busybox/editors/patch_toybox.c

/* Adapted from toybox's patch. Currently unused */

/* vi: set sw=4 ts=4:
 *
 * patch.c - Apply a "universal" diff.
 *
 * Copyright 2007 Rob Landley <rob@landley.net>
 *
 * see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
 * (But only does -u, because who still cares about "ed"?)
 *
 * TODO:
 * -b backup
 * -l treat all whitespace as a single space
 * -N ignore already applied
 * -d chdir first
 * -D define wrap #ifdef and #ifndef around changes
 * -o outfile output here instead of in place
 * -r rejectfile write rejected hunks to this file
 *
 * -E remove empty files --remove-empty-files
 * -f force (no questions asked)
 * -F fuzz (number, default 2)
 * [file] which file to patch

USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR|TOYFLAG_BIN))

config PATCH
	bool "patch"
	default y
	help
	  usage: patch [-i file] [-p depth] [-Ru]

	  Apply a unified diff to one or more files.

	  -i	Input file (defaults=stdin)
	  -p	number of '/' to strip from start of file paths (default=all)
	  -R	Reverse patch.
	  -u	Ignored (only handles "unified" diffs)

	  This version of patch only handles unified diffs, and only modifies
	  a file when all all hunks to that file apply.  Patch prints failed
	  hunks to stderr, and exits with nonzero status if any hunks fail.

	  A file compared against /dev/null (or with a date <= the epoch) is
	  created/deleted as appropriate.
*/
#include "libbb.h"

struct double_list {
	struct double_list *next;
	struct double_list *prev;
	char *data;
};

// Return the first item from the list, advancing the list (which must be called
// as &list)
static
void *TOY_llist_pop(void *list)
{
	// I'd use a void ** for the argument, and even accept the typecast in all
	// callers as documentation you need the &, except the stupid compiler
	// would then scream about type-punned pointers.  Screw it.
	void **llist = (void **)list;
	void **next = (void **)*llist;
	*llist = *next;

	return (void *)next;
}

// Free all the elements of a linked list
// if freeit!=NULL call freeit() on each element before freeing it.
static
void TOY_llist_free(void *list, void (*freeit)(void *data))
{
	while (list) {
		void *pop = TOY_llist_pop(&list);
		if (freeit) freeit(pop);
		else free(pop);

		// End doubly linked list too.
		if (list==pop) break;
	}
}

// Add an entry to the end off a doubly linked list
static
struct double_list *dlist_add(struct double_list **list, char *data)
{
	struct double_list *line = xmalloc(sizeof(struct double_list));

	line->data = data;
	if (*list) {
		line->next = *list;
		line->prev = (*list)->prev;
		(*list)->prev->next = line;
		(*list)->prev = line;
	} else *list = line->next = line->prev = line;

	return line;
}

// Ensure entire path exists.
// If mode != -1 set permissions on newly created dirs.
// Requires that path string be writable (for temporary null terminators).
static
void xmkpath(char *path, int mode)
{
	char *p, old;
	mode_t mask;
	int rc;
	struct stat st;

	for (p = path; ; p++) {
		if (!*p || *p == '/') {
			old = *p;
			*p = rc = 0;
			if (stat(path, &st) || !S_ISDIR(st.st_mode)) {
				if (mode != -1) {
					mask = umask(0);
					rc = mkdir(path, mode);
					umask(mask);
				} else rc = mkdir(path, 0777);
			}
			*p = old;
			if(rc) bb_perror_msg_and_die("mkpath '%s'", path);
		}
		if (!*p) break;
	}
}

