[hackers] [farbfeld] Improve fread error handling in ff2* || Alexander Krotov

From: <git_AT_suckless.org>
Date: Thu, 19 May 2016 12:56:00 +0200 (CEST)

commit 3fa775e1dfd5dc38648f88c2f385be1f0fe45605
Author: Alexander Krotov <ilabdsf_AT_yandex.ru>
AuthorDate: Thu May 19 01:21:58 2016 +0300
Commit: FRIGN <dev_AT_frign.de>
CommitDate: Thu May 19 12:55:45 2016 +0200

    Improve fread error handling in ff2*
    
    In case of unexpected end of file errno is not set, and strerror(errno)
    returns "Success". Caller should distinguish between error and EOF by
    calling ferror(3) as described in fread(3).

diff --git a/ff2jpg.c b/ff2jpg.c
index 3da35e2..6f88a23 100644
--- a/ff2jpg.c
+++ b/ff2jpg.c
_AT_@ -80,8 +80,7 @@ main(int argc, char *argv[])
 
         /* header */
         if (fread(hdr, sizeof(*hdr), 4, stdin) != 4) {
- fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
- return 1;
+ goto readerr;
         }
         if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
                 fprintf(stderr, "%s: invalid magic value\n", argv0);
_AT_@ -124,8 +123,7 @@ main(int argc, char *argv[])
         /* write rows */
         for (i = 0; i < height; ++i) {
                 if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
- fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
- return 1;
+ goto readerr;
                 }
                 for (j = 0, k = 0; j < rowlen; j += 4, k += 3) {
                         a = ntohs(row[j + 3]);
_AT_@ -142,4 +140,12 @@ main(int argc, char *argv[])
         jpeg_destroy_compress(&cinfo);
 
         return 0;
+readerr:
+ if (ferror(stdin)) {
+ fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
+ } else {
+ fprintf(stderr, "%s: unexpected end of file\n", argv0);
+ }
+
+ return 1;
 }
diff --git a/ff2png.c b/ff2png.c
index 4304bbb..5731082 100644
--- a/ff2png.c
+++ b/ff2png.c
_AT_@ -81,8 +81,11 @@ main(int argc, char *argv[])
 
         return 0;
 readerr:
- fprintf(stderr, "%s: fread: ", argv0);
- perror(NULL);
+ if (ferror(stdin)) {
+ fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
+ } else {
+ fprintf(stderr, "%s: unexpected end of file\n", argv0);
+ }
 
         return 1;
 }
diff --git a/ff2ppm.c b/ff2ppm.c
index 880fa5b..2a67eb2 100644
--- a/ff2ppm.c
+++ b/ff2ppm.c
_AT_@ -60,8 +60,7 @@ main(int argc, char *argv[])
 
         /* header */
         if (fread(hdr, sizeof(*hdr), 4, stdin) != 4) {
- fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
- return 1;
+ goto readerr;
         }
         if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
                 fprintf(stderr, "%s: invalid magic value\n", argv0);
_AT_@ -90,8 +89,7 @@ main(int argc, char *argv[])
         /* write rows */
         for (i = 0; i < height; ++i) {
                 if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
- fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
- return 1;
+ goto readerr;
                 }
                 for (j = 0, k = 0; j < rowlen; j += 4, k += 3) {
                         a = ntohs(row[j + 3]);
_AT_@ -108,4 +106,12 @@ main(int argc, char *argv[])
         }
 
         return 0;
+readerr:
+ if (ferror(stdin)) {
+ fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
+ } else {
+ fprintf(stderr, "%s: unexpected end of file\n", argv0);
+ }
+
+ return 1;
 }
Received on Thu May 19 2016 - 12:56:00 CEST