sendmail: update from maintainer

2 files changed, 215 insertions, 157 deletions

diff --git a/include/usage.h b/include/usage.h
index 6b54a1266..e9770cea9 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -1026,17 +1026,19 @@ USE_FEATURE_BRCTL_FANCY("\n" \
        "        -v              Give fdisk version"
 
 #define fetchmail_trivial_usage \
-       "[-C dir] [-w timeout] [-U user] -P password [-X] [-t] [-z] server[:port]"
+       "[-w timeout] [-U user] -P password [-X] [-t] [-z] server[:port] maildir [prog]"
 #define fetchmail_full_usage \
        "Fetch content of remote mailbox to local Maildir." \
        "\n\nOptions:\n" \
-       "        -C dir          Set Maildir location\n" \
        "        -w timeout      Set timeout on network operations\n" \
        "        -U username     Authenticate with specified username\n" \
        "        -P password     Authenticate with specified password\n" \
        "        -X              Use openssl connection helper for secured servers\n" \
        "        -t              Get only headers\n" \
-       "        -z              Delete messages on server"
+       "        -z              Delete messages on server" \
+USE_FEATURE_FETCHMAIL_FILTER("\n" \
+       "        prog            Run prog <message file> on message delivery" \
+)
 
 #define findfs_trivial_usage \
        "LABEL=label or UUID=uuid"
@@ -3258,18 +3260,16 @@ USE_FEATURE_RUN_PARTS_FANCY("\n	-l	Prints names of all matching files even when
 #define selinuxenabled_full_usage
 
 #define sendmail_trivial_usage \
-       "[-C dir] [-w timeout] [-U user] [-P password] [-X]\n" \
-       "-t to [-t to] -f from [-n] [-s subject] [-c charset] server[:port] [body] [attachment ...]"
+       "[-w timeout] [-U user] [-P password] [-X]\n" \
+       "-t to [-t to]... [-n] [-s subject] [-c charset] server[:port] from [body] [attachment ...]"
 #define sendmail_full_usage \
        "Send an email with optional attachments." \
        "\n\nOptions:\n" \
-       "        -C dir          Change current directory to dir\n" \
        "        -w timeout      Set timeout on network operations\n" \
        "        -U username     Authenticate with specified username\n" \
        "        -P password     Authenticate with specified password\n" \
+       "        -t address      Recipient(s). May be multiple\n" \
        "        -X              Use openssl connection helper for secured servers\n" \
-       "        -t to           Recipient email. May be multiple\n" \
-       "        -f from         Sender address\n" \
        "        -n              Request delivery notification to sender\n" \
        "        -s subject      Subject\n" \
        "        -c charset      Assumed charset for body and subject [utf-8]"
diff --git a/networking/sendmail.c b/networking/sendmail.c
index b2fbc5a7a..adc6c7626 100644
--- a/networking/sendmail.c
+++ b/networking/sendmail.c
@@ -27,9 +27,13 @@ static void uuencode(char *fname, const char *text)
                 if (NOT_LONE_DASH(fname))
                         fd = xopen(fname, O_RDONLY);
                 src_buf = bb_common_bufsiz1;
-        } else {
+        // N.B. strlen(NULL) segfaults!
+        } else if (text) {
+                // though we do not call uuencode(NULL, NULL) explicitly
+                // still we do not want to break things suddenly
                 len = strlen(text);
-        }
+        } else
+                return;
 
         fflush(stdout); // sync stdio and unistd output
         while (1) {
@@ -59,7 +63,38 @@ static void uuencode(char *fname, const char *text)
                 close(fd);
 }
 