// Slow, but small.
static
char *get_rawline(int fd, long *plen, char end)
{
	char c, *buf = NULL;
	long len = 0;

	for (;;) {
		if (1>read(fd, &c, 1)) break;
		if (!(len & 63)) buf=xrealloc(buf, len+65);
		if ((buf[len++]=c) == end) break;
	}
	if (buf) buf[len]=0;
	if (plen) *plen = len;

	return buf;
}

static
char *get_line(int fd)
{
	long len;
	char *buf = get_rawline(fd, &len, '\n');

	if (buf && buf[--len]=='\n') buf[len]=0;

	return buf;
}

// Copy the rest of in to out and close both files.
static
void xsendfile(int in, int out)
{
	long len;
	char buf[4096];

	if (in<0) return;
	for (;;) {
		len = safe_read(in, buf, 4096);
		if (len<1) break;
		xwrite(out, buf, len);
	}
}

// Copy the rest of the data and replace the original with the copy.
static
void replace_tempfile(int fdin, int fdout, char **tempname)
{
	char *temp = xstrdup(*tempname);

	temp[strlen(temp)-6]=0;
	if (fdin != -1) {
		xsendfile(fdin, fdout);
		xclose(fdin);
	}
	xclose(fdout);
	rename(*tempname, temp);
	free(*tempname);
	free(temp);
	*tempname = NULL;
}

// Open a temporary file to copy an existing file into.
static
int copy_tempfile(int fdin, char *name, char **tempname)
{
	struct stat statbuf;
	int fd;

	*tempname = xasprintf("%sXXXXXX", name);
	fd = mkstemp(*tempname);
	if(-1 == fd) bb_perror_msg_and_die("no temp file");

	// Set permissions of output file
	fstat(fdin, &statbuf);
	fchmod(fd, statbuf.st_mode);

	return fd;
}

// Abort the copy and delete the temporary file.
static
void delete_tempfile(int fdin, int fdout, char **tempname)
{
	close(fdin);
	close(fdout);
	unlink(*tempname);
	free(*tempname);
	*tempname = NULL;
}


struct globals {
	struct double_list *plines;
	long linenum;
	int context;
	int hunknum;
	int filein;
	int fileout;
	int state;
	char *tempname;
	smallint exitval;
};
#define TT (*ptr_to_globals)
#define INIT_TT() do { \
	SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
} while (0)


//bbox had: "p:i:RN"
#define FLAG_STR "Rup:i:"
/* FLAG_REVERSE must be == 1! Code uses this fact. */
#define FLAG_REVERSE (1 << 0)
#define FLAG_u       (1 << 1)
#define FLAG_PATHLEN (1 << 2)
#define FLAG_INPUT   (1 << 3)

// Dispose of a line of input, either by writing it out or discarding it.

// state < 2: just free
// state = 2: write whole line to stderr
// state = 3: write whole line to fileout
// state > 3: write line+1 to fileout when *line != state

static void do_line(void *data)
{
	struct double_list *dlist = (struct double_list *)data;

	if (TT.state>1 && *dlist->data != TT.state)
		fdprintf(TT.state == 2 ? 2 : TT.fileout,
			"%s\n", dlist->data+(TT.state>3 ? 1 : 0));

	free(dlist->data);
	free(data);
}

static void finish_oldfile(void)
{
	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
	TT.fileout = TT.filein = -1;
}

static void fail_hunk(void)
{
	if (!TT.plines) return;
	TT.plines->prev->next = 0;

	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
	TT.exitval = 1;

	// If we got to this point, we've seeked to the end.  Discard changes to
	// this file and advance to next file.

	TT.state = 2;
	TOY_llist_free(TT.plines, do_line);
	TT.plines = NULL;
	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
	TT.state = 0;
}

static int apply_hunk(void)
{
	struct double_list *plist, *buf = NULL, *check;
	int i = 0, backwards = 0, matcheof = 0,
		reverse = option_mask32 & FLAG_REVERSE;

	// Break doubly linked list so we can use singly linked traversal function.
	TT.plines->prev->next = NULL;

	// Match EOF if there aren't as many ending context lines as beginning
	for (plist = TT.plines; plist; plist = plist->next) {
		if (plist->data[0]==' ') i++;
		else i = 0;
	}
	if (i < TT.context) matcheof++;

	// Search for a place to apply this hunk.  Match all context lines and
	// lines to be removed.
	plist = TT.plines;
	buf = NULL;
	i = 0;

