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/* Routines for dealing with '\0' separated environment vectors
Copyright (C) 1995-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <malloc.h>
#include <string.h>
#include <envz.h>
/* The character separating names from values in an envz. */
#define SEP '='
/* Returns a pointer to the entry in ENVZ for NAME, or 0 if there is none.
If NAME contains the separator character, only the portion before it is
used in the comparison. */
char *
envz_entry (const char *envz, size_t envz_len, const char *name)
{
while (envz_len)
{
const char *p = name;
const char *entry = envz; /* Start of this entry. */
/* See how far NAME and ENTRY match. */
while (envz_len && *p == *envz && *p && *p != SEP)
p++, envz++, envz_len--;
if ((*envz == '\0' || *envz == SEP) && (*p == '\0' || *p == SEP))
/* Bingo! */
return (char *) entry;
/* No match, skip to the next entry. */
while (envz_len && *envz)
envz++, envz_len--;
if (envz_len)
envz++, envz_len--; /* skip '\0' */
}
return NULL;
}
libc_hidden_def (envz_entry)
/* Returns a pointer to the value portion of the entry in ENVZ for NAME, or 0
if there is none. */
char *
envz_get (const char *envz, size_t envz_len, const char *name)
{
char *entry = envz_entry (envz, envz_len, name);
if (entry)
{
while (*entry && *entry != SEP)
entry++;
if (*entry)
entry++;
else
entry = NULL; /* A null entry. */
}
return entry;
}
/* Remove the entry for NAME from ENVZ & ENVZ_LEN, if any. */
void
envz_remove (char **envz, size_t *envz_len, const char *name)
{
char *entry = envz_entry (*envz, *envz_len, name);
if (entry)
argz_delete (envz, envz_len, entry);
}
libc_hidden_def (envz_remove)
/* Adds an entry for NAME with value VALUE to ENVZ & ENVZ_LEN. If an entry
with the same name already exists in ENVZ, it is removed. If VALUE is
NULL, then the new entry will a special null one, for which envz_get will
return NULL, although envz_entry will still return an entry; this is handy
because when merging with another envz, the null entry can override an
entry in the other one. Null entries can be removed with envz_strip (). */
error_t
envz_add (char **envz, size_t *envz_len, const char *name, const char *value)
{
envz_remove (envz, envz_len, name);
if (value)
/* Add the new value, if there is one. */
{
size_t name_len = strlen (name);
size_t value_len = strlen (value);
size_t old_envz_len = *envz_len;
size_t new_envz_len = old_envz_len + name_len + 1 + value_len + 1;
char *new_envz = realloc (*envz, new_envz_len);
if (new_envz)
{
memcpy (new_envz + old_envz_len, name, name_len);
new_envz[old_envz_len + name_len] = SEP;
memcpy (new_envz + old_envz_len + name_len + 1, value, value_len);
new_envz[new_envz_len - 1] = 0;
*envz = new_envz;
*envz_len = new_envz_len;
return 0;
}
else
return ENOMEM;
}
else
/* Add a null entry. */
return __argz_add (envz, envz_len, name);
}
/* Adds each entry in ENVZ2 to ENVZ & ENVZ_LEN, as if with envz_add(). If
OVERRIDE is true, then values in ENVZ2 will supersede those with the same
name in ENV, otherwise not. */
error_t
envz_merge (char **envz, size_t *envz_len, const char *envz2,
size_t envz2_len, int override)
{
error_t err = 0;
while (envz2_len && ! err)
{
char *old = envz_entry (*envz, *envz_len, envz2);
size_t new_len = strlen (envz2) + 1;
if (! old)
err = __argz_append (envz, envz_len, envz2, new_len);
else if (override)
{
argz_delete (envz, envz_len, old);
err = __argz_append (envz, envz_len, envz2, new_len);
}
envz2 += new_len;
envz2_len -= new_len;
}
return err;
}
/* Remove null entries. */
void
envz_strip (char **envz, size_t *envz_len)
{
char *entry = *envz;
size_t left = *envz_len;
while (left)
{
size_t entry_len = strlen (entry) + 1;
left -= entry_len;
if (! strchr (entry, SEP))
/* Null entry. */
memmove (entry, entry + entry_len, left);
else
entry += entry_len;
}
*envz_len = entry - *envz;
}
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