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Diffstat (limited to 'src/lib/libast/path/pathexists.c')
| -rw-r--r-- | src/lib/libast/path/pathexists.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/src/lib/libast/path/pathexists.c b/src/lib/libast/path/pathexists.c new file mode 100644 index 0000000..90b4ae7 --- /dev/null +++ b/src/lib/libast/path/pathexists.c @@ -0,0 +1,134 @@ +/*********************************************************************** +* * +* This software is part of the ast package * +* Copyright (c) 1985-2011 AT&T Intellectual Property * +* and is licensed under the * +* Eclipse Public License, Version 1.0 * +* by AT&T Intellectual Property * +* * +* A copy of the License is available at * +* http://www.eclipse.org/org/documents/epl-v10.html * +* (with md5 checksum b35adb5213ca9657e911e9befb180842) * +* * +* Information and Software Systems Research * +* AT&T Research * +* Florham Park NJ * +* * +* Glenn Fowler <gsf@research.att.com> * +* David Korn <dgk@research.att.com> * +* Phong Vo <kpv@research.att.com> * +* * +***********************************************************************/ +#pragma prototyped +/* + * Glenn Fowler + * AT&T Research + * + * return 1 if path exisis + * maintains a cache to minimize stat(2) calls + * path is modified in-place but restored on return + * path components checked in pairs to cut stat()'s + * in half by checking ENOTDIR vs. ENOENT + * case ignorance infection unavoidable here + */ + +#include "lclib.h" + +#include <ls.h> +#include <error.h> + +typedef struct Tree_s +{ + struct Tree_s* next; + struct Tree_s* tree; + int mode; + char name[1]; +} Tree_t; + +int +pathexists(char* path, int mode) +{ + register char* s; + register char* e; + register Tree_t* p; + register Tree_t* t; + register int c; + char* ee; + int cc; + int x; + struct stat st; + int (*cmp)(const char*, const char*); + + static Tree_t tree; + + t = &tree; + e = (c = *path) == '/' ? path + 1 : path; + cmp = strchr(astconf("PATH_ATTRIBUTES", path, NiL), 'c') ? strcasecmp : strcmp; + if ((ast.locale.set & (AST_LC_debug|AST_LC_find)) == (AST_LC_debug|AST_LC_find)) + sfprintf(sfstderr, "locale test %s\n", path); + while (c) + { + p = t; + for (s = e; *e && *e != '/'; e++); + c = *e; + *e = 0; + for (t = p->tree; t && (*cmp)(s, t->name); t = t->next); + if (!t) + { + if (!(t = newof(0, Tree_t, 1, strlen(s)))) + { + *e = c; + return 0; + } + strcpy(t->name, s); + t->next = p->tree; + p->tree = t; + if (c) + { + *e = c; + for (s = ee = e + 1; *ee && *ee != '/'; ee++); + cc = *ee; + *ee = 0; + } + else + ee = 0; + if ((ast.locale.set & (AST_LC_debug|AST_LC_find)) == (AST_LC_debug|AST_LC_find)) + sfprintf(sfstderr, "locale stat %s\n", path); + x = stat(path, &st); + if (ee) + { + e = ee; + c = cc; + if (!x || errno == ENOENT) + t->mode = PATH_READ|PATH_EXECUTE; + if (!(p = newof(0, Tree_t, 1, strlen(s)))) + { + *e = c; + return 0; + } + strcpy(p->name, s); + p->next = t->tree; + t->tree = p; + t = p; + } + if (x) + { + *e = c; + return 0; + } + if (st.st_mode & (S_IRUSR|S_IRGRP|S_IROTH)) + t->mode |= PATH_READ; + if (st.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH)) + t->mode |= PATH_WRITE; + if (st.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) + t->mode |= PATH_EXECUTE; + if (!S_ISDIR(st.st_mode)) + t->mode |= PATH_REGULAR; + } + *e++ = c; + if (!t->mode || c && (t->mode & PATH_REGULAR)) + return 0; + } + mode &= (PATH_READ|PATH_WRITE|PATH_EXECUTE|PATH_REGULAR); + return (t->mode & mode) == mode; +} |