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PostgreSQL/src/bin/psql/common.c

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#include <c.h>
#include "common.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#ifndef HAVE_STRDUP
#include <strdup.h>
#endif
#include <signal.h>
#ifndef WIN32
#include <unistd.h> /* for write() */
#else
#include <io.h> /* for _write() */
#endif
#include <libpq-fe.h>
#include <postgres_ext.h>
#include <pqsignal.h>
#include <version.h>
#include "settings.h"
#include "variables.h"
#include "copy.h"
#include "prompt.h"
#include "print.h"
#ifdef WIN32
#define popen(x,y) _popen(x,y)
#define pclose(x) _pclose(x)
#define write(a,b,c) _write(a,b,c)
#endif
/* xstrdup()
*
* "Safe" wrapper around strdup()
* (Using this also avoids writing #ifdef HAVE_STRDUP in every file :)
*/
char *
xstrdup(const char *string)
{
char *tmp;
if (!string)
{
fprintf(stderr, "xstrdup: Cannot duplicate null pointer.\n");
exit(EXIT_FAILURE);
}
tmp = strdup(string);
if (!tmp)
{
perror("strdup");
exit(EXIT_FAILURE);
}
return tmp;
}
/*
* setQFout
* -- handler for -o command line option and \o command
*
* Tries to open file fname (or pipe if fname starts with '|')
* and stores the file handle in pset)
* Upon failure, sets stdout and returns false.
*/
bool
setQFout(const char *fname)
{
bool status = true;
/* Close old file/pipe */
if (pset.queryFout && pset.queryFout != stdout && pset.queryFout != stderr)
{
if (pset.queryFoutPipe)
pclose(pset.queryFout);
else
fclose(pset.queryFout);
}
/* If no filename, set stdout */
if (!fname || fname[0] == '\0')
{
pset.queryFout = stdout;
pset.queryFoutPipe = false;
}
else if (*fname == '|')
{
pset.queryFout = popen(fname + 1, "w");
pset.queryFoutPipe = true;
}
else
{
pset.queryFout = fopen(fname, "w");
pset.queryFoutPipe = false;
}
if (!(pset.queryFout))
{
fprintf(stderr, "%s: %s: %s\n", pset.progname, fname, strerror(errno));
pset.queryFout = stdout;
pset.queryFoutPipe = false;
status = false;
}
/* Direct signals */
if (pset.queryFoutPipe)
pqsignal(SIGPIPE, SIG_IGN);
else
pqsignal(SIGPIPE, SIG_DFL);
return status;
}
/*
* simple_prompt
*
* Generalized function especially intended for reading in usernames and
* password interactively. Reads from stdin.
*
* prompt: The prompt to print
* maxlen: How many characters to accept
* echo: Set to false if you want to hide what is entered (for passwords)
*
* Returns a malloc()'ed string with the input (w/o trailing newline).
*/
char *
simple_prompt(const char *prompt, int maxlen, bool echo)
{
int length;
char *destination;
#ifdef HAVE_TERMIOS_H
struct termios t_orig,
t;
#endif
destination = (char *) malloc(maxlen + 2);
if (!destination)
return NULL;
if (prompt)
fputs(prompt, stdout);
#ifdef HAVE_TERMIOS_H
if (!echo)
{
tcgetattr(0, &t);
t_orig = t;
t.c_lflag &= ~ECHO;
tcsetattr(0, TCSADRAIN, &t);
}
#endif
fgets(destination, maxlen, stdin);
#ifdef HAVE_TERMIOS_H
if (!echo)
{
tcsetattr(0, TCSADRAIN, &t_orig);
puts("");
}
#endif
length = strlen(destination);
if (length > 0 && destination[length - 1] != '\n')
{
/* eat rest of the line */
char buf[512];
do
{
fgets(buf, 512, stdin);
} while (buf[strlen(buf) - 1] != '\n');
}
if (length > 0 && destination[length - 1] == '\n')
/* remove trailing newline */
destination[length - 1] = '\0';
return destination;
}
/*
* Code to support query cancellation
*
* Before we start a query, we enable a SIGINT signal catcher that sends a
* cancel request to the backend. Note that sending the cancel directly from
* the signal handler is safe because PQrequestCancel() is written to make it
* so. We have to be very careful what else we do in the signal handler. This
* includes using write() for output.
*/
static PGconn *cancelConn;
#define write_stderr(String) write(fileno(stderr), String, strlen(String))
static void
handle_sigint(SIGNAL_ARGS)
{
if (cancelConn == NULL)
return;
/* Try to send cancel request */
if (PQrequestCancel(cancelConn))
write_stderr("\nCancel request sent\n");
else
{
write_stderr("\nCould not send cancel request: ");
write_stderr(PQerrorMessage(cancelConn));
}
}
/*
* PSQLexec
*
* This is the way to send "backdoor" queries (those not directly entered
* by the user). It is subject to -E but not -e.