-static pid_t helper_pid;
+static const char *const init_xargs[9] = {
+        "openssl", "s_client", "-quiet", "-connect",
+        NULL, "-tls1", "-starttls", "smtp"
+};
+
+struct globals {
+        pid_t helper_pid;
+        unsigned timeout;
+        // arguments for SSL connection helper
+        const char *xargs[9];
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+        // arguments for postprocess helper
+        const char *fargs[3];
+#endif
+};
+#define G (*ptr_to_globals)
+#define helper_pid      (G.helper_pid)
+#define timeout         (G.timeout   )
+#define xargs           (G.xargs     )
+#define fargs           (G.fargs     )
+#define INIT_G() do { \
+        PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+        memcpy(xargs, init_xargs, sizeof(init_xargs)); \
+        fargs[0] = "utf-8"; \
+} while (0)
+
+#define opt_connect       (xargs[4])
+#define opt_after_connect (xargs[5])
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+#define opt_charset       (fargs[0])
+#define opt_subject       (fargs[1])
+#endif
 
 static void kill_helper(void)
 {
@@ -71,7 +106,7 @@ static void kill_helper(void)
 // generic signal handler
 static void signal_handler(int signo)
 {
-        int err;
+#define err signo
 
         if (SIGALRM == signo) {
                 kill_helper();
@@ -107,20 +142,19 @@ static void launch_helper(const char **argv)
                                 close(pipes[i]);
         if (!helper_pid) {
                 // child - try to execute connection helper
-                BB_EXECVP(argv[0], (char **)argv);
+//              close(STDERR_FILENO);
+                BB_EXECVP(*argv, (char **)argv);
                 _exit(127);
         }
         // parent - check whether child is alive
-        bb_signals_recursive(0
-                        + (1 << SIGCHLD)
-                        + (1 << SIGALRM)
-                        , signal_handler);
+        bb_signals(0
+                + (1 << SIGCHLD)
+                + (1 << SIGALRM)
+                , signal_handler);
         signal_handler(SIGCHLD);
         // child seems OK -> parent goes on
 }
 
-static unsigned timeout;
-
 static char *command(const char *fmt, const char *param)
 {
         char *msg = (char *)fmt;
@@ -145,7 +179,9 @@ static int smtp_checkp(const char *fmt, const char *param, int code)
         // if code != -1 then checks whether the number equals the code
         // if not equal -> die saying msg
 #if ENABLE_FEATURE_SENDMAIL_EHLO
-        while ((answer = xmalloc_getline(stdin)) && '-' == answer[3]) ;
+        while ((answer = xmalloc_getline(stdin)) != NULL)
+                if (strlen(answer) <= 3 || '-' != answer[3])
+                        break;
 #else
         answer = xmalloc_getline(stdin);
 #endif
@@ -169,15 +205,31 @@ static int smtp_check(const char *fmt, int code)
         return smtp_checkp(fmt, NULL, code);
 }
 
+// strip argument of bad chars
+static char *sane(char *str)
+{
+        char *s = str;
+        char *p = s;
+        while (*s) {
+                if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
+                        *p++ = *s;
+                }
+                s++;
+        }
+        *p = '\0';
+        return str;
+}
+
+#if ENABLE_FETCHMAIL
 static void pop3_checkr(const char *fmt, const char *param, char **ret)
 {
         char *msg = command(fmt, param);
         char *answer = xmalloc_getline(stdin);
-        if (answer && '+' == answer[0]) {
+        if (answer && '+' == *answer) {
                 alarm(0);
                 if (ret)
-                        *ret = answer;
-                else
+                        *ret = answer+4; // skip "+OK "
+                else if (ENABLE_FEATURE_CLEAN_UP)
                         free(answer);
                 return;
         }
@@ -190,28 +242,16 @@ static void pop3_check(const char *fmt, const char *param)
         pop3_checkr(fmt, param, NULL);
 }
 
