/**
* mds — A micro-display server
* Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MDS_LIBMDSSERVER_UTIL_H
#define MDS_LIBMDSSERVER_UTIL_H
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
/**
* Convert a client ID string into a client ID integer
*
* @param str The client ID string
* @return The client ID integer
*/
uint64_t parse_client_id(const char* str);
/**
* Read an environment variable, but handle it as undefined if empty
*
* @param var The environment variable's name
* @return The environment variable's value, `NULL` if empty or not defined
*/
char* getenv_nonempty(const char* var);
/**
* Prepare the server so that it can reexec into
* a newer version of the executed file.
*
* This is required for two reasons:
* 1: We cannot use argv[0] as PATH-resolution may
* cause it to reexec into another pathname, and
* maybe to wrong program. Additionally argv[0]
* may not even refer to the program, and chdir
* could also hinter its use.
* 2: The kernel appends ` (deleted)` to
* `/proc/self/exe` once it has been removed,
* so it cannot be replaced.
*
* The function will should be called immediately, it
* will store the content of `/proc/self/exe`.
*
* @return Zero on success, -1 on error
*/
int prepare_reexec(void);
/**
* Re-exec the server.
* This function only returns on failure.
*
* If `prepare_reexec` failed or has not been called,
* `argv[0]` will be used as a fallback.
*
* @param argc The number of elements in `argv`
* @param argv The command line arguments
* @param reexeced Whether the server has previously been re-exec:ed
*/
void reexec_server(int argc, char** argv, int reexeced);
/**
* Set up a signal trap.
* This function should only be used for common mds
* signals and signals that does not require and
* special settings. This function may choose to add
* additional behaviour depending on the signal, such
* as blocking other signals.
*
* @param signo The signal to trap
* @param function The function to run when the signal is caught
* @return Zero on success, -1 on error
*/
int xsigaction(int signo, void (*function)(int signo));
/**
* Send a message over a socket
*
* @param socket The file descriptor of the socket
* @param message The message to send
* @param length The length of the message
* @return The number of bytes that have been sent (even on error)
*/
size_t send_message(int socket, const char* message, size_t length);
/**
* A version of `atoi` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoi(const char* str, int* value, int min, int max);
/**
* A version of `atoj` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoj(const char* str, intmax_t* value, intmax_t min, intmax_t max);
/**
* A version of `atouj` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atouj(const char* str, uintmax_t* value, uintmax_t min, uintmax_t max);
/**
* A version of `atoh` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoh(const char* str, short int* value, int min, int max);
/**
* A version of `atouh` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atouh(const char* str, unsigned short int* value, unsigned int min, unsigned int max);
/**
* A version of `atou` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atou(const char* str, unsigned int* value, unsigned int min, unsigned int max);
/**
* A version of `atol` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atol(const char* str, long int* value, long int min, long int max);
/**
* A version of `atoul` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoul(const char* str, unsigned long int* value, unsigned long int min, unsigned long int max);
/**
* A version of `atoll` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoll(const char* str, long long int* value, long long int min, long long int max);
/**
* A version of `atoull` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoull(const char* str, unsigned long long int* value,
unsigned long long int min, unsigned long long int max);
/**
* A version of `atoz` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoz(const char* str, size_t* value, size_t min, size_t max);
/**
* A version of `atosz` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atosz(const char* str, ssize_t* value, ssize_t min, ssize_t max);
/**
* A version of `ato8` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_ato8(const char* str, int8_t* value, int min, int max);
/**
* A version of `atou8` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atou8(const char* str, uint8_t* value, int min, int max);
/**
* A version of `ato16` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_ato16(const char* str, int16_t* value, int min, int max);
/**
* A version of `atou16` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atou16(const char* str, uint16_t* value, unsigned int min, unsigned int max);
/**
* A version of `ato32` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_ato32(const char* str, int32_t* value, int32_t min, int32_t max);
/**
* A version of `atou32` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atou32(const char* str, uint32_t* value, uint32_t min, uint32_t max);
/**
* A version of `ato64` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_ato64(const char* str, int64_t* value, int64_t min, int64_t max);
/**
* A version of `atou64` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atou64(const char* str, uint64_t* value, uint64_t min, uint64_t max);
/**
* Send a buffer into a file and ignore interruptions
