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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
***/
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/utsname.h>
#include "sd-id128.h"
#include "alloc-util.h"
#include "hostname-util.h"
#include "macro.h"
#include "specifier.h"
#include "string-util.h"
#include "strv.h"
#include "user-util.h"
/*
* Generic infrastructure for replacing %x style specifiers in
* strings. Will call a callback for each replacement.
*
*/
/* Any ASCII character or digit: our pool of potential specifiers,
* and "%" used for escaping. */
#define POSSIBLE_SPECIFIERS ALPHANUMERICAL "%"
int specifier_printf(const char *text, const Specifier table[], void *userdata, char **_ret) {
size_t l, allocated = 0;
_cleanup_free_ char *ret = NULL;
char *t;
const char *f;
bool percent = false;
int r;
assert(text);
assert(table);
l = strlen(text);
if (!GREEDY_REALLOC(ret, allocated, l + 1))
return -ENOMEM;
t = ret;
for (f = text; *f; f++, l--)
if (percent) {
if (*f == '%')
*(t++) = '%';
else {
const Specifier *i;
for (i = table; i->specifier; i++)
if (i->specifier == *f)
break;
if (i->lookup) {
_cleanup_free_ char *w = NULL;
size_t k, j;
r = i->lookup(i->specifier, i->data, userdata, &w);
if (r < 0)
return r;
j = t - ret;
k = strlen(w);
if (!GREEDY_REALLOC(ret, allocated, j + k + l + 1))
return -ENOMEM;
memcpy(ret + j, w, k);
t = ret + j + k;
} else if (strchr(POSSIBLE_SPECIFIERS, *f))
/* Oops, an unknown specifier. */
return -EBADSLT;
else {
*(t++) = '%';
*(t++) = *f;
}
}
percent = false;
} else if (*f == '%')
percent = true;
else
*(t++) = *f;
/* If string ended with a stray %, also end with % */
if (percent)
*(t++) = '%';
*(t++) = 0;
/* Try to deallocate unused bytes, but don't sweat it too much */
if ((size_t)(t - ret) < allocated) {
t = realloc(ret, t - ret);
if (t)
ret = t;
}
*_ret = TAKE_PTR(ret);
return 0;
}
/* Generic handler for simple string replacements */
int specifier_string(char specifier, void *data, void *userdata, char **ret) {
char *n;
n = strdup(strempty(data));
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
int specifier_machine_id(char specifier, void *data, void *userdata, char **ret) {
sd_id128_t id;
char *n;
int r;
r = sd_id128_get_machine(&id);
if (r < 0)
return r;
n = new(char, 33);
if (!n)
return -ENOMEM;
*ret = sd_id128_to_string(id, n);
return 0;
}
int specifier_boot_id(char specifier, void *data, void *userdata, char **ret) {
sd_id128_t id;
char *n;
int r;
r = sd_id128_get_boot(&id);
if (r < 0)
return r;
n = new(char, 33);
if (!n)
return -ENOMEM;
*ret = sd_id128_to_string(id, n);
return 0;
}
int specifier_host_name(char specifier, void *data, void *userdata, char **ret) {
char *n;
n = gethostname_malloc();
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
int specifier_kernel_release(char specifier, void *data, void *userdata, char **ret) {
struct utsname uts;
char *n;
int r;
r = uname(&uts);
if (r < 0)
return -errno;
n = strdup(uts.release);
if (!n)
return -ENOMEM;
*ret = n;
return 0;
}
int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
char *t;
/* If we are UID 0 (root), this will not result in NSS, otherwise it might. This is good, as we want to be able
* to run this in PID 1, where our user ID is 0, but where NSS lookups are not allowed.
* We don't use getusername_malloc() here, because we don't want to look at $USER, to remain consistent with
* specifer_user_id() below.
*/
t = uid_to_name(getuid());
if (!t)
return -ENOMEM;
*ret = t;
return 0;
}
int specifier_user_id(char specifier, void *data, void *userdata, char **ret) {
if (asprintf(ret, UID_FMT, getuid()) < 0)
return -ENOMEM;
return 0;
}
int specifier_user_home(char specifier, void *data, void *userdata, char **ret) {
/* On PID 1 (which runs as root) this will not result in NSS,
* which is good. See above */
return get_home_dir(ret);
}
int specifier_user_shell(char specifier, void *data, void *userdata, char **ret) {
/* On PID 1 (which runs as root) this will not result in NSS,
* which is good. See above */
return get_shell(ret);
}
int specifier_escape_strv(char **l, char ***ret) {
char **z, **p, **q;
assert(ret);
if (strv_isempty(l)) {
*ret = NULL;
return 0;
}
z = new(char*, strv_length(l)+1);
if (!z)
return -ENOMEM;
for (p = l, q = z; *p; p++, q++) {
*q = specifier_escape(*p);
if (!*q) {
strv_free(z);
return -ENOMEM;
}
}
*q = NULL;
*ret = z;
return 0;
}
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