1 files changed, 564 insertions, 0 deletions
diff --git a/lib/procfs.c b/lib/procfs.c
new file mode 100644
index 0000000..4d6d25b
--- /dev/null
+++ b/lib/procfs.c
@@ -0,0 +1,564 @@
+/*
+ * No copyright is claimed.  This code is in the public domain; do with
+ * it what you wish.
+ *
+ * Written by Karel Zak <kzak@redhat.com>
+ */
+#include <ctype.h>
+#include <unistd.h>
+#include <sys/vfs.h>
+#include <errno.h>
+
+#include "c.h"
+#include "pathnames.h"
+#include "procfs.h"
+#include "fileutils.h"
+#include "all-io.h"
+#include "debug.h"
+#include "strutils.h"
+#include "statfs_magic.h"
+
+static void procfs_process_deinit_path(struct path_cxt *pc);
+
+/*
+ * Debug stuff (based on include/debug.h)
+ */
+static UL_DEBUG_DEFINE_MASK(ulprocfs);
+UL_DEBUG_DEFINE_MASKNAMES(ulprocfs) = UL_DEBUG_EMPTY_MASKNAMES;
+
+#define ULPROCFS_DEBUG_INIT	(1 << 1)
+#define ULPROCFS_DEBUG_CXT	(1 << 2)
+
+#define DBG(m, x)       __UL_DBG(ulprocfs, ULPROCFS_DEBUG_, m, x)
+#define ON_DBG(m, x)    __UL_DBG_CALL(ulprocfs, ULPROCFS_DEBUG_, m, x)
+
+#define UL_DEBUG_CURRENT_MASK	UL_DEBUG_MASK(ulprocfs)
+#include "debugobj.h"
+
+void ul_procfs_init_debug(void)
+{
+	if (ulprocfs_debug_mask)
+		return;
+	__UL_INIT_DEBUG_FROM_ENV(ulprocfs, ULPROCFS_DEBUG_, 0, ULPROCFS_DEBUG);
+}
+
+struct path_cxt *ul_new_procfs_path(pid_t pid, const char *prefix)
+{
+	struct path_cxt *pc = ul_new_path(NULL);
+
+	if (!pc)
+		return NULL;
+	if (prefix)
+		ul_path_set_prefix(pc, prefix);
+
+	if (procfs_process_init_path(pc, pid) != 0) {
+		ul_unref_path(pc);
+		return NULL;
+	}
+
+	DBG(CXT, ul_debugobj(pc, "alloc"));
+	return pc;
+}
+
+/*
+ * procfs_blkdev_* is procfs extension to ul_path_* API to read info about process.
+ *
+ * The function is possible to call in loop and without sysfs_procfs_deinit_path().
+ * The procfs_process_deinit_path() is automatically called by ul_unref_path().
+ *
+ */
+int procfs_process_init_path(struct path_cxt *pc, pid_t pid)
+{
+	struct procfs_process *prc;
+	int rc;
+	char buf[sizeof(_PATH_PROC) + sizeof(stringify_value(UINT32_MAX)) + 2];
+
+	/* define path to pid stuff */
+	snprintf(buf, sizeof(buf), _PATH_PROC "/%zu", (size_t) pid);
+	rc = ul_path_set_dir(pc, buf);
+	if (rc)
+		return rc;
+
+	/* make sure path exists */
+	rc = ul_path_get_dirfd(pc);
+	if (rc < 0)
+		return rc;
+
+	/* initialize procfs specific stuff */
+	prc = ul_path_get_dialect(pc);
+	if (!prc) {
+		DBG(CXT, ul_debugobj(pc, "alloc new procfs handler"));
+		prc = calloc(1, sizeof(struct procfs_process));
+		if (!prc)
+			return -ENOMEM;
+
+		ul_path_set_dialect(pc, prc, procfs_process_deinit_path);
+	}
+
+	DBG(CXT, ul_debugobj(pc, "init procfs stuff"));
+
+	prc->pid = pid;
+	return 0;
+}
+
+static void procfs_process_deinit_path(struct path_cxt *pc)
+{
+	struct procfs_process *prc;
+
+	if (!pc)
+		return;
+
+	DBG(CXT, ul_debugobj(pc, "deinit"));
+
+	prc = ul_path_get_dialect(pc);
+	if (!prc)
+		return;
+
+	free(prc);
+	ul_path_set_dialect(pc, NULL, NULL);
+}
+
+static ssize_t read_procfs_file(int fd, char *buf, size_t bufsz)
+{
+	ssize_t sz = 0;
+	size_t i;
+
+	if (fd < 0)
+		return -EINVAL;
+
+	sz = read_all(fd, buf, bufsz);
+	if (sz <= 0)
+		return sz;
+
+	for (i = 0; i < (size_t) sz; i++) {
+		if (buf[i] == '\0')
+			buf[i] = ' ';
+	}
+	buf[sz - 1] = '\0';
+	return sz;
+}
+
+static ssize_t procfs_process_get_line_for(struct path_cxt *pc, char *buf, size_t bufsz,