	// Start of for loop
	if (TT.context) for (;;) {
		char *data = get_line(TT.filein);

		TT.linenum++;

		// Skip lines of the hunk we'd be adding.
		while (plist && *plist->data == "+-"[reverse]) {
			if (data && !strcmp(data, plist->data+1)) {
				if (++backwards == TT.context)
					fdprintf(2,"Possibly reversed hunk %d at %ld\n",
						TT.hunknum, TT.linenum);
			} else backwards=0;
			plist = plist->next;
		}

		// Is this EOF?
		if (!data) {
			// Does this hunk need to match EOF?
			if (!plist && matcheof) break;

			// File ended before we found a place for this hunk.
			fail_hunk();
			goto done;
		}
		check = dlist_add(&buf, data);

		// todo: teach the strcmp() to ignore whitespace.

		for (;;) {
			// If we hit the end of a hunk that needed EOF and this isn't EOF,
			// or next line doesn't match, flush first line of buffered data and
			// recheck match until we find a new match or run out of buffer.

			if (!plist || strcmp(check->data, plist->data+1)) {
				// First line isn't a match, write it out.
				TT.state = 3;
				check = TOY_llist_pop(&buf);
				check->prev->next = buf;
				buf->prev = check->prev;
				do_line(check);
				plist = TT.plines;

				// Out of buffered lines?
				if (check==buf) {
					buf = 0;
					break;
				}
				check = buf;
			} else {
				// This line matches.  Advance plist, detect successful match.
				plist = plist->next;
				if (!plist && !matcheof) goto out;
				check = check->next;
				if (check == buf) break;
			}
		}
	}
out:
	// Got it.  Emit changed data.
	TT.state = "-+"[reverse];
	TOY_llist_free(TT.plines, do_line);
	TT.plines = NULL;
	TT.state = 1;
done:
	if (buf) {
		buf->prev->next = NULL;
		TOY_llist_free(buf, do_line);
	}

	return TT.state;
}

// state 0: Not in a hunk, look for +++.
// state 1: Found +++ file indicator, look for @@
// state 2: In hunk: counting initial context lines
// state 3: In hunk: getting body

int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int patch_main(int argc UNUSED_PARAM, char **argv)
{
	int opts;
	int reverse, state = 0;
	char *oldname = NULL, *newname = NULL;
	char *opt_p, *opt_i;
	int prefix;

	long oldline = 0, oldlen = 0, newline = 0, newlen = 0;

	INIT_TT();

	opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
	reverse = opts & FLAG_REVERSE;

	if (opts & FLAG_INPUT) xmove_fd(xopen(opt_i, O_RDONLY), STDIN_FILENO);
	prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
	TT.filein = TT.fileout = -1;

	// Loop through the lines in the patch
	for(;;) {
		char *patchline;

		patchline = get_line(STDIN_FILENO);
		if (!patchline) break;

		// Other versions of patch accept damaged patches,
		// so we need to also.
		if (!*patchline) {
			free(patchline);
			patchline = xstrdup(" ");
		}

		// Are we assembling a hunk?
		if (state >= 2) {
			if (*patchline==' ' || *patchline=='+' || *patchline=='-') {
				dlist_add(&TT.plines, patchline);

				if (*patchline != '+') oldlen--;
				if (*patchline != '-') newlen--;

				// Context line?
				if (*patchline==' ' && state==2) TT.context++;
				else state=3;

				// If we've consumed all expected hunk lines, apply the hunk.
				if (!oldlen && !newlen) state = apply_hunk();
				continue;
			}
			fail_hunk();
			state = 0;
			continue;
		}

		// Open a new file?
		if (!strncmp("--- ", patchline, 4) || !strncmp("+++ ", patchline, 4)) {
			char *s, **name = &oldname;
			int i;

			if (*patchline == '+') {
				name = &newname;
				state = 1;
			}

			free(*name);
			finish_oldfile();

			// Trim date from end of filename (if any).  We don't care.
			for (s = patchline+4; *s && *s!='\t'; s++)
				if (*s=='\\' && s[1]) s++;
			i = atoi(s);
			if (i && i<=1970)
				*name = xstrdup("/dev/null");
			else {
				*s = 0;
				*name = xstrdup(patchline+4);
			}

			// We defer actually opening the file because svn produces broken
			// patches that don't signal they want to create a new file the
			// way the patch man page says, so you have to read the first hunk
			// and _guess_.

