Subversion Repositories planix.SVN

/*
 * pANS stdio -- tmpfile
 *
 * Bug: contains a critical section.  Two executions by the same
 * user could interleave as follows, both yielding the same file:
 *      access fails
 *                      access fails
 *      fopen succeeds
 *                      fopen succeeds
 *      unlink succeeds
 *                      unlink fails
 * As I read the pANS, this can't reasonably use tmpnam to generate
 * the name, so that code is duplicated.
 */
#include "iolib.h"

static char tmpsmade[FOPEN_MAX][L_tmpnam+1];
static int ntmps = 0;

static void rmtmps(void);

FILE *tmpfile(void){
        FILE *f;
        static char name[]="/tmp/tf0000000000000";
        char *p;
        while(access(name, 0)==0){
                p=name+7;
                while(*p=='9') *p++='0';
                if(*p=='\0') return NULL;
                ++*p;
        }
        f=fopen(name, "wb+");
        if(f && ntmps<FOPEN_MAX){
                if(ntmps==0)
                        atexit(rmtmps);
                strcpy(tmpsmade[ntmps++], name);
        }
        return f;
}

static void
rmtmps(void)
{
        int i;
        
        for(i=0; i<ntmps; i++)
                remove(tmpsmade[i]);
}