postgresql/src/common/wait_error.c
Peter Eisentraut 2fe3bdbd69 Check return value of pclose() correctly
Some callers didn't check the return value of pclose() or
ClosePipeStream() correctly.  Either they didn't check it at all or
they treated it like the return of fclose().

The correct way is to first check whether the return value is -1, and
then report errno, and then check the return value like a result from
system(), for which we already have wait_result_to_str() to make it
simpler.  To make this more compact, expand wait_result_to_str() to
also handle -1 explicitly.

Reviewed-by: Ankit Kumar Pandey <itsankitkp@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/8cd9fb02-bc26-65f1-a809-b1cb360eef73@enterprisedb.com
2022-11-15 15:36:51 +01:00

129 lines
3.5 KiB
C

/*-------------------------------------------------------------------------
*
* wait_error.c
* Convert a wait/waitpid(2) result code to a human-readable string
*
*
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/common/wait_error.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include <signal.h>
#include <sys/wait.h>
/*
* Return a human-readable string explaining the reason a child process
* terminated. The argument is a return code returned by wait(2) or
* waitpid(2), which also applies to pclose(3) and system(3). The result is a
* translated, palloc'd or malloc'd string.
*/
char *
wait_result_to_str(int exitstatus)
{
char str[512];
/*
* To simplify using this after pclose() and system(), handle status -1
* first. In that case, there is no wait result but some error indicated
* by errno.
*/
if (exitstatus == -1)
{
snprintf(str, sizeof(str), "%m");
}
else if (WIFEXITED(exitstatus))
{
/*
* Give more specific error message for some common exit codes that
* have a special meaning in shells.
*/
switch (WEXITSTATUS(exitstatus))
{
case 126:
snprintf(str, sizeof(str), _("command not executable"));
break;
case 127:
snprintf(str, sizeof(str), _("command not found"));
break;
default:
snprintf(str, sizeof(str),
_("child process exited with exit code %d"),
WEXITSTATUS(exitstatus));
}
}
else if (WIFSIGNALED(exitstatus))
{
#if defined(WIN32)
snprintf(str, sizeof(str),
_("child process was terminated by exception 0x%X"),
WTERMSIG(exitstatus));
#else
snprintf(str, sizeof(str),
_("child process was terminated by signal %d: %s"),
WTERMSIG(exitstatus), pg_strsignal(WTERMSIG(exitstatus)));
#endif
}
else
snprintf(str, sizeof(str),
_("child process exited with unrecognized status %d"),
exitstatus);
return pstrdup(str);
}
/*
* Return true if a wait(2) result indicates that the child process
* died due to the specified signal.
*
* The reason this is worth having a wrapper function for is that
* there are two cases: the signal might have been received by our
* immediate child process, or there might've been a shell process
* between us and the child that died. The shell will, per POSIX,
* report the child death using exit code 128 + signal number.
*
* If there is no possibility of an intermediate shell, this function
* need not (and probably should not) be used.
*/
bool
wait_result_is_signal(int exit_status, int signum)
{
if (WIFSIGNALED(exit_status) && WTERMSIG(exit_status) == signum)
return true;
if (WIFEXITED(exit_status) && WEXITSTATUS(exit_status) == 128 + signum)
return true;
return false;
}
/*
* Return true if a wait(2) result indicates that the child process
* died due to any signal. We consider either direct child death
* or a shell report of child process death as matching the condition.
*
* If include_command_not_found is true, also return true for shell
* exit codes indicating "command not found" and the like
* (specifically, exit codes 126 and 127; see above).
*/
bool
wait_result_is_any_signal(int exit_status, bool include_command_not_found)
{
if (WIFSIGNALED(exit_status))
return true;
if (WIFEXITED(exit_status) &&
WEXITSTATUS(exit_status) > (include_command_not_found ? 125 : 128))
return true;
return false;
}