commit fad48ffa27af96ee0d9489ded88f80c1eeb238dc
parent 813a96b517ae96716fb018ff93ab2d6a4bbcda95
Author: Hiltjo Posthuma <hiltjo@codemadness.org>
Date: Mon, 14 Mar 2022 19:22:42 +0100
stricter error checking in file streams (input, output)
This also makes the programs exit with a non-zero status when a read or write
error occurs.
This makes checking the exit status more reliable in scripts.
A simple example to simulate a disk with no space left:
curl -s 'https://codemadness.org/atom.xml' | sfeed > f
/mnt/test: write failed, file system is full
echo $?
0
Which now produces:
curl -s 'https://codemadness.org/atom.xml' | sfeed > f
/mnt/test: write failed, file system is full
write error: <stdout>
echo $?
1
Tested with a small mfs on OpenBSD, fstab entry:
swap /mnt/test mfs rw,nodev,nosuid,-s=1M 0 0
Diffstat:
13 files changed, 73 insertions(+), 24 deletions(-)
diff --git a/sfeed.c b/sfeed.c
@@ -679,6 +679,9 @@ printfields(void)
putchar(FieldSeparator);
string_print_trimmed_multi(&ctx.fields[FeedFieldCategory].str);
putchar('\n');
+
+ if (ferror(stdout)) /* check for errors but do not flush */
+ checkfileerror(stdout, "<stdout>", 'w');
}
static int
@@ -1059,5 +1062,8 @@ main(int argc, char *argv[])
/* NOTE: getnext is defined in xml.h for inline optimization */
xml_parse(&parser);
+ checkfileerror(stdin, "<stdin>", 'r');
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_atom.c b/sfeed_atom.c
@@ -43,7 +43,8 @@ printfeed(FILE *fp, const char *feedname)
ssize_t linelen;
int c;
- while ((linelen = getline(&line, &linesize, fp)) > 0) {
+ while ((linelen = getline(&line, &linesize, fp)) > 0 &&
+ !ferror(stdout)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -141,19 +142,21 @@ main(int argc, char *argv[])
if (argc == 1) {
printfeed(stdin, "");
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
printfeed(fp, name);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
fclose(fp);
}
}
fputs("</feed>\n", stdout);
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_frames.c b/sfeed_frames.c
@@ -34,7 +34,8 @@ printfeed(FILE *fpitems, FILE *fpin, struct feed *f)
}
fputs("<pre>\n", fpitems);
- while ((linelen = getline(&line, &linesize, fpin)) > 0) {
+ while ((linelen = getline(&line, &linesize, fpin)) > 0 &&
+ !ferror(fpitems)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -114,6 +115,7 @@ main(int argc, char *argv[])
if (argc == 1) {
feeds[0].name = "";
printfeed(fpitems, stdin, &feeds[0]);
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
@@ -122,8 +124,8 @@ main(int argc, char *argv[])
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
printfeed(fpitems, fp, &feeds[i - 1]);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
+ checkfileerror(fpitems, "items.html", 'w');
fclose(fp);
}
}
@@ -174,10 +176,15 @@ main(int argc, char *argv[])
"</frameset>\n"
"</html>\n", fpindex);
+ checkfileerror(fpindex, "index.html", 'w');
+ checkfileerror(fpitems, "items.html", 'w');
+
fclose(fpindex);
fclose(fpitems);
- if (fpmenu)
+ if (fpmenu) {
+ checkfileerror(fpmenu, "menu.html", 'w');
fclose(fpmenu);
+ }
return 0;
}
diff --git a/sfeed_gopher.c b/sfeed_gopher.c
@@ -50,7 +50,8 @@ printfeed(FILE *fpitems, FILE *fpin, struct feed *f)
fprintf(fpitems, "i\t\t%s\t%s\r\n", host, port);
}
- while ((linelen = getline(&line, &linesize, fpin)) > 0) {
+ while ((linelen = getline(&line, &linesize, fpin)) > 0 &&
+ !ferror(fpitems)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -150,6 +151,8 @@ main(int argc, char *argv[])
if (argc == 1) {
f.name = "";
printfeed(stdout, stdin, &f);
+ checkfileerror(stdin, "<stdin>", 'r');
+ checkfileerror(stdout, "<stdout>", 'w');
} else {
if ((p = getenv("SFEED_GOPHER_PATH")))
prefixpath = p;
@@ -172,8 +175,8 @@ main(int argc, char *argv[])
if (!(fpitems = fopen(path, "wb")))
err(1, "fopen");
printfeed(fpitems, fp, &f);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
+ checkfileerror(fpitems, path, 'w');
fclose(fp);
fclose(fpitems);
@@ -186,6 +189,7 @@ main(int argc, char *argv[])
fprintf(fpindex, "\t%s\t%s\r\n", host, port);
}
fputs(".\r\n", fpindex);
+ checkfileerror(fpindex, "index", 'w');
fclose(fpindex);
}
diff --git a/sfeed_html.c b/sfeed_html.c
@@ -34,7 +34,8 @@ printfeed(FILE *fp, struct feed *f)
}
fputs("<pre>\n", stdout);
- while ((linelen = getline(&line, &linesize, fp)) > 0) {
