--- /dev/null
+/*
+ * sendfrom.c -- postproc that selects user, and then mail server, from draft
+ *
+ * Author: David Levine <levinedl@acm.org>
+ *
+ * This program fits between send(1) and post(1), as a postproc. It makes
+ * up for the facts that send doesn't parse the message draft and post
+ * doesn't load the profile.
+ *
+ * To use:
+ *
+ * 1) Add profile entries of the form:
+ *
+ * sendfrom-<email address or domain name>: <post(1) switches>
+ *
+ * The email address is extracted from the From: header line of the message draft. Multiple
+ * profile entries, with different email addresses or domain names, are supported. This
+ * allows different switches to post(1), such as -user, to be associated with different email
+ * addresses. If a domain name is used, it matches all users in that domain.
+ *
+ * Example profile entry using OAuth for account hosted by gmail:
+ *
+ * sendfrom-gmail_address@example.com: -saslmech xoauth2 -authservice gmail -tls
+ * -server smtp.gmail.com -user gmail_login@example.com
+ *
+ * (Indentation indicates a continued line, as supported in MH profiles.) The username
+ * need not be the same as the sender address, which was extracted from the From: header line.
+ *
+ * Example profile entries that use an nmh credentials file:
+ *
+ * credentials: file:nmhcreds
+ * sendfrom-sendgrid_address@example.com: -sasl -tls -server smtp.sendgrid.net
+ * sendfrom-outbound.att.net: -sasl -initialtls -server outbound.att.net -port 465
+ * sendfrom-fastmail.com: -initialtls -sasl -saslmech LOGIN
+ * -server smtps-proxy.messagingengine.com -port 80
+ *
+ * where nmhcreds is in the user's nmh directory (from the Path profile component) and contains:
+ *
+ * machine smtp.sendgrid.net
+ * login sendgrid_login@example.com
+ * password ********
+ * machine outbound.att.net
+ * login att_login@example.com
+ * password ********
+ * machine smtps-proxy.messagingengine.com
+ * login fastmail_login@example.com
+ * password ********
+ *
+ * 2) To enable, add a line like this to your profile:
+ *
+ * postproc: <docdir>/contrib/sendfrom
+ *
+ * with <docdir> expanded. This source file is in docdir. Also, "mhparam docdir" will show it.
+ *
+ * For more information on authentication to mail servers, see mhlogin(1) for OAuth
+ * services, and mh-profile(5) for login credentials.
+ *
+ * This program follows these steps:
+ * 1) Loads profile.
+ * 2) Saves command line arguments in vec.
+ * 3) Extracts address and domain name from From: header line in draft.
+ * 4) Extracts any address or host specific switches to post(1) from profile. Appends
+ to vec, along with implied switches, such as OAUTH access token.
+ * 5) Calls post, or with -dryrun, echos how it would be called.
+ */
+
+#include <h/mh.h>
+#include <h/fmt_scan.h>
+#include <h/fmt_compile.h>
+#include <h/utils.h>
+
+#ifdef OAUTH_SUPPORT
+#include <h/oauth.h>
+
+static int setup_oauth_params(char *vec[], int *, int, const char **);
+#endif /* OAUTH_SUPPORT */
+
+extern char *mhlibexecdir; /* from config.c */
+
+static int get_from_header_info(const char *, const char **, const char **, const char **);
+static const char *get_message_header_info(FILE *, char *);
+static void merge_profile_entry(const char *, const char *, char *vec[], int *vecp);
+static int run_program(char *, char **);
+
+int
+main(int argc, char **argv) {
+ /* Make sure that nmh's post gets called by specifying its full path. */
+ char *realpost = concat(mhlibexecdir, "/", "post", NULL);
+ int whom = 0, dryrun = 0, snoop = 0;
+ char **arguments, **argp;
+ char *program, **vec;
+ int vecp = 0;
+ char *msg = NULL;
+
+ /* Load profile. */
+ if (nmh_init(argv[0], 1)) { return NOTOK; }
+
+ /* Save command line arguments in vec, except for the last argument, if it's the draft file path. */
+ vec = argsplit(realpost, &program, &vecp);
+ for (argp = arguments = getarguments(invo_name, argc, argv, 1); *argp; ++argp) {
+ /* Don't pass -dryrun to post by putting it in vec. */
+ if (strcmp(*argp, "-dryrun") == 0) {
+ dryrun = 1;
+ } else {
+ vec[vecp++] = getcpy(*argp);
+
+ if (strcmp(*argp, "-snoop") == 0) {
+ snoop = 1;
+ } else if (strcmp(*argp, "-whom") == 0) {
+ whom = 1;
+ } else {