		// Start a new hunk?
		} else if (state == 1 && !strncmp("@@ -", patchline, 4)) {
			int i;

			i = sscanf(patchline+4, "%ld,%ld +%ld,%ld",
					&oldline, &oldlen, &newline, &newlen);
			if (i != 4)
				bb_error_msg_and_die("corrupt hunk %d at %ld", TT.hunknum, TT.linenum);

			TT.context = 0;
			state = 2;

			// If this is the first hunk, open the file.
			if (TT.filein == -1) {
				int oldsum, newsum, del = 0;
				char *s, *name;

				oldsum = oldline + oldlen;
				newsum = newline + newlen;

				name = reverse ? oldname : newname;

				// We're deleting oldname if new file is /dev/null (before -p)
				// or if new hunk is empty (zero context) after patching
				if (!strcmp(name, "/dev/null") || !(reverse ? oldsum : newsum)) {
					name = reverse ? newname : oldname;
					del++;
				}

				// handle -p path truncation.
				for (i=0, s = name; *s;) {
					if ((option_mask32 & FLAG_PATHLEN) && prefix == i)
						break;
					if (*(s++)=='/') {
						name = s;
						i++;
					}
				}

				if (del) {
					printf("removing %s\n", name);
					xunlink(name);
					state = 0;
				// If we've got a file to open, do so.
				} else if (!(option_mask32 & FLAG_PATHLEN) || i <= prefix) {
					// If the old file was null, we're creating a new one.
					if (!strcmp(oldname, "/dev/null") || !oldsum) {
						printf("creating %s\n", name);
						s = strrchr(name, '/');
						if (s) {
							*s = 0;
							xmkpath(name, -1);
							*s = '/';
						}
						TT.filein = xopen3(name, O_CREAT|O_EXCL|O_RDWR, 0666);
					} else {
						printf("patching file %s\n", name);
						TT.filein = xopen(name, O_RDWR);
					}
					TT.fileout = copy_tempfile(TT.filein, name, &TT.tempname);
					TT.linenum = 0;
					TT.hunknum = 0;
				}
			}

			TT.hunknum++;

			continue;
		}

		// If we didn't continue above, discard this line.
		free(patchline);
	}

	finish_oldfile();