-// strip argument of bad chars
-static char *sane(char *str)
-{
-        char *s = str;
-        char *p = s;
-        while (*s) {
-                if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
-                        *p++ = *s;
-                }
-                s++;
-        }
-        *p = '\0';
-        return str;
-}
-
-static void pop3_message(int fd)
+static void pop3_message(const char *filename)
 {
+        int fd;
         char *answer;
-        // read stdin, copy to file fd
+        // create and open file filename
+        // read stdin, copy to created file
+        fd = xopen(filename, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL);
         while ((answer = xmalloc_fgets_str(stdin, "\r\n"))) {
                 char *s = answer;
-                if ('.' == answer[0]) {
+                if ('.' == *answer) {
                         if ('.' == answer[1])
                                 s++;
                         else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
@@ -222,64 +262,56 @@ static void pop3_message(int fd)
         }
         close(fd);
 }
-
-static const char *args[] = {
-        "openssl", "s_client", "-quiet", "-connect", NULL, "-tls1", "-starttls", "smtp", NULL
-};
-#define opt_connect     args[4]
-#define opt_after_connect args[5]
+#endif
 
 int sendgetmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sendgetmail_main(int argc, char **argv)
 {
-        llist_t *recipients = NULL;
-        char *from;
-        const char *subject;
-        char *charset = (char *)"utf-8";
+        llist_t *opt_recipients = NULL;
+#if !ENABLE_FEATURE_FETCHMAIL_FILTER
+        char *opt_subject;
+        char *opt_charset = (char *)"utf-8";
+#endif
 
         const char *opt_user;
         const char *opt_pass;
-        const char *opt_timeout;
-        const char *opt_chdir;
 
         enum {
-                OPT_C = 1 << 0,         // chdir
-                OPT_w = 1 << 1,         // network timeout
-                OPT_U = 1 << 2,         // user
-                OPT_P = 1 << 3,         // password
-                OPT_X = 1 << 4,         // use openssl connection helper
+                OPT_w = 1 << 0,         // network timeout
+                OPT_U = 1 << 1,         // user
+                OPT_P = 1 << 2,         // password
+                OPT_X = 1 << 3,         // connect using openssl s_client helper
 
-                OPTS_t = 1 << 5,        // sendmail "to"
-                OPTF_t = 1 << 5,        // fetchmail "TOP"
+                OPTS_n = 1 << 4,        // sendmail: request notification
+                OPTF_t = 1 << 4,        // fetchmail: use "TOP" not "RETR"
 
-                OPTS_f = 1 << 6,        // sendmail "from"
-                OPTF_z = 1 << 6,        // fetchmail "delete"
+                OPTS_s = 1 << 5,        // sendmail: subject
+                OPTF_z = 1 << 5,        // fetchmail: delete from server
 
-                OPTS_n = 1 << 7,        // notification
-                OPTS_s = 1 << 8,        // subject given
-                OPTS_c = 1 << 9,        // charset for subject and body
+                OPTS_c = 1 << 6,        // sendmail: assumed charset
+                OPTS_t = 1 << 7,        // sendmail: recipient(s)
         };
 
         const char *options;
         unsigned opts;
 
-        // SENDMAIL
-        if ('s' == applet_name[0]) {
-                // save initial stdin
+        INIT_G();
+
+        if (!ENABLE_FETCHMAIL || 's' == applet_name[0]) {
+                // SENDMAIL
+                // save initial stdin (body or attachements can be piped!)
                 xdup2(STDIN_FILENO, INITIAL_STDIN_FILENO);
-                // -f must be specified
-                // -t may be multiple
-                opt_complementary = "-1:f:t::";
-                options = "C:w:U:P:X" "t:f:ns:c:";
-        // FETCHMAIL
+                opt_complementary = "-2:w+:t:t::"; // count(-t) > 0
+                options = "w:U:P:X" "ns:c:t:";
         } else {
+                // FETCHMAIL
                 opt_after_connect = NULL;
-                opt_complementary = "=1:P";
-                options = "C:w:U:P:X" "tz";
+                opt_complementary = "-2:w+:P";
+                options = "w:U:P:X" "tz";
         }
         opts = getopt32(argv, options,
-                &opt_chdir, &opt_timeout, &opt_user, &opt_pass,
-                &recipients, &from, &subject, &charset
+                &timeout, &opt_user, &opt_pass,
+                &opt_subject, &opt_charset, &opt_recipients
         );
 