+					    const char *fname)
+{
+	int fd = ul_path_open(pc, O_RDONLY|O_CLOEXEC, fname);
+
+	if (fd >= 0) {
+		ssize_t sz = read_procfs_file(fd, buf, bufsz);
+		close(fd);
+		return sz;
+	}
+	return -errno;
+}
+
+ssize_t procfs_process_get_cmdline(struct path_cxt *pc, char *buf, size_t bufsz)
+{
+	return procfs_process_get_line_for(pc, buf, bufsz, "cmdline");
+}
+
+ssize_t procfs_process_get_cmdname(struct path_cxt *pc, char *buf, size_t bufsz)
+{
+	return procfs_process_get_line_for(pc, buf, bufsz, "comm");
+}
+
+ssize_t procfs_process_get_stat(struct path_cxt *pc, char *buf, size_t bufsz)
+{
+	return procfs_process_get_line_for(pc, buf, bufsz, "stat");
+}
+
+int procfs_process_get_uid(struct path_cxt *pc, uid_t *uid)
+{
+	struct stat sb;
+	int rc;
+
+	if ((rc = ul_path_stat(pc, &sb, 0, NULL)) == 0)
+		*uid = sb.st_uid;
+	return rc;
+}
+
+/*
+ * returns the next task TID, the @sub is automatically initialized
+ * when called first time and closed after last call or you can
+ * call closedir()* when you need to break the loop.
+ *
+ * Returns: <0 on error, 0 on success, >1 done
+ *
+ * Example:
+ *
+ * pid_t tid;
+ * DIR *sub = NULL;
+ * path_cxt *pc = ul_new_procfs_path(123, NULL);
+ *
+ * while (procfs_process_next_tid(pc, &sub, &tid) == 0)
+ *	printf("task: %d", (int) tid);
+ *
+ */
+int procfs_process_next_tid(struct path_cxt *pc, DIR **sub, pid_t *tid)
+{
+	struct dirent *d;
+
+	if (!pc || !sub || !tid)
+		return -EINVAL;
+
+	if (!*sub) {
+		*sub = ul_path_opendir(pc, "task");
+		if (!*sub)
+			return -errno;
+	}
+
+	while ((d = xreaddir(*sub))) {
+		if (procfs_dirent_get_pid(d, tid) == 0)
+			return 0;
+	}
+
+	closedir(*sub);
+	*sub = NULL;
+	return 1;
+}
+
+int procfs_process_next_fd(struct path_cxt *pc, DIR **sub, int *fd)
+{
+	struct dirent *d;
+
+	if (!pc || !sub || !fd)
+		return -EINVAL;
+
+	if (!*sub) {
+		*sub = ul_path_opendir(pc, "fd");
+		if (!*sub)
+			return -errno;
+	}
+
+	while ((d = xreaddir(*sub))) {
+		uint64_t num;
+#ifdef _DIRENT_HAVE_D_TYPE
+		if (d->d_type != DT_LNK && d->d_type != DT_UNKNOWN)
+			continue;
+#endif
+		if (ul_strtou64(d->d_name, &num, 10) < 0)
+			continue;
+		*fd = num;
+		return 0;
+	}
+
+	closedir(*sub);
+	*sub = NULL;
+	return 1;
+}
+
+/*
+ * Simple 'dirent' based stuff for use-cases where procfs_process_* API is overkill
+ */
+
+/* stupid, but good enough as a basic filter */
+int procfs_dirent_is_process(struct dirent *d)
+{
+#ifdef _DIRENT_HAVE_D_TYPE
+	if (d->d_type != DT_DIR && d->d_type != DT_UNKNOWN)
+		return 0;
+#endif
+	if (!isdigit((unsigned char) *d->d_name))
+		return 0;
+
+	return 1;
+}
+
+int procfs_dirent_get_pid(struct dirent *d, pid_t *pid)
+{
+	uint64_t num;
+
+	if (!procfs_dirent_is_process(d))
+		return -EINVAL;
+
+	if (ul_strtou64(d->d_name, &num, 10) < 0)
+		return -EINVAL;
+
+	*pid = (pid_t) num;
+	return 0;
+}
+
+int procfs_dirent_get_uid(DIR *procfs, struct dirent *d, uid_t *uid)
+{
+	struct stat st;
+
+	if (!procfs_dirent_is_process(d))
+		return -EINVAL;
+
+	if (fstatat(dirfd(procfs), d->d_name, &st, 0))
+		return -EINVAL;
+
+	*uid = st.st_uid;
+	return 0;
+}
+
+int procfs_dirent_match_uid(DIR *procfs, struct dirent *d, uid_t uid)
+{
+	uid_t x;
+
+	if (procfs_dirent_get_uid(procfs, d, &x) == 0)
+		return x == uid;
+
+	return 0;
+}
+
+/* "name" of process; may be truncated, see prctl(2) and PR_SET_NAME.
