Mercurial > hg > octave-nkf > gnulib-hg
changeset 937:8147b16806cd
Rewrite using save-cwd.c and chdir to remove quadratic component of complexity.
Before, it processed O(n^2) directory name components via stat and mkdir.
Now it's O(n). This makes mkdir -p a lot more efficient when creating
directories with very many components. On a Linux 2.0.30 ext2fs filesystem
this command: mkdir -p `perl -e 'print "a/" x 500'` now runs in 0.77 seconds
(user+sys). Contrast that with the 9.5(!) seconds it took before.
author | Jim Meyering <jim@meyering.net> |
---|---|
date | Sun, 15 Jun 1997 13:34:47 +0000 |
parents | b354dcdd3dc4 |
children | 28d73bdb3f50 |
files | lib/makepath.c |
diffstat | 1 files changed, 94 insertions(+), 26 deletions(-) [+] |
line wrap: on
line diff
--- a/lib/makepath.c +++ b/lib/makepath.c @@ -1,5 +1,5 @@ /* makepath.c -- Ensure that a directory path exists. - Copyright (C) 1990 Free Software Foundation, Inc. + Copyright (C) 1990, 1997 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 @@ -28,7 +28,7 @@ # include <alloca.h> # else # ifdef _AIX - #pragma alloca + # pragma alloca # else char *alloca (); # endif @@ -76,9 +76,34 @@ typedef int gid_t; #endif +#include "save-cwd.h" #include "makepath.h" +#include "error.h" + +void strip_trailing_slashes (); -void error (); +#define CLEANUP_CWD \ + do \ + { \ + /* We're done operating on basename_dir. \ + Restore working directory. */ \ + if (saved_cwd) \ + { \ + int fail = restore_cwd (&cwd, NULL, NULL); \ + free_cwd (&cwd); \ + if (fail) \ + return 1; \ + } \ + } \ + while (0) + +#define CLEANUP \ + do \ + { \ + umask (oldmask); \ + CLEANUP_CWD; \ + } \ + while (0) /* Ensure that the directory ARGPATH exists. Remove any trailing slashes from ARGPATH before calling this function. @@ -120,17 +145,10 @@ const char *verbose_fmt_string; #endif { - char *dirpath; /* A copy we can scribble NULs on. */ struct stat stats; int retval = 0; - int oldmask = umask (0); - /* FIXME: move this alloca and strcpy into the if-block. - Set dirpath to argpath in the else-block. */ - dirpath = (char *) alloca (strlen (argpath) + 1); - strcpy (dirpath, argpath); - - if (stat (dirpath, &stats)) + if (stat (argpath, &stats)) { char *slash; int tmp_mode; /* Initial perms for leading dirs. */ @@ -141,6 +159,19 @@ struct ptr_list *next; }; struct ptr_list *p, *leading_dirs = NULL; + int saved_cwd = 0; + struct saved_cwd cwd; + char *basename_dir; + int first_subdir = 1; + char *dirpath; + + /* Temporarily relax umask in case it's overly restrictive. */ + int oldmask = umask (0); + + /* Make a copy of ARGPATH that we can scribble NULs on. */ + dirpath = (char *) alloca (strlen (argpath) + 1); + strcpy (dirpath, argpath); + strip_trailing_slashes (dirpath); /* If leading directories shouldn't be writable or executable, or should have set[ug]id or sticky bits set and we are setting @@ -159,17 +190,36 @@ } slash = dirpath; + + /* Skip over leading slashes. */ while (*slash == '/') slash++; - while ((slash = strchr (slash, '/'))) + + while (1) { + /* slash points to the leftmost unprocessed component of dirpath. */ + basename_dir = slash; + + slash = strchr (slash, '/'); + if (slash == NULL) + break; + + if (first_subdir) + { + first_subdir = 0; + saved_cwd = !save_cwd (&cwd); + } + + if (!saved_cwd) + basename_dir = dirpath; + *slash = '\0'; - if (stat (dirpath, &stats)) + if (stat (basename_dir, &stats)) { - if (mkdir (dirpath, tmp_mode)) + if (mkdir (basename_dir, tmp_mode)) { error (0, errno, "cannot create directory `%s'", dirpath); - umask (oldmask); + CLEANUP; return 1; } else @@ -178,15 +228,17 @@ error (0, 0, verbose_fmt_string, dirpath); if (owner != (uid_t) -1 && group != (gid_t) -1 - && chown (dirpath, owner, group) + && chown (basename_dir, owner, group) #if defined(AFS) && defined (EPERM) && errno != EPERM #endif ) { error (0, errno, "%s", dirpath); - retval = 1; + CLEANUP; + return 1; } + if (re_protect) { struct ptr_list *new = (struct ptr_list *) @@ -200,7 +252,14 @@ else if (!S_ISDIR (stats.st_mode)) { error (0, 0, "`%s' exists but is not a directory", dirpath); - umask (oldmask); + CLEANUP; + return 1; + } + + if (saved_cwd && chdir (basename_dir) < 0) + { + error (0, errno, "cannot chdir to directory, %s", dirpath); + CLEANUP; return 1; } @@ -212,40 +271,49 @@ slash++; } + if (!saved_cwd) + basename_dir = dirpath; + /* 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 (dirpath, &stats) && mkdir (dirpath, mode)) + if (stat (basename_dir, &stats) && mkdir (basename_dir, mode)) { error (0, errno, "cannot create directory `%s'", dirpath); - umask (oldmask); + CLEANUP; return 1; } + + /* Done creating directories. Restore original umask. */ + umask (oldmask); + if (verbose_fmt_string != NULL) error (0, 0, verbose_fmt_string, dirpath); if (owner != (uid_t) -1 && group != (gid_t) -1) { - if (chown (dirpath, owner, group) + if (chown (basename_dir, owner, group) #ifdef AFS && errno != EPERM #endif ) { - error (0, errno, "%s", dirpath); + error (0, errno, "cannot chown %s", dirpath); retval = 1; } /* chown may have turned off some permission bits we wanted. */ - if ((mode & 07000) != 0 && chmod (dirpath, mode)) + if ((mode & 07000) != 0 && chmod (basename_dir, mode)) { - error (0, errno, "%s", dirpath); + error (0, errno, "cannot chmod %s", dirpath); retval = 1; } } + CLEANUP_CWD; + /* If the mode for leading directories didn't include owner "wx" privileges, we have to reset their protections to the correct value. */ @@ -263,10 +331,11 @@ { /* We get here if the entire path already exists. */ + const char *dirpath = argpath; + if (!S_ISDIR (stats.st_mode)) { error (0, 0, "`%s' exists but is not a directory", dirpath); - umask (oldmask); return 1; } @@ -296,6 +365,5 @@ } } - umask (oldmask); return retval; }