         //argc -= optind;
@@ -288,16 +320,9 @@ int sendgetmail_main(int argc, char **argv)
         // first argument is remote server[:port]
         opt_connect = *argv++;
 
-        if (opts & OPT_w)
-                timeout = xatou(opt_timeout);
-
-        // chdir
-        if (opts & OPT_C)
-                xchdir(opt_chdir);
-
         // connect to server
         if (opts & OPT_X) {
-                launch_helper(args);
+                launch_helper(xargs);
         } else {
                 // no connection helper provided -> make plain connect
                 int fd = create_and_connect_stream_or_die(opt_connect, 0);
@@ -305,24 +330,30 @@ int sendgetmail_main(int argc, char **argv)
                 xdup2(STDIN_FILENO, STDOUT_FILENO);
         }
 
-        // randomize
-        srand(time(NULL));
-
-        // SENDMAIL
-        if (recipients) {
+#if ENABLE_FETCHMAIL
+        if (opt_after_connect)
+#endif
+        {
+                // SENDMAIL
+                char *opt_from;
                 int code;
                 char *boundary;
+                const char *fmt;
+                const char *p;
+                char *q;
 
                 // wait for initial OK on plain connect
                 if (!(opts & OPT_X))
                         smtp_check(NULL, 220);
 
-                sane(from);
+                // get specified sender
+                opt_from = sane(*argv++);
+
                 // introduce to server
                 // should we respect modern (but useless here) EHLO?
                 // or should they respect we wanna be tiny?!
-                if (!ENABLE_FEATURE_SENDMAIL_EHLO || 250 != smtp_checkp("EHLO %s", from, -1)) {
-                        smtp_checkp("HELO %s", from, 250);
+                if (!ENABLE_FEATURE_SENDMAIL_EHLO || 250 != smtp_checkp("EHLO %s", opt_from, -1)) {
+                        smtp_checkp("HELO %s", opt_from, 250);
                 }
 
                 // set sender
@@ -330,13 +361,13 @@ int sendgetmail_main(int argc, char **argv)
                 // no authentication is possible
                 code = (opts & OPT_P) ? -1 : 250;
                 // first try softly without authentication
-                while (250 != smtp_checkp("MAIL FROM:<%s>", from, code)) {
+                while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
                         // MAIL FROM failed -> authentication needed
                         // do we have username?
                         if (!(opts & OPT_U)) {
                                 // no! fetch it from "from" option
                                 //opts |= OPT_U;
-                                opt_user = xstrdup(from);
+                                opt_user = xstrdup(opt_from);
                                 *strchrnul(opt_user, '@') = '\0';
                         }
                         // now it seems we have username
@@ -351,30 +382,35 @@ int sendgetmail_main(int argc, char **argv)
                         // but now die on failure
                         code = 250;
                 }
+
                 // set recipients
-                for (llist_t *to = recipients; to; to = to->link) {
+                for (llist_t *to = opt_recipients; to; to = to->link) {
                         smtp_checkp("RCPT TO:<%s>", sane(to->data), 250);
                 }
 
