diff options
Diffstat (limited to 'runtime/srutils.c')
| -rw-r--r-- | runtime/srutils.c | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/runtime/srutils.c b/runtime/srutils.c index c403b312..1452c9b7 100644 --- a/runtime/srutils.c +++ b/runtime/srutils.c @@ -166,10 +166,22 @@ uchar *srUtilStrDup(uchar *pOld, size_t len) /* creates a path recursively - * Return 0 on success, -1 otherwise. On failure, errno - * hold the last OS error. - * Param "mode" holds the mode that all non-existing directories - * are to be created with. + * Return 0 on success, -1 otherwise. On failure, errno * hold the last OS error. + * Param "mode" holds the mode that all non-existing directories are to be + * created with. + * Note that we have a potential race inside that code, a race that even exists + * outside of the rsyslog process (if multiple instances run, or other programs + * generate directories): If the directory does not exist, a context switch happens, + * at that moment another process creates it, then our creation on the context + * switch back fails. This actually happened in practice, and depending on the + * configuration it is even likely to happen. We can not solve this situation + * with a mutex, as that works only within out process space. So the solution + * is that we take the optimistic approach, try the creation, and if it fails + * with "already exists" we go back and do one retry of the check/create + * sequence. That should then succeed. If the directory is still not found but + * the creation fails in the similar way, we return an error on that second + * try because otherwise we would potentially run into an endless loop. + * loop. -- rgerhards, 2010-03-25 */ int makeFileParentDirs(uchar *szFile, size_t lenFile, mode_t mode, uid_t uid, gid_t gid, int bFailOnChownFail) @@ -177,6 +189,8 @@ int makeFileParentDirs(uchar *szFile, size_t lenFile, mode_t mode, uchar *p; uchar *pszWork; size_t len; + int err; + int iTry = 0; int bErr = 0; assert(szFile != NULL); @@ -190,8 +204,9 @@ int makeFileParentDirs(uchar *szFile, size_t lenFile, mode_t mode, if(*p == '/') { /* temporarily terminate string, create dir and go on */ *p = '\0'; +again: if(access((char*)pszWork, F_OK)) { - if(mkdir((char*)pszWork, mode) == 0) { + if((err = mkdir((char*)pszWork, mode)) == 0) { if(uid != (uid_t) -1 || gid != (gid_t) -1) { /* we need to set owner/group */ if(chown((char*)pszWork, uid, gid) != 0) @@ -201,8 +216,13 @@ int makeFileParentDirs(uchar *szFile, size_t lenFile, mode_t mode, * to do so. */ } - } else + } else { + if(err == EEXIST && iTry == 0) { + iTry = 1; + goto again; + } bErr = 1; + } if(bErr) { int eSave = errno; free(pszWork); |