	if (ENABLE_FEATURE_CLEAN_UP) {
		free(oldname);
		free(newname);
	}

	return TT.exitval;
}
1	/* Adapted from toybox's patch. Currently unused */
2
3	/* vi: set sw=4 ts=4:
4	*
5	* patch.c - Apply a "universal" diff.
6	*
7	* Copyright 2007 Rob Landley <rob@landley.net>
8	*
9	* see http://www.opengroup.org/onlinepubs/009695399/utilities/patch.html
10	* (But only does -u, because who still cares about "ed"?)
11	*
12	* TODO:
13	* -b backup
14	* -l treat all whitespace as a single space
15	* -N ignore already applied
16	* -d chdir first
17	* -D define wrap #ifdef and #ifndef around changes
18	* -o outfile output here instead of in place
19	* -r rejectfile write rejected hunks to this file
20	*
21	* -E remove empty files --remove-empty-files
22	* -f force (no questions asked)
23	* -F fuzz (number, default 2)
24	* [file] which file to patch
25
26	USE_PATCH(NEWTOY(patch, "up#i:R", TOYFLAG_USR\|TOYFLAG_BIN))
27
28	config PATCH
29	bool "patch"
30	default y
31	help
32	usage: patch [-i file] [-p depth] [-Ru]
33
34	Apply a unified diff to one or more files.
35
36	-i Input file (defaults=stdin)
37	-p number of '/' to strip from start of file paths (default=all)
38	-R Reverse patch.
39	-u Ignored (only handles "unified" diffs)
40
41	This version of patch only handles unified diffs, and only modifies
42	a file when all all hunks to that file apply. Patch prints failed
43	hunks to stderr, and exits with nonzero status if any hunks fail.
44
45	A file compared against /dev/null (or with a date <= the epoch) is
46	created/deleted as appropriate.
47	*/
48	#include "libbb.h"
49
50	struct double_list {
51	struct double_list *next;
52	struct double_list *prev;
53	char *data;
54	};
55
56	// Return the first item from the list, advancing the list (which must be called
57	// as &list)
58	static
59	void TOY_llist_pop(void list)
60	{
61	// I'd use a void ** for the argument, and even accept the typecast in all
62	// callers as documentation you need the &, except the stupid compiler
63	// would then scream about type-punned pointers. Screw it.
64	void llist = (void )list;
65	void next = (void )*llist;
66	llist = next;
67
68	return (void *)next;
69	}
70
71	// Free all the elements of a linked list
72	// if freeit!=NULL call freeit() on each element before freeing it.
73	static
74	void TOY_llist_free(void list, void (freeit)(void *data))
75	{
76	while (list) {
77	void *pop = TOY_llist_pop(&list);
78	if (freeit) freeit(pop);
79	else free(pop);
80
81	// End doubly linked list too.
82	if (list==pop) break;
83	}
84	}
85
86	// Add an entry to the end off a doubly linked list
87	static
88	struct double_list dlist_add(struct double_list list, char data)
89	{
90	struct double_list *line = xmalloc(sizeof(struct double_list));
91
92	line->data = data;
93	if (*list) {
94	line->next = *list;
95	line->prev = (*list)->prev;
96	(*list)->prev->next = line;
97	(*list)->prev = line;
98	} else *list = line->next = line->prev = line;
99
100	return line;
101	}
102
103	// Ensure entire path exists.
104	// If mode != -1 set permissions on newly created dirs.
105	// Requires that path string be writable (for temporary null terminators).
106	static
107	void xmkpath(char *path, int mode)
108	{
109	char *p, old;
110	mode_t mask;
111	int rc;
112	struct stat st;
113
114	for (p = path; ; p++) {
115	if (!p \|\| p == '/') {
116	old = *p;
117	*p = rc = 0;
118	if (stat(path, &st) \|\| !S_ISDIR(st.st_mode)) {
119	if (mode != -1) {
120	mask = umask(0);
121	rc = mkdir(path, mode);
122	umask(mask);
123	} else rc = mkdir(path, 0777);
124	}
125	*p = old;
126	if(rc) bb_perror_msg_and_die("mkpath '%s'", path);
