switch mail.local to getline()

[Omar Polo]

As per subject.  While here I couldn't resist simplifying the "From "
check too, although it is indipendent from the rest of the diff.
(could commit separately if preferred.)

ok?

diff /usr/src
commit - 79631e141468cced94e502d777a484fa0eb1f60f
path + /usr/src
blob - 815fe58323c8b912f5676a7d5a29cc90b5bb434c
file + libexec/mail.local/mail.local.c
--- libexec/mail.local/mail.local.c
+++ libexec/mail.local/mail.local.c
@@ -111,9 +111,10 @@ storemail(char *from)
 {
        FILE *fp = NULL;
        time_t tval;
-       int fd, eline;
-       size_t len;
-       char *line, *tbuf;
+       int fd, eline = 1;
+       char *tbuf, *line = NULL;
+       size_t linesize = 0;
+       ssize_t linelen;
 
        if ((tbuf = strdup(_PATH_LOCTMP)) == NULL)
                merr(EX_OSERR, "unable to allocate memory");
@@ -125,23 +126,13 @@ storemail(char *from)
        (void)time(&tval);
        (void)fprintf(fp, "From %s %s", from, ctime(&tval));
 
-       for (eline = 1, tbuf = NULL; (line = fgetln(stdin, &len));) {
-               /* We have to NUL-terminate the line since fgetln does not */
-               if (line[len - 1] == '\n')
-                       line[len - 1] = '\0';
-               else {
-                       /* No trailing newline, so alloc space and copy */
-                       if ((tbuf = malloc(len + 1)) == NULL)
-                               merr(EX_OSERR, "unable to allocate memory");
-                       memcpy(tbuf, line, len);
-                       tbuf[len] = '\0';
-                       line = tbuf;
-               }
+       while ((linelen = getline(&line, &linesize, stdin)) != -1) {
+               if (line[linelen - 1] == '\n')
+                       line[linelen - 1] = '\0';
                if (line[0] == '\0')
                        eline = 1;
                else {
-                       if (eline && line[0] == 'F' && len > 5 &&
-                           !memcmp(line, "From ", 5))
+                       if (eline && !strncmp(line, "From ", 5))
                                (void)putc('>', fp);
                        eline = 0;
                }
@@ -149,7 +140,7 @@ storemail(char *from)
                if (ferror(fp))
                        break;
        }
-       free(tbuf);
+       free(line);
 
        /* Output a newline; note, empty messages are allowed. */
        (void)putc('\n', fp);