Code and docs review for multiple -c and -f options in psql.

Commit d5563d7df94488bf drew complaints from Coverity, which quite
correctly complained that one copy of each -c or -f string was being
leaked.  What's more, simple_action_list_append was allocating enough space
for still a third copy of each string as part of the SimpleActionListCell,
even though that coding method had been superseded by a separate strdup
operation.  There were some other minor coding infelicities too.  The
documentation needed more work as well, eg it forgot to explain that -c
causes psql not to accept any interactive input.

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 47e9da2c8a5778a9af752a83a7f3fd8692396808..a416c1de9f9c64a1d6cc63cc1d40dbda6283c59f 100644 (file)
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -39,9 +39,9 @@ PostgreSQL documentation
      queries interactively, issue them to
      PostgreSQL, and see the query results.
      Alternatively, input can be from a file or from command line
-     arguments. In addition, it provides a number of meta-commands and various
-     shell-like features to facilitate writing scripts and automating a wide
-     variety of tasks.
+     arguments. In addition, psql provides a
+     number of meta-commands and various shell-like features to
+     facilitate writing scripts and automating a wide variety of tasks.
     
  
 
@@ -90,42 +90,50 @@ PostgreSQL documentation
       --command=command
       
       
-      Specifies that psql is to execute the given
-      command string, command.
-      This option can be repeated and combined in any order with
-      the -f option.
+       Specifies that psql is to execute the given
+       command string, command.
+       This option can be repeated and combined in any order with
+       the -f option.  When either -c
+       or -f is specified, psql
+       does not read commands from standard input; instead it terminates
+       after processing all the -c and -f
+       options in sequence.
       
       
-      command must be either
-      a command string that is completely parsable by the server (i.e.,
-      it contains no psql-specific features),
-      or a single backslash command. Thus you cannot mix
-      SQL and psql
-      meta-commands with this option. To achieve that, you could
-      use repeated -c options or pipe the string
-      into psql, for example:
-      psql -c '\x' -c 'SELECT * FROM foo;' or
-      echo '\x \\ SELECT * FROM foo;' | psql.
-      (\\ is the separator meta-command.)
+       command must be either
+       a command string that is completely parsable by the server (i.e.,
+       it contains no psql-specific features),
+       or a single backslash command. Thus you cannot mix
+       SQL and psql
+       meta-commands within a -c option. To achieve that,
+       you could use repeated -c options or pipe the string
+       into psql, for example:
+
+psql -c '\x' -c 'SELECT * FROM foo;'
+
+       or
+
+echo '\x \\ SELECT * FROM foo;' | psql
+
+       (\\ is the separator meta-command.)
       
       
-       Each command string passed to -c is sent to the server
-       as a single query. Because of this, the server executes it as a single
-       transaction, even if a command string contains
-       multiple SQL commands, unless there are
-       explicit BEGIN/COMMIT commands included in the
-       string to divide it into multiple transactions.  Also, the server only
-       returns the result of the last SQL command to the
-       client.  This is different from the behavior when the same string with
-       multiple SQL commands is fed
-       to psql's standard input because
-       then psql sends each SQL
-       command separately.
+       Each SQL command string passed
+       to -c is sent to the server as a single query.
+       Because of this, the server executes it as a single transaction even
+       if the string contains multiple SQL commands,
+       unless there are explicit BEGIN/COMMIT
+       commands included in the string to divide it into multiple
+       transactions.  Also, psql only prints the
+       result of the last SQL command in the string.
+       This is different from the behavior when the same string is read from
+       a file or fed to psql's standard input,
+       because then psql sends
+       each SQL command separately.
       
       
-       Putting more than one command in the -c string often
-       has unexpected results.  This is a result of the fact that the whole
-       string is sent to the server as a single query.
+       Because of this behavior, putting more than one command in a
+       single -c string often has unexpected results.
        It's better to use repeated -c commands or feed
        multiple commands to psql's standard input,
        either using echo as illustrated above, or
@@ -192,18 +200,26 @@ EOF
       --file=filename
       
       
-      Use the file filename
-      as the source of commands instead of reading commands interactively.
-      This option can be repeated and combined in any order with
-      the -c option.  After the commands in
-      every -c command string and -f file
-      are processed, psql terminates.  This option
-      is in many ways equivalent to the meta-command \i.
+       Read commands from the
+       file filename,
+       rather than standard input.
+       This option can be repeated and combined in any order with
+       the -c option.  When either -c
+       or -f is specified, psql
+       does not read commands from standard input; instead it terminates
+       after processing all the -c and -f
+       options in sequence.
+       Except for that, this option is largely equivalent to the
+       meta-command \i.
       
