forked from soccera/rdo
b2caacbf68
Before we made the ensuredir() function recurse on itself if we couldn't open /run/rdo, after mkdir()'ing it, to retry opening the directory. Now we simplify and add a simple fd = open([...]) directly after the mkdir(), to avoid the recursion. If the second open fails, we error out.
147 lines
2.7 KiB
C
147 lines
2.7 KiB
C
#pragma once
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#include <limits.h>
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <time.h>
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int getpstartts(int pid, unsigned long long* startts) {
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char path[255], fc[1024];
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char* ptr = fc;
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snprintf(path, sizeof(path), "/proc/%d/stat", pid);
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int fd = open(path, O_RDONLY);
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if (fd < 0)
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err(1, "Could not open %s", path);
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int bytes_read = read(fd, fc, sizeof(fc));
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close(fd);
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if (bytes_read < 0)
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err(1, "Could not read %s", path);
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fc[bytes_read] = '\0';
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if (memchr(ptr, '\0', bytes_read) != NULL)
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return -1;
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ptr = strrchr(fc, ')');
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char* token = strtok(ptr, " ");
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for (int i = 0; i<20 && token; i++)
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token = strtok(NULL, " ");
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if (!token)
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return -1;
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unsigned long long temp_ts = strtoull(token, NULL, 10);
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if (temp_ts == 0 || temp_ts == ULLONG_MAX)
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return -1;
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*startts = temp_ts;
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return 0;
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}
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int ensuredir() {
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struct stat st;
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int fd = open("/run/rdo", O_RDONLY, O_DIRECTORY | O_NOFOLLOW);
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if (fd < 0) {
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if (errno == ENOENT) {
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if (mkdir("/run/rdo", 0700) < 0)
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err(1, "Could not create /run/rdo");
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fd = open("/run/rdo", O_RDONLY, O_DIRECTORY | O_NOFOLLOW);
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if (fd < 0)
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err(1, "Could not open /run/rdo");
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}
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else
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err(1, "Could not open /run/rdo");
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}
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if (fstat(fd, &st) < 0) {
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close(fd);
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err(1, "Could not fstat /run/rdo");
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}
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close(fd);
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if (st.st_uid != 0 || st.st_mode != (0700 | S_IFDIR))
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return -1;
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return 0;
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}
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void setsession(int pid, unsigned int ts_ttl) {
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if (ts_ttl == 0)
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return;
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unsigned long long startts;
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char path[1024], ts_str[32];
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if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
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return;
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snprintf(path, sizeof(path), "/run/rdo/%d-%llu", pid, startts);
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int fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0700);
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if (fd < 0) {
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if (errno == EEXIST)
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return;
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err(1, "Could not open %s", path);
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}
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snprintf(ts_str, sizeof(ts_str), "%llu", (unsigned long long)time(NULL));
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if (write(fd, ts_str, strlen(ts_str)) < 0) {
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close(fd);
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err(1, "Could not write to %s", path);
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}
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close(fd);
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return;
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}
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int getsession(int pid, unsigned int ts_ttl) {
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if (ts_ttl == 0)
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return -1;
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unsigned long long startts, current;
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char path[1024], ts_str[32];
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if (ensuredir() < 0 || getpstartts(pid, &startts) < 0)
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return -1;
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snprintf(path, sizeof(path), "/run/rdo/%d-%llu", pid, startts);
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int fd = open(path, O_RDONLY);
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if (fd < 0) {
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if (errno == ENOENT)
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return -1;
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err(1, "Could not open %s", path);
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}
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int bytes_read = read(fd, ts_str, sizeof(ts_str));
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close(fd);
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if (bytes_read < 0)
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err(1, "Could not read %s", path);
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ts_str[bytes_read] = '\0';
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startts = strtoull(ts_str, NULL, 10);
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current = time(NULL);
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if (current - startts > ts_ttl) {
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unlink(path);
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return -1;
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}
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return 0;
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}
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