55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
/*
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* wchan.c - kernel symbol handling
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*
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* Copyright © 2015-2023 Jim Warner <james.warner@comcast.net>
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* Copyright © 1998-2003 Albert Cahalan
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "wchan.h" // to verify prototype
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const char *lookup_wchan (int pid) {
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static __thread char buf[64];
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const char *ret = buf;
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ssize_t num;
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int fd;
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snprintf(buf, sizeof buf, "/proc/%d/wchan", pid);
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fd = open(buf, O_RDONLY);
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if (fd==-1) return "?";
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num = read(fd, buf, sizeof buf - 1);
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close(fd);
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if (num<1) return "?"; // allow for "0"
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buf[num] = '\0';
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if (buf[0]=='0' && buf[1]=='\0') return "-";
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// lame ppc64 has a '.' in front of every name
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if (*ret=='.') ret++;
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while(*ret=='_') ret++;
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return ret;
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}
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