+ while ((linelen = getline(&line, &linesize, fp)) > 0 &&
+ !ferror(stdout)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -109,8 +110,7 @@ main(int argc, char *argv[])
if (argc == 1) {
feeds[0].name = "";
printfeed(stdin, &feeds[0]);
- if (ferror(stdin))
- err(1, "ferror: <stdin>:");
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
@@ -118,8 +118,7 @@ main(int argc, char *argv[])
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
printfeed(fp, &feeds[i - 1]);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
fclose(fp);
}
}
@@ -150,5 +149,7 @@ main(int argc, char *argv[])
fprintf(stdout, "\t</body>\n\t<title>(%lu/%lu) - Newsfeed</title>\n</html>\n",
totalnew, total);
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_mbox.c b/sfeed_mbox.c
@@ -63,7 +63,8 @@ printfeed(FILE *fp, const char *feedname)
ssize_t linelen;
int ishtml;
- while ((linelen = getline(&line, &linesize, fp)) > 0) {
+ while ((linelen = getline(&line, &linesize, fp)) > 0 &&
+ !ferror(stdout)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
hash = djb2((unsigned char *)line, 5381ULL);
@@ -163,17 +164,19 @@ main(int argc, char *argv[])
if (argc == 1) {
printfeed(stdin, "");
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
printfeed(fp, name);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
fclose(fp);
}
}
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_opml_import.c b/sfeed_opml_import.c
@@ -101,5 +101,8 @@ main(void)
xml_parse(&parser);
fputs("}\n", stdout);
+ checkfileerror(stdin, "<stdin>", 'r');
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_plain.c b/sfeed_plain.c
@@ -19,7 +19,8 @@ printfeed(FILE *fp, const char *feedname)
time_t parsedtime;
ssize_t linelen;
- while ((linelen = getline(&line, &linesize, fp)) > 0) {
+ while ((linelen = getline(&line, &linesize, fp)) > 0 &&
+ !ferror(stdout)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -69,17 +70,18 @@ main(int argc, char *argv[])
if (argc == 1) {
printfeed(stdin, "");
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
printfeed(fp, name);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
fclose(fp);
}
}
+ checkfileerror(stdout, "<stdout>", 'w');
return 0;
}
diff --git a/sfeed_twtxt.c b/sfeed_twtxt.c
@@ -17,7 +17,8 @@ printfeed(FILE *fp, const char *feedname)
time_t parsedtime;
ssize_t linelen;
- while ((linelen = getline(&line, &linesize, fp)) > 0) {
+ while ((linelen = getline(&line, &linesize, fp)) > 0 &&
+ !ferror(stdout)) {
if (line[linelen - 1] == '\n')
line[--linelen] = '\0';
parseline(line, fields);
@@ -54,17 +55,19 @@ main(int argc, char *argv[])
if (argc == 1) {
printfeed(stdin, "");
+ checkfileerror(stdin, "<stdin>", 'r');
} else {
for (i = 1; i < argc; i++) {
if (!(fp = fopen(argv[i], "r")))
err(1, "fopen: %s", argv[i]);
name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
printfeed(fp, name);
- if (ferror(fp))
- err(1, "ferror: %s", argv[i]);
+ checkfileerror(fp, argv[i], 'r');
fclose(fp);
}
}
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_web.c b/sfeed_web.c
@@ -136,5 +136,8 @@ main(int argc, char *argv[])
/* NOTE: getnext is defined in xml.h for inline optimization */
xml_parse(&parser);
+ checkfileerror(stdin, "<stdin>", 'r');
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/sfeed_xmlenc.c b/sfeed_xmlenc.c
@@ -56,5 +56,8 @@ main(void)
/* NOTE: getnext is defined in xml.h for inline optimization */
xml_parse(&parser);
+ checkfileerror(stdin, "<stdin>", 'r');
+ checkfileerror(stdout, "<stdout>", 'w');
+
return 0;
}
diff --git a/util.c b/util.c
@@ -46,6 +46,16 @@ errx(int exitstatus, const char *fmt, ...)
exit(exitstatus);
}
+/* Handle read or write errors for a FILE * stream */
+void
+checkfileerror(FILE *fp, const char *name, int mode)
+{
+ if (mode == 'r' && ferror(fp))
+ errx(1, "read error: %s", name);
+ else if (mode == 'w' && (fflush(fp) || ferror(fp)))
+ errx(1, "write error: %s", name);
+}
+
/* strcasestr() included for portability */
char *
strcasestr(const char *h, const char *n)
diff --git a/util.h b/util.h
@@ -64,6 +64,7 @@ int uri_hasscheme(const char *);
int uri_makeabs(struct uri *, struct uri *, struct uri *);
int uri_parse(const char *, struct uri *);
+void checkfileerror(FILE *, const char *, int);
void parseline(char *, char *[FieldLast]);
void printutf8pad(FILE *, const char *, size_t, int);
int strtotime(const char *, time_t *);
