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-rw-r--r--libdwfl/linux-proc-maps.c285
1 files changed, 285 insertions, 0 deletions
diff --git a/libdwfl/linux-proc-maps.c b/libdwfl/linux-proc-maps.c
new file mode 100644
index 00000000..2611c73a
--- /dev/null
+++ b/libdwfl/linux-proc-maps.c
@@ -0,0 +1,285 @@
+/* Standard libdwfl callbacks for debugging a live Linux process.
+ Copyright (C) 2005 Red Hat, Inc.
+
+ This program is Open Source software; you can redistribute it and/or
+ modify it under the terms of the Open Software License version 1.0 as
+ published by the Open Source Initiative.
+
+ You should have received a copy of the Open Software License along
+ with this program; if not, you may obtain a copy of the Open Software
+ License version 1.0 from http://www.opensource.org/licenses/osl.php or
+ by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
+ 3001 King Ranch Road, Ukiah, CA 95482. */
+
+#include "libdwflP.h"
+#include <inttypes.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+#include <endian.h>
+
+
+#define PROCMAPSFMT "/proc/%d/maps"
+#define PROCMEMFMT "/proc/%d/mem"
+#define PROCAUXVFMT "/proc/%d/auxv"
+
+
+/* Search /proc/PID/auxv for the AT_SYSINFO_EHDR tag. */
+
+static int
+find_sysinfo_ehdr (pid_t pid, GElf_Addr *sysinfo_ehdr)
+{
+ char *fname = NULL;
+ asprintf (&fname, PROCAUXVFMT, pid);
+ if (fname == NULL)
+ return ENOMEM;
+
+ int fd = open64 (fname, O_RDONLY);
+ free (fname);
+ if (fd < 0)
+ return errno == ENOENT ? 0 : errno;
+
+ ssize_t nread;
+ do
+ {
+ union
+ {
+ char buffer[sizeof (long int) * 2 * 64];
+ Elf64_auxv_t a64[sizeof (long int) * 2 * 64 / sizeof (Elf64_auxv_t)];
+ Elf32_auxv_t a32[sizeof (long int) * 2 * 32 / sizeof (Elf32_auxv_t)];
+ } d;
+ nread = read (fd, &d, sizeof d);
+ if (nread > 0)
+ {
+ switch (sizeof (long int))
+ {
+ case 4:
+ for (size_t i = 0; (char *) &d.a32[i] < &d.buffer[nread]; ++i)
+ if (d.a32[i].a_type == AT_SYSINFO_EHDR)
+ {
+ *sysinfo_ehdr = d.a32[i].a_un.a_val;
+ nread = 0;
+ break;
+ }
+ break;
+ case 8:
+ for (size_t i = 0; (char *) &d.a64[i] < &d.buffer[nread]; ++i)
+ if (d.a64[i].a_type == AT_SYSINFO_EHDR)
+ {
+ *sysinfo_ehdr = d.a64[i].a_un.a_val;
+ nread = 0;
+ break;
+ }
+ break;
+ default:
+ abort ();
+ break;
+ }
+ }
+ }
+ while (nread > 0);
+
+ close (fd);
+
+ return nread < 0 ? errno : 0;
+}
+
+int
+dwfl_linux_proc_report (Dwfl *dwfl, pid_t pid)
+{
+ if (dwfl == NULL)
+ return -1;
+
+ /* We'll notice the AT_SYSINFO_EHDR address specially when we hit it. */
+ GElf_Addr sysinfo_ehdr = 0;
+ int result = find_sysinfo_ehdr (pid, &sysinfo_ehdr);
+ if (result != 0)
+ return result;
+
+ char *fname = NULL;
+ asprintf (&fname, PROCMAPSFMT, pid);
+ if (fname == NULL)
+ return ENOMEM;
+
+ FILE *f = fopen (fname, "r");
+ free (fname);
+ if (f == NULL)
+ return errno;
+
+ (void) __fsetlocking (f, FSETLOCKING_BYCALLER);
+
+ unsigned int last_dmajor = -1, last_dminor = -1;
+ uint64_t last_ino = -1;
+ char *last_file = NULL;
+ Dwarf_Addr low = 0, high = 0;
+
+ inline bool report (void)
+ {
+ if (last_file != NULL)
+ {
+ if (INTUSE(dwfl_report_module) (dwfl, last_file, low, high) == NULL)
+ {
+ free (last_file);
+ return true;
+ }
+ last_file = NULL;
+ }
+ return false;
+ }
+
+ char *line = NULL;
