From e370d4056b0071584b41ff4eba164245161a9ddd Mon Sep 17 00:00:00 2001 From: Martin Kletzander Date: Thu, 18 Nov 2021 16:13:52 +0100 Subject: [PATCH] util: Add virProcessGetStat MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reads and separates all fields from /proc//stat or /proc//task//stat as there are easy mistakes to be done in the implementation. Some tests are added to show it works correctly. No number parsing is done as it would be unused for most of the fields most, if not all, of the time. No struct is used for the result as the length can vary (new fields can be added in the future). Signed-off-by: Martin Kletzander Reviewed-by: Ján Tomko --- src/libvirt_private.syms | 1 + src/util/virprocess.c | 77 +++++++++++++++++++++++ src/util/virprocess.h | 66 ++++++++++++++++++++ tests/meson.build | 1 + tests/virprocessstatdata/complex/stat | 2 + tests/virprocessstatdata/simple/stat | 1 + tests/virprocessstattest.c | 88 +++++++++++++++++++++++++++ 7 files changed, 236 insertions(+) create mode 100644 tests/virprocessstatdata/complex/stat create mode 100644 tests/virprocessstatdata/simple/stat create mode 100644 tests/virprocessstattest.c diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index c11be4eafa..95bf1db39d 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -3100,6 +3100,7 @@ virProcessGetMaxMemLock; virProcessGetNamespaces; virProcessGetPids; virProcessGetStartTime; +virProcessGetStat; virProcessGroupGet; virProcessGroupKill; virProcessKill; diff --git a/src/util/virprocess.c b/src/util/virprocess.c index 81de90200e..1d5ef048b2 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -1721,3 +1721,80 @@ virProcessSetScheduler(pid_t pid G_GNUC_UNUSED, } #endif /* !WITH_SCHED_SETSCHEDULER */ + +/* + * Get all stat fields for a process based on pid and tid: + * - pid == 0 && tid == 0 => /proc/self/stat + * - pid != 0 && tid == 0 => /proc//stat + * - pid == 0 && tid != 0 => /proc/self/task//stat + * - pid != 0 && tid != 0 => /proc//task//stat + * and return them as array of strings. + */ +GStrv +virProcessGetStat(pid_t pid, + pid_t tid) +{ + int len = 10 * 1024; /* 10kB ought to be enough for everyone */ + g_autofree char *buf = NULL; + g_autofree char *path = NULL; + GStrv rest = NULL; + GStrv ret = NULL; + char *comm = NULL; + char *rparen = NULL; + size_t nrest = 0; + + if (pid) { + if (tid) + path = g_strdup_printf("/proc/%d/task/%d/stat", (int)pid, (int)tid); + else + path = g_strdup_printf("/proc/%d/stat", (int)pid); + } else { + if (tid) + path = g_strdup_printf("/proc/self/task/%d/stat", (int)tid); + else + path = g_strdup("/proc/self/stat"); + } + + len = virFileReadAllQuiet(path, len, &buf); + if (len < 0) + return NULL; + + /* eliminate trailing spaces */ + while (len > 0 && g_ascii_isspace(buf[--len])) + buf[len] = '\0'; + + /* Find end of the first field */ + if (!