127	}
128	if (!*p) break;
129	}
130	}
131
132	// Slow, but small.
133	static
134	char get_rawline(int fd, long plen, char end)
135	{
136	char c, *buf = NULL;
137	long len = 0;
138
139	for (;;) {
140	if (1>read(fd, &c, 1)) break;
141	if (!(len & 63)) buf=xrealloc(buf, len+65);
142	if ((buf[len++]=c) == end) break;
143	}
144	if (buf) buf[len]=0;
145	if (plen) *plen = len;
146
147	return buf;
148	}
149
150	static
151	char *get_line(int fd)
152	{
153	long len;
154	char *buf = get_rawline(fd, &len, '\n');
155
156	if (buf && buf[--len]=='\n') buf[len]=0;
157
158	return buf;
159	}
160
161	// Copy the rest of in to out and close both files.
162	static
163	void xsendfile(int in, int out)
164	{
165	long len;
166	char buf[4096];
167
168	if (in<0) return;
169	for (;;) {
170	len = safe_read(in, buf, 4096);
171	if (len<1) break;
172	xwrite(out, buf, len);
173	}
174	}
175
176	// Copy the rest of the data and replace the original with the copy.
177	static
178	void replace_tempfile(int fdin, int fdout, char **tempname)
179	{
180	char temp = xstrdup(tempname);
181
182	temp[strlen(temp)-6]=0;
183	if (fdin != -1) {
184	xsendfile(fdin, fdout);
185	xclose(fdin);
186	}
187	xclose(fdout);
188	rename(*tempname, temp);
189	free(*tempname);
190	free(temp);
191	*tempname = NULL;
192	}
193
194	// Open a temporary file to copy an existing file into.
195	static
196	int copy_tempfile(int fdin, char name, char *tempname)
197	{
198	struct stat statbuf;
199	int fd;
200
201	*tempname = xasprintf("%sXXXXXX", name);
202	fd = mkstemp(*tempname);
203	if(-1 == fd) bb_perror_msg_and_die("no temp file");
204
205	// Set permissions of output file
206	fstat(fdin, &statbuf);
207	fchmod(fd, statbuf.st_mode);
208
209	return fd;
210	}
211
212	// Abort the copy and delete the temporary file.
213	static
214	void delete_tempfile(int fdin, int fdout, char **tempname)
215	{
216	close(fdin);
217	close(fdout);
218	unlink(*tempname);
219	free(*tempname);
220	*tempname = NULL;
221	}
222
223
224
225	struct globals {
226	struct double_list *plines;
227	long linenum;
228	int context;
229	int hunknum;
230	int filein;
231	int fileout;
232	int state;
233	char *tempname;
234	smallint exitval;
235	};
236	#define TT (*ptr_to_globals)
237	#define INIT_TT() do { \
238	SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
239	} while (0)
240
241
242	//bbox had: "p:i:RN"
243	#define FLAG_STR "Rup:i:"
244	/* FLAG_REVERSE must be == 1! Code uses this fact. */
245	#define FLAG_REVERSE (1 << 0)
246	#define FLAG_u (1 << 1)
247	#define FLAG_PATHLEN (1 << 2)
248	#define FLAG_INPUT (1 << 3)
249
250	// Dispose of a line of input, either by writing it out or discarding it.
251
252	// state < 2: just free
253	// state = 2: write whole line to stderr
254	// state = 3: write whole line to fileout
255	// state > 3: write line+1 to fileout when *line != state
256
257	static void do_line(void *data)
258	{
259	struct double_list dlist = (struct double_list )data;
260
261	if (TT.state>1 && *dlist->data != TT.state)
262	fdprintf(TT.state == 2 ? 2 : TT.fileout,
263	"%s\n", dlist->data+(TT.state>3 ? 1 : 0));
264
265	free(dlist->data);
266	free(data);
267	}
268
269	static void finish_oldfile(void)
270	{
271	if (TT.tempname) replace_tempfile(TT.filein, TT.fileout, &TT.tempname);
272	TT.fileout = TT.filein = -1;
273	}
274
275	static void fail_hunk(void)
276	{
277	if (!TT.plines) return;
278	TT.plines->prev->next = 0;
279
280	fdprintf(2, "Hunk %d FAILED.\n", TT.hunknum);
281	TT.exitval = 1;
282
283	// If we got to this point, we've seeked to the end. Discard changes to
