Edit
kc3-lang/smtp/src/mailx.c
humphreyj
- src/mailx.c
-
/** * @file * @brief POSIX mailx utility. * @author James Humphrey (mail@somnisoft.com) * @version 0.99 * * Implementation of POSIX mailx utility in send mode. * * mailx [-s subject] [[-S option]...] [[-a attachment]...] address... * * This software has been placed into the public domain using CC0. */ /** * Required on some POSIX systems to include some standard functions. */ #define _POSIX_C_SOURCE 200809L #include <err.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "smtp.h" /** * Stores the to and from email addresses. */ struct mailx_address{ /** * See @ref smtp_address_type. */ enum smtp_address_type address_type; /** * Email address. */ char email[1000]; }; /** * The attachment name and path stored for each attachment to send to the * recipient. */ struct mailx_attachment{ /** * File name for this attachment to display to the recipient. */ char name[1000]; /** * Local file path pointing to the attachment to send. */ char path[1000]; }; /** * The mailx context structure containing the parameters for setting up the * SMTP connection and sending the email. */ struct mailx{ /** * SMTP client context. */ struct smtp *smtp; /** * Email subject line. */ const char *subject; /** * Email body text. */ char *body; /** * SMTP server name or IP address. */ char *server; /** * SMTP server port number. */ char *port; /** * SMTP account user name used for authenticating. */ char *user; /** * SMTP account password used for authenticating. */ char *pass; /** * From email address or name. */ char *from; /** * Determine if using a TLS encrypted connection or plain socket. */ enum smtp_connection_security connection_security; /** * SMTP user account authentication method. */ enum smtp_authentication_method auth_method; /** * Miscellaneous control flags for smtp-lib. * * See @ref smtp_flag for more details. */ enum smtp_flag smtp_flags; /** * List of email addresses to send to. */ struct mailx_address *address_list; /** * Number of email addresses in @ref address_list. */ size_t num_address; /** * List of files to attach in the email. */ struct mailx_attachment *attachment_list; /** * Number of attachments in @ref attachment_list. */ size_t num_attachment; }; /** * Read the entire contents of a file stream and store the data into a * dynamically allocated buffer. * * @param[in] stream File stream already opened by the caller. * @param[out] bytes_read Number of bytes stored in the return buffer. * @retval char* A dynamically allocated buffer which contains the entire * contents of @p stream. The caller must free this memory * when done. * @retval NULL Memory allocation or file read error. */ static char * smtp_ffile_get_contents(FILE *stream, size_t *bytes_read){ char *read_buf; size_t bufsz; char *new_buf; const size_t BUFSZ_INCREMENT = 512; read_buf = NULL; bufsz = 0; if(bytes_read){ *bytes_read = 0; } do{ size_t bytes_read_loop; if((new_buf = realloc(read_buf, bufsz + BUFSZ_INCREMENT)) == NULL){ free(read_buf); return NULL; } read_buf = new_buf; bufsz += BUFSZ_INCREMENT; bytes_read_loop = fread(&read_buf[bufsz - BUFSZ_INCREMENT], sizeof(char), BUFSZ_INCREMENT, stream); if(bytes_read){ *bytes_read += bytes_read_loop; } if(ferror(stream)){ free(read_buf); return NULL; } } while(!feof(stream)); return read_buf; } /** * Append this email to the list of email addresses to send to. * * @param[in] mailx Append the email address into this mailx context. * @param[in] address_type See @ref smtp_address_type. * @param[in] email Email address to send to. */ static void mailx_address_append(struct mailx *const mailx, enum smtp_address_type address_type, const char *const email){ struct mailx_address *new_address; size_t new_address_list_sz; mailx->num_address += 1; new_address_list_sz = mailx->num_address * sizeof(*mailx->address_list); if((mailx->address_list = realloc(mailx->address_list, new_address_list_sz)) == NULL){ err(1, "realloc"); } new_address = &mailx->address_list[mailx->num_address - 1]; new_address->address_type = address_type; strncpy(new_address->email, email, sizeof(new_address->email)); new_address->email[sizeof(new_address->email) - 1] = '\0'; } /** * Send the email using the configuration options in the @p mailx context. * * @param[in] mailx Email context. */ static void mailx_send(struct mailx *const mailx){ int rc; size_t i; const struct mailx_address *address; const struct mailx_attachment *attachment; smtp_open(mailx->server, mailx->port, mailx->connection_security, mailx->smtp_flags, &mailx->smtp); smtp_auth(mailx->smtp, mailx->auth_method, mailx->user, mailx->pass); for(i = 0; i < mailx->num_address; i++){ address = &mailx->address_list[i]; smtp_address_add(mailx->smtp, address->address_type, address->email, NULL); } for(i = 0; i < mailx->num_attachment; i++){ attachment = &mailx->attachment_list[i]; smtp_attachment_add_path(mailx->smtp, attachment->name, attachment->path); } smtp_header_add(mailx->smtp, "Subject", mailx->subject); smtp_mail(mailx->smtp, mailx->body); rc = smtp_close(mailx->smtp); if(rc != SMTP_STATUS_OK){ errx(1, "%s", smtp_status_code_errstr(rc)); } } /** * Attach a file to the @p mailx context. * * @param[in] mailx Store the attachment details into this mailx context. * @param[in] filename File name to display to the recipient. * @param[in] path Local path of file to attach. */ static void mailx_append_attachment(struct mailx *const mailx, const char *const filename, const char *const path){ struct mailx_attachment *new_attachment; size_t new_attachment_list_sz; new_attachment_list_sz = (mailx->num_attachment + 1) * sizeof(*mailx->attachment_list); if((mailx->attachment_list = realloc(mailx->attachment_list, new_attachment_list_sz)) == NULL){ err(1, "realloc: attachment list"); } new_attachment = &mailx->attachment_list[mailx->num_attachment]; mailx->num_attachment += 1; strncpy(new_attachment->name, filename, sizeof(new_attachment->name)); new_attachment->name[sizeof(new_attachment->name) - 1] = '\0'; strncpy(new_attachment->path, path, sizeof(new_attachment->path)); new_attachment->path[sizeof(new_attachment->path) - 1] = '\0'; } /** * Parse the file name and path and attach it to the @p mailx context. * * @param[in] mailx Store the attachment details into this mailx context. * @param[in] attach_arg String with format: 'filename:filepath'. */ static void mailx_append_attachment_arg(struct mailx *const mailx, const char *const attach_arg){ char *attach_arg_dup; char *filename; char *filepath; if((attach_arg_dup = strdup(attach_arg)) == NULL){ err(1, "strdup: %s", attach_arg); } filename = strtok(attach_arg_dup, ":"); filepath = strtok(NULL, ":"); mailx_append_attachment(mailx, filename, filepath); free(attach_arg_dup); } /** * Parses the -S option which contains a key/value pair separated by an '=' * character. * * @param[in] mailx Store the results of the option parsing into the relevant * field in this mailx context. * @param[in] option String containing key/value option to parse. */ static void mailx_parse_smtp_option(struct mailx *const mailx, const char *const option){ char *optdup; char *opt_key; char *opt_value; int rc; rc = 0; if((optdup = strdup(option)) == NULL){ err(1, "strdup: option: %s", option); } if((opt_key = strtok(optdup, "=")) == NULL){ errx(1, "strtok: %s", optdup); } opt_value = strtok(NULL, "="); if(strcmp(opt_key, "smtp-security") == 0){ if(strcmp(opt_value, "none") == 0){ mailx->connection_security = SMTP_SECURITY_NONE; } else if(strcmp(opt_value, "tls") == 0){ mailx->connection_security = SMTP_SECURITY_TLS; } else if(strcmp(opt_value, "starttls") == 0){ mailx->connection_security = SMTP_SECURITY_STARTTLS; } else{ rc = -1; } } else if(strcmp(opt_key, "smtp-auth") == 0){ if(strcmp(opt_value, "none") == 0){ mailx->auth_method = SMTP_AUTH_NONE; } else if(strcmp(opt_value, "plain") == 0){ mailx->auth_method = SMTP_AUTH_PLAIN; } else if(strcmp(opt_value, "login") == 0){ mailx->auth_method = SMTP_AUTH_LOGIN; } else if(strcmp(opt_value, "cram-md5") == 0){ mailx->auth_method = SMTP_AUTH_CRAM_MD5; } else{ rc = -1; } } else if(strcmp(opt_key, "smtp-flag") == 0){ if(strcmp(opt_value, "debug") == 0){ mailx->smtp_flags |= SMTP_DEBUG; } else if(strcmp(opt_value, "no-cert-verify") == 0){ mailx->smtp_flags |= SMTP_NO_CERT_VERIFY; } else{ rc = -1; } } else if(strcmp(opt_key, "smtp-server") == 0){ if((mailx->server = strdup(opt_value)) == NULL){ err(1, "strdup"); } } else if(strcmp(opt_key, "smtp-port") == 0){ if((mailx->port = strdup(opt_value)) == NULL){ err(1, "strdup"); } } else if(strcmp(opt_key, "smtp-user") == 0){ if((mailx->user = strdup(opt_value)) == NULL){ err(1, "strdup"); } } else if(strcmp(opt_key, "smtp-pass") == 0){ if((mailx->pass = strdup(opt_value)) == NULL){ err(1, "strdup"); } } else if(strcmp(opt_key, "smtp-from") == 0){ if((mailx->from = strdup(opt_value)) == NULL){ err(1, "strdup"); } } else{ rc = -1; } free(optdup); if(rc < 0){ errx(1, "invalid argument: %s", option); } } /** * Initialize and set the default options in the mailx context. * * See description of -S argument in main for more details. * * @param[in] mailx The mailx content to initialize. */ static void mailx_init_default_values(struct mailx *const mailx){ memset(mailx, 0, sizeof(*mailx)); mailx->subject = ""; mailx->connection_security = SMTP_SECURITY_NONE; mailx->auth_method = SMTP_AUTH_NONE; } /** * Frees the allocated memory associated with the mailx context. * * @param[in] mailx The mailx context to free. */ static void mailx_free(const struct mailx *const mailx){ free(mailx->body); free(mailx->server); free(mailx->port); free(mailx->user); free(mailx->pass); free(mailx->from); } /** * Main program entry point for the mailx utility. * * This program supports the following options: * - -a 'name:path' - Attach a file with name to display to recipient and * file path pointing to file location on local storage. * - -s subject - Email subject line. * - -S key=value - A key/value pair to set various configuration options, * controlling the behavior of the SMTP client connection. * * The following list contains possible options for the -S argument: * - smtp-security - none, tls, starttls * - smtp-auth - none, plain, login, cram-md5 * - smtp-flag - debug, no-cert-verify * - smtp-server - server name or IP address * - smtp-port - server port number * - smtp-user - server authentication user name * - smtp-pass - server authentication user password * * The following list shows the default option for -S argument if not provided: * - smtp-security - none * - smtp-auth - none * - smtp-flag - none * - smtp-server - localhost * - smtp-port - 25 * - smtp-user - none * - smtp-pass - none * * @param[in] argc Number of arguments in @p argv. * @param[in] argv String array containing the program name and any optional * parameters described above. * @retval 0 Email has been sent. * @retval 1 An error occurred while sending email. Although unlikely, an email * can still get sent even after returning with this error code. */ int main(int argc, char *argv[]){ int rc; int i; struct mailx mailx; mailx_init_default_values(&mailx); while((rc = getopt(argc, argv, "s:S:")) != -1){ switch(rc){ case 'a': mailx_append_attachment_arg(&mailx, optarg); break; case 's': mailx.subject = optarg; break; case 'S': mailx_parse_smtp_option(&mailx, optarg); break; default: return 1; } } argc -= optind; argv += optind; if(argc < 1){ errx(1, "must provide at least one email destination address"); } if(mailx.from == NULL){ errx(1, "must provide a FROM address"); } if(mailx.server == NULL){ if((mailx.server = strdup("localhost")) == NULL){ err(1, "strdup"); } } if(mailx.port == NULL){ if((mailx.port = strdup("25")) == NULL){ err(1, "strdup"); } } if((mailx.body = smtp_ffile_get_contents(stdin, NULL)) == NULL){ err(1, "failed to read email body from stdin"); } mailx_address_append(&mailx, SMTP_ADDRESS_FROM, mailx.from); for(i = 0; i < argc; i++){ mailx_address_append(&mailx, SMTP_ADDRESS_TO, argv[i]); } mailx_send(&mailx); mailx_free(&mailx); return 0; }