busybox/editors/patch.c
Denys Vlasenko 0c4dbd481a regularize format of source file headers, no code changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-09-18 16:28:43 +02:00

573 lines
15 KiB
C

/* vi: set sw=4 ts=4:
*
* Apply a "universal" diff.
* Adapted from toybox's patch implementation.
*
* 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
* -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
* --dry-run (regression!)
*
* -f force (no questions asked)
* -F fuzz (number, default 2)
* [file] which file to patch
*/
//config:config PATCH
//config: bool "patch (9.1 kb)"
//config: default y
//config: help
//config: Apply a unified diff formatted patch.
//applet:IF_PATCH(APPLET(patch, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_PATCH) += patch.o
//usage:#define patch_trivial_usage
//usage: "[OPTIONS] [ORIGFILE [PATCHFILE]]"
//usage:#define patch_full_usage "\n\n"
//usage: IF_LONG_OPTS(
//usage: " -p,--strip N Strip N leading components from file names"
//usage: "\n -i,--input DIFF Read DIFF instead of stdin"
//usage: "\n -R,--reverse Reverse patch"
//usage: "\n -N,--forward Ignore already applied patches"
/*usage: "\n --dry-run Don't actually change files" - TODO */
//usage: "\n -E,--remove-empty-files Remove output files if they become empty"
//usage: )
//usage: IF_NOT_LONG_OPTS(
//usage: " -p N Strip N leading components from file names"
//usage: "\n -i DIFF Read DIFF instead of stdin"
//usage: "\n -R Reverse patch"
//usage: "\n -N Ignore already applied patches"
//usage: "\n -E Remove output files if they become empty"
//usage: )
/* -u "interpret as unified diff" is supported but not documented: this info is not useful for --help */
/* -x "debug" is supported but does nothing */
//usage:
//usage:#define patch_example_usage
//usage: "$ patch -p1 < example.diff\n"
//usage: "$ patch -p0 -i example.diff"
#include "libbb.h"
// libbb candidate?
struct double_list {
struct double_list *next;
struct double_list *prev;
char *data;
};
// Free all the elements of a linked list
// Call freeit() on each element before freeing it.
static void dlist_free(struct double_list *list, void (*freeit)(void *data))
{
while (list) {
void *pop = list;
list = list->next;
freeit(pop);
// Bail out also if list is circular.
if (list == pop) break;
}
}
// Add an entry before "list" element in (circular) doubly linked list
static struct double_list *dlist_add(struct double_list **list, char *data)
{
struct double_list *llist;
struct double_list *line = xmalloc(sizeof(*line));
line->data = data;
llist = *list;
if (llist) {
struct double_list *p;
line->next = llist;
p = line->prev = llist->prev;
// (list is circular, we assume p is never NULL)
p->next = line;
llist->prev = line;
} else
*list = line->next = line->prev = line;
return line;
}
struct globals {
char *infile;
long prefix;
struct double_list *current_hunk;
long oldline, oldlen, newline, newlen;
long linenum;
int context, state, hunknum;
int filein, fileout;
char *tempname;
int exitval;
};
#define TT (*ptr_to_globals)
#define INIT_TT() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(TT))); \
} while (0)
#define FLAG_STR "Rup:i:NEx"
/* 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)
#define FLAG_IGNORE (1 << 4)
#define FLAG_RMEMPTY (1 << 5)
/* Enable this bit and use -x for debug output: */
#define FLAG_DEBUG (0 << 6)
// 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
#define PATCH_DEBUG (option_mask32 & FLAG_DEBUG)
static void do_line(void *data)
{
struct double_list *dlist = 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));
if (PATCH_DEBUG) fdprintf(2, "DO %d: %s\n", TT.state, dlist->data);
free(dlist->data);
free(dlist);
}
static void finish_oldfile(void)
{
if (TT.tempname) {
// Copy the rest of the data and replace the original with the copy.
char *temp;
if (TT.filein != -1) {
bb_copyfd_eof(TT.filein, TT.fileout);
xclose(TT.filein);
}
xclose(TT.fileout);
temp = xstrdup(TT.tempname);
temp[strlen(temp) - 6] = '\0';
rename(TT.tempname, temp);
free(temp);
free(TT.tempname);
TT.tempname = NULL;
}
TT.fileout = TT.filein = -1;
}
static void fail_hunk(void)
{
if (!TT.current_hunk) return;
fdprintf(2, "Hunk %d FAILED %ld/%ld.\n", TT.hunknum, TT.oldline, TT.newline);
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;
TT.current_hunk->prev->next = NULL;
dlist_free(TT.current_hunk, do_line);
TT.current_hunk = NULL;
// Abort the copy and delete the temporary file.
close(TT.filein);
close(TT.fileout);
unlink(TT.tempname);
free(TT.tempname);
TT.tempname = NULL;
TT.state = 0;
}
// Given a hunk of a unified diff, make the appropriate change to the file.
