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libpq was not consistently checking for memory allocation failures. This

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patch adds missing checks to the call sites of malloc(), strdup(),
PQmakeEmptyPGresult(), pqResultAlloc(), and pqResultStrdup(), and updates
the documentation. Per original report from Volkan Yazici about
PQmakeEmptyPGresult() not checking for malloc() failure.
This commit is contained in:
Neil Conway
2005-06-12 00:00:21 +00:00
parent 2f1210629c
commit 72a5db15d1
8 changed files with 206 additions and 117 deletions
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55
doc/src/sgml/libpq.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.184 2005/06/10 03:02:01 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.185 2005/06/12 00:00:20 neilc Exp $
-->
<chapter id="libpq">
@ -581,14 +581,15 @@ typedef struct
</para>
<para>
Returns a connection options array. This may
be used to determine all possible <function>PQconnectdb</function> options and their
Returns a connection options array. This may be used to determine
all possible <function>PQconnectdb</function> options and their
current default values. The return value points to an array of
<structname>PQconninfoOption</structname> structures, which ends with an entry having a null
<structfield>keyword</> pointer. Note that the current default values
(<structfield>val</structfield> fields)
will depend on environment variables and other context.
Callers must treat the connection options data as read-only.
<structname>PQconninfoOption</structname> structures, which ends
with an entry having a null <structfield>keyword</> pointer. The
null pointer is returned if memory could not be allocated. Note that
the current default values (<structfield>val</structfield> fields)
will depend on environment variables and other context. Callers
must treat the connection options data as read-only.
</para>
<para>
@ -1651,18 +1652,22 @@ void PQclear(PGresult *res);
<para>
Constructs an empty <structname>PGresult</structname> object with the given status.
<synopsis>
PGresult* PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status);
PGresult *PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status);
</synopsis>
</para>
<para>
This is <application>libpq</>'s internal function to allocate and initialize an empty
<structname>PGresult</structname> object. It is exported because some applications find it
useful to generate result objects (particularly objects with error
status) themselves. If <parameter>conn</parameter> is not null and <parameter>status</> indicates an error,
the current error message of the specified connection is copied into the <structname>PGresult</structname>.
Note that <function>PQclear</function> should eventually be called on the object, just
as with a <structname>PGresult</structname> returned by <application>libpq</application> itself.
This is <application>libpq</>'s internal function to allocate and
initialize an empty <structname>PGresult</structname> object. This
function returns NULL if memory could not be allocated. It is exported
because some applications find it useful to generate result objects
(particularly objects with error status) themselves. If
<parameter>conn</parameter> is not null and <parameter>status</>
indicates an error, the current error message of the specified
connection is copied into the <structname>PGresult</structname>. Note
that <function>PQclear</function> should eventually be called on the
object, just as with a <structname>PGresult</structname> returned by
<application>libpq</application> itself.
</para>
</listitem>
</varlistentry>
@ -2266,15 +2271,15 @@ unsigned char *PQescapeBytea(const unsigned char *from,
<para>
<function>PQescapeBytea</> returns an escaped version of the
<parameter>from</parameter> parameter binary string in memory
allocated with <function>malloc()</>. This memory must be freed
using <function>PQfreemem</> when the result is no longer needed.
The return string has all special characters replaced so that they
can be properly processed by the
<productname>PostgreSQL</productname> string literal parser, and
the <type>bytea</type> input function. A terminating zero byte is
also added. The single quotes that must surround
<productname>PostgreSQL</productname> string literals are not part
of the result string.
allocated with <function>malloc()</> (a null pointer is returned if
memory could not be allocated). This memory must be freed using
<function>PQfreemem</> when the result is no longer needed. The
return string has all special characters replaced so that they can
be properly processed by the <productname>PostgreSQL</productname>
string literal parser, and the <type>bytea</type> input function. A
terminating zero byte is also added. The single quotes that must
surround <productname>PostgreSQL</productname> string literals are
not part of the result string.
</para>
</listitem>
</varlistentry>