+ * The minimal of the @buf has to be 32 bytes. */
+int procfs_dirent_get_name(DIR *procfs, struct dirent *d, char *buf, size_t bufsz)
+{
+	FILE *f;
+	size_t sz;
+	char tmp[1024], *p, *end = NULL;
+
+	if (bufsz < 32)
+		return -EINVAL;
+	if (!procfs_dirent_is_process(d))
+		return -EINVAL;
+
+	snprintf(tmp, sizeof(tmp), "%s/stat", d->d_name);
+	f = fopen_at(dirfd(procfs), tmp, O_CLOEXEC|O_RDONLY, "r");
+	if (!f)
+		return -errno;
+
+	p = fgets(tmp, sizeof(tmp), f);
+	fclose(f);
+	if (!p)
+		return -errno;
+
+	/* skip PID */
+	while (*p && *p != '(')
+		p++;
+
+	/* skip extra '(' */
+	while (*p && *p == '(')
+		p++;
+
+	end = p;
+	while (*end && *end != ')')
+		end++;
+
+	sz = end - p;
+	if (sz > bufsz)
+		sz = bufsz - 1;
+
+	memcpy(buf, p, sz);
+	buf[sz] = '\0';
+
+	return 0;
+}
+
+int procfs_dirent_match_name(DIR *procfs, struct dirent *d, const char *name)
+{
+	char buf[33];
+
+	if (procfs_dirent_get_name(procfs, d, buf, sizeof(buf)) == 0)
+		return strcmp(name, buf) == 0;
+
+	return 0;
+}
+
+/* checks if fd is file in a procfs;
+ * returns 1 if true, 0 if false or couldn't determine */
+int fd_is_procfs(int fd)
+{
+	struct statfs st;
+	int ret;
+
+	do {
+		errno = 0;
+		ret = fstatfs(fd, &st);
+
+		if (ret < 0) {
+			if (errno != EINTR && errno != EAGAIN)
+				return 0;
+			xusleep(250000);
+		}
+	} while (ret != 0);
+
+	return st.f_type == STATFS_PROC_MAGIC;
+}
+
+static char *strdup_procfs_file(pid_t pid, const char *name)
+{
+	char buf[BUFSIZ];
+	char *re = NULL;
+	int fd;
+
+	snprintf(buf, sizeof(buf), _PATH_PROC "/%d/%s", (int) pid, name);
+	fd = open(buf, O_CLOEXEC|O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	if (read_procfs_file(fd, buf, sizeof(buf)) > 0)
+		re = strdup(buf);
+	close(fd);
+	return re;
+}
+
+char *pid_get_cmdname(pid_t pid)
+{
+	return strdup_procfs_file(pid, "comm");
+}
+
+char *pid_get_cmdline(pid_t pid)
+{
+	return strdup_procfs_file(pid, "cmdline");
+}
+
+#ifdef TEST_PROGRAM_PROCFS
+
+static int test_tasks(int argc, char *argv[])
+{
+	DIR *sub = NULL;
+	struct path_cxt *pc;
+	pid_t tid = 0, pid;
+
+	if (argc != 2)
+		return EXIT_FAILURE;
+
+	pid = strtol(argv[1], (char **) NULL, 10);
+	printf("PID=%d, TIDs:", pid);
+
+	pc = ul_new_procfs_path(pid, NULL);
+	if (!pc)
+		err(EXIT_FAILURE, "alloc procfs handler failed");
+
+	while (procfs_process_next_tid(pc, &sub, &tid) == 0)
+		printf(" %d", tid);
+
+	printf("\n");
+        ul_unref_path(pc);
+	return EXIT_SUCCESS;
+}
+
+static int test_fds(int argc, char *argv[])
+{
+	DIR *sub = NULL;
+	struct path_cxt *pc;
+	pid_t pid;
+	int fd = -1;
+
+	if (argc != 2)
+		return EXIT_FAILURE;
+
+	pid = strtol(argv[1], (char **) NULL, 10);
+	printf("PID=%d, FDs:", pid);
+
+	pc = ul_new_procfs_path(pid, NULL);
+	if (!pc)
+		err(EXIT_FAILURE, "alloc procfs handler failed");
+