// This does not use the location information, but instead treats a hunk
// as a sort of regex. Copies data from input to output until it finds
// the change to be made, then outputs the changed data and returns.
// (Finding EOF first is an error.) This is a single pass operation, so
// multiple hunks must occur in order in the file.
static int apply_one_hunk(void)
{
struct double_list *plist, *buf = NULL, *check;
int matcheof = 0, reverse = option_mask32 & FLAG_REVERSE, backwarn = 0;
/* Do we try "dummy" revert to check whether
* to silently skip this hunk? Used to implement -N.
*/
int dummy_revert = 0;
// Break doubly linked list so we can use singly linked traversal function.
TT.current_hunk->prev->next = NULL;
// Match EOF if there aren't as many ending context lines as beginning
for (plist = TT.current_hunk; plist; plist = plist->next) {
if (plist->data[0]==' ') matcheof++;
else matcheof = 0;
if (PATCH_DEBUG) fdprintf(2, "HUNK:%s\n", plist->data);
}
matcheof = !matcheof || matcheof < TT.context;
if (PATCH_DEBUG) fdprintf(2,"MATCHEOF=%c\n", matcheof ? 'Y' : 'N');
// Loop through input data searching for this hunk. Match all context
// lines and all lines to be removed until we've found the end of a
// complete hunk.
plist = TT.current_hunk;
buf = NULL;
if (reverse ? TT.oldlen : TT.newlen) for (;;) {
char *data = xmalloc_reads(TT.filein, NULL);
TT.linenum++;
// Figure out which line of hunk to compare with next. (Skip lines
// of the hunk we'd be adding.)
while (plist && *plist->data == "+-"[reverse]) {
if (data && strcmp(data, plist->data+1) == 0) {
if (!backwarn) {
backwarn = TT.linenum;
if (option_mask32 & FLAG_IGNORE) {
dummy_revert = 1;
reverse ^= 1;
continue;
}
}
}
plist = plist->next;
}
// Is this EOF?
if (!data) {
if (PATCH_DEBUG) fdprintf(2, "INEOF\n");
// Does this hunk need to match EOF?
if (!plist && matcheof) break;
if (backwarn)
fdprintf(2,"Possibly reversed hunk %d at %ld\n",
TT.hunknum, TT.linenum);
// File ended before we found a place for this hunk.
fail_hunk();
goto done;
}
if (PATCH_DEBUG) fdprintf(2, "IN: %s\n", data);
check = dlist_add(&buf, data);
// Compare this line with next expected line of hunk.
// todo: teach the strcmp() to ignore whitespace.
// A match can fail because the next line doesn't match, or because
// we hit the end of a hunk that needed EOF, and this isn't EOF.
// If match failed, flush first line of buffered data and
// recheck buffered data for a new match until we find one or run
// out of buffer.
for (;;) {
while (plist && *plist->data == "+-"[reverse]) {
if (strcmp(check->data, plist->data+1) == 0
&& !backwarn
) {
backwarn = TT.linenum;
if (option_mask32 & FLAG_IGNORE) {
dummy_revert = 1;
reverse ^= 1;
}
}
plist = plist->next;
}
if (!plist || strcmp(check->data, plist->data+1)) {
// Match failed. Write out first line of buffered data and
// recheck remaining buffered data for a new match.
if (PATCH_DEBUG)
fdprintf(2, "NOT: %s\n", plist ? plist->data : "EOF");
TT.state = 3;
check = buf;
buf = buf->next;
check->prev->next = buf;
buf->prev = check->prev;
do_line(check);
plist = TT.current_hunk;
// If we've reached the end of the buffer without confirming a
// match, read more lines.
if (check == buf) {
buf = NULL;
break;
}
check = buf;
} else {
if (PATCH_DEBUG)
fdprintf(2, "MAYBE: %s\n", plist->data);
// This line matches. Advance plist, detect successful match.
plist = plist->next;
if (!plist && !matcheof) goto out;
check = check->next;
if (check == buf) break;
}
}
}
out:
// We have a match. Emit changed data.
TT.state = "-+"[reverse ^ dummy_revert];
dlist_free(TT.current_hunk, do_line);
TT.current_hunk = NULL;
TT.state = 1;
done:
if (buf) {
buf->prev->next = NULL;
dlist_free(buf, do_line);
}
return TT.state;
}
// Read a patch file and find hunks, opening/creating/deleting files.
