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/*
* Utility routines.
*
* Copyright (C) many different people.
* If you wrote this, please acknowledge your work.
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <common.h>
#include <libbb.h>
#include <linux/stat.h>
#include <fs.h>
#include <xfuncs.h>
#include <malloc.h>
#include <environment.h>
/* concatenate path and file name to new allocation buffer,
* not adding '/' if path name already has '/'
*/
char *concat_path_file(const char *path, const char *filename)
{
char *lc, *str;
if (!path)
path = "";
lc = last_char_is(path, '/');
while (*filename == '/')
filename++;
str = xmalloc(strlen(path) + (lc==NULL ? 1 : 0) + strlen(filename) + 1);
sprintf(str, "%s%s%s", path, (lc==NULL ? "/" : ""), filename);
return str;
}
EXPORT_SYMBOL(concat_path_file);
/*
* This function make special for recursive actions with usage
* concat_path_file(path, filename)
* and skipping "." and ".." directory entries
*/
char *concat_subpath_file(const char *path, const char *f)
{
if (f && DOT_OR_DOTDOT(f))
return NULL;
return concat_path_file(path, f);
}
EXPORT_SYMBOL(concat_subpath_file);
/* check if path points to an executable file;
* return 1 if found;
* return 0 otherwise;
*/
int execable_file(const char *name)
{
struct stat s;
return (!stat(name, &s) && S_ISREG(s.st_mode));
}
EXPORT_SYMBOL(execable_file);
/* search $PATH for an executable file;
* return allocated string containing full path if found;
* return NULL otherwise;
*/
char *find_execable(const char *filename)
{
char *path, *p, *n;
p = path = strdup(getenv("PATH"));
while (p) {
n = strchr(p, ':');
if (n)
*n++ = '\0';
if (*p != '\0') { /* it's not a PATH="foo::bar" situation */
p = concat_path_file(p, filename);
if (execable_file(p)) {
free(path);
return p;
}
free(p);
}
p = n;
}
free(path);
return NULL;
}
EXPORT_SYMBOL(find_execable);
/* Find out if the last character of a string matches the one given.
* Don't underrun the buffer if the string length is 0.
*/
char* last_char_is(const char *s, int c)
{
if (s && *s) {
size_t sz = strlen(s) - 1;
s += sz;
if ( (unsigned char)*s == c)
return (char*)s;
}
return NULL;
}
EXPORT_SYMBOL(last_char_is);
/* Like strncpy but make sure the resulting string is always 0 terminated. */
char * safe_strncpy(char *dst, const char *src, size_t size)
{
if (!size) return dst;
dst[--size] = '\0';
return strncpy(dst, src, size);
}
EXPORT_SYMBOL(safe_strncpy);
char *simple_itoa(unsigned int i)
{
/* 21 digits plus null terminator, good for 64-bit or smaller ints */
static char local[22];
char *p = &local[21];
*p-- = '\0';
do {
*p-- = '0' + i % 10;
i /= 10;
} while (i > 0);
return p + 1;
}
EXPORT_SYMBOL(simple_itoa);
/*
* write_full - write to filedescriptor
*
* Like write, but guarantees to write the full buffer out, else
* it returns with an error.
*/
int write_full(int fd, void *buf, size_t size)
{
size_t insize = size;
int now;
while (size) {
now = write(fd, buf, size);
if (now <= 0)
return now;
size -= now;
buf += now;
}
return insize;
}
EXPORT_SYMBOL(write_full);
/*
* read_full - read from filedescriptor
*
* Like read, but this function only returns less bytes than
* requested when the end of file is reached.
*/
int read_full(int fd, void *buf, size_t size)
{
size_t insize = size;
int now;
int total = 0;
while (size) {
now = read(fd, buf, size);
if (now == 0)
return total;
if (now < 0)
return now;
total += now;
size -= now;
buf += now;
}
return insize;
}
EXPORT_SYMBOL(read_full);
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