Improve fread error handling in ff2* - farbfeld - suckless image format with conversion tools
(HTM) git clone git://git.suckless.org/farbfeld
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---
(DIR) commit 3fa775e1dfd5dc38648f88c2f385be1f0fe45605
(DIR) parent c494437937ee01c6d3eb5b630a15e207aae76c25
(HTM) Author: Alexander Krotov <ilabdsf@yandex.ru>
Date: Thu, 19 May 2016 01:21:58 +0300
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).
Diffstat:
M ff2jpg.c | 14 ++++++++++----
M ff2png.c | 7 +++++--
M ff2ppm.c | 14 ++++++++++----
3 files changed, 25 insertions(+), 10 deletions(-)
---
(DIR) diff --git a/ff2jpg.c b/ff2jpg.c
@@ -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);
@@ -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]);
@@ -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;
}
(DIR) diff --git a/ff2png.c b/ff2png.c
@@ -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;
}
(DIR) diff --git a/ff2ppm.c b/ff2ppm.c
@@ -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);
@@ -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]);
@@ -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;
}