                 // now put message
                 smtp_check("DATA", 354);
                 // put address headers
-                printf("From: %s\r\n", from);
-                for (llist_t *to = recipients; to; to = to->link) {
+                printf("From: %s\r\n", opt_from);
+                for (llist_t *to = opt_recipients; to; to = to->link) {
                         printf("To: %s\r\n", to->data);
                 }
                 // put encoded subject
                 if (opts & OPTS_c)
-                        sane(charset);
+                        sane((char *)opt_charset);
                 if (opts & OPTS_s) {
-                        printf("Subject: =?%s?B?", charset);
-                        uuencode(NULL, subject);
+                        printf("Subject: =?%s?B?", opt_charset);
+                        uuencode(NULL, opt_subject);
                         printf("?=\r\n");
                 }
                 // put notification
                 if (opts & OPTS_n)
-                        printf("Disposition-Notification-To: %s\r\n", from);
+                        printf("Disposition-Notification-To: %s\r\n", opt_from);
                 // put common headers and body start
+                // randomize
+#if ENABLE_FEATURE_SENDMAIL_BLOATY
+                srand(time(NULL));
+#endif
                 boundary = xasprintf("%d-%d-%d", rand(), rand(), rand());
                 printf(
                         USE_FEATURE_SENDMAIL_BLOATY("X-Mailer: busybox " BB_VER " sendmail\r\n")
@@ -386,16 +422,16 @@ int sendgetmail_main(int argc, char **argv)
                         , boundary
                 );
                 // put body + attachment(s)
-        {
-                const char *fmt =
+
+                fmt =
                         "\r\n--%s\r\n"
                         "%stext/plain; charset=%s\r\n"
                         "%s%s\r\n"
                         "%s"
                 ;
-                const char *p = charset;
-                char *q = (char *)"";
-                while (argv[0]) {
+                p = opt_charset;
+                q = (char *)"";
+                while (*argv) {
                         printf(
                                 fmt
                                 , boundary
@@ -414,9 +450,9 @@ int sendgetmail_main(int argc, char **argv)
                         ;
                         uuencode(*argv, NULL);
                         if (*(++argv))
-                                q = bb_get_last_path_component_strip(argv[0]);
+                                q = bb_get_last_path_component_strip(*argv);
                 }
-        }
+
                 // put terminator
                 printf("\r\n--%s--\r\n" "\r\n", boundary);
                 if (ENABLE_FEATURE_CLEAN_UP)
@@ -426,11 +462,25 @@ int sendgetmail_main(int argc, char **argv)
                 smtp_check(".", 250);
                 smtp_check("QUIT", 221);
 
-        // FETCHMAIL
+#if ENABLE_FETCHMAIL
         } else {
-                // authenticate
+                // FETCHMAIL
                 char *buf;
                 unsigned nmsg;
+                char *hostname;
+                pid_t pid;
+                // cache fetch command
+                const char *retr = (opts & OPTF_t) ? "TOP %u 0" : "RETR %u";
+
+                // goto maildir
+                xchdir(*argv++);
+
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+                // cache postprocess program
+                *fargs = *argv;
+#endif
+                
+                // authenticate
                 if (!(opts & OPT_U)) {
                         //opts |= OPT_U;
                         opt_user = getenv("USER");
@@ -438,25 +488,29 @@ int sendgetmail_main(int argc, char **argv)
 #if ENABLE_FEATURE_FETCHMAIL_APOP
                 pop3_checkr(NULL, NULL, &buf);
                 // server supports APOP?
-                if ('<' == buf[4]) {
+                if ('<' == *buf) {
                         md5_ctx_t md5;
-                        uint8_t hex[16*2 + 1];
                         // yes. compose <stamp><password>
                         char *s = strchr(buf, '>');
                         if (s)
                                 strcpy(s+1, opt_pass);
-                        s = buf+4;
+                        s = buf;
                         // get md5 sum of <stamp><password>
                         md5_begin(&md5);
                         md5_hash(s, strlen(s), &md5);
                         md5_end(s, &md5);
-                        bin2hex(hex, s, 16);
+                        // NOTE: md5 struct contains enough space
+                        // so we reuse md5 space instead of xzalloc(16*2+1)
+#define md5_hex ((uint8_t *)&md5)
+//                      uint8_t *md5_hex = (uint8_t *)&md5;
+                        *bin2hex(md5_hex, s, 16) = '\0';
                         // APOP
-                        s = xasprintf("%s %s", opt_user, hex);
+                        s = xasprintf("%s %s", opt_user, md5_hex);
+#undef md5_hex
                         pop3_check("APOP %s", s);
                         if (ENABLE_FEATURE_CLEAN_UP) {
                                 free(s);
-                                free(buf);
+                                free(buf-4); // buf is "+OK " away from malloc'ed string
                         }
                 } else {
 #else
@@ -472,60 +526,64 @@ int sendgetmail_main(int argc, char **argv)
                 // get statistics
                 pop3_checkr("STAT", NULL, &buf);
 
