Add error control to iofile

write can write less bytes than we request, so it is necessary check the
return value, in case of error print a message and don't continnue writing
in the file.
---
 st.c |   39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

1 files changed, 30 insertions, 9 deletions

diff --git a/st.c b/st.c
index f967d2c..e19cefd 100644
--- a/st.c
+++ b/st.c
@@ -340,6 +340,7 @@ static int utf8encode(long *, char *);
 static int utf8size(char *);
 static int isfullutf8(char *, int);
 
+static ssize_t xwrite(int, char *, size_t);
 static void *xmalloc(size_t);
 static void *xrealloc(void *, size_t);
 static void *xcalloc(size_t nmemb, size_t size);
@@ -379,6 +380,21 @@ static char *opt_embed = NULL;
 static char *opt_class = NULL;
 static char *opt_font = NULL;
 
+
+ssize_t
+xwrite(int fd, char *s, size_t len) {
+        size_t aux = len;
+
+        while(len > 0) {
+                ssize_t r = write(fd, s, len);
+                if(r < 0)
+                        return r;
+                len -= r;
+                s += r;
+        }
+        return aux;
+}
+
 void *
 xmalloc(size_t len) {
         void *p = malloc(len);
@@ -926,13 +942,12 @@ ttynew(void) {
                 cmdfd = m;
                 signal(SIGCHLD, sigchld);
                 if(opt_io) {
-                        if(!strcmp(opt_io, "-")) {
-                                iofd = STDOUT_FILENO;
-                        } else {
-                                if((iofd = open(opt_io, O_WRONLY | O_CREAT, 0666)) < 0) {
-                                        fprintf(stderr, "Error opening %s:%s\n",
-                                                opt_io, strerror(errno));
-                                }
+                        iofd = (!strcmp(opt_io, "-")) ?
+                                  STDOUT_FILENO :
+                                  open(opt_io, O_WRONLY | O_CREAT, 0666);
+                        if(iofd < 0) {
+                                fprintf(stderr, "Error opening %s:%s\n",
+                                        opt_io, strerror(errno));
                         }
                 }
         }
@@ -1793,8 +1808,14 @@ tputc(char *c, int len) {
         uchar ascii = *c;
         bool control = ascii < '\x20' || ascii == 0177;
 
-        if(iofd != -1)
-                write(iofd, c, len);
+        if(iofd != -1) {
+                if (xwrite(iofd, c, len) < 0) {
+                        fprintf(stderr, "Error writting in %s:%s\n",
+                                opt_io, strerror(errno));
+                        close(iofd);
+                        iofd = -1;
+                }
+        }
         /*
          * STR sequences must be checked before of anything
          * because it can use some control codes as part of the sequence