117 lines
2.5 KiB
C
117 lines
2.5 KiB
C
/* vi: set sw=8 ts=8: */
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/*
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* Utility routines.
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*
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* Copyright (C) many different people.
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* If you wrote this, please acknowledge your work.
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include <common.h>
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#include <libbb.h>
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#include <linux/stat.h>
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#include <fs.h>
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#include <xfuncs.h>
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#include <malloc.h>
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#include <environment.h>
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/* concatenate path and file name to new allocation buffer,
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* not adding '/' if path name already has '/'
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*/
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char *concat_path_file(const char *path, const char *filename)
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{
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char *lc, *str;
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if (!path)
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path = "";
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lc = last_char_is(path, '/');
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while (*filename == '/')
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filename++;
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str = xmalloc(strlen(path) + (lc==NULL ? 1 : 0) + strlen(filename) + 1);
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sprintf(str, "%s%s%s", path, (lc==NULL ? "/" : ""), filename);
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return str;
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}
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EXPORT_SYMBOL(concat_path_file);
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/*
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* This function make special for recursive actions with usage
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* concat_path_file(path, filename)
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* and skipping "." and ".." directory entries
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*/
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char *concat_subpath_file(const char *path, const char *f)
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{
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if (f && DOT_OR_DOTDOT(f))
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return NULL;
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return concat_path_file(path, f);
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}
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EXPORT_SYMBOL(concat_subpath_file);
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/* check if path points to an executable file;
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* return 1 if found;
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* return 0 otherwise;
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*/
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int execable_file(const char *name)
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{
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struct stat s;
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return (!stat(name, &s) && S_ISREG(s.st_mode));
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}
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EXPORT_SYMBOL(execable_file);
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/* search $PATH for an executable file;
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* return allocated string containing full path if found;
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* return NULL otherwise;
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*/
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char *find_execable(const char *filename)
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{
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char *path, *p, *n;
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p = path = strdup(getenv("PATH"));
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while (p) {
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n = strchr(p, ':');
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if (n)
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*n++ = '\0';
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if (*p != '\0') { /* it's not a PATH="foo::bar" situation */
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p = concat_path_file(p, filename);
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if (execable_file(p)) {
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free(path);
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return p;
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}
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free(p);
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}
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p = n;
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}
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free(path);
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return NULL;
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}
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EXPORT_SYMBOL(find_execable);
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/* Find out if the last character of a string matches the one given.
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* Don't underrun the buffer if the string length is 0.
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*/
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char* last_char_is(const char *s, int c)
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{
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if (s && *s) {
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size_t sz = strlen(s) - 1;
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s += sz;
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if ( (unsigned char)*s == c)
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return (char*)s;
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}
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return NULL;
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}
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EXPORT_SYMBOL(last_char_is);
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/* Like strncpy but make sure the resulting string is always 0 terminated. */
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char * safe_strncpy(char *dst, const char *src, size_t size)
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{
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if (!size) return dst;
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dst[--size] = '\0';
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return strncpy(dst, src, size);
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}
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EXPORT_SYMBOL(safe_strncpy);
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