system.c

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/*-------------------------------------------------------------------------
 *
 * system.c
 *     Win32 system() and popen() replacements
 *
 *
 *  Win32 needs double quotes at the beginning and end of system()
 *  strings.  If not, it gets confused with multiple quoted strings.
 *  It also requires double-quotes around the executable name and
 *  any files used for redirection.  Filter other args through
 *  appendShellString() to quote them.
 *
 *  Generated using Win32 "CMD /?":
 *
 *  1. If all of the following conditions are met, then quote characters
 *  on the command line are preserved:
 *
 *   - no /S switch
 *   - exactly two quote characters
 *   - no special characters between the two quote characters, where special
 *     is one of: &<>()@^|
 *   - there are one or more whitespace characters between the two quote
 *     characters
 *   - the string between the two quote characters is the name of an
 *     executable file.
 *
 *   2. Otherwise, old behavior is to see if the first character is a quote
 *   character and if so, strip the leading character and remove the last
 *   quote character on the command line, preserving any text after the last
 *   quote character.
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 *
 * src/port/system.c
 *
 *-------------------------------------------------------------------------
 */
 
#if defined(WIN32) && !defined(__CYGWIN__)
 
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
 
#include <fcntl.h>
 
#undef system
#undef popen
 
int
pgwin32_system(const char *command)
{
    size_t      cmdlen = strlen(command);
    char       *buf;
    int         save_errno;
    int         res;
 
    /*
     * Create a malloc'd copy of the command string, enclosed with an extra
     * pair of quotes
     */
    buf = malloc(cmdlen + 2 + 1);
    if (buf == NULL)
    {
        errno = ENOMEM;
        return -1;
    }
    buf[0] = '"';
    memcpy(&buf[1], command, cmdlen);
    buf[cmdlen + 1] = '"';
    buf[cmdlen + 2] = '\0';
 
    res = system(buf);
 
    save_errno = errno;
    free(buf);
    errno = save_errno;
 
    return res;
}
 
 
FILE *
pgwin32_popen(const char *command, const char *type)
{
    size_t      cmdlen = strlen(command);
    char       *buf;
    int         save_errno;
    FILE       *res;
 
    /*
     * Create a malloc'd copy of the command string, enclosed with an extra
     * pair of quotes
     */
    buf = malloc(cmdlen + 2 + 1);
    if (buf == NULL)
    {
        errno = ENOMEM;
        return NULL;
    }
    buf[0] = '"';
    memcpy(&buf[1], command, cmdlen);
    buf[cmdlen + 1] = '"';
    buf[cmdlen + 2] = '\0';
 
    res = _popen(buf, type);
 
    save_errno = errno;
    free(buf);
    errno = save_errno;
 
    return res;
}
 
#endif