*
* @param fd The file descriptor
* @param buffer The buffer
* @param length The length of the buffer
* @return Zero on success, -1 on error
*/
int full_write(int fd, const char* buffer, size_t length);
/**
* Read a file completely and ignore interruptions
*
* @param fd The file descriptor
* @param length Output parameter for the length of the file, may be `NULL`
* @return The content of the file, you will need to free it. `NULL` on error
*/
char* full_read(int fd, size_t* length);
/**
* Send a full message even if interrupted
*
* @param socket The file descriptor for the socket to use
* @param message The message to send
* @param length The length of the message
* @return Zero on success, -1 on error
*/
int full_send(int socket, const char* message, size_t length);
/**
* Check whether a string begins with a specific string,
* where neither of the strings are necessarily NUL-terminated
*
* @param haystack The string that should start with the other string
* @param needle The string the first string should start with
* @param haystack_n The length of `haystack`
* @param needle_n The length of `needle`
* @return Whether the `haystack` begins with `needle`
*/
int startswith_n(const char* haystack, const char* needle, size_t haystack_n, size_t needle_n) __attribute__((pure));
/**
* Wrapper around `waitpid` that never returns on an interruption unless
* it is interrupted 100 times within the same second
*
* @param pid See description of `pid` in the documentation for `waitpid`
* @param status See description of `status` in the documentation for `waitpid`
* @param options See description of `options` in the documentation for `waitpid`
* @return See the documentation for `waitpid`
*/
pid_t uninterruptable_waitpid(pid_t pid, int* restrict status, int options);
/**
* Check whether a NUL-terminated string is encoded in UTF-8
*
* @param string The string
* @param allow_modified_nul Whether Modified UTF-8 is allowed, which allows a two-byte encoding for NUL
* @return Zero if good, -1 on encoding error
*/
int verify_utf8(const char* string, int allow_modified_nul) __attribute__((pure));
/**
* Construct an error message to be sent to a client
*
* @param recv_client_id The client ID attached on the message that was received, must not be `NULL`
* @param recv_message_id The message ID attached on the message that was received, must not be `NULL`
* @param recv_command The value of the `Command`-header on the message that was received,
* must not be `NULL`
* @param custom Non-zero if the error is a custom error
* @param errnum The error number, `errno` should be used if the error
* is not a custom error, zero should be used on success,
* a negative integer, such as -1, indicates that the error
* message should not include an error number,
* it is not allowed to have this value be negative and
* `custom` be zero at the same time
* @param message The description of the error, the line feed at the end
* is added automatically, `NULL` if the description should
* be omitted
* @param send_buffer Pointer to the buffer where the message should be stored,
* it should contain the current send buffer, must not be `NULL`
* @param send_buffer_size Pointer to the allocation size of `*send_buffer`, it should
* contain the current size of `*send_buffer` and will be updated
* with the new size, must not be `NULL`
* @param message_id The message ID of this message
* @return The length of the message, zero on error
*/
size_t construct_error_message(const char* restrict recv_client_id, const char* restrict recv_message_id,
const char* restrict recv_command, int custom, int errnum,
const char* restrict message, char** restrict send_buffer,
size_t* restrict send_buffer_size,
uint32_t message_id) __attribute__((nonnull(1, 2, 3, 7, 8)));
/**
* Send an error message
*
* @param recv_client_id The client ID attached on the message that was received, must not be `NULL`
* @param recv_message_id The message ID attached on the message that was received, must not be `NULL`
* @param recv_command The value of the `Command`-header on the message that was received,
* must not be `NULL`
* @param custom Non-zero if the error is a custom error
* @param errnum The error number, `errno` should be used if the error
* is not a custom error, zero should be used on success,
* a negative integer, such as -1, indicates that the error
* message should not include an error number,
* it is not allowed to have this value be negative and
* `custom` be zero at the same time
* @param message The description of the error, the line feed at the end
* is added automatically, `NULL` if the description should
* be omitted
* @param send_buffer Pointer to the buffer where the message should be stored,
* it should contain the current send buffer, must not be `NULL`
* @param send_buffer_size Pointer to the allocation size of `*send_buffer`, it should
* contain the current size of `*send_buffer` and will be updated
* with the new size, must not be `NULL`
* @param message_id The message ID of this message
* @param socket_fd The file descriptor of the socket
* @return Zero on success, -1 on error
*/
int send_error(const char* restrict recv_client_id, const char* restrict recv_message_id,
const char* restrict recv_command, int custom, int errnum, const char* restrict message,
char** restrict send_buffer, size_t* restrict send_buffer_size, uint32_t message_id,
int socket_fd) __attribute__((nonnull(1, 2, 3, 7, 8)));
#endif