(comm = strchr(buf, ' '))) + return NULL; + *comm = '\0'; + + /* Check start of the second field (filename of the executable, in + * parentheses) */ + comm++; + if (*comm != '(') + return NULL; + comm++; + + /* Check end of the second field (last closing parenthesis) */ + rparen = strrchr(comm, ')'); + if (!rparen) + return NULL; + *rparen = '\0'; + + /* We need to check that the next char is not '\0', but why not just opt in + * for the safer way of checking whether it is ' ' (space) instead */ + if (rparen[1] != ' ') + return NULL; + + rest = g_strsplit(rparen + 2, " ", 0); + nrest = g_strv_length(rest); + ret = g_new0(char *, nrest + 3); + ret[0] = g_strdup(buf); + ret[1] = g_strdup(comm); + memcpy(ret + 2, rest, nrest * sizeof(char *)); + + /* Do not use g_strfreev() as individual elements they were moved to @ret. */ + VIR_FREE(rest); + + return ret; +} diff --git a/src/util/virprocess.h b/src/util/virprocess.h index 9910331a0c..82b7403964 100644 --- a/src/util/virprocess.h +++ b/src/util/virprocess.h @@ -117,6 +117,72 @@ int virProcessSetupPrivateMountNS(void); int virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, int priority); + +GStrv virProcessGetStat(pid_t pid, pid_t tid); + +/* These constants are modelled after proc(5) */ +enum { + VIR_PROCESS_STAT_PID, + VIR_PROCESS_STAT_COMM, + VIR_PROCESS_STAT_STATE, + VIR_PROCESS_STAT_PPID, + VIR_PROCESS_STAT_PGRP, + VIR_PROCESS_STAT_SESSION, + VIR_PROCESS_STAT_TTY_NR, + VIR_PROCESS_STAT_TPGID, + VIR_PROCESS_STAT_FLAGS, + VIR_PROCESS_STAT_MINFLT, + VIR_PROCESS_STAT_CMINFLT, + VIR_PROCESS_STAT_MAJFLT, + VIR_PROCESS_STAT_CMAJFLT, + VIR_PROCESS_STAT_UTIME, + VIR_PROCESS_STAT_STIME, + VIR_PROCESS_STAT_CUTIME, + VIR_PROCESS_STAT_CSTIME, + VIR_PROCESS_STAT_PRIORITY, + VIR_PROCESS_STAT_NICE, + VIR_PROCESS_STAT_NUM_THREADS, + VIR_PROCESS_STAT_ITREALVALUE, + VIR_PROCESS_STAT_STARTTIME, + VIR_PROCESS_STAT_VSIZE, + VIR_PROCESS_STAT_RSS, + VIR_PROCESS_STAT_RSSLIM, + VIR_PROCESS_STAT_STARTCODE, + VIR_PROCESS_STAT_ENDCODE, + VIR_PROCESS_STAT_STARTSTACK, + VIR_PROCESS_STAT_KSTKESP, + VIR_PROCESS_STAT_KSTKEIP, + VIR_PROCESS_STAT_SIGNAL, + VIR_PROCESS_STAT_BLOCKED, + VIR_PROCESS_STAT_SIGIGNORE, + VIR_PROCESS_STAT_SIGCATCH, + VIR_PROCESS_STAT_WCHAN, + VIR_PROCESS_STAT_NSWAP, + VIR_PROCESS_STAT_CNSWAP, + VIR_PROCESS_STAT_EXIT_SIGNAL, + VIR_PROCESS_STAT_PROCESSOR, + VIR_PROCESS_STAT_RT_PRIORITY, + VIR_PROCESS_STAT_POLICY, + VIR_PROCESS_STAT_DELAYACCT_BLKIO_TICKS, + VIR_PROCESS_STAT_GUEST_TIME, + VIR_PROCESS_STAT_CGUEST_TIME, + VIR_PROCESS_STAT_START_DATA, + VIR_PROCESS_STAT_END_DATA, + VIR_PROCESS_STAT_START_BRK, + VIR_PROCESS_STAT_ARG_START, + VIR_PROCESS_STAT_ARG_END, + VIR_PROCESS_STAT_ENV_START, + VIR_PROCESS_STAT_ENV_END, + VIR_PROCESS_STAT_EXIT_CODE, +}; + +/* + * At the time of writing there are 52 values reported in /proc/.../stat, the + * line below checks that the last one has the right value, increase accordingly + * based on proc(5) whenever adding new fields. +*/ +G_STATIC_ASSERT(VIR_PROCESS_STAT_EXIT_CODE == 51); + typedef enum { VIR_PROCESS_NAMESPACE_MNT = (1 << 1), VIR_PROCESS_NAMESPACE_IPC = (1 << 2), diff --git a/tests/meson.build b/tests/meson.build index 1948c07ae3..f75c248720 100644 --- a/tests/meson.build +++ b/tests/meson.build @@ -347,6 +347,7 @@ if host_machine.system() == 