busybox/editors/diff.c
James Byrne 6937487be7 libbb: reduce the overhead of single parameter bb_error_msg() calls
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().

This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.

Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.

This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.

The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):

Arm:     -92 bytes
MIPS:    -52 bytes
PPC:   -1836 bytes
x86_64: -938 bytes

Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.

Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 11:35:03 +02:00

1059 lines
30 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini diff implementation for busybox, adapted from OpenBSD diff.
*
* Copyright (C) 2010 by Matheus Izvekov <mizvekov@gmail.com>
* Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com>
* Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/*
* The following code uses an algorithm due to Harold Stone,
* which finds a pair of longest identical subsequences in
* the two files.
*
* The major goal is to generate the match vector J.
* J[i] is the index of the line in file1 corresponding
* to line i in file0. J[i] = 0 if there is no
* such line in file1.
*
* Lines are hashed so as to work in core. All potential
* matches are located by sorting the lines of each file
* on the hash (called "value"). In particular, this
* collects the equivalence classes in file1 together.
* Subroutine equiv replaces the value of each line in
* file0 by the index of the first element of its
* matching equivalence in (the reordered) file1.
* To save space equiv squeezes file1 into a single
* array member in which the equivalence classes
* are simply concatenated, except that their first
* members are flagged by changing sign.
*
* Next the indices that point into member are unsorted into
* array class according to the original order of file0.
*
* The cleverness lies in routine stone. This marches
* through the lines of file0, developing a vector klist
* of "k-candidates". At step i a k-candidate is a matched
* pair of lines x,y (x in file0, y in file1) such that
* there is a common subsequence of length k
* between the first i lines of file0 and the first y
* lines of file1, but there is no such subsequence for
* any smaller y. x is the earliest possible mate to y
* that occurs in such a subsequence.
*
* Whenever any of the members of the equivalence class of
* lines in file1 matable to a line in file0 has serial number
* less than the y of some k-candidate, that k-candidate
* with the smallest such y is replaced. The new
* k-candidate is chained (via pred) to the current
* k-1 candidate so that the actual subsequence can
* be recovered. When a member has serial number greater
* that the y of all k-candidates, the klist is extended.
* At the end, the longest subsequence is pulled out
* and placed in the array J by unravel
*
* With J in hand, the matches there recorded are
* checked against reality to assure that no spurious
* matches have crept in due to hashing. If they have,
* they are broken, and "jackpot" is recorded--a harmless
* matter except that a true match for a spuriously
* mated line may now be unnecessarily reported as a change.
*
* Much of the complexity of the program comes simply
* from trying to minimize core utilization and
* maximize the range of doable problems by dynamically
* allocating what is needed and reusing what is not.
* The core requirements for problems larger than somewhat
* are (in words) 2*length(file0) + length(file1) +
* 3*(number of k-candidates installed), typically about
* 6n words for files of length n.
*/
//config:config DIFF
//config: bool "diff (13 kb)"
//config: default y
//config: help
//config: diff compares two files or directories and outputs the
//config: differences between them in a form that can be given to
//config: the patch command.
//config:
//config:config FEATURE_DIFF_LONG_OPTIONS
//config: bool "Enable long options"
//config: default y
//config: depends on DIFF && LONG_OPTS
//config:
//config:config FEATURE_DIFF_DIR
//config: bool "Enable directory support"
//config: default y
//config: depends on DIFF
//config: help
//config: This option enables support for directory and subdirectory
//config: comparison.
