patch: replace it with toybox's implementation

Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 306 insertions, 0 deletions

diff --git a/editors/patch_bbox.c b/editors/patch_bbox.c
new file mode 100644
index 000000000..62477af16
--- /dev/null
+++ b/editors/patch_bbox.c
@@ -0,0 +1,306 @@
+/* vi: set sw=4 ts=4: */
+/*
+ *  busybox patch applet to handle the unified diff format.
+ *  Copyright (C) 2003 Glenn McGrath
+ *
+ *  Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ *
+ *  This applet is written to work with patches generated by GNU diff,
+ *  where there is equivalent functionality busybox patch shall behave
+ *  as per GNU patch.
+ *
+ *  There is a SUSv3 specification for patch, however it looks to be
+ *  incomplete, it doesnt even mention unified diff format.
+ *  http://www.opengroup.org/onlinepubs/007904975/utilities/patch.html
+ *
+ *  Issues
+ *   - Non-interactive
+ *   - Patches must apply cleanly or patch (not just one hunk) will fail.
+ *   - Reject file isnt saved
+ */
+
+#include "libbb.h"
+
+static unsigned copy_lines(FILE *src_stream, FILE *dst_stream, unsigned lines_count)
+{
+	while (src_stream && lines_count) {
+		char *line;
+		line = xmalloc_fgets(src_stream);
+		if (line == NULL) {
+			break;
+		}
+		if (fputs(line, dst_stream) == EOF) {
+			bb_perror_msg_and_die("error writing to new file");
+		}
+		free(line);
+		lines_count--;
+	}
+	return lines_count;
+}
+
+/* If patch_level is -1 it will remove all directory names
+ * char *line must be greater than 4 chars
+ * returns NULL if the file doesnt exist or error
+ * returns malloc'ed filename
+ * NB: frees 1st argument!
+ */
+static char *extract_filename(char *line, int patch_level, const char *pat)
+{
+	char *temp = NULL, *filename_start_ptr = line + 4;
+
+	if (strncmp(line, pat, 4) == 0) {
+		/* Terminate string at end of source filename */
+		line[strcspn(line, "\t\n\r")] = '\0';
+
+		/* Skip over (patch_level) number of leading directories */
+		while (patch_level--) {
+			temp = strchr(filename_start_ptr, '/');
+			if (!temp)
+				break;
+			filename_start_ptr = temp + 1;
+		}
+		temp = xstrdup(filename_start_ptr);
+	}
+	free(line);
+	return temp;
+}
+
+int patch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int patch_main(int argc UNUSED_PARAM, char **argv)
+{
+	struct stat saved_stat;
+	char *patch_line;
+	FILE *patch_file;
+	int patch_level;
+	int ret = 0;
+	char plus = '+';
+	unsigned opt;
+	enum {
+		OPT_R = (1 << 2),
+		OPT_N = (1 << 3),
+		/*OPT_f = (1 << 4), ignored */
+		/*OPT_E = (1 << 5), ignored, this is the default */
+		/*OPT_g = (1 << 6), ignored */
+		OPT_dry_run = (1 << 7) * ENABLE_LONG_OPTS,
+	};
+
+	xfunc_error_retval = 2;
+	{
+		const char *p = "-1";
+		const char *i = "-"; /* compat */
+#if ENABLE_LONG_OPTS
+		static const char patch_longopts[] ALIGN1 =
+			"strip\0"                 Required_argument "p"
+			"input\0"                 Required_argument "i"
+			"reverse\0"               No_argument       "R"
+			"forward\0"               No_argument       "N"
+		/* "Assume user knows what [s]he is doing, do not ask any questions": */
+			"force\0"                 No_argument       "f" /*ignored*/
+# if ENABLE_DESKTOP
+			"remove-empty-files\0"    No_argument       "E" /*ignored*/
+		/* "Controls actions when a file is under RCS or SCCS control,
+		 * and does not exist or is read-only and matches the default version,
+		 * or when a file is under ClearCase control and does not exist..."
+		 * IOW: rather obscure option.
