diff options
Diffstat (limited to 'src/fileio.c')
| -rw-r--r-- | src/fileio.c | 170 |
1 files changed, 45 insertions, 125 deletions
diff --git a/src/fileio.c b/src/fileio.c index 31fd84512e1..b7e3b71a475 100644 --- a/src/fileio.c +++ b/src/fileio.c @@ -97,6 +97,7 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ #include <allocator.h> #include <careadlinkat.h> #include <stat-time.h> +#include <tempname.h> #include <binary-io.h> @@ -655,149 +656,67 @@ In Unix-syntax, this function just removes the final slash. */) return val; } -static const char make_temp_name_tbl[64] = -{ - 'A','B','C','D','E','F','G','H', - 'I','J','K','L','M','N','O','P', - 'Q','R','S','T','U','V','W','X', - 'Y','Z','a','b','c','d','e','f', - 'g','h','i','j','k','l','m','n', - 'o','p','q','r','s','t','u','v', - 'w','x','y','z','0','1','2','3', - '4','5','6','7','8','9','-','_' -}; - -static unsigned make_temp_name_count, make_temp_name_count_initialized_p; - -/* Value is a temporary file name starting with PREFIX, a string. +DEFUN ("make-temp-file-internal", Fmake_temp_file_internal, + Smake_temp_file_internal, 3, 3, 0, + doc: /* Generate a new file whose name starts with PREFIX, a string. +Return the name of the generated file. If DIR-FLAG is zero, do not +create the file, just its name. Otherwise, if DIR-FLAG is non-nil, +create an empty directory. The file name should end in SUFFIX. - The Emacs process number forms part of the result, so there is - no danger of generating a name being used by another process. - In addition, this function makes an attempt to choose a name - which has no existing file. To make this work, PREFIX should be - an absolute file name. +Signal an error if the file could not be created. - BASE64_P means add the pid as 3 characters in base64 - encoding. In this case, 6 characters will be added to PREFIX to - form the file name. Otherwise, if Emacs is running on a system - with long file names, add the pid as a decimal number. - - This function signals an error if no unique file name could be - generated. */ - -Lisp_Object -make_temp_name (Lisp_Object prefix, bool base64_p) +This function does not grok magic file names. */) + (Lisp_Object prefix, Lisp_Object dir_flag, Lisp_Object suffix) { - Lisp_Object val, encoded_prefix; - ptrdiff_t len; - printmax_t pid; - char *p, *data; - char pidbuf[INT_BUFSIZE_BOUND (printmax_t)]; - int pidlen; - - CHECK_STRING (prefix); - - /* VAL is created by adding 6 characters to PREFIX. The first - three are the PID of this process, in base 64, and the second - three are incremented if the file already exists. This ensures - 262144 unique file names per PID per PREFIX. */ - - pid = getpid (); - - if (base64_p) - { - pidbuf[0] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidbuf[1] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidbuf[2] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidlen = 3; - } - else + bool make_temp_name = EQ (dir_flag, make_number (0)); + CHECK_STRING (suffix); + if (!make_temp_name) + prefix = Fexpand_file_name (prefix, Vtemporary_file_directory); + + Lisp_Object encoded_prefix = ENCODE_FILE (prefix); + Lisp_Object encoded_suffix = ENCODE_FILE (suffix); + ptrdiff_t prefix_len = SBYTES (encoded_prefix); + ptrdiff_t suffix_len = SBYTES (encoded_suffix); + if (INT_MAX < suffix_len) + args_out_of_range (prefix, suffix); + int nX = 6; + Lisp_Object val = make_uninit_string (prefix_len + nX + suffix_len); + char *data = SSDATA (val); + memcpy (data, SSDATA (encoded_prefix), prefix_len); + memset (data + prefix_len, 'X', nX); + memcpy (data + prefix_len + nX, SSDATA (encoded_suffix), suffix_len); + int kind = (NILP (dir_flag) ? GT_FILE + : make_temp_name ? GT_NOCREATE + : GT_DIR); + int fd = gen_tempname (data, suffix_len, O_BINARY | O_CLOEXEC, kind); + if (fd < 0 || (NILP (dir_flag) && emacs_close (fd) != 0)) { -#ifdef HAVE_LONG_FILE_NAMES - pidlen = sprintf (pidbuf, "%"pMd, pid); -#else - pidbuf[0] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidbuf[1] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidbuf[2] = make_temp_name_tbl[pid & 63], pid >>= 6; - pidlen = 3; -#endif - } - - encoded_prefix = ENCODE_FILE (prefix); - len = SBYTES (encoded_prefix); - val = make_uninit_string (len + 3 + pidlen); - data = SSDATA (val); - memcpy (data, SSDATA (encoded_prefix), len); - p = data + len; - - memcpy (p, pidbuf, pidlen); - p += pidlen; - - /* Here we try to minimize useless stat'ing when this function is - invoked many times successively with the same PREFIX. We achieve - this by initializing count to a random value, and incrementing it - afterwards. - - We don't want make-temp-name to be called while dumping, - because then make_temp_name_count_initialized_p would get set - and then make_temp_name_count would not be set when Emacs starts. */ - - if (!make_temp_name_count_initialized_p) - { - make_temp_name_count = time (NULL); - make_temp_name_count_initialized_p = 1; - } - - while (1) - { - unsigned num = make_temp_name_count; - - p[0] = make_temp_name_tbl[num & 63], num >>= 6; - p[1] = make_temp_name_tbl[num & 63], num >>= 6; - p[2] = make_temp_name_tbl[num & 63], num >>= 6; - - /* Poor man's congruential RN generator. Replace with - ++make_temp_name_count for debugging. */ - make_temp_name_count += 25229; - make_temp_name_count %= 225307; - - if (!check_existing (data)) + static char const kind_message[][32] = { - /* We want to return only if errno is ENOENT. */ - if (errno == ENOENT) - return DECODE_FILE (val); - else - /* The error here is dubious, but there is little else we - can do. The alternatives are to return nil, which is - as bad as (and in many cases worse than) throwing the - error, or to ignore the error, which will likely result - in looping through 225307 stat's, which is not only - dog-slow, but also useless since eventually nil would - have to be returned anyway. */ - report_file_error ("Cannot create temporary name for prefix", - prefix); - /* not reached */ - } + [GT_FILE] = "Creating file with prefix", + [GT_DIR] = "Creating directory with prefix", + [GT_NOCREATE] = "Creating file name with prefix" + }; + report_file_error (kind_message[kind], prefix); } + return DECODE_FILE (val); } DEFUN ("make-temp-name", Fmake_temp_name, Smake_temp_name, 1, 1, 0, doc: /* Generate temporary file name (string) starting with PREFIX (a string). -The Emacs process number forms part of the result, so there is no -danger of generating a name being used by another Emacs process -\(so long as only a single host can access the containing directory...). This function tries to choose a name that has no existing file. For this to work, PREFIX should be an absolute file name, and PREFIX and the returned string should both be non-magic. -There is a race condition between calling `make-temp-name' and creating the -file, which opens all kinds of security holes. For that reason, you should -normally use `make-temp-file' instead. */) +There is a race condition between calling `make-temp-name' and +later creating the file, which opens all kinds of security holes. +For that reason, you should normally use `make-temp-file' instead. */) (Lisp_Object prefix) { - return make_temp_name (prefix, 0); + return Fmake_temp_file_internal (prefix, make_number (0), + empty_unibyte_string); } DEFUN ("expand-file-name", Fexpand_file_name, Sexpand_file_name, 1, 2, 0, @@ -6168,6 +6087,7 @@ This includes interactive calls to `delete-file' and defsubr (&Sfile_name_as_directory); defsubr (&Sdirectory_name_p); defsubr (&Sdirectory_file_name); + defsubr (&Smake_temp_file_internal); defsubr (&Smake_temp_name); defsubr (&Sexpand_file_name); defsubr (&Ssubstitute_in_file_name); |