//applet:IF_DIFF(APPLET(diff, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_DIFF) += diff.o
//usage:#define diff_trivial_usage
//usage: "[-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"
//usage:#define diff_full_usage "\n\n"
//usage: "Compare files line by line and output the differences between them.\n"
//usage: "This implementation supports unified diffs only.\n"
//usage: "\n -a Treat all files as text"
//usage: "\n -b Ignore changes in the amount of whitespace"
//usage: "\n -B Ignore changes whose lines are all blank"
//usage: "\n -d Try hard to find a smaller set of changes"
//usage: "\n -i Ignore case differences"
//usage: "\n -L Use LABEL instead of the filename in the unified header"
//usage: "\n -N Treat absent files as empty"
//usage: "\n -q Output only whether files differ"
//usage: "\n -r Recurse"
//usage: "\n -S Start with FILE when comparing directories"
//usage: "\n -T Make tabs line up by prefixing a tab when necessary"
//usage: "\n -s Report when two files are the same"
//usage: "\n -t Expand tabs to spaces in output"
//usage: "\n -U Output LINES lines of context"
//usage: "\n -w Ignore all whitespace"
#include "libbb.h"
#include "common_bufsiz.h"
#if 0
# define dbg_error_msg(...) bb_error_msg(__VA_ARGS__)
#else
# define dbg_error_msg(...) ((void)0)
#endif
enum { /* print_status() and diffreg() return values */
STATUS_SAME, /* files are the same */
STATUS_DIFFER, /* files differ */
STATUS_BINARY, /* binary files differ */
};
enum { /* Commandline flags */
FLAG_a,
FLAG_b,
FLAG_d,
FLAG_i,
FLAG_L, /* never used, handled by getopt32 */
FLAG_N,
FLAG_q,
FLAG_r,
FLAG_s,
FLAG_S, /* never used, handled by getopt32 */
FLAG_t,
FLAG_T,
FLAG_U, /* never used, handled by getopt32 */
FLAG_w,
FLAG_u, /* ignored, this is the default */
FLAG_p, /* not implemented */
FLAG_B,
FLAG_E, /* not implemented */
};
#define FLAG(x) (1 << FLAG_##x)
/* We cache file position to avoid excessive seeking */
typedef struct FILE_and_pos_t {
FILE *ft_fp;
off_t ft_pos;
} FILE_and_pos_t;
struct globals {
smallint exit_status;
int opt_U_context;
const char *other_dir;
char *label[2];
struct stat stb[2];
};
#define G (*ptr_to_globals)
#define exit_status (G.exit_status )
#define opt_U_context (G.opt_U_context )
#define label (G.label )
#define stb (G.stb )
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
opt_U_context = 3; \
} while (0)
typedef int token_t;
enum {
/* Public */
TOK_EMPTY = 1 << 9, /* Line fully processed, you can proceed to the next */
TOK_EOF = 1 << 10, /* File ended */
/* Private (Only to be used by read_token() */
TOK_EOL = 1 << 11, /* we saw EOL (sticky) */
TOK_SPACE = 1 << 12, /* used -b code, means we are skipping spaces */
SHIFT_EOF = (sizeof(token_t)*8 - 8) - 1,
CHAR_MASK = 0x1ff, /* 8th bit is used to distinguish EOF from 0xff */
};
/* Restores full EOF from one 8th bit: */
//#define TOK2CHAR(t) (((t) << SHIFT_EOF) >> SHIFT_EOF)
/* We don't really need the above, we only need to have EOF != any_real_char: */
#define TOK2CHAR(t) ((t) & CHAR_MASK)
static void seek_ft(FILE_and_pos_t *ft, off_t pos)
{
if (ft->ft_pos != pos) {
ft->ft_pos = pos;
fseeko(ft->ft_fp, pos, SEEK_SET);
}
}
/* Reads tokens from given fp, handling -b and -w flags
* The user must reset tok every line start
*/
static int read_token(FILE_and_pos_t *ft, token_t tok)
{
tok |= TOK_EMPTY;
while (!(tok & TOK_EOL)) {
bool is_space;
int t;
t = fgetc(ft->ft_fp);
if (t != EOF)
ft->ft_pos++;
is_space = (t == EOF || isspace(t));
/* If t == EOF (-1), set both TOK_EOF and TOK_EOL */
tok |= (t & (TOK_EOF + TOK_EOL));
/* Only EOL? */
if (t == '\n')
tok |= TOK_EOL;
if (option_mask32 & FLAG(i)) /* Handcoded tolower() */
t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t;
if ((option_mask32 & FLAG(w)) && is_space)
continue;
/* Trim char value to low 9 bits */
t &= CHAR_MASK;
if (option_mask32 & FLAG(b)) {
/* Was prev char whitespace? */
if (tok & TOK_SPACE) { /* yes */
if (is_space) /* this one too, ignore it */
continue;
tok &= ~TOK_SPACE;
} else if (is_space) {
/* 1st whitespace char.
