DD_IBS_OBS && oc) {
w = full_write_or_warn(ofd, obuf, oc, outfile);
if (w < 0) goto out_status;
if (w > 0)
G.out_part++;
}
if (close(ifd) < 0) {
die_infile:
bb_perror_msg_and_die("%s", infile);
}
if (close(ofd) < 0) {
die_outfile:
bb_perror_msg_and_die("%s", outfile);
}
out_status:
dd_output_status(0);
return EXIT_SUCCESS;
}