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/*
* usersfile.c
* (C) 2000 Antonino Iannella, Stellar-X Pty Ltd
* Released under GPL, see COPYING-2.0 for details.
*
* These routines are to allow users attempting to use the proxy which
* have been explicitly allowed by the system administrator.
* The code originated from denyusers.c.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/stat.h>
#include <errno.h>
#include <time.h>
#include <ctype.h>
#include <sys/param.h>
#include <fcntl.h>
#include "usersfile.h"
#define NAMELEN 50 /* Maximum username length */
static int
name_cmp(const void *a, const void *b)
{
const char * const *A = a;
const char * const *B = b;
return strcasecmp(*A, *B);
}
static void
free_names(usersfile * uf)
{
int i;
for (i = 0; i < uf->Inuse; i++) {
if (uf->names[i])
free(uf->names[i]);
uf->names[i] = NULL;
}
uf->Inuse = 0;
}
/*
* Reads a file of usernames and stuffs them into an array
* of strings.
* Returns 0 if the user list was successfully loaded,
* and 1 in case of error.
*/
int
Read_usersfile(const char *path, usersfile * uf)
{
FILE *fp;
struct stat FileBuf;
char buf[1024];
free_names(uf);
if (NULL == path) {
path = uf->path;
} else {
if (uf->path)
free(uf->path);
uf->path = strdup(path);
}
/* Open the users file. Report any errors. */
fp = fopen(path, "r");
if (NULL == fp) {
uf->LMT = 0;
if (errno == ENOENT)
return 0;
syslog(LOG_ERR, "%s: %s", path, strerror(errno));
return 1;
}
/* Stat the file. If it does not exist, save the size as zero.
* Clear the allowed user string. Return. */
if (fstat(fileno(fp), &FileBuf) < 0) {
syslog(LOG_ERR, "%s: %s", path, strerror(errno));
return 1;
}
/* If it exists, save the modification time and size */
uf->LMT = FileBuf.st_mtime;
/* Handle the special case of a zero length file */
if (FileBuf.st_size == 0)
return 0;
/*
* Read the file into memory
* XXX assumes one username per input line
*/
while (fgets(buf, 1024, fp) != NULL) {
/* ensure no names longer than our limit */
buf[NAMELEN] = '\0';
/* skip bad input lines */
if (NULL == strtok(buf, "\r\n"))
continue;
/* grow the list if necessary */
if (0 == uf->Alloc) {
uf->Alloc = 256;
uf->names = calloc(uf->Alloc, sizeof(*uf->names));
} else if (uf->Inuse == uf->Alloc) {
uf->Alloc = uf->Alloc << 1;
uf->names = realloc(uf->names, uf->Alloc * sizeof(*uf->names));
/* zero out the newly allocated memory */
memset(&uf->names[uf->Alloc >> 1],
'\0',
(uf->Alloc >> 1) * sizeof(*uf->names));
}
uf->names[uf->Inuse] = strdup(buf);
uf->Inuse++;
}
fclose(fp);
fp = NULL;
/* sort the names for searching */
qsort(uf->names, uf->Inuse, sizeof(*uf->names), name_cmp);
return 0;
}
/*
* Check to see if the username provided by Squid appears in the
* user list. Returns 0 if the user was not found, and 1 if they were.
*/
int
Check_userlist(usersfile * uf, char *User)
{
void *p;
/* Empty users are always in the list */
if (User[0] == '\0')
return 1;
/* If allowed user list is empty, allow all users.
* If no users are supposed to be using the proxy, stop squid instead. */
if (0 == uf->Inuse)
return 1;
/* Check if username string is found in the allowed user list.
* If so, allow. If not, deny. Reconstruct the username
* to have whitespace, to avoid finding wrong string subsets. */
p = bsearch(&User,
uf->names,
uf->Inuse,
sizeof(*uf->names),
name_cmp);
if (NULL == p) {
return 0;
}
return 1;
}
/*
* Checks if there has been a change in a users file.
* If the modification time has changed, then reload the user list.
*/
void
Check_forfilechange(usersfile * uf)
{
struct stat ChkBuf; /* Stat data buffer */
/* Stat the allowed users file. If it cannot be accessed, return. */
if (uf->path == NULL)
return;
if (stat(uf->path, &ChkBuf) < 0) {
if (errno == ENOENT) {
uf->LMT = 0;
free_names(uf);
} else { /* Report error when accessing file */
syslog(LOG_ERR, "%s: %s", uf->path, strerror(errno));
}
return;
}
/* return if no change */
if (ChkBuf.st_mtime == uf->LMT)
return;
/*
* The file changed, so re-read it.
*/
syslog(LOG_INFO, "Check_forfilechange: Reloading user list '%s'.", uf->path);
Read_usersfile(NULL, uf);
}
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