* Set TOK_SPACE and replace char by ' ' */
t = TOK_SPACE + ' ';
}
}
/* Clear EMPTY */
tok &= ~(TOK_EMPTY + CHAR_MASK);
/* Assign char value (low 9 bits) and maybe set TOK_SPACE */
tok |= t;
break;
}
#if 0
bb_error_msg("fp:%p tok:%x '%c'%s%s%s%s", fp, tok, tok & 0xff
, tok & TOK_EOF ? " EOF" : ""
, tok & TOK_EOL ? " EOL" : ""
, tok & TOK_EMPTY ? " EMPTY" : ""
, tok & TOK_SPACE ? " SPACE" : ""
);
#endif
return tok;
}
struct cand {
int x;
int y;
int pred;
};
static int search(const int *c, int k, int y, const struct cand *list)
{
int i, j;
if (list[c[k]].y < y) /* quick look for typical case */
return k + 1;
for (i = 0, j = k + 1;;) {
const int l = (i + j) >> 1;
if (l > i) {
const int t = list[c[l]].y;
if (t > y)
j = l;
else if (t < y)
i = l;
else
return l;
} else
return l + 1;
}
}
static void stone(const int *a, int n, const int *b, int *J, int pref)
{
const unsigned isq = isqrt(n);
const unsigned bound =
(option_mask32 & FLAG(d)) ? UINT_MAX : MAX(256, isq);
int clen = 1;
int clistlen = 100;
int k = 0;
struct cand *clist = xzalloc(clistlen * sizeof(clist[0]));
struct cand cand;
struct cand *q;
int *klist = xzalloc((n + 2) * sizeof(klist[0]));
/*clist[0] = (struct cand){0}; - xzalloc did it */
/*klist[0] = 0; */
for (cand.x = 1; cand.x <= n; cand.x++) {
int j = a[cand.x], oldl = 0;
unsigned numtries = 0;
if (j == 0)
continue;
cand.y = -b[j];
cand.pred = klist[0];
do {
int l, tc;
if (cand.y <= clist[cand.pred].y)
continue;
l = search(klist, k, cand.y, clist);
if (l != oldl + 1)
cand.pred = klist[l - 1];
if (l <= k && clist[klist[l]].y <= cand.y)
continue;
if (clen == clistlen) {
clistlen = clistlen * 11 / 10;
clist = xrealloc(clist, clistlen * sizeof(clist[0]));
}
clist[clen] = cand;
tc = klist[l];
klist[l] = clen++;
if (l <= k) {
cand.pred = tc;
oldl = l;
numtries++;
} else {
k++;
break;
}
} while ((cand.y = b[++j]) > 0 && numtries < bound);
}
/* Unravel */
for (q = clist + klist[k]; q->y; q = clist + q->pred)
J[q->x + pref] = q->y + pref;
free(klist);
free(clist);
}
struct line {
/* 'serial' is not used in the beginning, so we reuse it
* to store line offsets, thus reducing memory pressure
*/
union {
unsigned serial;
off_t offset;
};
unsigned value;
};
static void equiv(struct line *a, int n, struct line *b, int m, int *c)
{
int i = 1, j = 1;
while (i <= n && j <= m) {
if (a[i].value < b[j].value)
a[i++].value = 0;
else if (a[i].value == b[j].value)
a[i++].value = j;
else
j++;
}
while (i <= n)
a[i++].value = 0;
b[m + 1].value = 0;
j = 0;
while (++j <= m) {
c[j] = -b[j].serial;
while (b[j + 1].value == b[j].value) {
j++;
c[j] = b[j].serial;
}
}
c[j] = -1;
}
static void unsort(const struct line *f, int l, int *b)
{
int i;
int *a = xmalloc((l + 1) * sizeof(a[0]));
for (i = 1; i <= l; i++)
a[f[i].serial] = f[i].value;
for (i = 1; i <= l; i++)
b[i] = a[i];
free(a);
}
static int line_compar(const void *a, const void *b)
{
#define l0 ((const struct line*)a)
#define l1 ((const struct line*)b)
int r = l0->value - l1->value;
if (r)
return r;
return l0->serial - l1->serial;
#undef l0
#undef l1
}
static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch)
{
int i, j, col;
for (i = a; i <= b; i++) {
seek_ft(ft, ix[i - 1]);
putchar(ch);
if (option_mask32 & FLAG(T))
putchar('\t');
for (j = 0, col = 0; j < ix[i] - ix[i - 1]; j++) {
int c = fgetc(ft->ft_fp);
if (c == EOF) {
puts("\n\\ No newline at end of file");
return;
}
ft->ft_pos++;
if (c == '\t' && (option_mask32 & FLAG(t)))
do putchar(' '); while (++col & 7);
else {
putchar(c);
col++;
}
}
}
}
/* Creates the match vector J, where J[i] is the index
* of the line in the new file corresponding to the line i
* in the old file. Lines start at 1 instead of 0, that value
* being used instead to denote no corresponding line.