+                // prepare message filename suffix
+                hostname = xzalloc(MAXHOSTNAMELEN+1);
+                gethostname(hostname, MAXHOSTNAMELEN);
+                pid = getpid();
+
                 // get number of messages
-                nmsg = atoi(buf+4);
+                // NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
+                // we only need nmsg and atoi is just exactly what we need
+                // if atoi fails to convert buf into number it returns 0
+                // in this case the following loop simply will not be executed 
+                nmsg = atoi(buf);
                 if (ENABLE_FEATURE_CLEAN_UP)
-                        free(buf);
-
-                // lock maildir
-                ////USE_FEATURE_CLEAN_UP(close)(xopen(".lock", O_CREAT | O_WRONLY | O_TRUNC | O_EXCL));
-                
-                // make tempnam(dir, salt) respect dir argument
-                unsetenv("TMPDIR");
-
-                // TODO: piping through external filter argv... if *argv
+                        free(buf-4); // buf is "+OK " away from malloc'ed string
 
-                // cache fetch command
-        {
-                const char *retr = (opts & OPTF_t) ? "TOP %u 0" : "RETR %u";
                 // loop through messages
                 for (; nmsg; nmsg--) {
-                        int fd;
-                        char tmp_name[sizeof("tmp/XXXXXX")];
-                        char new_name[sizeof("new/XXXXXX")];
-
+                        char *filename = xasprintf("tmp/%llu.%u.%s", monotonic_us(), pid, hostname);
+                        char *target;
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+                int rc;
+#endif
                         // retrieve message in ./tmp
-                        strcpy(tmp_name, "tmp/XXXXXX");
-                        fd = mkstemp(tmp_name);
-                        if (fd < 0)
-                                bb_perror_msg_and_die("cannot create unique file");
                         pop3_check(retr, (const char *)nmsg);
-                        pop3_message(fd); // NB: closes fd
-
-                        // move file to ./new atomically
-                        strncpy(new_name, "new", 3);
-                        strcpy(new_name + 3, tmp_name + 3);
-                        if (rename(tmp_name, new_name) < 0) {
-                                // rats! such file exists! try to make unique name
-                                strcpy(new_name + 3, "tmp/XXXXXX" + 3);
-                                fd = mkstemp(new_name);
-                                if (fd < 0)
-                                        bb_perror_msg_and_die("cannot create unique file");
-                                close(fd);
-                                xrename(tmp_name, new_name);
-                        }
-
+                        pop3_message(filename);
                         // delete message from server
                         if (opts & OPTF_z)
                                 pop3_check("DELE %u", (const char*)nmsg);
+
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+                        // run postprocessing program
+                        if (*fargs) {
+                                fargs[1] = filename;
+                                rc = wait4pid(spawn((char **)fargs));
+                                if (99 == rc)
+                                        break;
+                                if (1 == rc)
+                                        goto skip;
+                        }
+#endif
+                        // atomically move message to ./new
+                        target = xstrdup(filename);
+                        strncpy(target, "new", 3);
+                        // ... or just stop receiving on error
+                        if (rename_or_warn(filename, target))
+                                break;
+                        free(target);
+#if ENABLE_FEATURE_FETCHMAIL_FILTER
+ skip:
+#endif
+                        free(filename);
                 }
-        }
+
+                if (ENABLE_FEATURE_CLEAN_UP)
+                        free(hostname);
 
                 // Bye
                 pop3_check("QUIT", NULL);
-
-                // unlock maildir
-                ////unlink(".lock");
+#endif // ENABLE_FETCHMAIL
         }
 
         return 0;