From: "Paul 'Shag' Walmsley" <ccshag@cclabs.missouri.edu>
Date: Thu, 11 Jul 1996 03:02:44 -0500 (CDT)
Subject: [PG95]: Another libpq robustness patch for the adventurous 

The previous patch that I posted for libpq was against fe-exec.c.  The
following patch is to prevent any inadvertent null pointer dereferences
from fe-connect.c.

To be extra-clear about what's going on here, this patch complements the
one I recently posted - and re-posted - that was against
src/libpq/fe-exec.c.  The patch below is against src/libpq/fe-connect.c.

I paid more attention to return values this time :-)


- - Paul "Shag" Walmsley <ccshag@cclabs.missouri.edu>
  "Knowing is not enough." -- Hal Hartley, "Surviving Desire"

- --------[ cut here ]---------------------------------------------------
*** src/libpq/fe-connect.c	Thu Jul 11 02:43:34 1996
- --- src/libpq/fe-connect.c.new	Thu Jul 11 02:39:44 1996
***************
*** 70,76 ****
      char *tmp;
  
      conn = (PGconn*)malloc(sizeof(PGconn));
! 
      conn->Pfout = NULL;
      conn->Pfin = NULL;
      conn->Pfdebug = NULL;
- --- 70,81 ----
      char *tmp;
  
      conn = (PGconn*)malloc(sizeof(PGconn));
!     
!     if (!conn) {
! 	fprintf(stderr,"FATAL: pqsetdb() -- unable to allocate memory for a PGconn");
! 	return (PGconn*)NULL;
!     }
! 	
      conn->Pfout = NULL;
      conn->Pfin = NULL;
      conn->Pfdebug = NULL;
***************
*** 307,315 ****
  void
  PQfinish(PGconn *conn)
  {
!   if (conn->status == CONNECTION_OK)
!     closePGconn(conn);
!   freePGconn(conn);
  }
  
  /* PQreset :
- --- 312,324 ----
  void
  PQfinish(PGconn *conn)
  {
!   if (!conn) {
!     fprintf(stderr,"PQfinish() -- pointer to PGconn is null");
!   } else {
!     if (conn->status == CONNECTION_OK)
! 	closePGconn(conn);
!     freePGconn(conn);
!   }
  }
  
  /* PQreset :
***************
*** 319,326 ****
- --- 328,339 ----
  void
  PQreset(PGconn *conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQreset() -- pointer to PGconn is null");
+   } else {
      closePGconn(conn);
      conn->status = connectDB(conn);
+   }
  }
  
  /*
***************
*** 395,400 ****
- --- 408,418 ----
  char* 
  PQdb(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQdb() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->dbName;
  }
  
***************
*** 401,406 ****
- --- 419,429 ----
  char* 
  PQhost(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQhost() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->pghost;
  }
  
***************
*** 407,412 ****
- --- 430,440 ----
  char* 
  PQoptions(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQoptions() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->pgoptions;
  }
  
***************
*** 413,418 ****
- --- 441,451 ----
  char* 
  PQtty(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQtty() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->pgtty;
  }
  
***************
*** 419,424 ****
- --- 452,462 ----
  char*
  PQport(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQport() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->pgport;
  }
  
***************
*** 425,430 ****
- --- 463,473 ----
  ConnStatusType
  PQstatus(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQstatus() -- pointer to PGconn is null");
+     return CONNECTION_BAD;
+   }
+ 
    return conn->status;
  }
  
***************
*** 431,436 ****
- --- 474,484 ----
  char* 
  PQerrorMessage(PGconn* conn)
  {
+   if (!conn) {
+     fprintf(stderr,"PQerrorMessage() -- pointer to PGconn is null");
+     return (char *)NULL;
+   }
+ 
    return conn->errorMessage;
  }

- ----------[ cut here ]---------------------------------------------------