* This vector is dynamically allocated and must be freed by the caller.
*
* * fp is an input parameter, where fp[0] and fp[1] are the open
* old file and new file respectively.
* * nlen is an output variable, where nlen[0] and nlen[1]
* gets the number of lines in the old and new file respectively.
* * ix is an output variable, where ix[0] and ix[1] gets
* assigned dynamically allocated vectors of the offsets of the lines
* of the old and new file respectively. These must be freed by the caller.
*/
static NOINLINE int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2])
{
int *J, slen[2], *class, *member;
struct line *nfile[2], *sfile[2];
int pref = 0, suff = 0, i, j, delta;
/* Lines of both files are hashed, and in the process
* their offsets are stored in the array ix[fileno]
* where fileno == 0 points to the old file, and
* fileno == 1 points to the new one.
*/
for (i = 0; i < 2; i++) {
unsigned hash;
token_t tok;
size_t sz = 100;
nfile[i] = xmalloc((sz + 3) * sizeof(nfile[i][0]));
/* ft gets here without the correct position, cant use seek_ft */
ft[i].ft_pos = 0;
fseeko(ft[i].ft_fp, 0, SEEK_SET);
nlen[i] = 0;
/* We could zalloc nfile, but then zalloc starts showing in gprof at ~1% */
nfile[i][0].offset = 0;
goto start; /* saves code */
while (1) {
tok = read_token(&ft[i], tok);
if (!(tok & TOK_EMPTY)) {
/* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */
/*hash = hash * 128 - hash + TOK2CHAR(tok);
* gcc insists on optimizing above to "hash * 127 + ...", thus... */
unsigned o = hash - TOK2CHAR(tok);
hash = hash * 128 - o; /* we want SPEED here */
continue;
}
if (nlen[i]++ == sz) {
sz = sz * 3 / 2;
nfile[i] = xrealloc(nfile[i], (sz + 3) * sizeof(nfile[i][0]));
}
/* line_compar needs hashes fit into positive int */
nfile[i][nlen[i]].value = hash & INT_MAX;
/* like ftello(ft[i].ft_fp) but faster (avoids lseek syscall) */
nfile[i][nlen[i]].offset = ft[i].ft_pos;
if (tok & TOK_EOF) {
/* EOF counts as a token, so we have to adjust it here */
nfile[i][nlen[i]].offset++;
break;
}
start:
hash = tok = 0;
}
/* Exclude lone EOF line from the end of the file, to make fetch()'s job easier */
if (nfile[i][nlen[i]].offset - nfile[i][nlen[i] - 1].offset == 1)
nlen[i]--;
/* Now we copy the line offsets into ix */
ix[i] = xmalloc((nlen[i] + 2) * sizeof(ix[i][0]));
for (j = 0; j < nlen[i] + 1; j++)
ix[i][j] = nfile[i][j].offset;
}
/* length of prefix and suffix is calculated */
for (; pref < nlen[0] && pref < nlen[1] &&
nfile[0][pref + 1].value == nfile[1][pref + 1].value;
pref++);
for (; suff < nlen[0] - pref && suff < nlen[1] - pref &&
nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value;
suff++);
/* Arrays are pruned by the suffix and prefix length,
* the result being sorted and stored in sfile[fileno],
* and their sizes are stored in slen[fileno]
*/
for (j = 0; j < 2; j++) {
sfile[j] = nfile[j] + pref;
slen[j] = nlen[j] - pref - suff;
for (i = 0; i <= slen[j]; i++)
sfile[j][i].serial = i;
qsort(sfile[j] + 1, slen[j], sizeof(*sfile[j]), line_compar);
}
/* nfile arrays are reused to reduce memory pressure
* The #if zeroed out section performs the same task as the
* one in the #else section.
