New --chmod support routines.

chmod.c

+#include "rsync.h"
+
+extern int orig_umask;
+
+#define FLAG_X_KEEP (1<<0)
+#define FLAG_DIRS_ONLY (1<<1)
+#define FLAG_FILES_ONLY (1<<2)
+
+struct chmod_mode_struct {
+	struct chmod_mode_struct *next;
+	int ModeAND, ModeOR;
+	char flags;
+};
+
+#define CHMOD_ADD 1
+#define CHMOD_SUB 2
+#define CHMOD_EQ  3
+
+#define STATE_ERROR 0
+#define STATE_1ST_HALF 1
+#define STATE_2ND_HALF 2
+
+/* Parse a chmod-style argument, and break it down into one or more AND/OR
+ * pairs in a linked list.  We use a state machine to walk through the
+ * options. */
+struct chmod_mode_struct *parse_chmod(char *modestr)
+{
+	int state = STATE_1ST_HALF;
+	int where = 0, what = 0, op = 0, topbits = 0, topoct = 0, flags = 0;
+	struct chmod_mode_struct *first_mode = NULL, *curr_mode = NULL,
+	    *prev_mode = NULL;
+
+	while (state != STATE_ERROR) {
+		if (!*modestr || *modestr == ',') {
+			int bits;
+
+			if (!op) {
+				state = STATE_ERROR;
+				break;
+			}
+			prev_mode = curr_mode;
+			curr_mode = new_array(struct chmod_mode_struct, 1);
+			if (prev_mode)
+				prev_mode->next = curr_mode;
+			else
+				first_mode = curr_mode;
+			curr_mode->next = NULL;
+
+			if (where)
+				bits = where * what;
+			else {
+				where = 0111;
+				bits = (where * what) & ~orig_umask;
+			}
+
+			switch (op) {
+			case CHMOD_ADD:
+				curr_mode->ModeAND = 07777;
+				curr_mode->ModeOR  = bits + topoct;
+				break;
+			case CHMOD_SUB:
+				curr_mode->ModeAND = 07777 - bits - topoct;
+				curr_mode->ModeOR  = 0;
+				break;
+			case CHMOD_EQ:
+				curr_mode->ModeAND = 07777 - (where * 7) - (topoct ? topbits : 0);
+				curr_mode->ModeOR  = bits + topoct;
+				break;
+			}
+
+			curr_mode->flags = flags;
+
+			if (!*modestr)
+				break;
+			modestr++;
+
+			state = STATE_1ST_HALF;
+			where = what = op = topoct = topbits = flags = 0;
+		}
+
+		if (state != STATE_2ND_HALF) {
+			switch (*modestr) {
+			case 'D':
+				if (flags & FLAG_FILES_ONLY)
+					state = STATE_ERROR;
+			  	flags |= FLAG_DIRS_ONLY;
+				break;
+			case 'F':
+				if (flags & FLAG_DIRS_ONLY)
+					state = STATE_ERROR;
+			  	flags |= FLAG_FILES_ONLY;
+				break;
+			case 'u':
+				where |= 0100;
+				topbits |= 04000;
+				break;
+			case 'g':
+				where |= 0010;
+				topbits |= 02000;
+				break;
+			case 'o':
+				where |= 0001;
+				break;
+			case 'a':
+				where |= 0111;
+				break;
+			case '+':
+				op = CHMOD_ADD;
+				state = STATE_2ND_HALF;
+				break;
+			case '-':
+				op = CHMOD_SUB;
+				state = STATE_2ND_HALF;
+				break;
+			case '=':
+				op = CHMOD_EQ;
+				state = STATE_2ND_HALF;
+				break;
+			default:
+				state = STATE_ERROR;
+				break;
+			}
+		} else {
+			switch (*modestr) {
+			case 'r':
+				what |= 4;
+				break;
+			case 'w':
+				what |= 2;
+				break;
+			case 'X':
+			  	flags |= FLAG_X_KEEP;
+				/* FALL THROUGH */
+			case 'x':
+				what |= 1;
+				break;
+			case 's':
+				if (topbits)
+					topoct |= topbits;
+				else
+					topoct = 04000;
+				break;
+			case 't':
+				topoct |= 01000;
+				break;
+			default:
+				state = STATE_ERROR;
+				break;
+			}
+		}
+		modestr++;
+	}
+
+	if (state == STATE_ERROR) {
+		free_chmod_mode(first_mode);
+		first_mode = NULL;
+	}
+	return first_mode;
+}
+
+
+/* Takes an existing file permission and a list of AND/OR changes, and
+ * create a new permissions. */
+int tweak_mode(int mode, struct chmod_mode_struct *chmod_modes)
+{
+	int IsX = mode & 0111;
+	int NonPerm = mode & ~07777;
+
+	for ( ; chmod_modes; chmod_modes = chmod_modes->next) {
+		if ((chmod_modes->flags & FLAG_DIRS_ONLY) && !S_ISDIR(NonPerm))
+			continue;
+		if ((chmod_modes->flags & FLAG_FILES_ONLY) && S_ISDIR(NonPerm))
+			continue;
+		mode &= chmod_modes->ModeAND;
+		if ((chmod_modes->flags & FLAG_X_KEEP) && !IsX && !S_ISDIR(NonPerm))
+			mode |= chmod_modes->ModeOR & ~0111;
+		else
+			mode |= chmod_modes->ModeOR;
+	}
+
+	return mode | NonPerm;
+}
+
+/* Free the linked list created by parse_chmod. */
+int free_chmod_mode(struct chmod_mode_struct *chmod_modes)
+{
+	struct chmod_mode_struct *next;
+
+	while (chmod_modes) {
+		next = chmod_modes->next;
+		free(chmod_modes);
+		chmod_modes = next;
+	}
+	return 0;
+}