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Fix minor fallout from sysctl strings being nulterminated now. The dmesg

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code can read the buffer via sysctl or from a core file.  In the core file
case there will be no nulterm, and the code copes with that, but now in the
sysctl case there is a nulterm (there didn't used to be).  The least
disruptive way to restore the old behavior (and eliminate a spurious '\000'
at the end of the output) is to remove the nulterm (by decrementing the
buffer length) in the sysctl case.
This commit is contained in:
Ian Lepore 2015-03-16 21:09:11 +00:00
parent 0232255f90
commit 93c3ad10f1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=280156
1 changed files with 6 additions and 2 deletions
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8
sbin/dmesg/dmesg.c
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@ -111,8 +111,10 @@ main(int argc, char *argv[])
if (memf == NULL) {
/*
* Running kernel. Use sysctl. This gives an unwrapped
* buffer as a side effect.
* Running kernel. Use sysctl. This gives an unwrapped buffer
* as a side effect. Remove nulterm (if present) so the value
* returned by sysctl is formatted as the rest of the code
* expects (the same as the value read from a core file below).
*/
if (sysctlbyname("kern.msgbuf", NULL, &buflen, NULL, 0) == -1)
err(1, "sysctl kern.msgbuf");
@ -120,6 +122,8 @@ main(int argc, char *argv[])
errx(1, "malloc failed");
if (sysctlbyname("kern.msgbuf", bp, &buflen, NULL, 0) == -1)
err(1, "sysctl kern.msgbuf");
if (buflen > 0 && bp[buflen - 1] == '\0')
buflen--;
if (clear)
if (sysctlbyname("kern.msgbuf_clear", NULL, NULL, &clear, sizeof(int)))
err(1, "sysctl kern.msgbuf_clear");