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250 lines
7.6 KiB
250 lines
7.6 KiB
/* util.h
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* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* Logging and other utility functions.
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*/
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#ifndef _UTIL_H_
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#define _UTIL_H_
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <syslog.h>
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#include <unistd.h>
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#include "libsyscalls.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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* Silence compiler warnings for unused variables/functions.
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*
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* If the definition is actually used, the attribute should be removed, but if
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* it's forgotten or left in place, it doesn't cause a problem.
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*
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* If the definition is actually unused, the compiler is free to remove it from
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* the output so as to save size. If you want to make sure the definition is
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* kept (e.g. for ABI compatibility), look at the "used" attribute instead.
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*/
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#define attribute_unused __attribute__((__unused__))
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/*
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* Mark the symbol as "weak" in the ELF output. This provides a fallback symbol
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* that may be overriden at link time. See this page for more details:
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* https://en.wikipedia.org/wiki/Weak_symbol
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*/
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#define attribute_weak __attribute__((__weak__))
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/*
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* Mark the function as a printf-style function.
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* @format_idx The index in the function argument list where the format string
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* is passed (where the first argument is "1").
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* @check_idx The index in the function argument list where the first argument
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* used in the format string is passed.
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* Some examples:
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* foo([1] const char *format, [2] ...): format=1 check=2
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* foo([1] int, [2] const char *format, [3] ...): format=2 check=3
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* foo([1] const char *format, [2] const char *, [3] ...): format=1 check=3
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*/
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#define attribute_printf(format_idx, check_idx) \
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__attribute__((__format__(__printf__, format_idx, check_idx)))
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/* clang-format off */
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#define die(_msg, ...) \
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do_fatal_log(LOG_ERR, "libminijail[%d]: " _msg, getpid(), ## __VA_ARGS__)
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#define pdie(_msg, ...) \
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die(_msg ": %m", ## __VA_ARGS__)
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#define warn(_msg, ...) \
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do_log(LOG_WARNING, "libminijail[%d]: " _msg, getpid(), ## __VA_ARGS__)
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#define pwarn(_msg, ...) \
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warn(_msg ": %m", ## __VA_ARGS__)
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#define info(_msg, ...) \
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do_log(LOG_INFO, "libminijail[%d]: " _msg, getpid(), ## __VA_ARGS__)
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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/* clang-format on */
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extern const char *log_syscalls[];
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extern const size_t log_syscalls_len;
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enum logging_system_t {
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/* Log to syslog. This is the default. */
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LOG_TO_SYSLOG = 0,
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/* Log to a file descriptor. */
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LOG_TO_FD,
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};
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/*
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* Even though this function internally calls abort(2)/exit(2), it is
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* intentionally not marked with the noreturn attribute. When marked as
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* noreturn, clang coalesces several of the do_fatal_log() calls in methods that
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* have a large number of such calls (like minijail_enter()), making it
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* impossible for breakpad to correctly identify the line where it was called,
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* making the backtrace somewhat useless.
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*/
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extern void do_fatal_log(int priority, const char *format, ...)
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attribute_printf(2, 3);
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extern void do_log(int priority, const char *format, ...)
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attribute_printf(2, 3);
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static inline int is_android(void)
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{
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#if defined(__ANDROID__)
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return 1;
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#else
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return 0;
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#endif
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}
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static inline bool compiled_with_asan(void)
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{
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#if defined(__SANITIZE_ADDRESS__)
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/* For gcc. */
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return true;
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#elif defined(__has_feature)
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/* For clang. */
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return __has_feature(address_sanitizer) ||
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__has_feature(hwaddress_sanitizer);
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#else
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return false;
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#endif
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}
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void __asan_init(void) attribute_weak;
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void __hwasan_init(void) attribute_weak;
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static inline bool running_with_asan(void)
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{
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/*
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* There are some configurations under which ASan needs a dynamic (as
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* opposed to compile-time) test. Some Android processes that start
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* before /data is mounted run with non-instrumented libminijail.so, so
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* the symbol-sniffing code must be present to make the right decision.
