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/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
*
* This file is released under the LGPL.
*/
#include "lib.h"
#include "lvm-file.h"
#include "lvm-string.h"
#include <unistd.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <fcntl.h>
#include <dirent.h>
/*
* Creates a temporary filename, and opens a descriptor to the
* file. Both the filename and descriptor are needed so we can
* rename the file after successfully writing it. Grab
* NFS-supported exclusive fcntl discretionary lock.
*/
int create_temp_name(const char *dir, char *buffer, size_t len, int *fd)
{
int i, num;
pid_t pid;
char hostname[255];
struct flock lock = {
l_type:F_WRLCK,
l_whence:0,
l_start:0,
l_len:0
};
num = rand();
pid = getpid();
if (gethostname(hostname, sizeof(hostname)) < 0) {
log_sys_error("gethostname", "");
strcpy(hostname, "nohostname");
}
for (i = 0; i < 20; i++, num++) {
if (lvm_snprintf(buffer, len, "%s/.lvm_%s_%d_%d",
dir, hostname, pid, num) == -1) {
log_err("Not enough space to build temporary file "
"string.");
return 0;
}
*fd = open(buffer, O_CREAT | O_EXCL | O_WRONLY | O_APPEND,
S_IRUSR | S_IRGRP | S_IROTH |
S_IWUSR | S_IWGRP | S_IWOTH);
if (*fd < 0)
continue;
if (!fcntl(*fd, F_SETLK, &lock))
return 1;
close(*fd);
}
return 0;
}
/*
* NFS-safe rename of a temporary file to a common name, designed
* to avoid race conditions and not overwrite the destination if
* it exists.
*
* Try to create the new filename as a hard link to the original.
* Check the link count of the original file to see if it worked.
* (Assumes nothing else touches our temporary file!) If it
* worked, unlink the old filename.
*/
int lvm_rename(const char *old, const char *new)
{
struct stat buf;
link(old, new);
if (stat(old, &buf)) {
log_sys_error("stat", old);
return 0;
}
if (buf.st_nlink != 2) {
log_error("%s: rename to %s failed", old, new);
return 0;
}
if (unlink(old)) {
log_sys_error("unlink", old);
return 0;
}
return 1;
}
int path_exists(const char *path)
{
struct stat info;
if (!*path)
return 0;
if (stat(path, &info) < 0)
return 0;
return 1;
}
int dir_exists(const char *path)
{
struct stat info;
if (!*path)
return 0;
if (stat(path, &info) < 0)
return 0;
if (!S_ISDIR(info.st_mode))
return 0;
return 1;
}
static int _create_dir_recursive(const char *dir)
{
char *orig, *s;
int rc;
log_verbose("Creating directory \"%s\"", dir);
/* Create parent directories */
orig = s = dbg_strdup(dir);
while ((s = strchr(s, '/')) != NULL) {
*s = '\0';
if (*orig) {
rc = mkdir(orig, 0777);
if (rc < 0 && errno != EEXIST) {
log_sys_error("mkdir", orig);
dbg_free(orig);
return 0;
}
}
*s++ = '/';
}
dbg_free(orig);
/* Create final directory */
rc = mkdir(dir, 0777);
if (rc < 0 && errno != EEXIST) {
log_sys_error("mkdir", dir);
return 0;
}
return 1;
}
int create_dir(const char *dir)
{
struct stat info;
if (!*dir)
return 1;
if (stat(dir, &info) < 0)
return _create_dir_recursive(dir);
if (S_ISDIR(info.st_mode))
return 1;
log_error("Directory \"%s\" not found", dir);
return 0;
}
int is_empty_dir(const char *dir)
{
struct dirent *dirent;
DIR *d;
if (!(d = opendir(dir))) {
log_sys_error("opendir", dir);
return 0;
}
while ((dirent = readdir(d)))
if (strcmp(dirent->d_name, ".") && strcmp(dirent->d_name, ".."))
break;
if (closedir(d)) {
log_sys_error("closedir", dir);
}
return dirent ? 0 : 1;
}
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