pathtemp.c revision da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2007 AT&T Knowledge Ventures *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Knowledge Ventures *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* AT&T Research
*
* generate a temp file / name
*
* [<dir>/][<pfx>]<bas>.<suf>
*
* length(<pfx>)<=5
* length(<bas>)==3
* length(<suf>)==3
*
* pathtmp(a,b,c,d) pathtemp(a,L_tmpnam,b,c,0)
* tmpfile() char*p=pathtemp(0,0,0,"tf",&sp);
* remove(p);
* free(p)
* tmpnam(0) static char p[L_tmpnam];
* pathtemp(p,sizeof(p),0,"tn",0)
* tmpnam(p) pathtemp(p,L_tmpnam,0,"tn",0)
* tempnam(d,p) pathtemp(0,d,p,0)
*
* if buf==0 then space is malloc'd
* buf size is size
* dir and pfx may be 0
* only first 5 chars of pfx are used
* if fdp!=0 then the path is opened O_EXCL and *fdp is the open fd
* malloc'd space returned by successful pathtemp() calls
* must be freed by the caller
*
* generated names are pseudo-randomized to avoid both
* collisions and predictions (same alg in sfio/sftmp.c)
*
* / as first pfx char provides tmp file generation control
* 0 returned for unknown ops
*
* /cycle dir specifies TMPPATH cycle control
* automatic (default) cycled with each tmp file
* manual cycled by application with dir=(nil)
* (nil) cycle TMPPATH
* /prefix dir specifies the default prefix (default ast)
* /TMPPATH dir overrides the env value
* /TMPDIR dir overrides the env value
*/
#include <ast.h>
#include <ls.h>
#include <tm.h>
#define ATTEMPT 10
#define TMP_ENV "TMPDIR"
#define TMP_PATH_ENV "TMPPATH"
#define TMP1 "/tmp"
#define TMP2 "/usr/tmp"
#define VALID(d) (*(d)&&!eaccess(d,W_OK|X_OK))
static struct
{
mode_t mode;
char** vec;
char** dir;
unsigned long key;
unsigned long rng;
pid_t pid;
int manual;
char* pfx;
char* tmpdir;
char* tmppath;
} tmp = { S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH };
char*
pathtemp(char* buf, size_t len, const char* dir, const char* pfx, int* fdp)
{
register char* d;
register char* b;
register char* s;
register char* x;
char* fmt;
int m;
int n;
int z;
int attempt;
if (pfx && *pfx == '/')
{
pfx++;
if (streq(pfx, "cycle"))
{
if (!dir)
{
tmp.manual = 1;
if (tmp.dir && !*tmp.dir++)
tmp.dir = tmp.vec;
}
else
tmp.manual = streq(dir, "manual");
return (char*)pfx;
}
else if (streq(pfx, "prefix"))
{
if (tmp.pfx)
free(tmp.pfx);
tmp.pfx = dir ? strdup(dir) : (char*)0;
return (char*)pfx;
}
else if (streq(pfx, "private"))
tmp.mode = S_IRUSR|S_IWUSR;
else if (streq(pfx, "public"))
tmp.mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
else if (streq(pfx, TMP_ENV))
{
if (tmp.vec)
{
free(tmp.vec);
tmp.vec = 0;
}
if (tmp.tmpdir)
free(tmp.tmpdir);
tmp.tmpdir = dir ? strdup(dir) : (char*)0;
