Date: Mon, 21 Jan 2013 22:30:01 GMT From: "Mikhail T." <mi+thun@aldan.algebra.com> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/175491: elf_getdata may return NULL without setting error-message Message-ID: <201301212230.r0LMU1ce089488@freefall.freebsd.org>
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The following reply was made to PR bin/175491; it has been noted by GNATS.
From: "Mikhail T." <mi+thun@aldan.algebra.com>
To: bug-followup@FreeBSD.org, mi@aldan.algebra.com
Cc:
Subject: Re: bin/175491: elf_getdata may return NULL without setting error-message
Date: Mon, 21 Jan 2013 17:23:27 -0500
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The test-program...
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name="libelftest.c"
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filename="libelftest.c"
#include <err.h>
#include <fcntl.h>
#include <libelf.h>
#include <stdio.h>
#include <sysexits.h>
#include <unistd.h>
int
main(int argc, char *argv[])
{
int fd;
Elf *elf;
Elf_Scn *scn;
Elf_Data *data;
unsigned int elfversion;
elfversion = elf_version(EV_CURRENT);
printf("elfversion returned %u\n", elfversion);
fd = open(argv[argc-1], O_RDONLY);
if (fd == -1)
err(EX_NOINPUT, "%s", argv[argc-1]);
elf = elf_begin(fd, ELF_C_READ, NULL);
if (elf == NULL)
errx(EX_DATAERR, "%s: %s: %s", argv[argc-1], "elf_begin",
elf_errmsg(elf_errno()));
/*
* Section 0:
*/
scn = elf_getscn(elf, 0);
if (scn == NULL)
errx(EX_DATAERR, "%s: %s: %s", argv[argc-1], "elf_getscn",
elf_errmsg(elf_errno()));
data = elf_getdata(scn, NULL);
if (data == NULL)
warnx("%s: %s: %s", argv[argc-1], "elf_getscn",
elf_errmsg(elf_errno()));
/*
* Enumerate through valid sections
*/
for (scn = elf_nextscn(elf, NULL); scn; scn = elf_nextscn(elf, scn)) {
data = elf_getdata(scn, NULL);
if (data == NULL) {
int errnum;
const char *msg;
errnum = elf_errno();
msg = errnum ? elf_errmsg(errnum) : "errnum was zero";
if (errnum && msg)
printf("Section %zd has no data: %s\n",
elf_ndxscn(scn), msg);
else
warnx("Section %zd: elf_getdata() return NULL "
"without explanation", elf_ndxscn(scn));
} else {
printf("Section %zd has data %p\n",
elf_ndxscn(scn), data);
}
}
return EX_OK;
}
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