sled

чување cec2b429688d1cf8995d8675aee116801fe55513
родитељ eae3b7176476cfa5fdcc49475d81fa31daa02ce9
Аутор: Страхиња Радић <contact@strahinja.org>
Датум:   Sat,  2 Mar 2024 20:19:04 +0100

Copy file to backup instead of rename(2)-ing it (crontab -e fix)

Signed-off-by: Страхиња Радић <contact@strahinja.org>

Diffstat:
M
TODO
 | 
16
----------------
M
TODO.done
 | 
16
++++++++++++++++
M
draw.c
 | 
2
+-
M
sled.c
 | 
79
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
M
util.h
 | 
3
++-

измењених датотека: 5, додавања: 89(+), брисања: 27(-)
diff --git a/TODO b/TODO
@@ -5,22 +5,6 @@ TODO
 
 [ ] Switch to strlcpy, strlcat; check u8_*/u32_*
 
-[ ] Change the backup method, as `crontab -e` doesn't like inode changes
-    (crontab -e with CREATE_BACKUPS gives:
-
-	crontab: crontab temp file moved, editor may create backup files\
-improperly
-	crontab: no changes made to crontab
-
-    - Currently:
-    	mv file file~
-	write to file
-
-    - Planned:
-	cp file file~		\ very inelegant, but the
-	<change file~ mtime?>	/ only way to appease crontab -e
-	write to file
-
 
 Legend
 ------
diff --git a/TODO.done b/TODO.done
@@ -1,6 +1,22 @@
 Done or canceled todos
 ======================
 
+[x] Change the backup method, as `crontab -e` doesn't like inode changes
+    (crontab -e with CREATE_BACKUPS gives:
+
+	crontab: crontab temp file moved, editor may create backup files\
+improperly
+	crontab: no changes made to crontab
+
+    - Currently:
+    	mv file file~
+	write to file
+
+    - Planned:
+	cp file file~		\ very inelegant, but the
+	<change file~ mtime?>	/ only way to appease crontab -e
+	write to file
+
 [/] Investigate segfault:
 	sled README
 	C-\
diff --git a/draw.c b/draw.c
@@ -51,7 +51,7 @@ const char* errors[]           = {
 	[ERR_CANT_ALLOC]       = "Memory allocation failed",
 	[ERR_CANT_SAVE]	       = "File is not writeable",
 	[ERR_CANT_OPEN]	       = "Cannot read file",
-	[ERR_CANT_MOVE]	       = "Cannot move temporary file",
+	[ERR_CANT_COPY]	       = "Cannot create the backup file",
 	[ERR_INPUT_NONNUM]     = "Input must be numerical",
 	[ERR_INVALID_NUM]      = "Invalid input"};
 const char* actions[]  = {
diff --git a/sled.c b/sled.c
@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #define TB_OPT_V1_COMPAT
@@ -39,7 +40,7 @@ enum {
 	SAVE_ERR_NONE		= 0,
 	SAVE_ERR_CANT_ALLOC	= 1,
 	SAVE_ERR_CANT_OPEN_FILE = 2,
-	SAVE_ERR_CANT_MOVE_FILE = 3,
+	SAVE_ERR_CANT_COPY_FILE = 3,
 	SAVE_ERR_CANT_STAT_FILE = 4,
 	SAVE_ERR_CANT_READLINK	= 5,
 	SAVE_ERR_CANT_SYMLINK	= 6,
@@ -59,6 +60,7 @@ extern const char* prompt_reread_dirty;
 extern const char* program_name;
 
 int clear_selection(struct DrawState* state);
+int cp(const char* from, const char* to);
 int create_file(struct DrawState* dstate);
 char* dirname(char* path);
 int do_search_replace(struct DrawState* state);
@@ -95,6 +97,66 @@ clear_selection(struct DrawState* state)
 }
 