// Call apply_one_hunk() on each hunk.
// 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
// Like GNU patch, we don't require a --- line before the +++, and
// also allow the --- after the +++ line.
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;
long oldlen = oldlen; /* for compiler */
long newlen = newlen; /* for compiler */
INIT_TT();
opts = getopt32(argv, FLAG_STR, &opt_p, &opt_i);
argv += optind;
reverse = opts & FLAG_REVERSE;
TT.prefix = (opts & FLAG_PATHLEN) ? xatoi(opt_p) : 0; // can be negative!
TT.filein = TT.fileout = -1;
if (opts & FLAG_INPUT) {
xmove_fd(xopen_stdin(opt_i), STDIN_FILENO);
} else {
if (argv[0] && argv[1]) {
xmove_fd(xopen_stdin(argv[1]), STDIN_FILENO);
}
}
// Loop through the lines in the patch
for(;;) {
char *patchline;
patchline = xmalloc_fgetline(stdin);
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.current_hunk, 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_one_hunk();
continue;
}
fail_hunk();
state = 0;
continue;
}
// Open a new file?
if (is_prefixed_with(patchline, "--- ") || is_prefixed_with(patchline, "+++ ")) {
char *s, **name = reverse ? &newname : &oldname;
int i;
if (*patchline == '+') {
name = reverse ? &oldname : &newname;
state = 1;
}
finish_oldfile();
if (!argv[0]) {
free(*name);
// 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>1900 && 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? Usually @@ -oldline,oldlen +newline,newlen @@
// but a missing ,value means the value is 1.
} else if (state == 1 && is_prefixed_with(patchline, "@@ -")) {
int i;
char *s = patchline+4;
// Read oldline[,oldlen] +newline[,newlen]
TT.oldlen = oldlen = TT.newlen = newlen = 1;
TT.oldline = strtol(s, &s, 10);
if (*s == ',') TT.oldlen = oldlen = strtol(s+1, &s, 10);
TT.newline = strtol(s+2, &s, 10);
if (*s == ',') TT.newlen = newlen = strtol(s+1, &s, 10);
if (oldlen < 1 && newlen < 1)
bb_error_msg_and_die("Really? %s", patchline);
TT.context = 0;
state = 2;
// If the --- line is missing or malformed, either oldname
// or (for -R) newname could be NULL -- but not both. Like
// GNU patch, proceed based on the +++ line, and avoid SEGVs.
if (!oldname)
oldname = xstrdup("MISSING_FILENAME");
if (!newname)
newname = xstrdup("MISSING_FILENAME");
// If this is the first hunk, open the file.
if (TT.filein == -1) {
int oldsum, newsum, empty = 0;
char *name;
oldsum = TT.oldline + oldlen;
newsum = TT.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") == 0 || !(reverse ? oldsum : newsum)) {
name = reverse ? newname : oldname;
empty = 1;
}
// Handle -p path truncation.
for (i = 0, s = name; *s;) {
if ((option_mask32 & FLAG_PATHLEN) && TT.prefix == i)
break;
if (*s++ != '/')
continue;
while (*s == '/')
s++;
i++;
name = s;
}
// If "patch FILE_TO_PATCH", completely ignore name from patch
if (argv[0])
name = argv[0];
if (empty) {
// File is empty after the patches have been applied
state = 0;
if (option_mask32 & FLAG_RMEMPTY) {
// If flag -E or --remove-empty-files is set
printf("removing %s\n", name);
xunlink(name);
} else {
printf("patching file %s\n", name);
xclose(xopen(name, O_WRONLY | O_TRUNC));
}
// If we've got a file to open, do so.
} else if (!(option_mask32 & FLAG_PATHLEN) || i <= TT.prefix) {
struct stat statbuf;
// If the old file was null, we're creating a new one.
if (strcmp(oldname, "/dev/null") == 0 || !oldsum) {
printf("creating %s\n", name);
s = strrchr(name, '/');
if (s) {
*s = 0;
bb_make_directory(name, -1, FILEUTILS_RECUR);
*s = '/';
}
TT.filein = xopen(name, O_CREAT|O_EXCL|O_RDWR);
} else {
printf("patching file %s\n", name);
TT.filein = xopen(name, O_RDONLY);
}
TT.tempname = xasprintf("%sXXXXXX", name);
TT.fileout = xmkstemp(TT.tempname);
// Set permissions of output file
fstat(TT.filein, &statbuf);
fchmod(TT.fileout, statbuf.st_mode);
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;
}