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authorDavid Kalnischkies <david@kalnischkies.de>2017-04-28 17:43:29 +0200
committerDavid Kalnischkies <david@kalnischkies.de>2017-06-26 23:31:15 +0200
commite91dd46e3f65517ed9dbc6e431a56112a403cb3e (patch)
tree47235bf4e16b5664e0dd4ddc096105164a83acd0 /apt-pkg/contrib
parent24fbb6adb071c39e24f9b0a89aadc7d5673a8775 (diff)
ident a CD without changing directory
Diffstat (limited to 'apt-pkg/contrib')
-rw-r--r--apt-pkg/contrib/cdromutl.cc46
1 files changed, 23 insertions, 23 deletions
diff --git a/apt-pkg/contrib/cdromutl.cc b/apt-pkg/contrib/cdromutl.cc
index 428ef0161..3628f6173 100644
--- a/apt-pkg/contrib/cdromutl.cc
+++ b/apt-pkg/contrib/cdromutl.cc
@@ -184,26 +184,32 @@ bool IdentCdrom(string CD,string &Res,unsigned int Version)
MD5Summation Hash;
bool writable_media = false;
+ int dirfd = open(CD.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ if (dirfd == -1)
+ return _error->Errno("open",_("Unable to read %s"),CD.c_str());
+
// if we are on a writable medium (like a usb-stick) that is just
// used like a cdrom don't use "." as it will constantly change,
// use .disk instead
- if (access(CD.c_str(), W_OK) == 0 && DirectoryExists(CD+string("/.disk")))
+ if (faccessat(dirfd, ".", W_OK, 0) == 0)
{
- writable_media = true;
- CD = CD.append("/.disk");
- if (_config->FindB("Debug::aptcdrom",false) == true)
- std::clog << "Found writable cdrom, using alternative path: " << CD
- << std::endl;
+ int diskfd = openat(dirfd, "./.disk", O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0);
+ if (diskfd != -1)
+ {
+ close(dirfd);
+ dirfd = diskfd;
+ writable_media = true;
+ CD = CD.append("/.disk");
+ if (_config->FindB("Debug::aptcdrom",false) == true)
+ std::clog << "Found writable cdrom, using alternative path: " << CD
+ << std::endl;
+ }
}
- string StartDir = SafeGetCWD();
- if (chdir(CD.c_str()) != 0)
- return _error->Errno("chdir",_("Unable to change to %s"),CD.c_str());
-
- DIR *D = opendir(".");
- if (D == 0)
+ DIR * const D = fdopendir(dirfd);
+ if (D == nullptr)
return _error->Errno("opendir",_("Unable to read %s"),CD.c_str());
-
+
/* Run over the directory, we assume that the reader order will never
change as the media is read-only. In theory if the kernel did
some sort of wacked caching this might not be true.. */
@@ -222,31 +228,24 @@ bool IdentCdrom(string CD,string &Res,unsigned int Version)
else
{
struct stat Buf;
- if (stat(Dir->d_name,&Buf) != 0)
+ if (fstatat(dirfd, Dir->d_name, &Buf, 0) != 0)
continue;
strprintf(S, "%lu", (unsigned long)Buf.st_mtime);
}
Hash.Add(S.c_str());
Hash.Add(Dir->d_name);
- };
-
- if (chdir(StartDir.c_str()) != 0) {
- _error->Errno("chdir",_("Unable to change to %s"),StartDir.c_str());
- closedir(D);
- return false;
}
- closedir(D);
// Some stats from the fsys
std::string S;
if (_config->FindB("Debug::identcdrom",false) == false)
{
struct statvfs Buf;
- if (statvfs(CD.c_str(),&Buf) != 0)
+ if (fstatvfs(dirfd, &Buf) != 0)
return _error->Errno("statfs",_("Failed to stat the cdrom"));
- // We use a kilobyte block size to advoid overflow
+ // We use a kilobyte block size to avoid overflow
if (writable_media)
{
strprintf(S, "%lu", (unsigned long)(Buf.f_blocks*(Buf.f_bsize/1024)));
@@ -260,6 +259,7 @@ bool IdentCdrom(string CD,string &Res,unsigned int Version)
else
strprintf(S, "-%u.debug", Version);
+ closedir(D);
Res = Hash.Result().Value() + S;
return true;
}