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Do not ignore any possible errors that fseeko() may have. The fact

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is that fseeko() fails in very predictable and frequent ways on ia64.
This is because the offset is actually an address in the process'
address space, which on ia64 can be larger than long (for lseek) or
off_t (for fseeko). The crux is the signedness. The register stack
and memory stack are in region 4 on ia64. This means that the sign bit
is 1. The large positive virtual address is wrongly interpreted as
a negative file offset.

There's no quick fix. Even if you get around the API by using a
SEEK_SET up to LONG_MAX and follow it up with a SEEK_CUR for the
remainder, the kernel simply cannot deal with it. and the second
seek will just fail.

Therefore, this change does not actually fix the root cause. It just
makes sure we're not spitting out all kinds of garbage or that the
get_struct() function in particular does not cause truss(1) to exit.
This, I might add, invariably happened way too soon for truss(1) to
be of any use on ia64...
This commit is contained in:
Marcel Moolenaar 2003-11-13 09:04:24 +00:00
parent b70d5d25f2
commit 4e92419dcd
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=122606
1 changed files with 24 additions and 22 deletions
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46
usr.bin/truss/syscalls.c
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@ -171,12 +171,14 @@ get_struct(int procfd, void *offset, void *buf, int len) {
err(1, "dup");
if ((p = fdopen(fd, "r")) == NULL)
err(1, "fdopen");
fseeko(p, (uintptr_t)offset, SEEK_SET);
for (pos = (char *)buf; len--; pos++) {
if ((c = fgetc(p)) == EOF)
return -1;
*pos = c;
}
if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
for (pos = (char *)buf; len--; pos++) {
if ((c = fgetc(p)) == EOF)
return (-1);
*pos = c;
}
} else
bzero(buf, len);
fclose(p);
return 0;
}
@ -201,27 +203,27 @@ get_string(int procfd, void *offset, int max) {
buf = malloc( size = (max ? max : 64 ) );
len = 0;
buf[0] = 0;
fseeko(p, (uintptr_t)offset, SEEK_SET);
while ((c = fgetc(p)) != EOF) {
buf[len++] = c;
if (c == 0 || len == max) {
buf[len] = 0;
break;
}
if (len == size) {
char *tmp;
tmp = realloc(buf, size+64);
if (tmp == NULL) {
if (fseeko(p, (uintptr_t)offset, SEEK_SET) == 0) {
while ((c = fgetc(p)) != EOF) {
buf[len++] = c;
if (c == 0 || len == max) {
buf[len] = 0;
fclose(p);
return buf;
break;
}
if (len == size) {
char *tmp;
tmp = realloc(buf, size+64);
if (tmp == NULL) {
buf[len] = 0;
break;
}
size += 64;
buf = tmp;
}
size += 64;
buf = tmp;
}
}
fclose(p);
return buf;
return (buf);
}