* Peak memory usage is higher, but one array copy is avoided
* by not using unsort()
*/
#if 0
member = xmalloc((slen[1] + 2) * sizeof(member[0]));
equiv(sfile[0], slen[0], sfile[1], slen[1], member);
free(nfile[1]);
class = xmalloc((slen[0] + 1) * sizeof(class[0]));
for (i = 1; i <= slen[0]; i++) /* Unsorting */
class[sfile[0][i].serial] = sfile[0][i].value;
free(nfile[0]);
#else
member = (int *)nfile[1];
equiv(sfile[0], slen[0], sfile[1], slen[1], member);
member = xrealloc(member, (slen[1] + 2) * sizeof(member[0]));
class = (int *)nfile[0];
unsort(sfile[0], slen[0], (int *)nfile[0]);
class = xrealloc(class, (slen[0] + 2) * sizeof(class[0]));
#endif
J = xmalloc((nlen[0] + 2) * sizeof(J[0]));
/* The elements of J which fall inside the prefix and suffix regions
* are marked as unchanged, while the ones which fall outside
* are initialized with 0 (no matches), so that function stone can
* then assign them their right values
*/
for (i = 0, delta = nlen[1] - nlen[0]; i <= nlen[0]; i++)
J[i] = i <= pref ? i :
i > (nlen[0] - suff) ? (i + delta) : 0;
/* Here the magic is performed */
stone(class, slen[0], member, J, pref);
J[nlen[0] + 1] = nlen[1] + 1;
free(class);
free(member);
/* Both files are rescanned, in an effort to find any lines
* which, due to limitations intrinsic to any hashing algorithm,
* are different but ended up confounded as the same
*/
for (i = 1; i <= nlen[0]; i++) {
if (!J[i])
continue;
seek_ft(&ft[0], ix[0][i - 1]);
seek_ft(&ft[1], ix[1][J[i] - 1]);
for (j = J[i]; i <= nlen[0] && J[i] == j; i++, j++) {
token_t tok0 = 0, tok1 = 0;
do {
tok0 = read_token(&ft[0], tok0);
tok1 = read_token(&ft[1], tok1);
if (((tok0 ^ tok1) & TOK_EMPTY) != 0 /* one is empty (not both) */
|| (!(tok0 & TOK_EMPTY) && TOK2CHAR(tok0) != TOK2CHAR(tok1))
) {
J[i] = 0; /* Break the correspondence */
}
} while (!(tok0 & tok1 & TOK_EMPTY));
}
}
return J;
}
static bool diff(FILE* fp[2], char *file[2])
{
int nlen[2];
off_t *ix[2];
FILE_and_pos_t ft[2];
typedef struct { int a, b; } vec_t[2];
vec_t *vec = NULL;
int i = 1, j, k, idx = -1;
bool anychange = false;
int *J;
ft[0].ft_fp = fp[0];
ft[1].ft_fp = fp[1];
/* note that ft[i].ft_pos is unintitalized, create_J()
* must not assume otherwise */
J = create_J(ft, nlen, ix);
do {
bool nonempty = false;
while (1) {
vec_t v;
for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++)
continue;
v[1].a = J[v[0].a - 1] + 1;
for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++)
continue;
v[1].b = J[v[0].b + 1] - 1;
/*
* Indicate that there is a difference between lines a and b of the 'from' file
* to get to lines c to d of the 'to' file. If a is greater than b then there
* are no lines in the 'from' file involved and this means that there were
* lines appended (beginning at b). If c is greater than d then there are
* lines missing from the 'to' file.
*/
if (v[0].a <= v[0].b || v[1].a <= v[1].b) {
/*
* If this change is more than 'context' lines from the
* previous change, dump the record and reset it.
