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authorJim Meyering <jim@meyering.net>1999-01-02 05:16:57 +0000
committerJim Meyering <jim@meyering.net>1999-01-02 05:16:57 +0000
commitcb1d4eb4f2ca94e74ebbf9ff42557ac40fceb000 (patch)
tree67b37a6bba20f3795f8105f44e9a9773546bf37f /lib
parent45ed22a319507209f8a9b74bf8454577aa430c76 (diff)
downloadcoreutils-cb1d4eb4f2ca94e74ebbf9ff42557ac40fceb000.tar.xz
(make_dir): New function, factored out of make_path.
(make_path): Use make_dir rather than open-coding it twice. This effectively reverses the order of the latter pair of stat/mkdir calls and fixes a race condition bug whereby one of two concurrent `mkdir -p' processes could fail with EEXIST.
Diffstat (limited to 'lib')
-rw-r--r--lib/makepath.c95
1 files changed, 60 insertions, 35 deletions
diff --git a/lib/makepath.c b/lib/makepath.c
index 99119a213..cf570d9ac 100644
--- a/lib/makepath.c
+++ b/lib/makepath.c
@@ -1,5 +1,5 @@
/* makepath.c -- Ensure that a directory path exists.
- Copyright (C) 1990, 1997, 1998 Free Software Foundation, Inc.
+ Copyright (C) 1990, 1997, 1998, 1999 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -99,9 +99,9 @@ void strip_trailing_slashes ();
Restore working directory. */ \
if (do_chdir) \
{ \
- int fail = restore_cwd (&cwd, NULL, NULL); \
+ int _fail = restore_cwd (&cwd, NULL, NULL); \
free_cwd (&cwd); \
- if (fail) \
+ if (_fail) \
return 1; \
} \
} \
@@ -115,6 +115,56 @@ void strip_trailing_slashes ();
} \
while (0)
+/* Attempt to create directory DIR (aka DIRPATH) with the specified MODE.
+ If CREATED_DIR_P is non-NULL, set *CREATED_DIR_P to non-zero if this
+ function creates DIR and to zero otherwise. Give a diagnostic and
+ return non-zero if DIR cannot be created or cannot be determined to
+ exist already. Use DIRPATH in any diagnostic, not DIR.
+ Note that if DIR already exists, this function will return zero
+ (indicating success) and will set *CREATED_DIR_P to zero. */
+
+static int
+make_dir (const char *dir, const char *dirpath, mode_t mode, int *created_dir_p)
+{
+ int fail = 0;
+ int created_dir;
+
+ created_dir = (mkdir (dir, mode) == 0);
+
+ if (!created_dir)
+ {
+ struct stat stats;
+
+ /* The mkdir and stat calls below may appear to be reversed.
+ They are not. It is important to call mkdir first and then to
+ call stat (to distinguish the three cases) only if mkdir fails.
+ The alternative to this approach is to `stat' each directory,
+ then to call mkdir if it doesn't exist. But if some other process
+ were to create the directory between the stat & mkdir, the mkdir
+ would fail with EEXIST. */
+
+ if (stat (dir, &stats))
+ {
+ error (0, errno, "cannot create directory `%s'", dirpath);
+ fail = 1;
+ }
+ else if (!S_ISDIR (stats.st_mode))
+ {
+ error (0, 0, "`%s' exists but is not a directory", dirpath);
+ fail = 1;
+ }
+ else
+ {
+ /* DIR (aka DIRPATH) already exists and is a directory. */
+ }
+ }
+
+ if (created_dir_p)
+ *created_dir_p = created_dir;
+
+ return fail;
+}
+
/* Ensure that the directory ARGPATH exists.
Remove any trailing slashes from ARGPATH before calling this function.
@@ -203,7 +253,8 @@ make_path (const char *argpath,
while (1)
{
- int newly_created_dir = 1;
+ int newly_created_dir;
+ int fail;
/* slash points to the leftmost unprocessed component of dirpath. */
basename_dir = slash;
@@ -217,34 +268,12 @@ make_path (const char *argpath,
if (!do_chdir)
basename_dir = dirpath;
- /* The mkdir and stat calls below appear to be reversed.
- They are not. It is important to call mkdir first and then to
- call stat (to distinguish the three cases) only if mkdir fails.
- The alternative to this approach is to `stat' each directory,
- then to call mkdir if it doesn't exist. But if some other process
- were to create the directory between the stat & mkdir, the mkdir
- would fail with EEXIST. */
-
*slash = '\0';
- if (mkdir (basename_dir, tmp_mode))
+ fail = make_dir (basename_dir, dirpath, tmp_mode, &newly_created_dir);
+ if (fail)
{
- if (stat (basename_dir, &stats))
- {
- error (0, errno, "cannot create directory `%s'", dirpath);
- CLEANUP;
- return 1;
- }
- else if (!S_ISDIR (stats.st_mode))
- {
- error (0, 0, "`%s' exists but is not a directory", dirpath);
- CLEANUP;
- return 1;
- }
- else
- {
- /* DIRPATH already exists and is a directory. */
- newly_created_dir = 0;
- }
+ CLEANUP;
+ return 1;
}
if (newly_created_dir)
@@ -299,12 +328,8 @@ make_path (const char *argpath,
/* We're done making leading directories.
Create the final component of the path. */
- /* The path could end in "/." or contain "/..", so test
- if we really have to create the directory. */
-
- if (stat (basename_dir, &stats) && mkdir (basename_dir, mode))
+ if (make_dir (basename_dir, dirpath, mode, NULL))
{
- error (0, errno, "cannot create directory `%s'", dirpath);
CLEANUP;
return 1;
}