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* In `nix-env -i|-u|-e', lock the profile to prevent races between

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concurrent nix-env operations on the same profile.  Fixes NIX-7.
This commit is contained in:
Eelco Dolstra 2006-06-15 11:56:49 +00:00
parent 49de87132f
commit 588cb0eade
3 changed files with 26 additions and 6 deletions
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11
src/libstore/pathlocks.cc
View file

@ -51,14 +51,14 @@ PathLocks::PathLocks()
} }
PathLocks::PathLocks(const PathSet & paths) PathLocks::PathLocks(const PathSet & paths, const string & waitMsg)
: deletePaths(false) : deletePaths(false)
{ {
lockPaths(paths); lockPaths(paths, waitMsg);
} }
void PathLocks::lockPaths(const PathSet & _paths) void PathLocks::lockPaths(const PathSet & _paths, const string & waitMsg)
{ {
/* May be called only once! */ /* May be called only once! */
assert(fds.empty()); assert(fds.empty());
@ -94,7 +94,10 @@ void PathLocks::lockPaths(const PathSet & _paths)
throw SysError(format("opening lock file `%1%'") % lockPath); throw SysError(format("opening lock file `%1%'") % lockPath);
/* Acquire an exclusive lock. */ /* Acquire an exclusive lock. */
lockFile(fd, ltWrite, true); if (!lockFile(fd, ltWrite, false)) {
if (waitMsg != "") printMsg(lvlError, waitMsg);
lockFile(fd, ltWrite, true);
}
debug(format("lock acquired on `%1%'") % lockPath); debug(format("lock acquired on `%1%'") % lockPath);

6
src/libstore/pathlocks.hh
View file

@ -18,8 +18,10 @@ private:
public: public:
PathLocks(); PathLocks();
PathLocks(const PathSet & paths); PathLocks(const PathSet & paths,
void lockPaths(const PathSet & _paths); const string & waitMsg = "");
void lockPaths(const PathSet & _paths,
const string & waitMsg = "");
~PathLocks(); ~PathLocks();
void setDeletion(bool deletePaths); void setDeletion(bool deletePaths);
}; };

15
src/nix-env/main.cc
View file

@ -10,6 +10,7 @@
#include "help.txt.hh" #include "help.txt.hh"
#include "nixexpr-ast.hh" #include "nixexpr-ast.hh"
#include "get-drvs.hh" #include "get-drvs.hh"
#include "pathlocks.hh"
#include <cerrno> #include <cerrno>
#include <ctime> #include <ctime>
@ -411,6 +412,14 @@ static void printMissing(EvalState & state, const DrvInfos & elems)
} }
static void lockProfile(PathLocks & lock, const Path & profile)
{
lock.lockPaths(singleton<PathSet>(profile),
(format("waiting for lock on profile `%1%'") % profile).str());
lock.setDeletion(true);
}
static void installDerivations(Globals & globals, static void installDerivations(Globals & globals,
const Strings & args, const Path & profile) const Strings & args, const Path & profile)
{ {
@ -426,6 +435,8 @@ static void installDerivations(Globals & globals,
/* Add in the already installed derivations, unless they have the /* Add in the already installed derivations, unless they have the
same name as a to-be-installed element. */ same name as a to-be-installed element. */
PathLocks lock;
lockProfile(lock, profile);
DrvInfos installedElems = queryInstalled(globals.state, profile); DrvInfos installedElems = queryInstalled(globals.state, profile);
DrvInfos allElems(newElems); DrvInfos allElems(newElems);
@ -480,6 +491,8 @@ static void upgradeDerivations(Globals & globals,
name and a higher version number. */ name and a higher version number. */
/* Load the currently installed derivations. */ /* Load the currently installed derivations. */
PathLocks lock;
lockProfile(lock, profile);
DrvInfos installedElems = queryInstalled(globals.state, profile); DrvInfos installedElems = queryInstalled(globals.state, profile);
/* Fetch all derivations from the input file. */ /* Fetch all derivations from the input file. */
@ -559,6 +572,8 @@ static void opUpgrade(Globals & globals,
static void uninstallDerivations(Globals & globals, DrvNames & selectors, static void uninstallDerivations(Globals & globals, DrvNames & selectors,
Path & profile) Path & profile)
{ {
PathLocks lock;
lockProfile(lock, profile);
DrvInfos installedElems = queryInstalled(globals.state, profile); DrvInfos installedElems = queryInstalled(globals.state, profile);
DrvInfos newElems; DrvInfos newElems;