 int
+cp(const char* from, const char* to)
+{
+	int fromfd, tofd;
+	int nread    = 0;
+	int nwritten = 0;
+	char buf[MAXCOPYBUF];
+	int result;
+	struct stat st;
+	struct timespec times[2];
+
+	fromfd = open(from, O_RDONLY);
+	if (fromfd < 0)
+		return -1;
+	tofd = open(to, O_WRONLY | O_CREAT | O_TRUNC);
+	if (tofd < 0)
+		return -1;
+
+	if (fstat(fromfd, &st) < 0)
+	{
+		result = -1;
+		goto cp_cleanup;
+	}
+	if (fchmod(tofd, st.st_mode) < 0)
+	{
+		result = -1;
+		goto cp_cleanup;
+	}
+	times[0] = st.st_atim;
+	times[1] = st.st_mtim;
+
+	result = 0;
+	while ((nread = read(fromfd, buf, MAXCOPYBUF)) > 0)
+	{
+		nwritten = write(tofd, buf, nread);
+		if (nwritten < nread)
+		{
+			result = -1;
+			goto cp_cleanup;
+		}
+		result += nwritten;
+	}
+
+	if (nread < 0)
+	{
+		result = -1;
+		goto cp_cleanup;
+	}
+
+	errno = 0;
+	if (futimens(tofd, times) < 0)
+		result = -1;
+
+cp_cleanup:
+	close(tofd);
+	close(fromfd);
+
+	return result;
+}
+
+int
 create_file(struct DrawState* state)
 {
 	struct BufferLine* newchunk = NULL;
@@ -890,21 +952,20 @@ save_file(struct DrawState* state)
 	if (state->backup_possible)
 	{
 		if (unlink(state->backup_filename) < 0 && errno != ENOENT)
-			return SAVE_ERR_CANT_MOVE_FILE;
+			return SAVE_ERR_CANT_COPY_FILE;
 		errno = 0;
-		rename(state->rfn_len > 0 ? state->real_filename
-					  : state->filename,
+		cp(state->rfn_len > 0 ? state->real_filename : state->filename,
 			state->backup_filename);
 		errno = 0; /* ignore errors */
 	}
 #else  /* !BACKUP_FAIL_OK */
 	if (unlink(state->backup_filename) < 0 && errno != ENOENT)
-		return SAVE_ERR_CANT_MOVE_FILE;
+		return SAVE_ERR_CANT_COPY_FILE;
 
-	if (rename(state->rfn_len > 0 ? state->real_filename : state->filename,
+	if (cp(state->rfn_len > 0 ? state->real_filename : state->filename,
 		    state->backup_filename)
 		== -1)
-		return SAVE_ERR_CANT_MOVE_FILE;
+		return SAVE_ERR_CANT_COPY_FILE;
 #endif /* BACKUP_FAIL_OK */
 #endif /* CREATE_BACKUPS */
 
@@ -2146,8 +2207,8 @@ write_file(struct DrawState* state)
 		strcpy(state->error, errors[ERR_CANT_SAVE]);
 		state->running = 0;
 		break;
-	case SAVE_ERR_CANT_MOVE_FILE:
-		strcpy(state->error, errors[ERR_CANT_MOVE]);
+	case SAVE_ERR_CANT_COPY_FILE:
+		strcpy(state->error, errors[ERR_CANT_COPY]);
 		state->running = 0;
 		break;
 	case SAVE_ERR_CANT_READLINK:
diff --git a/util.h b/util.h
@@ -28,7 +28,7 @@ enum {
 	ERR_CANT_ALLOC,
 	ERR_CANT_SAVE,
 	ERR_CANT_OPEN,
-	ERR_CANT_MOVE,
+	ERR_CANT_COPY,
 	ERR_INPUT_NONNUM,
 	ERR_INVALID_NUM
 };
@@ -37,6 +37,7 @@ enum { ACT_WRITING, ACT_READING };
 
 #define ALLOC_DELTA 50
 #define MAXBUFLINE  4096
+#define MAXCOPYBUF  8192
 #define MAXDATEBUF  80
 #define MAXFLAGSBUF (4 + 1)
 #define MAXMSGLINE  1024