From 370c7163c46a8966e3f13c28cc77d07b0dcc8fce Mon Sep 17 00:00:00 2001 From: Arnaud Giersch Date: Thu, 28 Feb 2019 15:35:19 +0100 Subject: [PATCH] Don't rely on random to generate temporary file names. --- src/smpi/internals/smpi_memory.cpp | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/smpi/internals/smpi_memory.cpp b/src/smpi/internals/smpi_memory.cpp index 14214de4a4..49e4ab19b6 100644 --- a/src/smpi/internals/smpi_memory.cpp +++ b/src/smpi/internals/smpi_memory.cpp @@ -184,10 +184,16 @@ smpi_privatization_region_t smpi_init_global_memory_segment_process() char path[24]; int status; - do { - snprintf(path, sizeof(path), "/smpi-buffer-%06x", rand() % 0xffffffU); + constexpr unsigned VAL_MASK = 0xffffffU; + static unsigned prev_val = VAL_MASK; + for (unsigned i = (prev_val + 1) & VAL_MASK; i != prev_val; i = (i + 1) & VAL_MASK) { + snprintf(path, sizeof(path), "/smpi-buffer-%06x", i); file_descriptor = shm_open(path, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); - } while (file_descriptor == -1 && errno == EEXIST); + if (file_descriptor != -1 || errno != EEXIST) { + prev_val = i; + break; + } + } if (file_descriptor < 0) { if (errno == EMFILE) { xbt_die("Impossible to create temporary file for memory mapping: %s\n\ -- 2.20.1