284	// this file and advance to next file.
285
286	TT.state = 2;
287	TOY_llist_free(TT.plines, do_line);
288	TT.plines = NULL;
289	delete_tempfile(TT.filein, TT.fileout, &TT.tempname);
290	TT.state = 0;
291	}
292
293	static int apply_hunk(void)
294	{
295	struct double_list plist, buf = NULL, *check;
296	int i = 0, backwards = 0, matcheof = 0,
297	reverse = option_mask32 & FLAG_REVERSE;
298
299	// Break doubly linked list so we can use singly linked traversal function.
300	TT.plines->prev->next = NULL;
301
302	// Match EOF if there aren't as many ending context lines as beginning
303	for (plist = TT.plines; plist; plist = plist->next) {
304	if (plist->data[0]==' ') i++;
305	else i = 0;
306	}
307	if (i < TT.context) matcheof++;
308
309	// Search for a place to apply this hunk. Match all context lines and
310	// lines to be removed.
311	plist = TT.plines;
312	buf = NULL;
313	i = 0;
314
315	// Start of for loop
316	if (TT.context) for (;;) {
317	char *data = get_line(TT.filein);
318
319	TT.linenum++;
320
321	// Skip lines of the hunk we'd be adding.
322	while (plist && *plist->data == "+-"[reverse]) {
323	if (data && !strcmp(data, plist->data+1)) {
324	if (++backwards == TT.context)
325	fdprintf(2,"Possibly reversed hunk %d at %ld\n",
326	TT.hunknum, TT.linenum);
327	} else backwards=0;
328	plist = plist->next;
329	}
330
331	// Is this EOF?
332	if (!data) {
333	// Does this hunk need to match EOF?
334	if (!plist && matcheof) break;
335
336	// File ended before we found a place for this hunk.
337	fail_hunk();
338	goto done;
339	}
340	check = dlist_add(&buf, data);
341
342	// todo: teach the strcmp() to ignore whitespace.
343
344	for (;;) {
345	// If we hit the end of a hunk that needed EOF and this isn't EOF,
346	// or next line doesn't match, flush first line of buffered data and
347	// recheck match until we find a new match or run out of buffer.
348
349	if (!plist \|\| strcmp(check->data, plist->data+1)) {
350	// First line isn't a match, write it out.
351	TT.state = 3;
352	check = TOY_llist_pop(&buf);
353	check->prev->next = buf;
354	buf->prev = check->prev;
355	do_line(check);
356	plist = TT.plines;
357
358	// Out of buffered lines?
359	if (check==buf) {
360	buf = 0;
361	break;
362	}
363	check = buf;
364	} else {
365	// This line matches. Advance plist, detect successful match.
366	plist = plist->next;
367	if (!plist && !matcheof) goto out;
368	check = check->next;
369	if (check == buf) break;
370	}
371	}
372	}
373	out:
374	// Got it. Emit changed data.
375	TT.state = "-+"[reverse];
376	TOY_llist_free(TT.plines, do_line);
377	TT.plines = NULL;
378	TT.state = 1;
379	done:
380	if (buf) {
381	buf->prev->next = NULL;
382	TOY_llist_free(buf, do_line);
383	}
384
385	return TT.state;
386	}
387
388	// state 0: Not in a hunk, look for +++.
389	// state 1: Found +++ file indicator, look for @@
390	// state 2: In hunk: counting initial context lines
391	// state 3: In hunk: getting body
392
393	int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
394	int patch_main(int argc UNUSED_PARAM, char **argv)
395	{
396	int opts;
397	int reverse, state = 0;
398	char oldname = NULL, newname = NULL;
399	char opt_p, opt_i;
400	int prefix;
401
402	long oldline = 0, oldlen = 0, newline = 0, newlen = 0;
403
404	INIT_TT();
405
406	opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
407	reverse = opts & FLAG_REVERSE;
408
409	if (opts & FLAG_INPUT) xmove_fd(xopen(opt_i, O_RDONLY), STDIN_FILENO);
410	prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
411	TT.filein = TT.fileout = -1;
412
413	// Loop through the lines in the patch
414	for(;;) {
