mailx.c File Reference

POSIX mailx utility. More...

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "smtp.h"

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Data Structures
struct	mailx_address
struct	mailx_attachment
struct	mailx

Macros
#define	_POSIX_C_SOURCE   200809L

Functions
static char *	smtp_ffile_get_contents (FILE *stream, size_t *bytes_read)
static void	mailx_address_append (struct mailx *const mailx, enum smtp_address_type address_type, const char *const email)
static void	mailx_send (struct mailx *const mailx)
static void	mailx_append_attachment (struct mailx *const mailx, const char *const filename, const char *const path)
static void	mailx_append_attachment_arg (struct mailx *const mailx, const char *const attach_arg)
static void	mailx_parse_smtp_option (struct mailx *const mailx, const char *const option)
static void	mailx_init_default_values (struct mailx *const mailx)
static void	mailx_free (const struct mailx *const mailx)
int	main (int argc, char *argv[])

Detailed Description

POSIX mailx utility.

Author

James Humphrey (mail@.nosp@m.somn.nosp@m.isoft.nosp@m..com)

Version

1.00

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.

Definition in file mailx.c.

Macro Definition Documentation

_POSIX_C_SOURCE

#define _POSIX_C_SOURCE   200809L

Required on some POSIX systems to include some standard functions.

Definition at line 17 of file mailx.c.

Function Documentation

mailx_address_append()

static void mailx_address_append ( struct mailx *const  mailx, enum smtp_address_type  address_type, const char *const  email  )

static

Append this email to the list of email addresses to send to.

Parameters

[in]	mailx	Append the email address into this mailx context.
[in]	address_type	See smtp_address_type.
[in]	email	Email address to send to.

Definition at line 200 of file mailx.c.

References mailx::address_list, mailx_address::address_type, mailx_address::email, mailx::num_address, and realloc.

Referenced by main().

                                             {
  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';
}

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mailx_append_attachment()

static void mailx_append_attachment ( struct mailx *const  mailx, const char *const  filename, const char *const  path  )

static

Attach a file to the mailx context.

Parameters

[in]	mailx	Store the attachment details into this mailx context.
[in]	filename	File name to display to the recipient.
[in]	path	Local path of file to attach.

Definition at line 270 of file mailx.c.

References mailx::attachment_list, mailx_attachment::name, mailx::num_attachment, mailx_attachment::path, and realloc.

Referenced by mailx_append_attachment_arg().

                                               {
  struct mailx_attachment *new_attachment;
  size_t new_attachment_list_sz;

  if(filename == NULL || path == NULL){
    errx(1, "must provide attachment with valid name:path");
  }

  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';
}

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mailx_append_attachment_arg()

static void mailx_append_attachment_arg ( struct mailx *const  mailx, const char *const  attach_arg  )

static

Parse the file name and path and attach it to the mailx context.

Parameters

[in]	mailx	Store the attachment details into this mailx context.
[in]	attach_arg	String with format: 'filename:filepath'.

Definition at line 303 of file mailx.c.

References mailx_append_attachment().

Referenced by main().

                                                         {
  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);
}

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mailx_free()

static void mailx_free ( const struct mailx *const  mailx )

static

Frees the allocated memory associated with the mailx context.

Parameters

[in]

mailx

The mailx context to free.

Definition at line 452 of file mailx.c.

References mailx::body, mailx::from, mailx::pass, mailx::port, mailx::server, and mailx::user.

Referenced by main().

                                           {
  free(mailx->body);
  free(mailx->server);
  free(mailx->port);
  free(mailx->user);
  free(mailx->pass);
  free(mailx->from);
}

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mailx_init_default_values()

static void mailx_init_default_values ( struct mailx *const  mailx )

static

Initialize and set the default options in the mailx context.

See description of -S argument in main for more details.

Parameters

[in]

mailx

The mailx content to initialize.

Definition at line 439 of file mailx.c.

References mailx::auth_method, mailx::connection_security, SMTP_AUTH_NONE, SMTP_SECURITY_NONE, and mailx::subject.

Referenced by main().

