mirror of
git://sourceware.org/git/lvm2.git
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174 lines
3.1 KiB
C
174 lines
3.1 KiB
C
/*
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* Copyright (C) 2001 Sistina Software (UK) Limited.
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*
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* This file is released under the LGPL.
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*/
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#include "log.h"
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#include "lvm-file.h"
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#include "lvm-string.h"
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/file.h>
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#include <fcntl.h>
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#include <dirent.h>
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/*
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* Creates a temporary filename, and opens a descriptor to the
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* file. Both the filename and descriptor are needed so we can
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* rename the file after successfully writing it. Grab
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* NFS-supported exclusive fcntl discretionary lock.
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*/
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int create_temp_name(const char *dir, char *buffer, size_t len, int *fd)
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{
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int i, num;
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pid_t pid;
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char hostname[255];
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struct flock lock = {
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l_type:F_WRLCK,
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l_whence:0,
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l_start:0,
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l_len:0
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};
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num = rand();
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pid = getpid();
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if (gethostname(hostname, sizeof(hostname)) < 0) {
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log_sys_error("gethostname", "");
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strcpy(hostname, "nohostname");
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}
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for (i = 0; i < 20; i++, num++) {
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if (lvm_snprintf(buffer, len, "%s/.lvm_%s_%d_%d",
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dir, hostname, pid, num) == -1) {
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log_err("Not enough space to build temporary file "
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"string.");
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return 0;
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}
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*fd = open(buffer, O_CREAT | O_EXCL | O_WRONLY | O_APPEND,
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S_IRUSR | S_IRGRP | S_IROTH |
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S_IWUSR | S_IWGRP | S_IWOTH);
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if (*fd < 0)
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continue;
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if (!fcntl(*fd, F_SETLK, &lock))
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return 1;
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close(*fd);
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}
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return 0;
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}
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/*
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* NFS-safe rename of a temporary file to a common name, designed
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* to avoid race conditions and not overwrite the destination if
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* it exists.
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*
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* Try to create the new filename as a hard link to the original.
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* Check the link count of the original file to see if it worked.
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* (Assumes nothing else touches our temporary file!) If it
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* worked, unlink the old filename.
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*/
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int lvm_rename(const char *old, const char *new)
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{
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struct stat buf;
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link(old, new);
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if (stat(old, &buf)) {
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log_sys_error("stat", old);
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return 0;
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}
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if (buf.st_nlink != 2) {
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log_error("%s: rename to %s failed", old, new);
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return 0;
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}
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if (unlink(old)) {
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log_sys_error("unlink", old);
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return 0;
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}
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return 1;
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}
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int path_exists(const char *path)
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{
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struct stat info;
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if (!*path)
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return 0;
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if (stat(path, &info) < 0)
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return 0;
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return 1;
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}
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int dir_exists(const char *path)
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{
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struct stat info;
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if (!*path)
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return 0;
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if (stat(path, &info) < 0)
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return 0;
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if (!S_ISDIR(info.st_mode))
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return 0;
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return 1;
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}
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/* FIXME: Make this create directories recursively */
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int create_dir(const char *dir)
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{
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struct stat info;
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if (!*dir)
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return 1;
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if (stat(dir, &info) < 0) {
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log_verbose("Creating directory \"%s\"", dir);
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if (!mkdir(dir, 0777))
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return 1;
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log_sys_error("mkdir", dir);
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return 0;
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}
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if (S_ISDIR(info.st_mode))
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return 1;
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log_error("Directory \"%s\" not found", dir);
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return 0;
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}
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int is_empty_dir(const char *dir)
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{
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struct dirent *dirent;
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DIR *d;
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if (!(d = opendir(dir))) {
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log_sys_error("opendir", dir);
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return 0;
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}
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while ((dirent = readdir(d)))
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if (strcmp(dirent->d_name, ".") && strcmp(dirent->d_name, ".."))
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break;
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if (closedir(d)) {
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log_sys_error("closedir", dir);
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}
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return dirent ? 0 : 1;
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}
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