diff options
Diffstat (limited to '')
| -rw-r--r-- | src/libmdsserver/util.c | 152 | ||||
| -rw-r--r-- | src/libmdsserver/util.h | 55 |
2 files changed, 207 insertions, 0 deletions
diff --git a/src/libmdsserver/util.c b/src/libmdsserver/util.c index 2d6be63..8378d59 100644 --- a/src/libmdsserver/util.c +++ b/src/libmdsserver/util.c @@ -789,3 +789,155 @@ int verify_utf8(const char* string, int allow_modified_nul) return read_bytes == 0 ? 0 : -1; } + +/** + * 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 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` + * @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, + int custom, int errnum, const char* restrict message, char** restrict send_buffer, + size_t* restrict send_buffer_size) +{ + ssize_t part_length; + size_t length = 0; + char* temp; + + /* Measure the length of mandatory headers and either values, + as well as the line to end the headers. The Error-header + however is currently measure without error number. */ + snprintf(NULL, 0, + "Command: error\n" + "To: %s\n" + "In response to: %s\n" + "Error: %s\n" + "\n%zn", + recv_client_id, recv_message_id, + custom ? "custom" : "", + &part_length), + length += (size_t)part_length; + + /* If the error number is custom and their is a number, + a blank space is required between the word ‘custom’ + and the number */ + if (custom && (errnum >= 0)) + length++; + /* Measure the length of the error number */ + if (errnum >= 0) + snprintf(NULL, 0, "%i%zn", errnum, &part_length), + length += (size_t)part_length; + + /* Measure the length of the error description and + the length of the header specifying its length */ + if (message != NULL) + snprintf(NULL, 0, "Length: %zu\n%zn", + strlen(message) + 1, &part_length), + length += (size_t)part_length + strlen(message) + 1; + + /* Ensure that the send buffer is large enough */ + if (length > *send_buffer_size) + { + if (yrealloc(temp, *send_buffer, length, char)) + return 0; + *send_buffer_size = length; + } + + /* Reset `length` to indicate that the currently written + message has zero in length */ + length = 0; + + /* Start writting the error message, begin with required + headers, but exclude the error number */ + sprintf((*send_buffer) + length, + "Command: error\n" + "To: %s\n" + "In response to: %s\n" + "Error: %s%zn", + recv_client_id, recv_message_id, + custom ? "custom" : "", + &part_length), + length += (size_t)part_length; + + /* If the error is custom and has a number we need + blank space before we write the error number */ + if (custom && (errnum >= 0)) + (*send_buffer)[length++] = ' '; + + /* Add the error number of there is one */ + if (errnum >= 0) + sprintf((*send_buffer) + length, "%i%zn", errnum, &part_length), + length += (size_t)part_length; + + /* End the Error-header line */ + (*send_buffer)[length++] = '\n'; + + /* Add the Length-header if there is a description */ + if (message != NULL) + sprintf((*send_buffer) + length, "Length: %zu\n%zn", + strlen(message) + 1, &part_length), + length += (size_t)part_length + strlen(message) + 1; + + /* Add an empty line to mark the end of headers */ + (*send_buffer)[length++] = '\n'; + + /* Write the description if there is one */ + if (message) + { + memcpy((*send_buffer) + length, message, strlen(message) * sizeof(char)); + length += strlen(message); + (*send_buffer)[length++] = '\n'; + } + + return length; +} + + +/** + * 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 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 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, + int custom, int errnum, const char* restrict message, char** restrict send_buffer, + size_t* restrict send_buffer_size, int socket_fd) +{ + size_t length = construct_error_message(recv_client_id, recv_message_id, custom, errnum, + message, send_buffer, send_buffer_size); + return length ? full_send(socket_fd, *send_buffer, length) : -1; +} + diff --git a/src/libmdsserver/util.h b/src/libmdsserver/util.h index 4761dc7..67a92f5 100644 --- a/src/libmdsserver/util.h +++ b/src/libmdsserver/util.h @@ -380,6 +380,61 @@ pid_t uninterruptable_waitpid(pid_t pid, int* restrict status, int options); */ 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 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` + * @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, + int custom, int errnum, const char* restrict message, char** restrict send_buffer, + size_t* restrict send_buffer_size) __attribute__((nonnull(1, 2, 6, 7))); +/* TODO document in info manual */ + +/** + * 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 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 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, + int custom, int errnum, const char* restrict message, char** restrict send_buffer, + size_t* restrict send_buffer_size, int socket_fd) __attribute__((nonnull(1, 2, 6, 7))); +/* TODO document in info manual */ + #endif |