*/
int ct = (2 * opt_U_context) + 1;
if (idx >= 0
&& v[0].a > vec[idx][0].b + ct
&& v[1].a > vec[idx][1].b + ct
) {
break;
}
for (j = 0; j < 2; j++)
for (k = v[j].a; k <= v[j].b; k++)
nonempty |= (ix[j][k] - ix[j][k - 1] != 1);
vec = xrealloc_vector(vec, 6, ++idx);
memcpy(vec[idx], v, sizeof(v));
}
i = v[0].b + 1;
if (i > nlen[0])
break;
J[v[0].b] = v[1].b;
}
if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty))
goto cont;
if (!(option_mask32 & FLAG(q))) {
int lowa;
vec_t span, *cvp = vec;
if (!anychange) {
/* Print the context/unidiff header first time through */
printf("--- %s\n", label[0] ? label[0] : file[0]);
printf("+++ %s\n", label[1] ? label[1] : file[1]);
}
printf("@@");
for (j = 0; j < 2; j++) {
int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context);
int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context);
printf(" %c%d", j ? '+' : '-', MIN(a, b));
if (a == b)
continue;
printf(",%d", (a < b) ? b - a + 1 : 0);
}
puts(" @@");
/*
* Output changes in "unified" diff format--the old and new lines
* are printed together.
*/
for (lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) {
bool end = cvp > &vec[idx];
fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' ');
if (end)
break;
for (j = 0; j < 2; j++)
fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-');
}
}
anychange = true;
cont:
idx = -1;
} while (i <= nlen[0]);
free(vec);
free(ix[0]);
free(ix[1]);
free(J);
return anychange;
}
static int diffreg(char *file[2])
{
FILE *fp[2];
bool binary = false, differ = false;
int status = STATUS_SAME, i;
fp[0] = stdin;
fp[1] = stdin;
for (i = 0; i < 2; i++) {
int fd = STDIN_FILENO;
if (!LONE_DASH(file[i])) {
if (!(option_mask32 & FLAG(N))) {
fd = open_or_warn(file[i], O_RDONLY);
if (fd == -1)
goto out;
} else {
/* -N: if some file does not exist compare it like empty */
fd = open(file[i], O_RDONLY);
if (fd == -1)
fd = xopen("/dev/null", O_RDONLY);
}
}
/* Our diff implementation is using seek.
* When we meet non-seekable file, we must make a temp copy.
*/
if (lseek(fd, 0, SEEK_SET) == -1 && errno == ESPIPE) {
char name[] = "/tmp/difXXXXXX";
int fd_tmp = xmkstemp(name);
unlink(name);
if (bb_copyfd_eof(fd, fd_tmp) < 0)
xfunc_die();
if (fd != STDIN_FILENO)
close(fd);
fd = fd_tmp;
xlseek(fd, 0, SEEK_SET);
}
fp[i] = fdopen(fd, "r");
}
setup_common_bufsiz();
while (1) {
const size_t sz = COMMON_BUFSIZE / 2;
char *const buf0 = bb_common_bufsiz1;
char *const buf1 = buf0 + sz;
int j, k;
i = fread(buf0, 1, sz, fp[0]);
j = fread(buf1, 1, sz, fp[1]);
if (i != j) {
differ = true;
i = MIN(i, j);
}
if (i == 0)
break;
for (k = 0; k < i; k++) {
if (!buf0[k] || !buf1[k])
binary = true;
if (buf0[k] != buf1[k])
differ = true;
}
}
if (differ) {
if (binary && !(option_mask32 & FLAG(a)))
status = STATUS_BINARY;
else if (diff(fp, file))
status = STATUS_DIFFER;
}
if (status != STATUS_SAME)
exit_status |= 1;
out:
fclose_if_not_stdin(fp[0]);
fclose_if_not_stdin(fp[1]);
return status;
}
static void print_status(int status, char *path[2])
{
switch (status) {
case STATUS_BINARY:
case STATUS_DIFFER:
if ((option_mask32 & FLAG(q)) || status == STATUS_BINARY)
printf("Files %s and %s differ\n", path[0], path[1]);
break;
case STATUS_SAME:
if (option_mask32 & FLAG(s))
printf("Files %s and %s are identical\n", path[0], path[1]);
break;
}
}
#if ENABLE_FEATURE_DIFF_DIR
struct dlist {
size_t len;
int s, e;
char **dl;
};
/* This function adds a filename to dl, the directory listing. */
static int FAST_FUNC add_to_dirlist(const char *filename,
struct stat *sb UNUSED_PARAM,
void *userdata, int depth UNUSED_PARAM)
{
struct dlist *const l = userdata;
const char *file = filename + l->len;
while (*file == '/')
file++;
l->dl = xrealloc_vector(l->dl, 6, l->e);
l->dl[l->e] = xstrdup(file);
l->e++;
return TRUE;
}
/* If recursion is not set, this function adds the directory
* to the list and prevents recursive_action from recursing into it.