+ /* Need to keep filename, from last arg (though it's not used below with -whom). */
+ msg = *argp;
+ }
+ }
+ }
+
+ free(arguments);
+
+ if (! whom && msg == NULL) {
+ adios(NULL, "requires exactly 1 filename argument");
+ } else {
+ char **vp;
+
+ /* With post, but without -whom, need to keep filename as last arg. */
+ if (! whom) {
+ /* At this point, vecp points to the next argument to be added. Back it up to
+ remove the last one, which is the filename. Add it back at the end of vec below. */
+ free(vec[--vecp]);
+ }
+ /* Null terminate vec because it's used below. */
+ vec[vecp] = NULL;
+
+ if (! whom) {
+ /* Some users might need the switch from the profile entry with -whom, but that would
+ require figuring out which command line argument has the filename. With -whom, it's
+ not necessarily the last one. */
+
+ const char *addr, *host;
+ const char *message;
+
+ /* Extract address and host from From: header line in draft. */
+ if (get_from_header_info(msg, &addr, &host, &message) != OK) {
+ adios(msg, message);
+ }
+
+ /* Merge in any address or host specific switches to post(1) from profile. */
+ merge_profile_entry(addr, host, vec, &vecp);
+ free((void *) host);
+ free((void *) addr);
+ }
+
+ vec[vecp] = NULL;
+ for (vp = vec; *vp; ++vp) {
+ if (strcmp(*vp, "xoauth2") == 0) {
+#ifdef OAUTH_SUPPORT
+ const char *message;
+
+ if (setup_oauth_params(vec, &vecp, snoop, &message) != OK) {
+ adios(NULL, message);
+ }
+ break;
+#else
+ NMH_UNUSED(snoop);
+ NMH_UNUSED(vp);
+ adios(NULL, "sendfrom built without OAUTH_SUPPORT, so -saslmech xoauth2 is not supported");
+#endif /* OAUTH_SUPPORT */
+ }
+ }
+
+ if (! whom) {
+ /* Append filename as last non-null vec entry. */
+ vec[vecp++] = getcpy(msg);
+ vec[vecp] = NULL;
+ }
+
+ /* Call post, or with -dryrun, echo how it would be called. */
+ if (dryrun) {
+ /* Show the program name, because run_program() won't. */
+ printf("%s ", realpost);
+ fflush(stdout);
+ }
+ if (run_program(dryrun ? "echo" : realpost, vec) != OK) {
+ adios(realpost, "failure in ");
+ }
+
+ arglist_free(program, vec);
+ free(realpost);
+ }
+
+ return 0;
+}
+
+
+
+#ifdef OAUTH_SUPPORT
+/*
+ * For XOAUTH2, append access token, from mh_oauth_do_xoauth(), for the user to vec.
+ */
+static
+int
+setup_oauth_params(char *vec[], int *vecp, int snoop, const char **message) {
+ const char *saslmech = NULL, *user = NULL, *auth_svc = NULL;
+ int i;
+
+ /* Make sure we have all the information we need. */
+ for (i = 1; i < *vecp; ++i) {
+ /* Don't support abbreviated switches, to avoid collisions in the future if new ones
+ are added. */
+ if (! strcmp(vec[i-1], "-saslmech")) {
+ saslmech = vec[i];
+ } else if (! strcmp(vec[i-1], "-user")) {
+ user = vec[i];
+ } else if (! strcmp(vec[i-1], "-authservice")) {
+ auth_svc = vec[i];
+ }
+ }
+
+ if (auth_svc == NULL) {
+ if (saslmech && ! strcasecmp(saslmech, "xoauth2")) {
+ *message = "must specify -authservice with -saslmech xoauth2";
+ return NOTOK;
+ }
+ } else {
+ if (user == NULL) {
+ *message = "must specify -user with -saslmech xoauth2";
+ return NOTOK;
+ }
+
+ vec[(*vecp)++] = getcpy("-authservice");
+ if (saslmech && ! strcasecmp(saslmech, "xoauth2")) {
+ vec[(*vecp)++] = mh_oauth_do_xoauth(user, auth_svc, snoop ? stderr : NULL);
+ } else {
+ vec[(*vecp)++] = getcpy(auth_svc);
+ }
+ }
+
+ return 0;
+}
+#endif /* OAUTH_SUPPORT */
+
+
+/*
+ * Extract user and domain from From: header line in draft.
+ */
+static
+int
+get_from_header_info(const char *filename, const char **addr, const char **host, const char **message) {
+ struct stat st;
+ FILE *in;
+
+ if (stat (filename, &st) == NOTOK) {
+ *message = "unable to stat draft file";
+ return NOTOK;
+ }
+
+ if ((in = fopen(filename, "r")) != NULL) {
+ char *addrformat = "%(addr{from})", *hostformat = "%(host{from})";
+
+ if ((*addr = get_message_header_info(in, addrformat)) == NULL) {
+ *message = "unable to find From: address in";
+ return NOTOK;
+ }
+ rewind(in);
+
+ if ((*host = get_message_header_info(in, hostformat)) == NULL) {
+ fclose(in);
+ *message = "unable to find From: host in";
+ return NOTOK;
+ }
+ fclose(in);
+
+ return OK;
+ } else {
+ *message = "unable to open";
+ return NOTOK;
+ }
+}
+
+
+/*
+ * Get formatted information from header of a message.
