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| author | Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> | 2023-08-24 13:42:19 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2023-09-05 13:08:59 -0300 |
| commit | e7190fc73dbc8a1f8f94f8ccacd9a190fa5e609c (patch) | |
| tree | 0070895e116c7250463b90b643f8727466bfbb5b | |
| parent | 0d6f9f626521678f330f8bfee89e1cdb7e2b1062 (diff) | |
| download | glibc-e7190fc73dbc8a1f8f94f8ccacd9a190fa5e609c.tar.xz glibc-e7190fc73dbc8a1f8f94f8ccacd9a190fa5e609c.zip | |
linux: Add pidfd_getpid
This interface allows to obtain the associated process ID from the
process file descriptor. It is done by parsing the procps fdinfo
information. Its prototype is:
pid_t pidfd_getpid (int fd)
It returns the associated pid or -1 in case of an error and sets the
errno accordingly. The possible errno values are those from open, read,
and close (used on procps parsing), along with:
- EBADF if the FD is negative, does not have a PID associated, or if
the fdinfo fields contain a value larger than pid_t.
- EREMOTE if the PID is in a separate namespace.
- ESRCH if the process is already terminated.
Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
44 files changed, 520 insertions, 0 deletions
@@ -27,6 +27,10 @@ Major new features: The pidfd functionality avoids the issue of PID reuse with the traditional posix_spawn interface. +* On Linux, the pidfd_getpid function has been added. It allows retrieving + the process ID associated with the process file descriptor created by + pid_spawn, fork_np, or pidfd_open. + Deprecated and removed features, and other changes affecting compatibility: [Add deprecations, removals and changes affecting compatibility here] diff --git a/manual/process.texi b/manual/process.texi index 68361c3f61..8254e5ee86 100644 --- a/manual/process.texi +++ b/manual/process.texi @@ -33,6 +33,7 @@ primitive functions to do each step individually instead. * Process Creation Concepts:: An overview of the hard way to do it. * Process Identification:: How to get the process ID of a process. * Creating a Process:: How to fork a child process. +* Querying a Process:: How to query a child process. * Executing a File:: How to make a process execute another program. * Process Completion:: How to tell when a child process has completed. * Process Completion Status:: How to interpret the status value @@ -362,6 +363,43 @@ the proper precautions for using @code{vfork}, your program will still work even if the system uses @code{fork} instead. @end deftypefun +@node Querying a Process +@section Querying a Process + +The file descriptor returned by the @code{pidfd_fork} function can be used to +query process extra information. + +@deftypefun pid_t pidfd_getpid (int @var{fd}) +@standards{GNU, sys/pidfd.h} +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} + +The @code{pidfd_getpid} function retrieves the process ID associated with process +file descriptor created with @code{pid_spawn}, @code{pidfd_fork}, or +@code{pidfd_open}. + +If the operation fails, @code{pidfd_getpid} return @code{-1} and the following +@code{errno} error conditionas are defined: + +@table @code +@item EBADF +The input file descriptor is invalid, does not have a pidfd associated, or an +error has occurred parsing the kernel data. +@item EREMOTE +There is no process ID to denote the process in the current namespace. +@item ESRCH +The process for which the file descriptor refers to is terminated. +@item ENOENT +The procfs is not mounted. +@item ENFILE. +Too many open files in system (@code{pidfd_open} tries to open a procfs file and +read its contents). +@item ENOMEM +Insufficient kernel memory was available. +@end table + +This function is specific to Linux. +@end deftypefun + @node Executing a File @section Executing a File @cindex executing a file diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 3ecfa184d0..063719bae6 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -213,6 +213,7 @@ tests += \ tst-ofdlocks \ tst-personality \ tst-pidfd \ + tst-pidfd_getpid \ tst-pkey \ tst-ppoll \ tst-prctl \ @@ -493,8 +494,10 @@ sysdep_headers += \ sysdep_routines += \ getcpu \ oldglob \ + pidfd_getpid \ pidfd_spawn \ pidfd_spawnp \ + procutils \ sched_getcpu \ spawnattr_getcgroup_np \ spawnattr_setcgroup_np \ diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index a8bae0c2a2..268ba1b6ac 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -322,6 +322,7 @@ libc { %endif } GLIBC_2.39 { + pidfd_getpid; pidfd_spawn; pidfd_spawnp; posix_spawnattr_getcgroup_np; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index 6f23556067..b3484be555 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2673,6 +2673,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 02c43beb13..09c03b0e3f 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2782,6 +2782,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist index dd8e5912d8..63761315d0 100644 --- a/sysdeps/unix/sysv/linux/arc/libc.abilist +++ b/sysdeps/unix/sysv/linux/arc/libc.abilist @@ -2434,6 +2434,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist index a751e5f5a9..d0860b25e0 100644 --- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist @@ -554,6 +554,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist index 0eda3459ed..b93819cab4 100644 --- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist @@ -551,6 +551,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist index 4f4e99427b..ca5db5cde5 100644 --- a/sysdeps/unix/sysv/linux/csky/libc.abilist +++ b/sysdeps/unix/sysv/linux/csky/libc.abilist @@ -2710,6 +2710,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index abc471dd0b..e736477ce6 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -2659,6 +2659,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 9f03c8a9a2..56263a5111 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2843,6 +2843,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index ce1d20b722..504b6a7fa7 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -2608,6 +2608,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist b/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist index 8c3640b004..3cdc2b9d85 100644 --- a/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist +++ b/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist @@ -2194,6 +2194,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index a594916319..1cbebfb162 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -555,6 +555,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index 7f61d4824d..8dd696a24e 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -2786,6 +2786,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist index 83ebb84ff3..ddfab38be7 100644 --- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist @@ -2759,6 +2759,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F GLIBC_2.39 pidfd_spawn F GLIBC_2.39 pidfd_spawnp F GLIBC_2.39 posix_spawnattr_getcgroup_np F diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist index 89a0ff83bf..88fd2a735f 100644 --- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist @@ -2756,6 +2756,7 @@ GLIBC_2.38 strlcat F GLIBC_2.38 strlcpy F GLIBC_2.38 wcslcat F GLIBC_2.38 wcslcpy F +GLIBC_2.39 pidfd_getpid F |