From f70a6250160d44cc58ceaf0df808a5a2d14d26e6 Mon Sep 17 00:00:00 2001 From: Joe Orton Date: Wed, 5 Jul 2023 14:13:44 +0100 Subject: [PATCH] Allow mod_dav_fs to tolerate race conditions between PROPFIND and an operation which removes a directory/file between apr_dir_read() and apr_stat(). Current behaviour is to abort the connection which seems inferior to tolerating (and logging) the error. * modules/dav/fs/repos.c (dav_fs_walker): If DAV_WALKTYPE_TOLERANT is set, ignore ENOENT from stat() rather than aborting the response. Log the error from stat either way. * modules/dav/main/mod_dav.c (dav_method_propfind): Set DAV_WALKTYPE_TOLERANT. * modules/dav/main/mod_dav.h: Add DAV_WALKTYPE_TOLERANT. --- modules/dav/fs/repos.c | 14 ++++++++++++++ modules/dav/main/mod_dav.c | 2 +- modules/dav/main/mod_dav.h | 1 + 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/modules/dav/fs/repos.c b/modules/dav/fs/repos.c index 889d728a1b7..701b4425e06 100644 --- a/modules/dav/fs/repos.c +++ b/modules/dav/fs/repos.c @@ -35,6 +35,7 @@ #include "mod_dav.h" #include "repos.h" +APLOG_USE_MODULE(dav_fs); /* to assist in debugging mod_dav's GET handling */ #define DEBUG_GET_HANDLER 0 @@ -1613,6 +1614,19 @@ static dav_error * dav_fs_walker(dav_fs_walker_context *fsctx, int depth) status = apr_stat(&fsctx->info1.finfo, fsctx->path1.buf, DAV_FINFO_MASK, pool); if (status != APR_SUCCESS && status != APR_INCOMPLETE) { + dav_resource_private *ctx = params->root->info; + + ap_log_rerror(APLOG_MARK, APLOG_ERR, status, ctx->r, + APLOGNO(10472) "could not access file (%s) during directory walk", + fsctx->path1.buf); + + /* If being tolerant, ignore failure due to losing a race + * with some other process deleting files out from under + * the directory walk. */ + if ((params->walk_type & DAV_WALKTYPE_TOLERANT) + && APR_STATUS_IS_ENOENT(status)) { + continue; + } /* woah! where'd it go? */ /* ### should have a better error here */ err = dav_new_error(pool, HTTP_NOT_FOUND, 0, status, NULL); diff --git a/modules/dav/main/mod_dav.c b/modules/dav/main/mod_dav.c index 4f8d748a13a..69e068807f8 100644 --- a/modules/dav/main/mod_dav.c +++ b/modules/dav/main/mod_dav.c @@ -2269,7 +2269,7 @@ static int dav_method_propfind(request_rec *r) return HTTP_BAD_REQUEST; } - ctx.w.walk_type = DAV_WALKTYPE_NORMAL | DAV_WALKTYPE_AUTH; + ctx.w.walk_type = DAV_WALKTYPE_NORMAL | DAV_WALKTYPE_AUTH | DAV_WALKTYPE_TOLERANT; ctx.w.func = dav_propfind_walker; ctx.w.walk_ctx = &ctx; ctx.w.pool = r->pool; diff --git a/modules/dav/main/mod_dav.h b/modules/dav/main/mod_dav.h index fcf146c694c..2bfec337573 100644 --- a/modules/dav/main/mod_dav.h +++ b/modules/dav/main/mod_dav.h @@ -1834,6 +1834,7 @@ typedef struct #define DAV_WALKTYPE_AUTH 0x0001 /* limit to authorized files */ #define DAV_WALKTYPE_NORMAL 0x0002 /* walk normal files */ #define DAV_WALKTYPE_LOCKNULL 0x0004 /* walk locknull resources */ +#define DAV_WALKTYPE_TOLERANT 0x0008 /* tolerate non-fatal errors */ /* callback function and a client context for the walk */ dav_error * (*func)(dav_walk_resource *wres, int calltype);