MDEV-26548: replace .mysql_history with .mariadb_history

Fall back to using .mysql_history if .mariadb_history isn't
present and .mysql_history is present.

Also replace the use of MYSQL_HISTFILE as an environment variable
with MARIADB_HISTFILE and fall back to using MYSQL_HISTFILE if
MARIADB_HISTFILE isn't present.

client/mysql.cc

@@ -1337,26 +1337,38 @@ int main(int argc,char *argv[])
   initialize_readline();
   if (!status.batch && !quick && !opt_html && !opt_xml)
   {
-    /* read-history from file, default ~/.mysql_history*/
-    if (getenv("MYSQL_HISTFILE"))
-      histfile=my_strdup(PSI_NOT_INSTRUMENTED, getenv("MYSQL_HISTFILE"),MYF(MY_WME));
-    else if (getenv("HOME"))
+    const char *home;
+    /* read-history from file, default ~/.mariadb_history*/
+    if ((histfile= getenv("MARIADB_HISTFILE"))
+        || (histfile= getenv("MYSQL_HISTFILE")))
+      histfile=my_strdup(PSI_NOT_INSTRUMENTED, histfile, MYF(MY_WME));
+    else if ((home= getenv("HOME")))
     {
       histfile=(char*) my_malloc(PSI_NOT_INSTRUMENTED,
-            strlen(getenv("HOME")) + strlen("/.mysql_history")+2, MYF(MY_WME));
+            strlen(home) + strlen("/.mariadb_history")+2, MYF(MY_WME));
       if (histfile)
-	sprintf(histfile,"%s/.mysql_history",getenv("HOME"));
-      char link_name[FN_REFLEN];
-      if (my_readlink(link_name, histfile, 0) == 0 &&
-          strncmp(link_name, "/dev/null", 10) == 0)
       {
-        /* The .mysql_history file is a symlink to /dev/null, don't use it */
-        my_free(histfile);
-        histfile= 0;
+        sprintf(histfile,"%s/.mariadb_history", home);
+        if (my_access(histfile, F_OK))
+        {
+          /* no .mariadb_history, look for historical name and use if present */
+          sprintf(histfile,"%s/.mysql_history", home);
+          /* and go back to original if not found */
+          if (my_access(histfile, F_OK))
+            sprintf(histfile,"%s/.mariadb_history", home);
+        }
+        char link_name[FN_REFLEN];
+        if (my_readlink(link_name, histfile, 0) == 0 &&
+            strncmp(link_name, "/dev/null", 10) == 0)
+        {
+          /* The .mariadb_history file is a symlink to /dev/null, don't use it */
+          my_free(histfile);
+          histfile= 0;
+        }
       }
     }
 
-    /* We used to suggest setting MYSQL_HISTFILE=/dev/null. */
+    /* We used to suggest setting MARIADB_HISTFILE=/dev/null. */
     if (histfile && strncmp(histfile, "/dev/null", 10) == 0)
       histfile= NULL;
 

man/mysql.1

@@ -1630,28 +1630,29 @@ SELECT
 statements when using
 \fB\-\-safe\-updates\fR\&. (Default value is 1,000\&.)
 .RE
-.\" MYSQL_HISTFILE environment variable
-.\" environment variable: MYSQL_HISTFILE
+.\" MARIADB_HISTFILE environment variable
+.\" environment variable: MARIADB_HISTFILE
 .\" HOME environment variable
 .\" environment variable: HOME
 .\" mysql history file
 .\" command-line history: mysql
-.\" .mysql_history file
+.\" .mariadb_history file
 .PP
 On Unix, the
 \fBmysql\fR
 client writes a record of executed statements to a history file\&. By default, this file is named
-\&.mysql_history
-and is created in your home directory\&. To specify a different file, set the value of the
-MYSQL_HISTFILE
-environment variable\&.
+\&.mariadb_history
+and is created in your home directory\&. For backwards compatibility \&.mysql_history will be used if present and
+\&.mariadb_history is missing\&. To specify a different file, set the value of the
+MARIADB_HISTFILE
+environment variable\&. The environment variable MYSQL_HISTFILE will be used if MARIADB_HISTFILE isn't present\&.
 .PP
 The
-\&.mysql_history
+\&.mariadb_history
 should be protected with a restrictive access mode because sensitive information might be written to it, such as the text of SQL statements that contain passwords\&.
 .PP
 If you do not want to maintain a history file, first remove
-\&.mysql_history
+\&.mariadb_history
 if it exists, and then use either of the following techniques:
 .sp
 .RS 4
@@ -1663,7 +1664,7 @@ if it exists, and then use either of the following techniques:
 .IP \(bu 2.3
 .\}
 Set the
-MYSQL_HISTFILE
+MARIADB_HISTFILE
 variable to
 /dev/null\&. To cause this setting to take effect each time you log in, put the setting in one of your shell\'s startup files\&.
 .RE
@@ -1677,7 +1678,7 @@ variable to
 .IP \(bu 2.3
 .\}
 Create
-\&.mysql_history
+\&.mariadb_history
 as a symbolic link to
 /dev/null:
 .sp
@@ -1685,7 +1686,7 @@ as a symbolic link to
 .RS 4
 .\}
 .nf
-shell> \fBln \-s /dev/null $HOME/\&.mysql_history\fR
+shell> \fBln \-s /dev/null $HOME/\&.mariadb_history\fR
 .fi
 .if n \{\
 .RE