61 lines
1.8 KiB
Diff
61 lines
1.8 KiB
Diff
From bb96fc42956c9ed926a1b958ab715f8b4a663dec Mon Sep 17 00:00:00 2001
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From: Craig Small <csmall@dropbear.xyz>
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Date: Sun, 5 Jan 2020 15:05:55 +1100
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Subject: [PATCH] pgrep: check sanity of SC_ARG_MAX
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A kernel change means we cannot trust what sysconf(SC_ARG_MAX)
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returns. We clamp it so its more than 4096 and less than 128*1024
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which is what findutils does.
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References:
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procps-ng/procps#152
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https://git.savannah.gnu.org/cgit/findutils.git/tree/lib/buildcmd.c#n535
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https://lwn.net/Articles/727862/
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---
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pgrep.c | 22 +++++++++++++++++++++-
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1 file changed, 21 insertions(+), 1 deletion(-)
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diff --git a/pgrep.c b/pgrep.c
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index 01563db..bde7448 100644
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--- a/pgrep.c
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+++ b/pgrep.c
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@@ -485,6 +485,26 @@ static regex_t * do_regcomp (void)
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return preg;
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}
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+/*
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+ * SC_ARG_MAX used to return the maximum size a command line can be
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+ * however changes to the kernel mean this can be bigger than we can
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+ * alloc. Clamp it to 128kB like xargs and friends do
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+ * Should also not be smaller than POSIX_ARG_MAX which is 4096
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+ */
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+static size_t get_arg_max(void)
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+{
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+#define MIN_ARG_SIZE 4096u
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+#define MAX_ARG_SIZE (128u * 1024u)
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+
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+ size_t val = sysconf(_SC_ARG_MAX);
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+
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+ if (val < MIN_ARG_SIZE)
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+ val = MIN_ARG_SIZE;
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+ if (val > MAX_ARG_SIZE)
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+ val = MAX_ARG_SIZE;
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+
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+ return val;
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+}
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static struct el * select_procs (int *num)
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{
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PROCTAB *ptp;
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@@ -497,7 +517,7 @@ static struct el * select_procs (int *num)
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regex_t *preg;
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pid_t myself = getpid();
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struct el *list = NULL;
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- long cmdlen = sysconf(_SC_ARG_MAX) * sizeof(char);
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+ long cmdlen = get_arg_max() * sizeof(char);
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char *cmdline = xmalloc(cmdlen);
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char *cmdsearch = xmalloc(cmdlen);
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char *cmdoutput = xmalloc(cmdlen);
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--
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2.22.0.windows.1
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