return (char*)pfx;
}
else if (streq(pfx, TMP_PATH_ENV))
{
if (tmp.vec)
{
free(tmp.vec);
tmp.vec = 0;
}
if (tmp.tmppath)
free(tmp.tmppath);
tmp.tmppath = dir ? strdup(dir) : (char*)0;
return (char*)pfx;
}
return 0;
}
if (!(d = (char*)dir) || *d && eaccess(d, W_OK|X_OK))
{
if (!tmp.vec)
{
if ((x = tmp.tmppath) || (x = getenv(TMP_PATH_ENV)))
{
n = 2;
s = x;
while (s = strchr(s, ':'))
{
s++;
n++;
}
if (!(tmp.vec = newof(0, char*, n, strlen(x) + 1)))
return 0;
tmp.dir = tmp.vec;
x = strcpy((char*)(tmp.dir + n), x);
*tmp.dir++ = x;
while (x = strchr(x, ':'))
{
*x++ = 0;
if (!VALID(*(tmp.dir - 1)))
tmp.dir--;
*tmp.dir++ = x;
}
if (!VALID(*(tmp.dir - 1)))
tmp.dir--;
*tmp.dir = 0;
}
else
{
if (((d = tmp.tmpdir) || (d = getenv(TMP_ENV))) && !VALID(d))
d = 0;
if (!(tmp.vec = newof(0, char*, 2, d ? (strlen(d) + 1) : 0)))
return 0;
if (d)
*tmp.vec = strcpy((char*)(tmp.vec + 2), d);
}
tmp.dir = tmp.vec;
}
if (!(d = *tmp.dir++))
{
tmp.dir = tmp.vec;
d = *tmp.dir++;
}
if (!d && (!*(d = astconf("TMP", NiL, NiL)) || eaccess(d, W_OK|X_OK)) && eaccess(d = TMP1, W_OK|X_OK) && eaccess(d = TMP2, W_OK|X_OK))
return 0;
}
if (!len)
len = PATH_MAX;
len--;
if (!(b = buf) && !(b = newof(0, char, len, 1)))
return 0;
if (buf && dir && pfx && (buf == (char*)dir && (buf + strlen(buf) + 1) == (char*)pfx || buf == (char*)pfx && !*dir) && !strcmp((char*)pfx + strlen(pfx) + 1, "XXXXX"))
{
z = 0;
d = (char*)dir;
len = m = strlen(d) + strlen(pfx) + 8;
fmt = "%03.3.32lu%03.3.32lu";
}
else
{
z = '.';
m = 5;
fmt = "%02.2.32lu.%03.3.32lu";
}
x = b + len;
s = b;
if (d)
{
while (s < x && (n = *d++))
*s++ = n;
if (s < x && s > b && *(s - 1) != '/')
*s++ = '/';
}
if (!pfx && !(pfx = tmp.pfx))
pfx = "ast";
if ((x - s) > m)
x = s + m;
while (s < x && (n = *pfx++))
{
if (n == '/' || n == '\\' || n == z)
n = '_';
*s++ = n;
}
*s = 0;
len -= (s - b);
for (attempt = 0; attempt < ATTEMPT; attempt++)
{
if (!tmp.rng || attempt || tmp.pid != getpid())
{
register int r;
/*
* get a quasi-random coefficient
*/
tmp.pid = getpid();
tmp.rng = (unsigned long)tmp.pid * ((unsigned long)time(NiL) ^ (((unsigned long)(&attempt)) >> 3) ^ (((unsigned long)tmp.dir) >> 3));
if (!tmp.key)
tmp.key = (tmp.rng >> 16) | ((tmp.rng & 0xffff) << 16);
tmp.rng ^= tmp.key;
/*
* Knuth vol.2, page.16, Thm.A
*/
if ((r = (tmp.rng - 1) & 03))
tmp.rng += 4 - r;
}
/*
* generate a pseudo-random name
*/
tmp.key = tmp.rng * tmp.key + 987654321L;
sfsprintf(s, len, fmt, (tmp.key >> 15) & 0x7fff, tmp.key & 0x7fff);
if (fdp)
{
if ((n = open(b, O_CREAT|O_RDWR|O_EXCL|O_TEMPORARY, tmp.mode)) >= 0)
{
*fdp = n;
return b;
}
}
else if (access(b, F_OK))
return b;
}
if (!buf)
free(b);
return 0;
}