415	char *patchline;
416
417	patchline = get_line(STDIN_FILENO);
418	if (!patchline) break;
419
420	// Other versions of patch accept damaged patches,
421	// so we need to also.
422	if (!*patchline) {
423	free(patchline);
424	patchline = xstrdup(" ");
425	}
426
427	// Are we assembling a hunk?
428	if (state >= 2) {
429	if (patchline==' ' \|\| patchline=='+' \|\| *patchline=='-') {
430	dlist_add(&TT.plines, patchline);
431
432	if (*patchline != '+') oldlen--;
433	if (*patchline != '-') newlen--;
434
435	// Context line?
436	if (*patchline==' ' && state==2) TT.context++;
437	else state=3;
438
439	// If we've consumed all expected hunk lines, apply the hunk.
440	if (!oldlen && !newlen) state = apply_hunk();
441	continue;
442	}
443	fail_hunk();
444	state = 0;
445	continue;
446	}
447
448	// Open a new file?
449	if (!strncmp("--- ", patchline, 4) \|\| !strncmp("+++ ", patchline, 4)) {
450	char s, *name = &oldname;
451	int i;
452
453	if (*patchline == '+') {
454	name = &newname;
455	state = 1;
456	}
457
458	free(*name);
459	finish_oldfile();
460
461	// Trim date from end of filename (if any). We don't care.
462	for (s = patchline+4; s && s!='\t'; s++)
463	if (*s=='\\' && s[1]) s++;
464	i = atoi(s);
465	if (i && i<=1970)
466	*name = xstrdup("/dev/null");
467	else {
468	*s = 0;
469	*name = xstrdup(patchline+4);
470	}
471
472	// We defer actually opening the file because svn produces broken
473	// patches that don't signal they want to create a new file the
474	// way the patch man page says, so you have to read the first hunk
475	// and _guess_.
476
477	// Start a new hunk?
478	} else if (state == 1 && !strncmp("@@ -", patchline, 4)) {
479	int i;
480
481	i = sscanf(patchline+4, "%ld,%ld +%ld,%ld",
482	&oldline, &oldlen, &newline, &newlen);
483	if (i != 4)
484	bb_error_msg_and_die("corrupt hunk %d at %ld", TT.hunknum, TT.linenum);
485
486	TT.context = 0;
487	state = 2;
488
489	// If this is the first hunk, open the file.
490	if (TT.filein == -1) {
491	int oldsum, newsum, del = 0;
492	char s, name;
493
494	oldsum = oldline + oldlen;
495	newsum = newline + newlen;
496
497	name = reverse ? oldname : newname;
498
499	// We're deleting oldname if new file is /dev/null (before -p)
500	// or if new hunk is empty (zero context) after patching
501	if (!strcmp(name, "/dev/null") \|\| !(reverse ? oldsum : newsum)) {
502	name = reverse ? newname : oldname;
503	del++;
504	}
505
506	// handle -p path truncation.
507	for (i=0, s = name; *s;) {
508	if ((option_mask32 & FLAG_PATHLEN) && prefix == i)
509	break;
510	if (*(s++)=='/') {
511	name = s;
512	i++;
513	}
514	}
515
516	if (del) {
517	printf("removing %s\n", name);
518	xunlink(name);
519	state = 0;
520	// If we've got a file to open, do so.
521	} else if (!(option_mask32 & FLAG_PATHLEN) \|\| i <= prefix) {
522	// If the old file was null, we're creating a new one.
523	if (!strcmp(oldname, "/dev/null") \|\| !oldsum) {
524	printf("creating %s\n", name);
525	s = strrchr(name, '/');
526	if (s) {
527	*s = 0;
528	xmkpath(name, -1);
529	*s = '/';
530	}
531	TT.filein = xopen3(name, O_CREAT\|O_EXCL\|O_RDWR, 0666);
532	} else {
533	printf("patching file %s\n", name);
534	TT.filein = xopen(name, O_RDWR);
535	}
536	TT.fileout = copy_tempfile(TT.filein, name, &TT.tempname);
537	TT.linenum = 0;
538	TT.hunknum = 0;
539	}
540	}
541
542	TT.hunknum++;
543
544	continue;
545	}
546
547	// If we didn't continue above, discard this line.
548	free(patchline);
549	}
550
551	finish_oldfile();
552
553	if (ENABLE_FEATURE_CLEAN_UP) {
554	free(oldname);
555	free(newname);
556	}
557
558	return TT.exitval;
559	}