+	while (procfs_process_next_fd(pc, &sub, &fd) == 0)
+		printf(" %d", fd);
+
+	fputc('\n', stdout);
+        ul_unref_path(pc);
+	return EXIT_SUCCESS;
+}
+
+static int test_processes(int argc, char *argv[])
+{
+	DIR *dir;
+	struct dirent *d;
+	char *name = NULL;
+	uid_t uid = (uid_t) -1;
+	char buf[128];
+
+	if (argc >= 3 && strcmp(argv[1], "--name") == 0)
+		name = argv[2];
+	if (argc >= 3 && strcmp(argv[1], "--uid") == 0)
+		uid = (uid_t) atol(argv[2]);
+
+	dir = opendir(_PATH_PROC);
+	if (!dir)
+		err(EXIT_FAILURE, "cannot open proc");
+
+	while ((d = xreaddir(dir))) {
+		pid_t pid = 0;
+
+		if (procfs_dirent_get_pid(d, &pid) != 0)
+			continue;
+		if (name && !procfs_dirent_match_name(dir, d, name))
+			continue;
+		if (uid != (uid_t) -1 && !procfs_dirent_match_uid(dir, d, uid))
+			continue;
+		procfs_dirent_get_name(dir, d, buf, sizeof(buf));
+		printf(" %d [%s]", pid, buf);
+	}
+
+	fputc('\n', stdout);
+	closedir(dir);
+	return EXIT_SUCCESS;
+}
+
+static int test_one_process(int argc, char *argv[])
+{
+	pid_t pid;
+	struct path_cxt *pc;
+	char buf[BUFSIZ];
+	uid_t uid = (uid_t) -1;
+
+	if (argc != 2)
+		return EXIT_FAILURE;
+	pid = strtol(argv[1], (char **) NULL, 10);
+
+	pc = ul_new_procfs_path(pid, NULL);
+	if (!pc)
+		err(EXIT_FAILURE, "cannot alloc procfs handler");
+
+	printf("%d\n", (int) pid);
+
+	procfs_process_get_uid(pc, &uid);
+	printf("   UID: %zu\n", (size_t) uid);
+
+	procfs_process_get_cmdline(pc, buf, sizeof(buf));
+	printf("   CMDLINE: '%s'\n", buf);
+
+	procfs_process_get_cmdname(pc, buf, sizeof(buf));
+	printf("   COMM: '%s'\n", buf);
+
+	ul_unref_path(pc);
+	return EXIT_SUCCESS;
+}
+
+static int test_isprocfs(int argc, char *argv[])
+{
+	const char *name = argc > 1 ? argv[1] : "/proc";
+	int fd = open(name, O_RDONLY);
+	int is = 0;
+
+	if (fd >= 0) {
+		is = fd_is_procfs(fd);
+		close(fd);
+	} else
+		err(EXIT_FAILURE, "cannot open %s", name);
+
+	printf("%s: %s procfs\n", name, is ? "is" : "is NOT");
+	return is ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc < 2) {
+		fprintf(stderr, "usage: %1$s --tasks <pid>\n"
+				"       %1$s --fds <pid>\n"
+				"       %1$s --is-procfs [<dir>]\n"
+				"       %1$s --processes [---name <name>] [--uid <uid>]\n"
+				"       %1$s --one <pid>\n",
+				program_invocation_short_name);
+		return EXIT_FAILURE;
+	}
+
+	if (strcmp(argv[1], "--tasks") == 0)
+		return test_tasks(argc - 1, argv + 1);
+	if (strcmp(argv[1], "--fds") == 0)
+		return test_fds(argc - 1, argv + 1);
+	if (strcmp(argv[1], "--processes") == 0)
+		return test_processes(argc - 1, argv + 1);
+	if (strcmp(argv[1], "--is-procfs") == 0)
+		return test_isprocfs(argc - 1, argv + 1);
+	if (strcmp(argv[1], "--one") == 0)
+		return test_one_process(argc - 1, argv + 1);
+
+	return EXIT_FAILURE;
+}
+#endif /* TEST_PROGRAM_PROCUTILS */