68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
#include "cache.h"
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#include "trace2/tr2_sid.h"
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#define TR2_ENVVAR_PARENT_SID "GIT_TR2_PARENT_SID"
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static struct strbuf tr2sid_buf = STRBUF_INIT;
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static int tr2sid_nr_git_parents;
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/*
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* Compute a "unique" session id (SID) for the current process. This allows
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* all events from this process to have a single label (much like a PID).
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*
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* Export this into our environment so that all child processes inherit it.
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*
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* If we were started by another git instance, use our parent's SID as a
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* prefix. (This lets us track parent/child relationships even if there
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* is an intermediate shell process.)
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*
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* Additionally, count the number of nested git processes.
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*/
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static void tr2_sid_compute(void)
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{
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uint64_t us_now;
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const char *parent_sid;
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if (tr2sid_buf.len)
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return;
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parent_sid = getenv(TR2_ENVVAR_PARENT_SID);
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if (parent_sid && *parent_sid) {
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const char *p;
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for (p = parent_sid; *p; p++)
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if (*p == '/')
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tr2sid_nr_git_parents++;
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strbuf_addstr(&tr2sid_buf, parent_sid);
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strbuf_addch(&tr2sid_buf, '/');
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tr2sid_nr_git_parents++;
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}
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us_now = getnanotime() / 1000;
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strbuf_addf(&tr2sid_buf, "%" PRIuMAX "-%" PRIdMAX, (uintmax_t)us_now,
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(intmax_t)getpid());
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setenv(TR2_ENVVAR_PARENT_SID, tr2sid_buf.buf, 1);
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}
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const char *tr2_sid_get(void)
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{
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if (!tr2sid_buf.len)
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tr2_sid_compute();
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return tr2sid_buf.buf;
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}
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int tr2_sid_depth(void)
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{
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if (!tr2sid_buf.len)
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tr2_sid_compute();
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return tr2sid_nr_git_parents;
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}
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void tr2_sid_release(void)
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{
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strbuf_release(&tr2sid_buf);
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}
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