*/
static int FAST_FUNC skip_dir(const char *filename,
struct stat *sb, void *userdata,
int depth)
{
if (!(option_mask32 & FLAG(r)) && depth) {
add_to_dirlist(filename, sb, userdata, depth);
return SKIP;
}
if (!(option_mask32 & FLAG(N))) {
/* -r without -N: no need to recurse into dirs
* which do not exist on the "other side".
* Testcase: diff -r /tmp /
* (it would recurse deep into /proc without this code) */
struct dlist *const l = userdata;
filename += l->len;
if (filename[0]) {
struct stat osb;
char *othername = concat_path_file(G.other_dir, filename);
int r = stat(othername, &osb);
free(othername);
if (r != 0 || !S_ISDIR(osb.st_mode)) {
/* other dir doesn't have similarly named
* directory, don't recurse; return 1 upon
* exit, just like diffutils' diff */
exit_status |= 1;
return SKIP;
}
}
}
return TRUE;
}
static void diffdir(char *p[2], const char *s_start)
{
struct dlist list[2];
int i;
memset(&list, 0, sizeof(list));
for (i = 0; i < 2; i++) {
/*list[i].s = list[i].e = 0; - memset did it */
/*list[i].dl = NULL; */
G.other_dir = p[1 - i];
/* We need to trim root directory prefix.
* Using list.len to specify its length,
* add_to_dirlist will remove it. */
list[i].len = strlen(p[i]);
recursive_action(p[i], ACTION_RECURSE | ACTION_FOLLOWLINKS,
add_to_dirlist, skip_dir, &list[i], 0);
/* Sort dl alphabetically.
* GNU diff does this ignoring any number of trailing dots.
* We don't, so for us dotted files almost always are
* first on the list.
*/
qsort_string_vector(list[i].dl, list[i].e);
/* If -S was set, find the starting point. */
if (!s_start)
continue;
while (list[i].s < list[i].e && strcmp(list[i].dl[list[i].s], s_start) < 0)
list[i].s++;
}
/* Now that both dirlist1 and dirlist2 contain sorted directory
* listings, we can start to go through dirlist1. If both listings
* contain the same file, then do a normal diff. Otherwise, behaviour
* is determined by whether the -N flag is set. */
while (1) {
char *dp[2];
int pos;
int k;
dp[0] = list[0].s < list[0].e ? list[0].dl[list[0].s] : NULL;
dp[1] = list[1].s < list[1].e ? list[1].dl[list[1].s] : NULL;
if (!dp[0] && !dp[1])
break;
pos = !dp[0] ? 1 : (!dp[1] ? -1 : strcmp(dp[0], dp[1]));
k = pos > 0;
if (pos && !(option_mask32 & FLAG(N))) {
printf("Only in %s: %s\n", p[k], dp[k]);
exit_status |= 1;
} else {
char *fullpath[2], *path[2]; /* if -N */
for (i = 0; i < 2; i++) {
if (pos == 0 || i == k) {
path[i] = fullpath[i] = concat_path_file(p[i], dp[i]);
stat(fullpath[i], &stb[i]);
} else {
fullpath[i] = concat_path_file(p[i], dp[1 - i]);
path[i] = (char *)bb_dev_null;
}
}
if (pos)
stat(fullpath[k], &stb[1 - k]);
if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode))
printf("Common subdirectories: %s and %s\n", fullpath[0], fullpath[1]);
else if (!S_ISREG(stb[0].st_mode) && !S_ISDIR(stb[0].st_mode))
printf("File %s is not a regular file or directory and was skipped\n", fullpath[0]);
else if (!S_ISREG(stb[1].st_mode) && !S_ISDIR(stb[1].st_mode))
printf("File %s is not a regular file or directory and was skipped\n", fullpath[1]);
else if (S_ISDIR(stb[0].st_mode) != S_ISDIR(stb[1].st_mode)) {
if (S_ISDIR(stb[0].st_mode))
printf("File %s is a %s while file %s is a %s\n", fullpath[0], "directory", fullpath[1], "regular file");
else
printf("File %s is a %s while file %s is a %s\n", fullpath[0], "regular file", fullpath[1], "directory");
} else
print_status(diffreg(path), fullpath);
free(fullpath[0]);