*/
PGresult *
PSQLexec(const char *query)
{
PGresult *res;
const char *var;
if (!pset.db)
{
fputs("You are currently not connected to a database.\n", stderr);
return NULL;
}
var = GetVariable(pset.vars, "ECHO_HIDDEN");
if (var)
{
printf("********* QUERY *********\n%s\n*************************\n\n", query);
fflush(stdout);
}
if (var && strcmp(var, "noexec") == 0)
return NULL;
cancelConn = pset.db;
pqsignal(SIGINT, handle_sigint); /* control-C => cancel */
res = PQexec(pset.db, query);
pqsignal(SIGINT, SIG_DFL); /* now control-C is back to normal */
if (PQstatus(pset.db) == CONNECTION_BAD)
{
if (!pset.cur_cmd_interactive)
{
fprintf(stderr, "%s: connection to server was lost", pset.progname);
exit(EXIT_BADCONN);
}
fputs("The connection to the server was lost. Attempting reset: ", stderr);
PQreset(pset.db);
if (PQstatus(pset.db) == CONNECTION_BAD)
{
fputs("Failed.\n", stderr);
PQfinish(pset.db);
PQclear(res);
pset.db = NULL;
SetVariable(pset.vars, "DBNAME", NULL);
SetVariable(pset.vars, "HOST", NULL);
SetVariable(pset.vars, "PORT", NULL);
SetVariable(pset.vars, "USER", NULL);
return NULL;
}
else
fputs("Succeeded.\n", stderr);
}
if (res && (PQresultStatus(res) == PGRES_COMMAND_OK ||
PQresultStatus(res) == PGRES_TUPLES_OK ||
PQresultStatus(res) == PGRES_COPY_IN ||
PQresultStatus(res) == PGRES_COPY_OUT)
)
return res;
else
{
fputs(PQerrorMessage(pset.db), stderr);
PQclear(res);
return NULL;
}
}
/*
* SendQuery: send the query string to the backend
* (and print out results)
*
* Note: This is the "front door" way to send a query. That is, use it to
* send queries actually entered by the user. These queries will be subject to
* single step mode.
* To send "back door" queries (generated by slash commands, etc.) in a
* controlled way, use PSQLexec().
*
* Returns true if the query executed successfully, false otherwise.
*/
bool
SendQuery(const char *query)
{
bool success = false;
PGresult *results;
PGnotify *notify;
if (!pset.db)
{
fputs("You are currently not connected to a database.\n", stderr);
return false;
}
if (GetVariableBool(pset.vars, "SINGLESTEP"))
{
char buf[3];
printf("***(Single step mode: Verify query)*********************************************\n"
"%s\n"
"***(press return to proceed or enter x and return to cancel)********************\n",
query);
fflush(stdout);
fgets(buf, 3, stdin);
if (buf[0] == 'x')
return false;
}
else
{
const char * var = GetVariable(pset.vars, "ECHO");
if (var && strcmp(var, "brief")==0)
puts(query);
}
cancelConn = pset.db;
pqsignal(SIGINT, handle_sigint);
results = PQexec(pset.db, query);
pqsignal(SIGINT, SIG_DFL);
if (results == NULL)
{
fputs(PQerrorMessage(pset.db), pset.queryFout);
success = false;
}
else
{
switch (PQresultStatus(results))
{
case PGRES_TUPLES_OK:
/* write output to \g argument, if any */
if (pset.gfname)
{
FILE * queryFout_copy = pset.queryFout;
bool queryFoutPipe_copy = pset.queryFoutPipe;
pset.queryFout = NULL; /* so it doesn't get closed */
/* open file/pipe */
if (!setQFout(pset.gfname))
{
success = false;
break;
}
printQuery(results, &pset.popt, pset.queryFout);
/* close file/pipe */
setQFout(NULL);
free(pset.gfname);
pset.gfname = NULL;
pset.queryFout = queryFout_copy;
pset.queryFoutPipe = queryFoutPipe_copy;
success = true;
break;
}
else
{
success = true;
printQuery(results, &pset.popt, pset.queryFout);
}
break;
case PGRES_EMPTY_QUERY:
success = true;
break;
case PGRES_COMMAND_OK:
{
char buf[10];
success = true;
sprintf(buf, "%u", (unsigned int)PQoidValue(results));
if (!QUIET())
fprintf(pset.queryFout, "%s\n", PQcmdStatus(results));
SetVariable(pset.vars, "LASTOID", buf);
break;
}
case PGRES_COPY_OUT:
success = handleCopyOut(pset.db, pset.queryFout);
break;
case PGRES_COPY_IN:
if (pset.cur_cmd_interactive && !QUIET())
puts("Enter data to be copied followed by a newline.\n"
"End with a backslash and a period on a line by itself.");
success = handleCopyIn(pset.db, pset.cur_cmd_source,
pset.cur_cmd_interactive ? get_prompt(PROMPT_COPY) : NULL);
break;
case PGRES_NONFATAL_ERROR:
case PGRES_FATAL_ERROR:
case PGRES_BAD_RESPONSE:
success = false;
fputs(PQerrorMessage(pset.db), stderr);
break;
}
fflush(pset.queryFout);
if (PQstatus(pset.db) == CONNECTION_BAD)
{
if (!pset.cur_cmd_interactive)
{
fprintf(stderr, "%s: connection to server was lost", pset.progname);
exit(EXIT_BADCONN);
}
fputs("The connection to the server was lost. Attempting reset: ", stderr);
PQreset(pset.db);
if (PQstatus(pset.db) == CONNECTION_BAD)
{
fputs("Failed.\n", stderr);
PQfinish(pset.db);
PQclear(results);
pset.db = NULL;
SetVariable(pset.vars, "DBNAME", NULL);
SetVariable(pset.vars, "HOST", NULL);
SetVariable(pset.vars, "PORT", NULL);
SetVariable(pset.vars, "USER", NULL);
return false;
}
else
fputs("Succeeded.\n", stderr);
}
/* check for asynchronous notification returns */
while ((notify = PQnotifies(pset.db)) != NULL)
{
fprintf(pset.queryFout, "Asynchronous NOTIFY '%s' from backend with pid '%d' received.\n",
notify->relname, notify->be_pid);
free(notify);
fflush(pset.queryFout);
}
if (results)
PQclear(results);
}
return success;
}
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