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/* error.c -- main error handling routines
*
* This code is Copyright (c) 2002, by the authors of nmh. See the
* COPYRIGHT file in the root directory of the nmh distribution for
* complete copyright information.
*/
#include "h/mh.h"
#include "error.h"
#include <sys/types.h>
#include <sys/uio.h>
#include "done.h"
#include "globals.h"
/* inform calls advertise() with no what and no tail.
* Thus the simple "[invo_name: ]fmt\n" results. */
void
inform(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
advertise(NULL, NULL, fmt, ap);
va_end(ap);
}
/* advise calls advertise() with no tail to print fmt, and perhaps what,
* to stderr.
* Thus "[invo_name: ]fmt[[ what]: errno]\n" results. */
void
advise (const char *what, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
advertise (what, NULL, fmt, ap);
va_end(ap);
}
/* adios is the same as advise(), but then "ends" the program.
* It calls advertise() with no tail to print fmt, and perhaps what, to
* stderr, and exits the program with an error status.
* Thus "[invo_name: ]fmt[[ what]: errno]\n" results.
*
* The route to exit is via the done function pointer and may not be
* straightforward, e.g. longjmp(3), but it must not return to adios().
* If it does then it's a bug and adios() will abort(3) as callers do
* not expect execution to continue. */
void NORETURN
adios (const char *what, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
advertise (what, NULL, fmt, ap);
va_end(ap);
done (1);
abort();
}
/* die is the same as adios(), but without the what as that's commonly
* NULL.
* Thus "[invo_name: ]fmt\n" results. */
void NORETURN
die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
advertise(NULL, NULL, fmt, ap);
va_end(ap);
done(1);
abort();
}
/* admonish calls advertise() with a tail indicating the program
* continues.
* Thus "[invo_name: ]fmt[[ what]: errno], continuing...\n" results. */
void
admonish (char *what, char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
advertise (what, "continuing...", fmt, ap);
va_end(ap);
}
/* advertise prints fmt and ap to stderr after flushing stdout.
* The print happens in a single syscall from a buffer.
* If invo_name isn't NULL or empty then "invo_name: " is buffered.
* Then fmt is buffered.
* If what isn't NULL or empty then " what" is buffered.
* If what isn't NULL and errno isn't 0 then ": errno" is buffered.
* If tail isn't NULL or empty then ", tail" is buffered.
* Then "\n" is buffered.
*
* Note, a what of "" doesn't print it or the preceding space, but does
* trigger the printing of a non-zero errno; such is the cunning design.
*
* In summary: "[invo_name: ]fmt[[ what]: errno][, tail]\n". */
void
advertise (const char *what, char *tail, const char *fmt, va_list ap)
{
int eindex = errno;
char buffer[NMH_BUFSIZ];
struct iovec iob[10], *iov;
size_t niov;
iov = iob;
#define APPEND_IOV(p, len) \
iov->iov_base = (p); \
iov->iov_len = (len); \
iov++
#define ADD_LITERAL(s) APPEND_IOV((s), LEN(s))
#define ADD_VAR(s) APPEND_IOV((s), strlen(s))
if (invo_name && *invo_name) {
ADD_VAR(invo_name);
ADD_LITERAL(": ");
}
vsnprintf (buffer, sizeof(buffer), fmt, ap);
ADD_VAR(buffer);
if (what) {
if (*what) {
ADD_LITERAL(" ");
ADD_VAR((void *)what);
}
if (eindex) {
ADD_LITERAL(": ");
char *err = strerror(eindex);
ADD_VAR(err);
}
}
if (tail && *tail) {
ADD_LITERAL(", ");
ADD_VAR(tail);
}
ADD_LITERAL("\n");
#undef ADD_LITERAL
#undef ADD_VAR
niov = iov - iob;
assert(niov <= DIM(iob));
fflush (stdout);
fflush (stderr);
if (writev(fileno(stderr), iob, niov) == -1) {
snprintf(buffer, sizeof buffer, "%s: write stderr failed: %d\n",
invo_name && *invo_name ? invo_name : "nmh", errno);
if (write(2, buffer, strlen(buffer)) == -1) {
/* Ignore. if-statement needed to shut up compiler. */
}
}
}
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