 
       
        If filename is -
-       (hyphen), then standard input is read.
+       (hyphen), then standard input is read until an EOF indication
+       or \q meta-command.  This can be used to intersperse
+       interactive input with input from files.  Note however that Readline
+       is not used in this case (much as if -n had been
+       specified).
       
 
       
@@ -550,12 +566,13 @@ EOF
       --single-transaction
       
        
-        When psql executes commands from a script
-        and/or a -c option, adding this option
-        wraps BEGIN/COMMIT around all of those
-        commands as a whole to execute them as a single transaction.  This
-        ensures that either all the commands complete successfully, or no
-        changes are applied.
+        This option can only be used in combination with one or more
+        -c and/or -f options.  It causes
+        psql to issue a BEGIN command
+        before the first such option and a COMMIT command after
+        the last one, thereby wrapping all the commands into a single
+        transaction.  This ensures that either all the commands complete
+        successfully, or no changes are applied.
        
 
        
@@ -3799,16 +3816,6 @@ PSQL_EDITOR_LINENUMBER_ARG='--line '
   Notes
 
     
-      
-      
-       In an earlier life psql allowed the
-       first argument of a single-letter backslash command to start
-       directly after the command, without intervening whitespace.
-       As of PostgreSQL 8.4 this is no
-       longer allowed.
-      
-      
-
       
       psql works best with servers of the same
        or an older major version.  Backslash commands are particularly likely
@@ -3824,8 +3831,8 @@ PSQL_EDITOR_LINENUMBER_ARG='--line '
        If you want to use psql to connect to several
        servers of different major versions, it is recommended that you use the
        newest version of psql.  Alternatively, you
-       can keep a copy of psql from each major
-       version around and be sure to use the version that matches the
+       can keep around a copy of psql from each
+       major version and be sure to use the version that matches the
        respective server.  But in practice, this additional complication should
        not be necessary.
       
@@ -3833,8 +3840,19 @@ PSQL_EDITOR_LINENUMBER_ARG='--line '
 
       
       
-       Before PostgreSQL 9.6, -c
-       implied -X; this is no longer the case.
+       Before PostgreSQL 9.6,
+       the -c option implied -X
+       (--no-psqlrc); this is no longer the case.
+      
+      
+
+      
+      
+       Before PostgreSQL 8.4,
+       psql allowed the
+       first argument of a single-letter backslash command to start
+       directly after the command, without intervening whitespace.
+       Now, some whitespace is required.
       
       
     

diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c
index 17fb943dfab7bd9133b5f28fd7ec9cfc11fb4d6b..004747810966ef163a00cbd0d2549050315fef4c 100644 (file)
--- a/src/bin/psql/startup.c
+++ b/src/bin/psql/startup.c
@@ -58,8 +58,8 @@ enum _actions
 typedef struct SimpleActionListCell
 {
    struct SimpleActionListCell *next;
-   int         action;
-   char       *val;
+   enum _actions action;
+   char       *val;
 } SimpleActionListCell;
 
 typedef struct SimpleActionList
@@ -84,11 +84,11 @@ struct adhoc_opts
 
 static void parse_psql_options(int argc, char *argv[],
                   struct adhoc_opts * options);
+static void simple_action_list_append(SimpleActionList *list,
+                         enum _actions action, const char *val);
 static void process_psqlrc(char *argv0);
 static void process_psqlrc_file(char *filename);
 static void showVersion(void);
-static void simple_action_list_append(SimpleActionList *list,
-                                     int action, const char *val);
 static void EstablishVariableSpace(void);
 
 #define NOPAGER        0
@@ -172,9 +172,6 @@ main(int argc, char *argv[])
    SetVariable(pset.vars, "PROMPT2", DEFAULT_PROMPT2);
    SetVariable(pset.vars, "PROMPT3", DEFAULT_PROMPT3);
 