                                                    {
  memset(mailx, 0, sizeof(*mailx));
  mailx->subject = "";
  mailx->connection_security = SMTP_SECURITY_NONE;
  mailx->auth_method = SMTP_AUTH_NONE;
}

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mailx_parse_smtp_option()

static void mailx_parse_smtp_option ( struct mailx *const  mailx, const char *const  option  )

static

Parses the -S option which contains a key/value pair separated by an '=' character.

Parameters

[in]	mailx	Store the results of the option parsing into the relevant field in this mailx context.
[in]	option	String containing key/value option to parse.

Definition at line 330 of file mailx.c.

References mailx::auth_method, mailx::connection_security, mailx::from, mailx::pass, mailx::port, mailx::server, SMTP_AUTH_CRAM_MD5, SMTP_AUTH_LOGIN, SMTP_AUTH_NONE, SMTP_AUTH_PLAIN, SMTP_DEBUG, mailx::smtp_flags, SMTP_NO_CERT_VERIFY, SMTP_SECURITY_NONE, SMTP_SECURITY_STARTTLS, SMTP_SECURITY_TLS, and mailx::user.

Referenced by main().

                                                 {
  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;
    }
#ifdef SMTP_OPENSSL
    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;
    }
#endif /* SMTP_OPENSSL */
    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;
    }
#ifdef SMTP_OPENSSL
    else if(strcmp(opt_value, "cram-md5") == 0){
      mailx->auth_method = SMTP_AUTH_CRAM_MD5;
    }
#endif /* SMTP_OPENSSL */
    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);
  }
}

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mailx_send()

static void mailx_send ( struct mailx *const  mailx )

static

Send the email using the configuration options in the mailx context.

Parameters

[in]

mailx

Email context.

Definition at line 225 of file mailx.c.

References mailx::address_list, mailx_address::address_type, mailx::attachment_list, mailx::auth_method, mailx::body, mailx::connection_security, mailx_address::email, mailx_attachment::name, mailx::num_address, mailx::num_attachment, mailx::pass, mailx_attachment::path, mailx::port, mailx::server, mailx::smtp, smtp_address_add(), smtp_attachment_add_path(), smtp_auth(), smtp_close(), mailx::smtp_flags, smtp_header_add(), smtp_mail(), smtp_open(), smtp_status_code_errstr(), SMTP_STATUS_OK, mailx::subject, and mailx::user.

Referenced by main().

                                     {
  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,
            NULL,
            &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));
  }
}

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main()

int main	(	int	argc,
		char *	argv[]
	)

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
• smtp-from - from email account

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
• smtp-from - none

Parameters

[in]	argc	Number of arguments in argv.
[in]	argv	String array containing the program name and any optional parameters described above.

Return values

0	Email has been sent.
1	An error occurred while sending email. Although unlikely, an email can still get sent even after returning with this error code.

Definition at line 498 of file mailx.c.

References mailx::body, mailx::from, mailx_address_append(), mailx_append_attachment_arg(), mailx_free(), mailx_init_default_values(), mailx_parse_smtp_option(), mailx_send(), mailx::port, mailx::server, SMTP_ADDRESS_FROM, SMTP_ADDRESS_TO, smtp_ffile_get_contents(), and mailx::subject.

                                {
  int rc;
  int i;
  struct mailx mailx;

  mailx_init_default_values(&mailx);

  while((rc = getopt(argc, argv, "a: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");
    }
  }

  puts("Reading email body from stdin");
  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;
}

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smtp_ffile_get_contents()

static char* smtp_ffile_get_contents ( FILE *  stream, size_t *  bytes_read  )

static

Read the entire contents of a file stream and store the data into a dynamically allocated buffer.

Parameters

[in]	stream	File stream already opened by the caller.
[out]	bytes_read	Number of bytes stored in the return buffer.

Return values

char*	A dynamically allocated buffer which contains the entire contents of stream. The caller must free this memory when done.
NULL	Memory allocation or file read error.

Definition at line 153 of file mailx.c.

References ferror, and realloc.

Referenced by main().

                                           {
  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;
}

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