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*/
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return compiled_with_asan() || &__asan_init != 0 || &__hwasan_init != 0;
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}
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static inline bool debug_logging_allowed(void) {
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#if defined(ALLOW_DEBUG_LOGGING)
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return true;
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#else
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return false;
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#endif
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}
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static inline size_t get_num_syscalls(void)
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{
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return syscall_table_size;
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}
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int lookup_syscall(const char *name, size_t *ind);
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const char *lookup_syscall_name(int nr);
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long int parse_single_constant(char *constant_str, char **endptr);
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long int parse_constant(char *constant_str, char **endptr);
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int parse_size(size_t *size, const char *sizespec);
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char *strip(char *s);
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/*
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* tokenize: locate the next token in @stringp using the @delim
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* @stringp A pointer to the string to scan for tokens
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* @delim The delimiter to split by
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*
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* Note that, unlike strtok, @delim is not a set of characters, but the full
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* delimiter. e.g. "a,;b,;c" with a delim of ",;" will yield ["a","b","c"].
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*
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* Note that, unlike strtok, this may return an empty token. e.g. "a,,b" with
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* strtok will yield ["a","b"], but this will yield ["a","","b"].
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*/
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char *tokenize(char **stringp, const char *delim);
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char *path_join(const char *external_path, const char *internal_path);
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/*
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* consumebytes: consumes @length bytes from a buffer @buf of length @buflength
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* @length Number of bytes to consume
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* @buf Buffer to consume from
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* @buflength Size of @buf
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*
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* Returns a pointer to the base of the bytes, or NULL for errors.
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*/
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void *consumebytes(size_t length, char **buf, size_t *buflength);
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/*
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* consumestr: consumes a C string from a buffer @buf of length @length
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* @buf Buffer to consume
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* @length Length of buffer
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*
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* Returns a pointer to the base of the string, or NULL for errors.
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*/
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char *consumestr(char **buf, size_t *buflength);
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/*
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* init_logging: initializes the module-wide logging.
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* @logger The logging system to use.
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* @fd The file descriptor to log into. Ignored unless
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* @logger = LOG_TO_FD.
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* @min_priority The minimum priority to display. Corresponds to syslog's
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priority parameter. Ignored unless @logger = LOG_TO_FD.
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*/
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void init_logging(enum logging_system_t logger, int fd, int min_priority);
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/*
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* minjail_free_env: Frees an environment array plus the environment strings it
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* points to. The environment and its constituent strings must have been
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* allocated (as opposed to pointing to static data), e.g. by using
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* minijail_copy_env() and minijail_setenv().
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*
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* @env The environment to free.
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*/
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void minijail_free_env(char **env);
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/*
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* minjail_copy_env: Copy an environment array (such as passed to execve),
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* duplicating the environment strings and the array pointing at them.
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*
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* @env The environment to copy.
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*
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* Returns a pointer to the copied environment or NULL on memory allocation
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* failure.
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*/
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char **minijail_copy_env(char *const *env);
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/*
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* minjail_setenv: Set an environment variable in @env. Semantics match the
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* standard setenv() function, but this operates on @env, not the global
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* environment. @env must be dynamically allocated (as opposed to pointing to
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* static data), e.g. via minijail_copy_env(). @name and @value get copied into
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* newly-allocated memory.
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*
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* @env Address of the environment to modify. Might be re-allocated to
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* make room for the new entry.
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* @name Name of the key to set.
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* @value The value to set.
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* @overwrite Whether to replace the existing value for @name. If non-zero and
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* the entry is already present, no changes will be made.
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*
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* Returns 0 and modifies *@env on success, returns an error code otherwise.
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*/
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int minijail_setenv(char ***env, const char *name, const char *value,
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int overwrite);
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#ifdef __cplusplus
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}; /* extern "C" */
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#endif
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#endif /* _UTIL_H_ */
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