diff options
| -rw-r--r-- | erts/emulator/drivers/common/efile_drv.c | 61 | ||||
| -rw-r--r-- | erts/emulator/test/efile_SUITE.erl | 49 |
2 files changed, 105 insertions, 5 deletions
diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c index a1b15a2199..4e1d2f0d7f 100644 --- a/erts/emulator/drivers/common/efile_drv.c +++ b/erts/emulator/drivers/common/efile_drv.c @@ -1261,6 +1261,50 @@ static void free_read_line(void *data) EF_FREE(d); } +void read_file_zero_size(struct t_data* d); +#define ZERO_FILE_CHUNK (64 * 1024) + +/* [ERL-327] Some special files like /proc/... have reported size 0 */ +void read_file_zero_size(struct t_data* d) { + size_t total_read_size = 0; + size_t allocated_size = ZERO_FILE_CHUNK; /* allocd in invoke_read_file */ + for (;;) { + size_t read_result; + + /* Read until we hit EOF (read less than FILE_SEGMENT_READ) */ + d->result_ok = efile_read(&d->errInfo, + EFILE_MODE_READ, + (int) d->fd, + (d->c.read_file.binp->orig_bytes + + total_read_size), + ZERO_FILE_CHUNK, + &read_result); + if (!d->result_ok) { + break; + } + + total_read_size += read_result; + d->c.read_file.offset += read_result; + if (read_result < ZERO_FILE_CHUNK) { + break; + } + + /* Grow before the next read call */ + allocated_size = total_read_size + ZERO_FILE_CHUNK; + d->c.read_file.binp = driver_realloc_binary(d->c.read_file.binp, + allocated_size); + } + + /* Finalize the memory usage. Hopefully it was read fully on the first + * go, so the binary allocation overhead becomes: + * alloc ZERO_FILE_CHUNK (64kb) -> realloc real_size */ + if (allocated_size != total_read_size) { + d->c.read_file.binp = driver_realloc_binary(d->c.read_file.binp, + total_read_size); + } + d->again = 0; +} + static void invoke_read_file(void *data) { struct t_data *d = (struct t_data *) data; @@ -1279,9 +1323,15 @@ static void invoke_read_file(void *data) } d->fd = fd; d->c.read_file.size = (int) size; - if (size < 0 || size != d->c.read_file.size || - ! (d->c.read_file.binp = - driver_alloc_binary(d->c.read_file.size))) { + + /* For zero sized files allocate a reasonable chunk to attempt reading + * anyway. Note: This will eat ZERO_FILE_CHUNK bytes for any 0 file + * and free them immediately after (if the file was empty). */ + ERTS_ASSERT(size >= 0); + d->c.read_file.binp = driver_alloc_binary(size != 0 ? (size_t)size + : ZERO_FILE_CHUNK); + + if (size < 0 || size != d->c.read_file.size || !d->c.read_file.binp) { d->result_ok = 0; d->errInfo.posix_errno = ENOMEM; goto close; @@ -1290,6 +1340,11 @@ static void invoke_read_file(void *data) } /* Invariant: d->c.read_file.size >= d->c.read_file.offset */ + if (d->c.read_file.size == 0) { + read_file_zero_size(d); + goto close; + } + read_size = (size_t) (d->c.read_file.size - d->c.read_file.offset); if (! read_size) goto close; chop = d->again && read_size >= FILE_SEGMENT_READ*2; diff --git a/erts/emulator/test/efile_SUITE.erl b/erts/emulator/test/efile_SUITE.erl index f0e1bcf04b..08d5597d78 100644 --- a/erts/emulator/test/efile_SUITE.erl +++ b/erts/emulator/test/efile_SUITE.erl @@ -19,16 +19,20 @@ -module(efile_SUITE). -export([all/0, suite/0]). --export([iter_max_files/1, async_dist/1]). +-export([async_dist/1, + iter_max_files/1, + proc_zero_sized_files/1 + ]). -export([do_iter_max_files/2, do_async_dist/1]). -include_lib("common_test/include/ct.hrl"). +-include_lib("stdlib/include/assert.hrl"). suite() -> [{ct_hooks,[ts_install_cth]}]. all() -> - [iter_max_files, async_dist]. + [iter_max_files, async_dist, proc_zero_sized_files]. do_async_dist(Dir) -> X = 100, @@ -162,3 +166,44 @@ open_files(Name) -> % io:format("Error reason: ~p", [_Reason]), [] end. + +%% @doc If /proc filesystem exists (no way to know if it is real proc or just +%% a /proc directory), let's read some zero sized files 500 times each, while +%% ensuring that response isn't empty << >> +proc_zero_sized_files(Config) when is_list(Config) -> + {Type, Flavor} = os:type(), + %% Some files which exist on Linux but might be missing on other systems + Inputs = ["/proc/cpuinfo", + "/proc/meminfo", + "/proc/partitions", + "/proc/swaps", + "/proc/version", + "/proc/uptime", + %% curproc is present on freebsd + "/proc/curproc/cmdline"], + case filelib:is_dir("/proc") of + false -> {skip, "/proc not found"}; % skip the test if no /proc + _ when Type =:= unix andalso Flavor =:= sunos -> + %% SunOS has a /proc, but no zero sized special files + {skip, "sunos does not have any zero sized special files"}; + true -> + %% Take away files which do not exist in proc + Inputs1 = lists:filter(fun filelib:is_file/1, Inputs), + + %% Fail if none of mentioned files exist in /proc, did we just get + %% a normal /proc directory without any special files? + ?assertNotEqual([], Inputs1), + + %% For 6 inputs and 500 attempts each this do run anywhere + %% between 500 and 3000 function calls. + lists:foreach( + fun(Filename) -> do_proc_zero_sized(Filename, 500) end, + Inputs1) + end. + +%% @doc Test one file N times to also trigger possible leaking fds and memory +do_proc_zero_sized(_Filename, 0) -> ok; +do_proc_zero_sized(Filename, N) -> + Data = file:read_file(Filename), + ?assertNotEqual(<<>>, Data), + do_proc_zero_sized(Filename, N-1). |