seq: slurp the file instead of mmap

mmap is not robust when there are writes possible.

Makefile

@@ -21,11 +21,12 @@ $(ALL) : % : %.o
 maddr magrep mdeliver mexport mflag mgenmid mhdr mpick mscan msed mshow \
   msort mthread : blaze822.o mymemmem.o mytimegm.o
 maddr magrep mexport mflag mgenmid mhdr mpick mscan msed mseq mshow msort \
-  mthread : seq.o
+  mthread : seq.o slurp.o
 maddr magrep mhdr mpick mscan mshow : rfc2047.o
 magrep mshow : rfc2045.o
 mshow : filter.o
 msort : mystrverscmp.o
+mmime : slurp.o
 
 README: man/mblaze.7
 	mandoc -Tutf8 $< | col -bx >$@

blaze822.h

@@ -77,3 +77,8 @@ int filter(char *input, size_t inlen, char *cmd, char **outputo, size_t *outleno
 // mygmtime.c
 
 time_t tm_to_secs(const struct tm *tm);
+
+
+// slurp.c
+
+int slurp(char *filename, char **bufo, off_t *leno);

seq.c

@@ -1,4 +1,3 @@
-#include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -50,23 +49,14 @@ blaze822_home_file(char *basename)
 char *
 blaze822_seq_open(char *file)
 {
-	int fd;
-	struct stat st;
-
-	// env $SEQ or something
 	if (!file)
 		file = getenv("MAILSEQ");
 	if (!file)
 		file = blaze822_home_file("seq");
-	fd = open(file, O_RDONLY);
-	if (!fd)
-		return 0;
 
-	fstat(fd, &st);
-	char *map = mmap(0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-	close(fd);
-
-	if (map == MAP_FAILED)
+	char *map;
+	off_t len;
+	if (slurp(file, &map, &len) != 0)
 		return 0;
 
 	return map;

slurp.c

@@ -0,0 +1,56 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+slurp(char *filename, char **bufo, off_t *leno)
+{
+	int fd;
+	struct stat st;
+	ssize_t nread = 0;
+	ssize_t n;
+	int r = 0;
+	
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		r = errno;
+		goto out;
+	}
+	if (fstat(fd, &st) < 0) {
+		r = errno;
+		goto out;
+	}
+	if (st.st_size == 0) {
+		*bufo = "";
+		*leno = 0;
+		return 0;
+	}
+	*bufo = malloc(st.st_size);
+	if (!*bufo) {
+		r = ENOMEM;
+		goto out;
+	}
+
+	do {
+		if ((n = read(fd, *bufo + nread, st.st_size - nread)) < 0) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				r = errno;
+				goto out;
+			}
+		}
+		if (!n)
+			break;
+		nread += n;
+	} while (nread < st.st_size);
+	*leno = nread;
+
+out:
+	close(fd);
+	return r;
+}