+ size_t linesz;
+ ssize_t len;
+ while ((len = getline (&line, &linesz, f)) > 0)
+ {
+ if (line[len - 1] == '\n')
+ line[len - 1] = '\0';
+
+ Dwarf_Addr start, end, offset;
+ unsigned int dmajor, dminor;
+ uint64_t ino;
+ int nread = -1;
+ if (sscanf (line, "%" PRIx64 "-%" PRIx64 " %*s %" PRIx64
+ " %x:%x %" PRIi64 " %n",
+ &start, &end, &offset, &dmajor, &dminor, &ino, &nread) < 6
+ || nread <= 0)
+ {
+ free (line);
+ return ENOEXEC;
+ }
+
+ /* If this is the special mapping AT_SYSINFO_EHDR pointed us at,
+ report the last one and then this special one. */
+ if (start == sysinfo_ehdr && start != 0)
+ {
+ if (report ())
+ {
+ bad_report:
+ free (line);
+ fclose (f);
+ return -1;
+ }
+
+ low = start;
+ high = end;
+ if (asprintf (&last_file, "[vdso: %d]", (int) pid) < 0
+ || report ())
+ goto bad_report;
+ }
+
+ char *file = line + nread + strspn (line + nread, " \t");
+ if (file[0] == '\0' || (ino == 0 && dmajor == 0 && dminor == 0))
+ /* This line doesn't indicate a file mapping. */
+ continue;
+
+ if (last_file != NULL
+ && ino == last_ino && dmajor == last_dmajor && dminor == last_dminor)
+ {
+ /* This is another portion of the same file's mapping. */
+ assert (!strcmp (last_file, file));
+ high = end;
+ }
+ else
+ {
+ /* This is a different file mapping. Report the last one. */
+ if (report ())
+ goto bad_report;
+ low = start;
+ high = end;
+ last_file = strdup (file);
+ last_ino = ino;
+ last_dmajor = dmajor;
+ last_dminor = dminor;
+ }
+ }
+ free (line);
+
+ result = ferror_unlocked (f) ? errno : feof_unlocked (f) ? 0 : ENOEXEC;
+ fclose (f);
+
+ /* Report the final one. */
+ bool lose = report ();
+
+ return result != 0 ? result : lose ? -1 : 0;
+}
+INTDEF (dwfl_linux_proc_report)
+
+
+static ssize_t
+read_proc_memory (void *arg, void *data, GElf_Addr address,
+ size_t minread, size_t maxread)
+{
+ const int fd = *(const int *) arg;
+ ssize_t nread = pread64 (fd, data, maxread, (off64_t) address);
+ if (nread > 0 && (size_t) nread < minread)
+ nread = 0;
+ return nread;
+}
+
+extern Elf *elf_from_remote_memory (GElf_Addr ehdr_vma,
+ GElf_Addr *loadbasep,
+ ssize_t (*read_memory) (void *arg,
+ void *data,
+ GElf_Addr address,
+ size_t minread,
+ size_t maxread),
+ void *arg);
+
+
+/* Dwfl_Callbacks.find_elf */
+
+int
+dwfl_linux_proc_find_elf (Dwfl_Module *mod __attribute__ ((unused)),
+ void **userdata __attribute__ ((unused)),
+ const char *module_name, Dwarf_Addr base,
+ char **file_name, Elf **elfp)
+{
+ if (module_name[0] == '/')
+ {
+ int fd = open64 (module_name, O_RDONLY);
+ if (fd >= 0)
+ {
+ *file_name = strdup (module_name);
+ if (*file_name == NULL)
+ {
+ close (fd);
+ return ENOMEM;
+ }
+ }
+ return fd;
+ }
+
+ int pid;
+ if (sscanf (module_name, "[vdso: %d]", &pid) == 1)
+ {
+ /* Special case for in-memory ELF image. */
+
+ char *fname = NULL;
+ asprintf (&fname, PROCMEMFMT, pid);
+ if (fname == NULL)
+ return -1;
+
+ int fd = open64 (fname, O_RDONLY);
+ free (fname);
+ if (fd < 0)
+ return -1;
+
+ *elfp = elf_from_remote_memory (base, NULL, &read_proc_memory, &fd);
+
+ close (fd);
+
+ *file_name = NULL;
+ return -1;
+ }
+
+ abort ();
+ return -1;
+}
+INTDEF (dwfl_linux_proc_find_elf)
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