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Bug #18152 » 0001-Fix-theoretical-bug-with-signals-qsort-a.patch

Simple, easy-to-audit patch for theoretical qsort async-signal bug - eggert (Paul Eggert), 09/06/2021 11:59 PM

View differences:

process.c
return 0;
}
/*
* Sort an array of pairs via intcmp. Unlike qsort, this is async-signal-safe.
* Although this uses insertion sort and does not scale well,
* in practice n invariably is small so scaling is not a practical issue.
*/
static void
pairsort(struct run_exec_dup2_fd_pair *pairs, long n)
{
long i, j;
for (i = 1; i < n; i++) {
struct run_exec_dup2_fd_pair key = pairs[i];
for (j = i; j > 0 && intcmp(&key, &pairs[j - 1]) < 0; j--)
pairs[j] = pairs[j - 1];
pairs[j] = key;
}
}
/* This function should be async-signal-safe when sargp is NULL. Hopefully it is. */
static int
run_exec_dup2(VALUE ary, VALUE tmpbuf, struct rb_execarg *sargp, char *errmsg, size_t errmsg_buflen)
......
/* sort the table by oldfd: O(n log n) */
if (!sargp)
qsort(pairs, n, sizeof(struct run_exec_dup2_fd_pair), intcmp); /* hopefully async-signal-safe */
pairsort(pairs, n); /* async-signal-safe */
else
qsort(pairs, n, sizeof(struct run_exec_dup2_fd_pair), intrcmp);
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