X-Git-Url: https://plomlompom.com/repos/feed.xml?a=blobdiff_plain;f=src%2Fcommon%2Freadwrite.c;h=c9e22d73d3ae16dd7fd37a19b17908cebc07921e;hb=6ac951c41a091ffc723840894ddf1e774739511d;hp=c27e86143bc7feb5ff0471df654f70ff960d4a33;hpb=778534bf6946fe0fef17e353c55678d248d8d09d;p=plomrogue

diff --git a/src/common/readwrite.c b/src/common/readwrite.c
index c27e861..c9e22d7 100644
--- a/src/common/readwrite.c
+++ b/src/common/readwrite.c
@@ -14,6 +14,24 @@
 
 
 
+/* Return "path" + suffix "_tmp". Value is malloc'd, must be free externally. */
+static char * build_temp_path(char * path);
+
+
+
+static char * build_temp_path(char * path)
+{
+    char * f_name = "build_temp_path";
+    char * suffix_tmp = "_tmp";
+    uint16_t size = strlen(path) + strlen(suffix_tmp) + 1;
+    char * path_tmp = try_malloc(size, f_name);
+    int test = sprintf(path_tmp, "%s%s", path, suffix_tmp);
+    exit_trouble(test < 0, f_name, "sprintf()");
+    return path_tmp;
+}
+
+
+
 extern FILE * try_fopen(char * path, char * mode, char * f)
 {
     char * f_name = "try_fopen()";
@@ -75,33 +93,64 @@ extern char * try_fgets(char * line, int linemax, FILE * file, char * f)
 
 
 
-extern void try_fclose_unlink_rename(FILE * file, char * p1, char * p2,
-                                     char * f)
+extern FILE * atomic_write_start(char * path, char ** path_tmp)
+{
+    char * f_name = "atomic_write_start()";
+    *path_tmp = build_temp_path(path);
+    return try_fopen(*path_tmp, "w", f_name);
+}
+
+
+
+extern void atomic_write_finish(FILE * file, char * path, char * path_tmp)
 {
-    char * f_name = "try_fclose_unlink_rename()";
-    try_fclose(file, f);
+    char * f_name = "atomic_write_finish()";
+    try_fclose(file, f_name);
     char * msg1 = "Trouble in ";
     char * msg4 = "'.";
-    if (!access(p2, F_OK))
+    if (!access(path, F_OK))
     {
         char * msg2 = " with unlink() on path '";
         uint16_t size = strlen(msg1) + strlen(msg2) + strlen(msg4)
-                        + strlen(f) + strlen(p2) + 1;
+                        + strlen(f_name) + strlen(path) + 1;
         char * msg = try_malloc(size, f_name);
-        int test = sprintf(msg, "%s%s%s%s%s", msg1, f, msg2, p2, msg4);
+        int test = sprintf(msg, "%s%s%s%s%s", msg1, f_name, msg2, path, msg4);
         exit_trouble(test < 0, f_name, "sprintf()");
-        exit_err(unlink(p2), msg);
+        exit_err(unlink(path), msg);
         free(msg);
     }
     char * msg2 = " with rename() from '";
     char * msg3 = "' to '";
-    uint16_t size = strlen(msg1) + strlen(f) + strlen(msg2) + strlen(p1)
-                    + strlen(msg3) + strlen(p2) + strlen(msg4) + 1;
+    uint16_t size =   strlen(msg1) + strlen(f_name) + strlen(msg2) +
+                    + strlen(path_tmp) + strlen(msg3) + strlen(path)
+                    + strlen(msg4) + 1;
+    char * msg = try_malloc(size, f_name);
+    int test = sprintf(msg, "%s%s%s%s%s%s%s",
+                            msg1, f_name, msg2, path_tmp, msg3, path, msg4);
+    exit_trouble(test < 0, f_name, "sprintf()");
+    exit_err(rename(path_tmp, path), msg);
+    free(msg);
+    free(path_tmp);
+}
+
+
+
+extern void detect_atomic_leftover(char * path)
+{
+    char * f_name = "detect_atomic_leftover()";
+    char * path_tmp = build_temp_path(path);
+    char * part1 = "Found file '";
+    char * part2 = "' that may be a leftover from an aborted previous attempt "
+                   "to write '";
+    char * part3 = "'. Aborting until the matter is solved by (re-)moving it.";
+    uint32_t size =   strlen(part1) + strlen(path_tmp) + strlen(part2)
+                    + strlen(path) + strlen(part3) + 1;
     char * msg = try_malloc(size, f_name);
-    int test = sprintf(msg, "%s%s%s%s%s%s%s", msg1,f,msg2,p1,msg3,p2,msg4);
+    int test = sprintf(msg, "%s%s%s%s%s", part1, path_tmp, part2, path, part3);
     exit_trouble(test < 0, f_name, "sprintf()");
-    exit_err(rename(p1, p2), msg);
+    exit_err(!access(path_tmp, F_OK), msg);
     free(msg);
+    free(path_tmp);
 }