+ * Adapted from process_single_file() in uip/fmttest.c.
+ */
+static
+const char *
+get_message_header_info(FILE *in, char *format) {
+ int dat[5];
+ struct format *fmt;
+ struct stat st;
+ int parsing_header;
+ m_getfld_state_t gstate = 0;
+ charstring_t buffer = charstring_create(0);
+ char *retval;
+
+ dat[0] = dat[1] = dat[4] = 0;
+ dat[2] = fstat(fileno(in), &st) == 0 ? st.st_size : 0;
+ dat[3] = INT_MAX;
+
+ (void) fmt_compile(new_fs(NULL, NULL, format), &fmt, 1);
+
+ /*
+ * Read in the message and process the header.
+ */
+ parsing_header = 1;
+ do {
+ char name[NAMESZ], rbuf[NMH_BUFSIZ];
+ int bufsz = sizeof rbuf;
+ int state = m_getfld(&gstate, name, rbuf, &bufsz, in);
+
+ switch (state) {
+ case FLD:
+ case FLDPLUS: {
+ int bucket = fmt_addcomptext(name, rbuf);
+
+ if (bucket != -1) {
+ while (state == FLDPLUS) {
+ bufsz = sizeof rbuf;
+ state = m_getfld(&gstate, name, rbuf, &bufsz, in);
+ fmt_appendcomp(bucket, name, rbuf);
+ }
+ }
+
+ while (state == FLDPLUS) {
+ bufsz = sizeof rbuf;
+ state = m_getfld(&gstate, name, rbuf, &bufsz, in);
+ }
+ break;
+ }
+ default:
+ parsing_header = 0;
+ }
+ } while (parsing_header);
+ m_getfld_state_destroy(&gstate);
+
+ fmt_scan(fmt, buffer, INT_MAX, dat, NULL);
+ fmt_free(fmt, 1);
+
+ /* Trim trailing newline, if any. */
+ retval = rtrim(charstring_buffer_copy((buffer)));
+ charstring_free(buffer);
+
+ return retval;
+}
+
+
+/*
+ * Look in profile for entry corresponding to addr or host, and add its contents to vec.
+ *
+ * Could do some of this automatically, by looking for:
+ * 1) access-$(mbox{from}) in oauth-svc file using mh_oauth_cred_load(), which isn't
+ * static and doesn't have side effects; free the result with mh_oauth_cred_free())
+ * 2) machine $(mbox{from}) in creds
+ * If no -server passed in from profile or commandline, could use smtp.<svc>.com for gmail,
+ * but that might not generalize for other svcs.
+ */
+static
+void
+merge_profile_entry(const char *addr, const char *host, char *vec[], int *vecp) {
+ char *addr_entry = concat("sendfrom-", addr, NULL);
+ char *profile_entry = context_find(addr_entry);
+
+ free(addr_entry);
+ if (profile_entry == NULL) {
+ /* No entry for the user. Look for one for the host. */
+ char *host_entry = concat("sendfrom-", host, NULL);
+
+ profile_entry = context_find(host_entry);
+ free(host_entry);
+ }
+
+ /* Use argsplit() to do the real work of splitting the args in the profile entry. */
+ if (profile_entry && strlen(profile_entry) > 0) {
+ int profile_vecp;
+ char *file;
+ char **profile_vec = argsplit(profile_entry, &file, &profile_vecp);
+ int i;
+
+ for (i = 0; i < profile_vecp; ++i) {
+ vec[(*vecp)++] = getcpy(profile_vec[i]);
+ }
+
+ arglist_free(file, profile_vec);
+ }
+}
+
+
+/*
+ * Fork and exec.
+ */
+static
+int
+run_program(char *realpost, char **vec) {
+ pid_t child_id;
+ int i;
+
+ for (i = 0; (child_id = fork()) == NOTOK && i < 5; ++i) { sleep(5); }
+
+ switch (child_id) {
+ case -1:
+ /* oops -- fork error */
+ return NOTOK;
+ case 0:
+ (void) execvp(realpost, vec);
+ fprintf(stderr, "unable to exec ");
+ perror(realpost);
+ _exit(-1);
+ default:
+ if (pidXwait(child_id, realpost)) {
+ return NOTOK;
+ }
+ }
+
+ return OK;
+}
projects / nmh / commitdiff