'linux' { 'name': 'scsihosttest' }, { 'name': 'vircaps2xmltest', 'link_whole': [ test_file_wrapper_lib ] }, { 'name': 'virnetdevbandwidthtest' }, + { 'name': 'virprocessstattest', 'link_whole': [ test_file_wrapper_lib ] }, { 'name': 'virresctrltest', 'link_whole': [ test_file_wrapper_lib ] }, { 'name': 'virscsitest' }, { 'name': 'virusbtest' }, diff --git a/tests/virprocessstatdata/complex/stat b/tests/virprocessstatdata/complex/stat new file mode 100644 index 0000000000..df0ecc149c --- /dev/null +++ b/tests/virprocessstatdata/complex/stat @@ -0,0 +1,2 @@ +1 (this) is ( a weird ) +)( (command ( ) 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 diff --git a/tests/virprocessstatdata/simple/stat b/tests/virprocessstatdata/simple/stat new file mode 100644 index 0000000000..97d6873537 --- /dev/null +++ b/tests/virprocessstatdata/simple/stat @@ -0,0 +1 @@ +1 (command) 3 4 5 diff --git a/tests/virprocessstattest.c b/tests/virprocessstattest.c new file mode 100644 index 0000000000..8fb82c48ef --- /dev/null +++ b/tests/virprocessstattest.c @@ -0,0 +1,88 @@ +#include + +#include "testutils.h" +#include "virfilewrapper.h" +#include "virprocess.h" + + +struct testData { + const char *filename; + const char *command; + size_t count; + bool self; +}; + + +static int +test_virProcessGetStat(const void *opaque) +{ + struct testData *data = (struct testData *) opaque; + g_autofree char *data_dir = NULL; + g_auto(GStrv) proc_stat = NULL; + size_t len = 0; + id_t id = data->self ? 0 : -1; + const char *command = NULL; + + data_dir = g_strdup_printf("%s/virprocessstatdata/%s/", + abs_srcdir, data->filename); + + /* We are using predictable id of -1 because this case we will clearly see + * that the test failed in case of virFileWrapper failure */ + if (id) + virFileWrapperAddPrefix("/proc/-1/task/-1/", data_dir); + else + virFileWrapperAddPrefix("/proc/self/", data_dir); + + proc_stat = virProcessGetStat(id, id); + + virFileWrapperClearPrefixes(); + + if (!proc_stat) { + fprintf(stderr, "Could not get process stats\n"); + return -1; + } + + len = g_strv_length(proc_stat); + if (data->count != len) { + fprintf(stderr, "Count incorrect, expected %zu, got %zu\n", + data->count, len); + return -1; + } + + command = proc_stat[VIR_PROCESS_STAT_COMM]; + if (!STREQ_NULLABLE(data->command, command)) { + fprintf(stderr, "Command incorrect, expected %s, got %s\n", + data->command, command); + return -1; + } + + return 0; +} + + +static int +mymain(void) +{ + struct testData data = {0}; + int ret = 0; + +#define DO_TEST(_filename, _command, _count, _self) \ + do { \ + data = (struct testData){ \ + .filename = _filename, \ + .command = _command, \ + .count = _count, \ + .self = _self, \ + }; \ + if (virTestRun("Reading process stat: " _filename, \ + test_virProcessGetStat, &data) < 0) \ + ret = -1; \ + } while (0) + + DO_TEST("simple", "command", 5, true); + DO_TEST("complex", "this) is ( a \t weird )\n)( (command ( ", 100, false); + + return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE; +} + +VIR_TEST_MAIN(mymain)