PostgreSQL 8.0.0beta5 (CVS HEAD)
Solaris 9
gcc 3.4.2

oid2name consistently dumps core:

% oid2name -d test -f 77199
From database "test":
Segmentation fault (core dumped)

(gdb) where
#0 0xfee473ec in realfree () from /usr/lib/libc.so.1
#1 0xfee47cec in cleanfree () from /usr/lib/libc.so.1
#2 0xfee46e18 in _malloc_unlocked () from /usr/lib/libc.so.1


On FreeBSD 4.10-STABLE oid2name runs but prints warnings about
freeing junk pointers:

% oid2name -d test -f 173181
From database "test":
oid2name in free(): warning: junk pointer, too low to make sense
oid2name in free(): warning: junk pointer, too low to make sense
Filenode Table Name
----------------------
173181 foo


The warnings are coming from these two lines (around lines 448 and 449):

free(comma_oids);
free(comma_tables);

Apparently the values of comma_oids and comma_tables are bogus.
I haven't looked more closely yet to see why.

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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On Wed, Dec 01, 2004 at 09:41:49PM -0700, Michael Fuhr wrote:

main() initializes my_opts->oids->num and my_opts->tables->num to 0.
sql_exec_searchtables() later sets comma_oids and comma_tables with
the following code:

comma_oids = get_comma_elts(opts->oids);
comma_tables = get_comma_elts(opts->tables);

get_comma_elts() starts with the following:

if (eary->num == 0)
return "";

sql_exec_searchtables() later tries to free the pointers to "".
Program fall down go boom.

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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On Wed, 2004-12-01 at 21:41 -0700, Michael Fuhr wrote:
I checked in a fix for this to HEAD; the patch is attached. I also
noticed various other brokenness in oid2name (access to uninitialized
variables, malloc() + sscanf() rather than strdup(), etc.), which I
fixed.

Thanks for the report.

-Neil


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Index: contrib/oid2name/oid2name.c
================================================== =================
RCS file: /var/lib/cvs/pgsql/contrib/oid2name/oid2name.c,v
retrieving revision 1.25
diff -c -r1.25 oid2name.c
*** contrib/oid2name/oid2name.c 5 Nov 2004 19:15:45 -0000 1.25
--- contrib/oid2name/oid2name.c 2 Dec 2004 06:03:36 -0000
***************
*** 46,51 ****
--- 46,52 ----
/* function prototypes */
void get_opts(int, char **, struct options *);
void *myalloc(size_t size);
+ char *mystrdup(const char *str);
void add_one_elt(char *eltname, eary *eary);
char *get_comma_elts(eary *eary);
PGconn *sql_conn(struct options *);
***************
*** 68,73 ****
--- 69,79 ----
my_opts->nodb = false;
my_opts->extended = false;
my_opts->tablespaces = false;
+ my_opts->dbname = NULL;
+ my_opts->hostname = NULL;
+ my_opts->port = NULL;
+ my_opts->username = NULL;
+ my_opts->password = NULL;

/* get opts */
while ((c = getopt(argc, argv, "H:U:P:d:t:f:qSxish?")) != -1)
***************
*** 76,83 ****
{
/* specify the database */
case 'd':
! my_opts->dbname = (char *) myalloc(strlen(optarg));
! sscanf(optarg, "%s", my_opts->dbname);
break;

/* specify one tablename to show */
--- 82,88 ----
{
/* specify the database */
case 'd':
! my_opts->dbname = mystrdup(optarg);
break;

/* specify one tablename to show */
***************
*** 102,127 ****

/* host to connect to */
case 'H':
! my_opts->hostname = (char *) myalloc(strlen(optarg));
! sscanf(optarg, "%s", my_opts->hostname);
break;

/* port to connect to on remote host */
case 'p':
! my_opts->port = (char *) myalloc(strlen(optarg));
! sscanf(optarg, "%s", my_opts->port);
break;

/* username */
case 'U':
! my_opts->username = (char *) myalloc(strlen(optarg));
! sscanf(optarg, "%s", my_opts->username);
break;

/* password */
case 'P':
! my_opts->password = (char *) myalloc(strlen(optarg));
! sscanf(optarg, "%s", my_opts->password);
break;

/* display system tables */
--- 107,128 ----

/* host to connect to */
case 'H':
! my_opts->hostname = mystrdup(optarg);
break;

/* port to connect to on remote host */
case 'p':
! my_opts->port = mystrdup(optarg);
break;

/* username */
case 'U':
! my_opts->username = mystrdup(optarg);
break;

/* password */
case 'P':
! my_opts->password = mystrdup(optarg);
break;

/* display system tables */
***************
*** 183,188 ****
--- 184,201 ----
return ptr;
}

+ char *
+ mystrdup(const char *str)
+ {
+ char *result = strdup(str);
+ if (!result)
+ {
+ fprintf(stderr, "out of memory");
+ exit(1);
+ }
+ return result;
+ }
+
/*
* add_one_elt
*
***************
*** 208,214 ****
}
}

! eary->array[eary->num] = strdup(eltname);
eary->num++;
}

--- 221,227 ----
}
}

! eary->array[eary->num] = mystrdup(eltname);
eary->num++;
}

***************
*** 227,233 ****
int i, length = 0;

if (eary->num == 0)
! return "";

/*
* PQescapeString wants 2 * length + 1 bytes of breath space. Add two
--- 240,246 ----
int i, length = 0;

if (eary->num == 0)
! return mystrdup("");

/*
* PQescapeString wants 2 * length + 1 bytes of breath space. Add two

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On Thu, Dec 02, 2004 at 05:11:22PM +1100, Neil Conway wrote:

I think they were mostly my bugs. Thanks for fixing.

--
Alvaro Herrera (<alvherre[@]dcc.uchile.cl>)
"I suspect most samba developers are already technically insane...
Of course, since many of them are Australians, you can't tell." (L. Torvalds)

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