+		 * But Gentoo's portage does use -g0 */
+			"get\0"                   Required_argument "g" /*ignored*/
+# endif
+			"dry-run\0"               No_argument       "\xfd"
+# if ENABLE_DESKTOP
+			"backup-if-mismatch\0"    No_argument       "\xfe" /*ignored*/
+			"no-backup-if-mismatch\0" No_argument       "\xff" /*ignored*/
+# endif
+			;
+		applet_long_options = patch_longopts;
+#endif
+		/* -f,-E,-g are ignored */
+		opt = getopt32(argv, "p:i:RN""fEg:", &p, &i, NULL);
+		if (opt & OPT_R)
+			plus = '-';
+		patch_level = xatoi(p); /* can be negative! */
+		patch_file = xfopen_stdin(i);
+	}
+
+	patch_line = xmalloc_fgetline(patch_file);
+	while (patch_line) {
+		FILE *src_stream;
+		FILE *dst_stream;
+		//char *old_filename;
+		char *new_filename;
+		char *backup_filename = NULL;
+		unsigned src_cur_line = 1;
+		unsigned dst_cur_line = 0;
+		unsigned dst_beg_line;
+		unsigned bad_hunk_count = 0;
+		unsigned hunk_count = 0;
+		smallint copy_trailing_lines_flag = 0;
+
+		/* Skip everything upto the "---" marker
+		 * No need to parse the lines "Only in <dir>", and "diff <args>"
+		 */
+		do {
+			/* Extract the filename used before the patch was generated */
+			new_filename = extract_filename(patch_line, patch_level, "--- ");
+			// was old_filename above
+			patch_line = xmalloc_fgetline(patch_file);
+			if (!patch_line) goto quit;
+		} while (!new_filename);
+		free(new_filename); // "source" filename is irrelevant
+
+		new_filename = extract_filename(patch_line, patch_level, "+++ ");
+		if (!new_filename) {
+			bb_error_msg_and_die("invalid patch");
+		}
+
+		/* Get access rights from the file to be patched */
+		if (stat(new_filename, &saved_stat) != 0) {
+			char *slash = strrchr(new_filename, '/');
+			if (slash) {
+				/* Create leading directories */
+				*slash = '\0';
+				bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
+				*slash = '/';
+			}
+			src_stream = NULL;
+			saved_stat.st_mode = 0644;
+		} else if (!(opt & OPT_dry_run)) {
+			backup_filename = xasprintf("%s.orig", new_filename);
+			xrename(new_filename, backup_filename);
+			src_stream = xfopen_for_read(backup_filename);
+		} else
+			src_stream = xfopen_for_read(new_filename);
+
+		if (opt & OPT_dry_run) {
+			dst_stream = xfopen_for_write("/dev/null");
+		} else {
+			dst_stream = xfopen_for_write(new_filename);
+			fchmod(fileno(dst_stream), saved_stat.st_mode);
+		}
+
+		printf("patching file %s\n", new_filename);
+
+		/* Handle all hunks for this file */
+		patch_line = xmalloc_fgets(patch_file);
+		while (patch_line) {
+			unsigned count;
+			unsigned src_beg_line;
+			unsigned hunk_offset_start;
+			unsigned src_last_line = 1;
+			unsigned dst_last_line = 1;
+
+			if ((sscanf(patch_line, "@@ -%d,%d +%d,%d", &src_beg_line, &src_last_line, &dst_beg_line, &dst_last_line) < 3)
+			 && (sscanf(patch_line, "@@ -%d +%d,%d", &src_beg_line, &dst_beg_line, &dst_last_line) < 2)
+			) {
+				/* No more hunks for this file */
+				break;
+			}
+			if (plus != '+') {
+				/* reverse patch */
+				unsigned tmp = src_last_line;
+				src_last_line = dst_last_line;
+				dst_last_line = tmp;
+				tmp = src_beg_line;
+				src_beg_line = dst_beg_line;
+				dst_beg_line = tmp;
+			}
+			hunk_count++;
+
+			if (src_beg_line && dst_beg_line) {
+				/* Copy unmodified lines upto start of hunk */
+				/* src_beg_line will be 0 if it's a new file */
+				count = src_beg_line - src_cur_line;
+				if (copy_lines(src_stream, dst_stream, count)) {
+					bb_error_msg_and_die("bad src file");
+				}
+				src_cur_line += count;
+				dst_cur_line += count;
+				copy_trailing_lines_flag = 1;
+			}
+			src_last_line += hunk_offset_start = src_cur_line;
+			dst_last_line += dst_cur_line;
+
+			while (1) {
+				free(patch_line);
+				patch_line = xmalloc_fgets(patch_file);
+				if (patch_line == NULL)
+					break; /* EOF */
+				if (!*patch_line) {
+					/* whitespace-damaged patch with "" lines */
+					free(patch_line);
+					patch_line = xstrdup(" ");
+				}
+				if ((*patch_line != '-') && (*patch_line != '+')
+				 && (*patch_line != ' ')
+				) {
+					break; /* End of hunk */
+				}
+				if (*patch_line != plus) { /* '-' or ' ' */
+					char *src_line = NULL;
+					if (src_cur_line == src_last_line)
+						break;
+					if (src_stream) {
+						src_line = xmalloc_fgets(src_stream);
+						if (src_line) {
+							int diff = strcmp(src_line, patch_line + 1);
+							src_cur_line++;
+							free(src_line);
+							if (diff)
+								src_line = NULL;
+						}
+					}
+					/* Do not patch an already patched hunk with -N */
+					if (src_line == 0 && (opt & OPT_N)) {
+						continue;
+					}
+					if (!src_line) {
+						bb_error_msg("hunk #%u FAILED at %u", hunk_count, hunk_offset_start);
+						bad_hunk_count++;
+						break;
+					}
+					if (*patch_line != ' ') { /* '-' */
+						continue;
+					}
+				}
+				if (dst_cur_line == dst_last_line)
+					break;
+				fputs(patch_line + 1, dst_stream);
+				dst_cur_line++;
+			} /* end of while loop handling one hunk */
+		} /* end of while loop handling one file */
+
+		/* Cleanup last patched file */
+		if (copy_trailing_lines_flag) {
+			copy_lines(src_stream, dst_stream, (unsigned)(-1));
+		}
+		if (src_stream) {
+			fclose(src_stream);
+		}
+		fclose(dst_stream);
+		if (bad_hunk_count) {
+			ret = 1;
+			bb_error_msg("%u out of %u hunk FAILED", bad_hunk_count, hunk_count);
+		} else {
+			/* It worked, we can remove the backup */
+			if (backup_filename) {
+				unlink(backup_filename);
+			}
+			if (!(opt & OPT_dry_run)
+			 && ((dst_cur_line == 0) || (dst_beg_line == 0))
+			) {
+				/* The new patched file is empty, remove it */
+				xunlink(new_filename);
+				// /* old_filename and new_filename may be the same file */
+				// unlink(old_filename);
+			}
+		}
+		free(backup_filename);
+		//free(old_filename);
+		free(new_filename);
+	} /* end of "while there are patch lines" */
+ quit:
+	/* 0 = SUCCESS
+	 * 1 = Some hunks failed
+	 * 2 = More serious problems (exited earlier)
+	 */
+	return ret;
+}