-   options.actions.head = NULL;
-   options.actions.tail = NULL;
-
    parse_psql_options(argc, argv, &options);
 
    /*
@@ -298,13 +295,13 @@ main(int argc, char *argv[])
        process_psqlrc(argv[0]);
 
    /*
-    * If any actions were given by caller, process them in the order in
-    * which they were specified.
+    * If any actions were given by user, process them in the order in which
+    * they were specified.  Note single_txn is only effective in this mode.
     */
    if (options.actions.head != NULL)
    {
-       PGresult        *res;
-       SimpleActionListCell    *cell;
+       PGresult   *res;
+       SimpleActionListCell *cell;
 
        successResult = EXIT_SUCCESS;   /* silence compiler */
 
@@ -341,8 +338,8 @@ main(int argc, char *argv[])
 
                scan_state = psql_scan_create();
                psql_scan_setup(scan_state,
-                           cell->val,
-                           strlen(cell->val));
+                               cell->val,
+                               strlen(cell->val));
 
                successResult = HandleSlashCmds(scan_state, NULL) != PSQL_CMD_ERROR
                    ? EXIT_SUCCESS : EXIT_FAILURE;
@@ -356,7 +353,7 @@ main(int argc, char *argv[])
            else
            {
                /* should never come here */
-               Assert(0);
+               Assert(false);
            }
 
            if (successResult != EXIT_SUCCESS && pset.on_error_stop)
@@ -473,11 +470,11 @@ parse_psql_options(int argc, char *argv[], struct adhoc_opts * options)
                if (optarg[0] == '\\')
                    simple_action_list_append(&options->actions,
                                              ACT_SINGLE_SLASH,
-                                             pstrdup(optarg + 1));
+                                             optarg + 1);
                else
                    simple_action_list_append(&options->actions,
                                              ACT_SINGLE_QUERY,
-                                             pstrdup(optarg));
+                                             optarg);
                break;
            case 'd':
                options->dbname = pg_strdup(optarg);
@@ -490,8 +487,8 @@ parse_psql_options(int argc, char *argv[], struct adhoc_opts * options)
                break;
            case 'f':
                simple_action_list_append(&options->actions,
-                                   ACT_FILE,
-                                   pg_strdup(optarg));
+                                         ACT_FILE,
+                                         optarg);
                break;
            case 'F':
                pset.popt.topt.fieldSep.separator = pg_strdup(optarg);
@@ -672,6 +669,33 @@ parse_psql_options(int argc, char *argv[], struct adhoc_opts * options)
 }
 
 
+/*
+ * Append a new item to the end of the SimpleActionList.
+ * Note that "val" is copied if it's not NULL.
+ */
+static void
+simple_action_list_append(SimpleActionList *list,
+                         enum _actions action, const char *val)
+{
+   SimpleActionListCell *cell;
+
+   cell = (SimpleActionListCell *) pg_malloc(sizeof(SimpleActionListCell));
+
+   cell->next = NULL;
+   cell->action = action;
+   if (val)
+       cell->val = pg_strdup(val);
+   else
+       cell->val = NULL;
+
+   if (list->tail)
+       list->tail->next = cell;
+   else
+       list->head = cell;
+   list->tail = cell;
+}
+
+
 /*
  * Load .psqlrc file, if found.
  */
@@ -945,39 +969,6 @@ show_context_hook(const char *newval)
 }
 
 
-/*
- * Support for list of actions. SimpleStringList cannot be used due possible
- * combination different actions with the requirement to save the order.
- */
-static void
-simple_action_list_append(SimpleActionList *list, int action, const char *val)
-{
-   SimpleActionListCell   *cell;
-   size_t                  vallen = 0;
-
-   if (val)
-       vallen = strlen(val);
-
-   cell = (SimpleActionListCell *)
-       pg_malloc(offsetof(SimpleActionListCell, val) + vallen + 1);
-
-   cell->next = NULL;
-   cell->action = action;
-   if (val)
-   {
-       cell->val = pg_malloc(vallen + 1);
-       strcpy(cell->val, val);
-   }
-   else
-       cell->val = NULL;
-
-   if (list->tail)
-       list->tail->next = cell;
-   else
-       list->head = cell;
-   list->tail = cell;
-}
-
 static void
 EstablishVariableSpace(void)
 {