free(fullpath[1]);
}
free(dp[k]);
list[k].s++;
if (pos == 0) {
free(dp[1 - k]);
list[1 - k].s++;
}
}
if (ENABLE_FEATURE_CLEAN_UP) {
free(list[0].dl);
free(list[1].dl);
}
}
#endif
#if ENABLE_FEATURE_DIFF_LONG_OPTIONS
static const char diff_longopts[] ALIGN1 =
"ignore-case\0" No_argument "i"
"ignore-tab-expansion\0" No_argument "E"
"ignore-space-change\0" No_argument "b"
"ignore-all-space\0" No_argument "w"
"ignore-blank-lines\0" No_argument "B"
"text\0" No_argument "a"
"unified\0" Required_argument "U"
"label\0" Required_argument "L"
"show-c-function\0" No_argument "p"
"brief\0" No_argument "q"
"expand-tabs\0" No_argument "t"
"initial-tab\0" No_argument "T"
"recursive\0" No_argument "r"
"new-file\0" No_argument "N"
"report-identical-files\0" No_argument "s"
"starting-file\0" Required_argument "S"
"minimal\0" No_argument "d"
;
# define GETOPT32 getopt32long
# define LONGOPTS ,diff_longopts
#else
# define GETOPT32 getopt32
# define LONGOPTS
#endif
int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int diff_main(int argc UNUSED_PARAM, char **argv)
{
int gotstdin = 0, i;
char *file[2], *s_start = NULL;
llist_t *L_arg = NULL;
INIT_G();
/* exactly 2 params; collect multiple -L <label>; -U N */
GETOPT32(argv, "^" "abdiL:*NqrsS:tTU:+wupBE" "\0" "=2"
LONGOPTS,
&L_arg, &s_start, &opt_U_context);
argv += optind;
while (L_arg)
label[!!label[0]] = llist_pop(&L_arg);
/* Compat: "diff file name_which_doesnt_exist" exits with 2 */
xfunc_error_retval = 2;
for (i = 0; i < 2; i++) {
file[i] = argv[i];
if (LONE_DASH(file[i])) {
fstat(STDIN_FILENO, &stb[i]);
gotstdin++;
} else if (option_mask32 & FLAG(N)) {
if (stat(file[i], &stb[i]))
xstat("/dev/null", &stb[i]);
} else {
xstat(file[i], &stb[i]);
}
}
xfunc_error_retval = 1;
if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode)))
bb_simple_error_msg_and_die("can't compare stdin to a directory");
/* Compare metadata to check if the files are the same physical file.
*
* Comment from diffutils source says:
* POSIX says that two files are identical if st_ino and st_dev are
* the same, but many file systems incorrectly assign the same (device,
* inode) pair to two distinct files, including:
* GNU/Linux NFS servers that export all local file systems as a
* single NFS file system, if a local device number (st_dev) exceeds
* 255, or if a local inode number (st_ino) exceeds 16777215.
*/
if (ENABLE_DESKTOP
&& stb[0].st_ino == stb[1].st_ino
&& stb[0].st_dev == stb[1].st_dev
&& stb[0].st_size == stb[1].st_size
&& stb[0].st_mtime == stb[1].st_mtime
&& stb[0].st_ctime == stb[1].st_ctime
&& stb[0].st_mode == stb[1].st_mode
&& stb[0].st_nlink == stb[1].st_nlink
&& stb[0].st_uid == stb[1].st_uid
&& stb[0].st_gid == stb[1].st_gid
) {
/* files are physically the same; no need to compare them */
return STATUS_SAME;
}
if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) {
#if ENABLE_FEATURE_DIFF_DIR
diffdir(file, s_start);
#else
bb_simple_error_msg_and_die("no support for directory comparison");
#endif
} else {
bool dirfile = S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode);
bool dir = S_ISDIR(stb[1].st_mode);
if (dirfile) {
const char *slash = strrchr(file[!dir], '/');
file[dir] = concat_path_file(file[dir], slash ? slash + 1 : file[!dir]);
xstat(file[dir], &stb[dir]);
}
/* diffreg can get non-regular files here */
print_status(gotstdin > 1 ? STATUS_SAME : diffreg(file), file);
if (dirfile)
free(file[dir]);
}
return exit_status;
}